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European Journal of Taxonomy 48: 1-242
http://dx.doi.org/10.5852/ejt.2013.48

This work is licensed under a Creative Commons Attribution 3.0 License.

ISSN 2118-9773
WWW. europeanj oumaloftaxonomy. eu

2013 • Ben Thuy

Monograph

um:lsid:zoobank.org:pub:E7080722-E348-448D-96E5-D537F4865BB5

Temporary expansion to shelf depths rather than an onshore-offshore
trend: the shallow-water rise and demise of the modern deep-sea
brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea)

Ben THUY

Musee national d’histoire naturelle du Euxembourg, seetion Paleontologie,

24 rue Munster, E-2160 Euxembourg
Email: nebyuht@yahoo.eom

um:lsid:zoobank.org: author: 04186A8C-3F 0D-485E-834A-08414A217ACA

Abstract. Hypotheses on the age and possible antiquity of the modem deep-sea fauna put forward to
date almost all agree on the assumption that the deep-sea fauna is largely the result of eolonisation from
shallow-water environments. Here, the fossil reeord of the Ophiaeanthidae, a modem deep-sea brittle
star family with extensive fossil oeeurrenees at shelf depths, is systematieally traeed against a ealibrated
phytogeny. Several lines of evidenee suggest that the Ophiaeanthidae originated and greatly diversified
in the deep sea, with most extant elades having diverged by the end of the Triassie at the latest. During
the Jurassie, the family temporarily invaded shelf environments, attaining relative abundanees and
diversities eomparable to those found in eoeval and modem deep-sea settings, and gradually deelined
in abundanee subsequently, to beeome largely restrieted to the deep-sea again. The pattern of temporary
expansion to shelf environments suggested here underpins the potential of deep-sea environments to
eontribute signifieantly to shallow-water biodiversity; an aspeet that has mostly been negleeted so far.
It is speeulated that the large-seale ophiaeanthid invasion of shelf environments around the Triassie-
Jurassie boundary was initiated by a ehange from thermohaline to halothermal eireulation, attenuating
the thermal stratifieation of the water eolumn and thus providing opportunities for enhaneed vertieal
migration of marine taxa.

Keywords. Ophiaeanthidae, fossil reeord, bathymetrie trends, onshore-offshore trends, evolution.

Thuy B. 2013. Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise
and demise of the modem deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea). European
Journal of Taxonomy 1-242. http://dx.doi.org/10.5852/eit.2013.48

Introduction

The deep sea is by far the most widespread environment on Earth, yet our knowledge of the eomposition,
biodiversity and origin of deep-sea biota remains remarkably poor (e.g. Gage & Tyler 1991). Sinee the
diseovery of unexpeetedly high speeies riehnesses in the deep sea, attempts have been made to explain the
origin of modem bathyal and abyssal eommunities (Menzies et al. 1973). Debates have largely eentred on
two eompeting hypotheses: deep-sea biota are either relatively reeent, resulting from multiple turnovers
linked to large dismptions of the deep-sea environment (Menzies et al. 1973; Jaeobs & Eindberg 1998;

European Journal of Taxonomy 48: 1-242 (2013)

Rex & Etter 2010), or they are aneient and presumably resilient to sueh ehanges (Zenkeviteh & Birstein
1960; Wilson 1999). Reeently, more sophistieated eoneepts have been artieulated; these aeknowledge
that the modem deep-sea fauna, rather than of single origin, is most probably the result of multiple
eolonisation events (MeClain & Minks Hardy 2010). However differentiated, all attempts at explanation
share the same potential pitfall: they almost invariably imply that the deep-sea fauna originated from
shallow-water aneestors (Menzies et al. 1973; Jaeobs & Lindberg 1998; Smith & Stoekley 2005;
Stmgnell et al. 2008).

It has been noted that evolutionary innovations, indeed, follow a shallow (onshore) to deep (offshore)
pattern (e.g. Jablonski etal. 1983; Bottjer & Jablonski 1988; Jablonski 2005). Regrettably, however, this
pattern has been eommonly mistaken for a general mle, although, originally, it was explieitly stressed
that it held tme only for orders and that families and genera eommonly diverted from the onshore-
offshore expansion eoneept. As a result, it has beeome widely aeeepted praetiee to ignore the possibility
of deep (offshore) to shallow (onshore) patterns of groups and to simply eelipse the role of the deep sea
in most maeroevolutionary proeesses.

Yet, there is solid evidenee for a reversed pattern implying deep origination with subsequent shallow
expansion in some groups. For example, using a worldwide phylogeny of stylasterid eorals, Lindner et al.
(2008) showed that the group first appeared in a deep-water setting, extensively diversified in the deep sea
and expanded to shallow-water habitats several times. Moura et al. (2012) stressed the importanee of the
deep sea in generating and aeeumulating lineages of plumulariid hydrozoans that may oeeasionally invade
eoastal waters in the northeast Atlantie. Clearly, the potential of the deep sea to eontribute to shallow-marine
biodiversity is a yet largely unexplored aspeet of maeroevolutionary proeesses (Miglietta et al. 2011).

Promising pieees of evidenee in this respeet are furnished by modem deep-sea groups with an extensive
shallow-water fossil reeord, sueh as isoerinid sea lilies (Hess et al. 1999) and glypheid emstaeeans
(Forest 2006), beeause of their potential to provide valuable insights into the eontrols and modalities
of bathymetrie shifts on maeroevolutionary time seales. Key questions revolve around the signifieanee
of the shallow-water fossil reeord, in partieular whether it refieets the shallow origin of the group
followed by retreat or migration into the deep sea, as eommonly suggested, or, alternatively, doeuments
a temporary shallow expansion of an originally deep group.

One of these groups is brittle star family Ophiaeanthidae (Eehinodermata: Ophiuroidea). Reeent
members of the family are found almost exelusively in bathyal (200-2000 m) and, to a slightly lesser
extent, abyssal (2000-6000 m) depths (Tyler 1980; Stohr et al. 2012) and eonstitute a eommon and
diverse eomponent of present-day deep-sea invertebrate eommunities (e.g. Metaxas & Giffin 2004;
O’Hara & Stohr 2006). The family has a well-doeumented, fairly extensive and diverse fossil reeord at
shelf depths in the Mesozoie, and has reeently been shown to extend as far baek as the early Late Triassie
(Camian) (Thuy et al. 2012).

In the present study, the global fossil reeord of the Ophiaeanthidae is systematieally explored in order
to assess the maeroevolutionary signifieanee of the extensive fossil oeeurrenees at shelf depths. As
a first step, the fossil reeord of individual ophiaeanthid lineages is traeed in time and along a eoarse
depth gradient to test whether they first oeeur at shelf depths or in the deep sea. Seeondly, the observed
first oeeurrenee dates at shelf depths and the timing of relative abundanee and diversity trends are
eompared with a revised phylogeny of the family ealibrated using a number of key fossil oeeurrenees
to braeket minimum divergenee times. The results strongly suggest that most of the early evolution of
the Ophiaeanthidae took plaee in the deep sea, and that the shelf fossil reeord doeuments a temporary
expansion of the bathymetrie distribution to shallower depths rather than an onshore (shallow) origination
followed by an offshore (deep) migration or retreat.

THUYB., Fossil record of ophiacanthid brittle stars

Material and methods

Sample selection and treatment

A total of 93 previously published and new ophiuroid assemblages from shallow-water (Table 1)
and seven from deep-sea settings (Table 2) ranging in age from the Early Triassic to the Miocene were
assessed, yielding the data base of the present study. In order to cover the ophiacanthid fossil record as
exhaustively as possible, care was taken to include assemblages from various types of habitats that were
as broadly distributed geographically and stratigraphically as possible. Almost all assemblages studied
herein comprise dissociated lateral arm plates, for several reasons:

1) dissociated lateral arm plates generally occur in great numbers in sediment bulk samples, even
in deep-sea sediment cores, whereas (semi-) articulated ophiuroid skeletons are preserved only under
exceptional conditions (e.g. Kerr & Twitchett 2004) and thus are extremely rare;

2) dissociated lateral arm plates have recently been shown to be identifiable to species level and to
yield insights into phylogenetic relationships (Thuy & Stohr 2011);

3) as previously shown, diagnostic fragmentary or disarticulated remains yield a much more accurate
picture of spatial and temporal echinoderm diversities and distributions than the patchy occurrences of
articulated specimens (Nebelsick 1992, 1996; Gordon & Donovan 1992; Donovan 2001, 2003; Kroh
2007); and finally

4) their generally high abundance in micropalaeontological samples and ease of extraction from the
matrix make dissociated lateral arm plates suitable for quantitative analysis.

More than two-thirds (n = 64) of the ophiuroid assemblages studied were previously unpublished.
They were retrieved from bulk sediment samples which were dried, processed (using H 2 O 2 whenever
needed) over a 100 pm sieve, graded and picked under a dissecting microscope. The lateral arm plates
were cleaned in an ultrasonic bath and sorted into individual species. Selected specimens from both
the new assemblages and, if available, the previously published non-type material were mounted on
aluminium stubs and gold-coated for scanning electron microscopy (SEM). After the first scanning
session, the plates were fiipped, remounted and coated for another SEM examination, in line with the
recommendation made by Thuy & Stohr (2011) to document both sides of the selected lateral arm plates.
All previously unpublished fossil specimens were deposited in the collections of a publicly accessible
institute (see below).

Institutional abbreviations

MnhnE

MHI

NHM

NHMB

NHMM

NHMW

GZG.INV

Natural History Museum Euxembourg
Muschelkalk Museum Hagdom Ingelfingen, Germany
Natural History Museum Eondon, United Kingdom
Natural History Museum Basel, Switzerland
Natural History Museum Maastricht, the Netherlands
Natural History Museum Wien, Vienna, Austria

Geoscientific Museum of the Georg-August-University Gottingen, Germany

Palaeo-depth classification of assemblages

In order to assess depth-related trends in the ophiacanthid fossil record, the assemblages studied are
assigned to different bathymetric categories. The boundary between “shallow water” and “deep sea”
is here defined at a depth of 200 m, as commonly adopted in deep-sea biological studies (e.g. Menzies
et al. 1973; Gage & Tyler 1991). This level is in line with a conservative interpretation of the average
continental shelf break depth at 130 m (Davis 1977), and approximates the base of the photic zone in
clear waters at low latitudes (Gill et al. 2004). Assemblages classified as “shallow” are subdivided as
follows:

European Journal of Taxonomy 48: 1-242 (2013)

1) shallow shelf, 0 to approximately 50 m, eorresponding to the zone of frequent storm wave
disturbanee, refleeted in the sedimentary reeord by well-developed tempestites; this zone eommonly
ineludes organisms that are dependent of high illumination levels sueh as the vast majority of
zooxanthellate eorals and green algae;

2) middle shelf, approximately from 50 to 100 m, eorresponding to the zone of oeeasional storm wave
influenee, refleeted in the sedimentary reeord by thin distal tempestites; 100 m is generally eonsidered as
the maximum depth of storm wave aetion (Bottjer & Jablonski 1988; Lindner et al. 2008);

3) deep shelf, approximately from 100 to 200 m, eorresponding to the zone below maximum storm
disturbanee, refleeted by the eomplete laek of tempestites and other wave-indueed sedimentary features;
often this zone still is within the photie zone, espeeially at low latitudes.

All assemblages elassifled as “shallow” are listed in Table 1, together with the literature items eonsulted
to determine palaeo-depth. If possible, the depositional setting of the shallow-water assemblages is
additionally interpreted in terms of substrate and possible organismal build-ups sueh as reefs and
mounds, thus allowing for the deteetion of potential patterns in the shallow-water fossil oeeurrenees of
ophiaeanthids in relation to habitat type.

A total of seven samples are interpreted here as deep-sea assemblages (Table 2). All of them refleet
deposition at bathyal (200-2000 m) depths. Further subdivisions used here are shallow (200-500 m),
middle (500-1000 m) and deep bathyal (1000-2000 m) (Gage & Tyler 1991).

Of partieular importanee for the purpose of the present study is the Glasenbaeh Gorge assemblage.
This is the oldest deep-sea assemblage doeumented to date and, being dated as late Sinemurian to early
Pliensbaehian, it bears witness to the late phase in the major early radiation predieted for ophiuroids
in general (Smith et al. 1995) and ophiaeanthids in partieular (Thuy et al. 2012). In view of the
enormous potential for the present study and in aeknowledgement of the diffleulties and pitfalls of
palaeobathymetries, partieular eare is given to a sound palaeo-depth estimate for the Glasenbaeh Gorge
assemblage.

The assemblage in question was retrieved from poorly lithifled sediments referred to as the
“Hauptknollenbrekzie” within the Adnet Formation, interpreted as a huge slumping mass of semi-
eonsolidated upper Sinemurian to lower Pliensbaehian pelagie red marls and limestones transported
downslope in the late Pliensbaehian as debris flows into deeper parts of the basin (Bohm et al. 1995).
The Adnet Formation, inelusive of the “Hauptknollenbrekzie”, is generally eonsidered to be a deep-sea
deposit (e.g. Bo hm 1992; Bohm & Braehert 1993; Bernoulli & Jenkyns 2009), mainly on aeeount of
the laek of light-dependent organisms, the elose lateral and vertieal assoeiation with radiolarian eherts,
and the striking lithologieal analogies with the slightly younger sediments direetly overlying oeeanie
erust and deeply submerged eontinental erust in the North Atlantie Oeean. Mieroendolithie iehnofossils
in shell fragments and belemnite eoleoids that eo-oeeur with the ophiuroid remains deseribed herein
eonsistently indieate aphotie eonditions (M. Wisshak pers. co mm . May 2012), whieh, in eombination
with the very low sedimentation rates (low turbidity) and the low palaeo-latitude (Seotese 1991), implies
an original palaeo-depth for the transported sediments of at least 250 m. Seeing that the souree of the
transported sediments was at the slope rather than the top of submarine highs, and that the top of the
latter also laek evidenee of photie eonditions, palaeo-depths were most probably in exeess of 250 m.

Phylogenetic analysis

In order to plaee the ophiaeanthid fossil reeord into a solid evolutionary eontext, the phylogeny of the
family as previously presented by Thuy et al. (2012) is revised. In addition to the speeies ineluded in the
original phylogeny, four reeently deseribed or reassessed fossil ophiaeanthids [Ophiosternle crinitum
(Quenstedt, 1876), Dermocoma wrighti Hess, 1964, Hanshessia trochitophila Thuy & Meyer, 2013

THUYB., Fossil record of ophiacanthid brittle stars

Table 1. Locality details of previously published and new shallow-water ophiuroid assemblages
(as studied herein), including reference-supported details on the age and, whenever available, the
stratigraphic unit, as well as palaeodepth classification (see section Material and methods) and substrate
interpretation. References for previously published ophiuroid assemblages are given. Country and state
acronyms: A = Austria; B = Belgium; CH = Switzerland; CN = China; CZ = Czech Republic; D =
Germany; E = Spain; F = France; GB = Great Britain; H = Hungary; I = Italy; IND = India; JP = Japan;
MO = Morocco; NF = Netherlands; P = Portugal; PF = Poland; S = Sweden; TX = Texas. Age acronyms:
E = early; F = late; M = middle; Cret. = Cretaceous; Jur. = Jurassic; Mioc. = Miocene; Tr. = Triassic.

Locality

Age

Palaeohabitat

References

Baden, A

Middle Eanghian, M. Mioc. (Rbgl et al.
2008)

Deep shelf, muddy bottom (Rbgl et al.
2008)

This paper

Rauchstallbrunngraben, A

Eanghian, M. Mioc. (Klihn 1952)

Shallow to middle shelf, bryozoan
thickets (Kiihn 1952)

This paper

Mannersdorf, A

Eanghian, M. Mioc. (Kroh 2007)

Shallow shelf, detrital sand bottom
(Kroh, pers. comm., 2012)

This paper

Wiesfleck, A

Eanghian, M. Mioc. (Kroh 2007)

Shallow shelf, coral patch reef (Kroh
2007)

This paper

Stotzing, A

Eanghian, M. Mioc. (Kroh 2007)

Shallow shelf, detrital sand bottom
(Kroh, pers. comm., 2012)

This paper

Obemalb, A

Early Burdigalian, E. Mioc. (Kroh &
Harzhauser 1999)

Shallow shelf, sandy bottom (Kroh &
Harzhauser 1999)

This paper

Seymour Island, Antarctica

Eate Eocene (Blake & Aronson 1998)

Shallow to middle shelf (Feldmann &
Woodburne 1988)

Blake & Aronson (1998)

Barton Cliff, GB

Bartonian, M. Eocene (Murray & Wright
1974)

Middle shelf, mud bottom (Murray &
Wright 1974)

Rasmussen (1972)

Grignon, F

Middle Eutetian, M. Eocene (Merle

2008)

Shallow shelf, calcareous sands (Merle
2008)

This paper

Eben Emael, B

Eatest Maastrichtian, Eanaye Member
and lower Maastricht Formation, E. Cret.
(Jagt 1999b)

Shallow shelf, calcareous muds and
sands, seagrass meadows (Jagt 1999b)

Jagt (1999a, 2000)

Maastricht, NE

Eate Maastrichtian, Gronsveld Member,

E. Cret. (Jagt 1999b)

Shallow shelf, carbonate sands, seagrass
meadows (Jagt 1999b)

Jagt (1999a, 2000)

Rtlgen, D

Early Maastrichtian, E. Cret. (Herrig

1996)

Deep shelf, mud bottom (Reich &

Frenzel 2002)

Kutscher & Jagt (2000)

Eagerdorf-Kronsmoor, D

Early Maastrichtian, E. Cret. (Schbnfeld
1990)

Middle to deep shelf, muddy bottom
(Hofmann 1996)

This paper

Haccourt, B

Early late Maastrichtian, Vijlen Member,
E. Cret. (Jagt 1999b)

Middle shelf, mud bottom (Jagt 1999b)

Jagt (1999a, 2000)

Aachen, D

Early to early late Maastrichtian, Vijlen
Member, E. Cret. (Jagt & Jagt-Yazykova
2012)

Shallow to middle shelf, muddy bottom
(Jagt & Jagt-Yazykova 2012)

Jagt(2000)

Haccourt, B

Eate Campanian, Zeven Wegen Member,
E. Cret. (Jagt 1999b)

Middle shelf, mud bottom (Jagt 1999b)

Jagt (1999a, 2000)

Eagerdorf-Alsen, D

Galerites vulgaris Zone, Eate

Campanian, E. Cret. (Schulzeta/. 1984)

Middle to deep shelf, muddy bottom
(Hofmann 1996)

This paper

Ivb Klack, S

Early Campanian, Belemnellocamax
mammillatus Zone, E. Cret. (Surlyk &
Sorensen 2010)

Shallow shelf, rocky shore (Surlyk &
Sorensen 2010)

This paper

European Journal of Taxonomy 48: 1-242 (2013)

Locality

Age

Palaeohabitat

References

Piesting, A

Late Santonian, L. Cret. (Summesberger
1997)

Shallow shelf, coral reef (Zagorsek &
Kroh 2003)

This paper

Upohlavy, CZ

Late Turanian, Teplice Formation, L.

Cret. (Store & Zitt 2008)

Middle shelf, muddy bottom (Wiese
et al. 2004)

Store & Zitt (2008)

Waco, TX

Early Cenomanian, L. Cret. (Blake &

Reid 1998)

Shallow to middle shelf, muddy bottom
(Blake & Reid 1998)

This paper

Saginaw, TX

Late Albian, Rostratum Zone, E. Cret.
(Blake & Reid 1998)

Shallow to middle shelf, muddy bottom
(Blake & Reid 1998)

This paper

Folkestone, GB

Middle Albian, Lautus (sample A) and
Loricatus (sample B) zones, “Gault
clay”, E. Cret. (Young et al. 2010)

Shallow to middle shelf, muddy bottom
(Young et al. 2010)

This paper

Leighton Buzzard, GB

Early Albian, Tardefurcata Zone, E. Cret.
(Hess & Gale 2010)

Shallow shelf, hardground with
carbonate muds (Hess & Gale 2010)

This paper

Wizard Way, TX

Latest Aptian, Echinoid marker bed, E.
Cret. (Smith & Rader 2009)

Shallow to middle shelf, carbonate
muds (Smith a Rader 2009)

This paper

Cuchia, E

Early Aptian, Marl Member, Caranceja
Formation (Wilmsen 2005)

Middle shelf, muddy bottom (Wilmsen
2005)

This paper

Serre de Bleyton, F

Late Barremian, E. Cret. (Lukeneder

2011)

Shallow to middle shelf-derived debris
in turbidites (Adatte et al. 2005)

Thuy&Kroh (2011)

Sarstedt, D

Latest Hauterivian, E. Cret. (Mutterlose
1997)

Middle shelf (Mutterlose 1997)

This paper

Neuchatel, CH

Late Hauterivian, E. Cret. (Hess 1970b)

Shallow shelf, hardground with
carbonate muds (Hess 1970b)

Hess (1970b)

Trancoso,P

Late Kimmeridgian, Amaral Formation,

L. Jur. (Schneider et al. 2009)

Shallow shelf, coral biostromes (Schmid
et al. 2001)

This paper

Geisingen, D

Early Kimmeridgian, Lacunosa Marls, L.
Jur. (M. Jager, pers. comm.)

Middle shelf, muddy bottom with
scattered sponges (A.S. Gale, pers.
comm.)

This paper

Pointe du Chay, F

Early Kimmeridgian, Cymodoce Zone, L.
Jur. (Olivier et al. 2003)

Shallow to middle shelf, muddy bottom
in part within in situ coral heads
(Olivier et al. 2003)

This paper

Plettenberg, D

Late Oxfordian, Bimammatum Zone, L.
Jur. (Olivier et al. 2004)

Deep shelf, sponge reefs (Olivier et al.
2004)

This paper

Guldental, CH

Late Oxfordian, Giinsberg Member, L.

Jur. (Allenbach 2001)

Shallow shelf, muddy bottom
(Allenbach 2001)

Hess (1975a)

Raedersdorf, F

Late Oxfordian, Humeralis Member, L.
Jur. (Allenbach 2001)

Shallow to middle shelf, muddy bottom
(Allenbach 2001)

Hess (1975b)

Savigna, F

Late Oxfordian, Bifurcatus Zone, L. Jur.
(Gale 2011) (samples 1, 2a and 2b)

Middle shelf, muddy bottom (Gale

2011)

Hess (1966); this paper

Guldental, CH

Late Oxfordian, Bifurcatus Zone, L. Jur.
(Allenbach 2001)

Middle shelf, muddy bottom (Allenbach
2001)

Hess (1966)

Foug, F

Middle Oxfordian, Transversarium Zone,
L. Jur. (Geister & Lathuiliere 1991)

Shallow shelf, microsolenid coral reef
(Insalaco et a/. 1997)

This paper

Chapois and Longecombe,
F

Early Oxfordian, Renggeri Member,
Barschwil Formation, L. Jur. (Allenbach
2001)

Middle shelf, muddy bottom (Allenbach
2001)

Hess (1965a)

Jumara, Kachchh, IND

Callovian, upper Chari Formation, M.

Jur. (Ftlrsich et a/. 2001) (samples 117,

119 and 121)

Middle shelf, muddy bottom (Fursich
et al. 2004)

This paper

THUYB., Fossil record of ophiacanthid brittle stars

Locality

Age

Palaeohabitat

References

Jumara, Kachchh, IND

Callovian, lower Chari Formation, M.

Jur. (Fiirsich et al. 2001) (samples 31
and 95)

Middle shelf, muddy bottom (Fursich
et al. 2004)

This paper

Bauer-Wehrland,
Hohensaaten and

Althtittendorf, D

Callovian, M. Jur. (Kutscher 1987)

Shallow to middle shelf (Piehkowski
et al. 2008)

Kutscher (1987)

Liesberg, CH

Early Callovian, Koenigi Zone, M. Jur.
(Hess 1963)

Middle shelf, muddy bottom (Dimter &
Smelror 1990)

Hess (1963)

Jumara, Kachchh, IND

Late Bathonian, Patcham Formation, M.
Jur. (Fiirsich et al. 2001a) (sample 24)

Middle shelf, muddy bottom with
sponge meadows (Fursich et al. 2004)

This paper

Jumara, Kachchh, IND

Middle Bathonian, Jhurio Formation, M.
Jur. (Fiirsich ct a/. 2001a) (samples 15
and 89)

Middle shelf, muddy bottom with
microsolenid corals (Fursich et al.

2004)

This paper

La Pouza, F

Early Bathonian, Zigzag Zone, M. Jur.
(Hess 2012)

Debris flows from middle shelf
hardground into deep shelf muddy
bottom (Hess 2012)

This paper

Delkhofen, D

Early Bajocian, Humphriesianum Zone,

M. Jur. (Geyer & Gwinner 1986)

Middle shelf, muddy bottom
(Piehkowski et al. 2008)

This paper

Cirey-les-Nolay, F

Early Bajocian, Humphriesianum Zone,

M. Jur. (Lathuiliere 2000)

Shallow shelf, coral reef (Lathuiliere
2000)

This paper

Longwy, F

Early Bajocian, Laeviuscula Zone
(Delsate 1993)

Shallow shelf, shell debris between
patch reefs (Delsate 1993)

This paper

Seewen, CH

Late Toarcian, Thouarsense Zone, E. Jur.
(Reisdorf et al. 2011)

Middle shelf, muddy bottom (Reisdorf
et al. 2011)

Hess (1962)

Le Clapier, F

Middle Toarcian, E. Jur. (Fursich et al.
2001) (2 samples)

Debris flows from middle shelf muddy
bottoms (Fursich et al. 2001)

This paper

Aix-sur-Cloie, B

Earliest Toarcian, Tenuicostatum Zone,

E. Jur. (Boulvain etal. 2001)

Shallow to middle shelf, muddy bottom
(Piehkowski et al. 2008)

This paper

Seewen, CH

Late Pliensbachian, Margaritatus Zone,

E. Jur. (Reisdorf et al. 2011)

Middle shelf, muddy bottom (Reisdorf
et al. 2011)

Hess (1962)

Amellago, MO

Late Pliensbachian, E. Jur. (Smith 2011)

Debris flows from middle shelf sponge/
coral reefs (Smith 2011)

This paper

Feuguerolles, F

Late Pliensbachian, E. Jur. (A.S. Gale,
pers. comm.)

Shallow shelf, rocky shore (A.S. Gale,
pers. comm.)

This paper

Blockley, GB

Early Pliensbachian, Davoei Zone, E.

Jur. (Simms et al. 2004)

Middle shelf, muddy bottom
(Piehkowski et al. 2008)

This paper

Sedan, F

Early Pliensbachian, Davoei Zone, E.

Jur. (Thuy2011)

Shallow shelf, muddy bottom with
bivalve aggregations (Thuy 2011)

This paper

Bishop’s Cleeve, GB

Late Sinemurian, Obtusum Zone, E. Jur.
(Simms et al. 2004)

Middle shelf, muddy bottom
(Piehkowski et al. 2008)

This paper

Remerschen, L

Early Sinemurian, Bucklandi Zone, E.

Jur. (Lucius 1948)

Shallow to middle shelf, muddy bottom
(Piehkowski et al. 2008)

This paper

Fontenoille, B

Hettangian, Liasicus Zone, E. Jur.

(Delsate et al. 2002)

Shallow shelf, muddy bottom with
biogenic sands (Delsate et al. 2002)

This paper

Vance,B

Hettangian, Planorbis Zone, E. Jur.
(Delsate & Thuy 2005) (samples Vanl
and Van2)

Shallow to middle shelf, muddy bottom
(Delsate & Thuy 2005)

Thuy (2005)

Fischerwiese, A

Rhaetian, Zlambach Marls, L. Tr. (Zapfe
1967)

Debris flows from shallow shelf coral
reefs (Zapfe 1967)

This paper

European Journal of Taxonomy 48: 1-242 (2013)

Locality

Age

Palaeohabitat

References

Jushui, Sichuan, CN

Late Carnian, upper Hanwang Formation,
L. Triassic (Wendt et al. 1989) (samples
C30, C33 and C36)

Deep shelf, hexactinellid sponge mounds
(Wendt eta/. 1989)

This paper

Alpe di Specie, I

Middle Carnian, Austriacum Zone, L. Tr.
(Russo 2005)

Shallow shelf, patch reefs (Russo 2005)

This paper

Romerlo, I

Early Carnian, Aonoides Zone, L. Tr.
(Feist-Burkhardt et al. 2008)

Shallow shelf, detrital sands (Feist-
Burkhardt et al. 2008)

This paper

Milieres, I

Early Carnian, Cassian Formation, L. Tr.
(Russo 2005)

Debris flows from shallow to middle
shelf reefs (Russo 2005)

This paper

Oberscheffach, D

Latest Anisian, Trochitenkalk Formation,
M. Tr. (Geyer & Gwinner 1986)

Shallow to middle shelf, muddy bottom
(Geyer & Gwinner 1986)

This paper

Schillingstadt, D

Late Anisian, Trochitenkalk Formation
(Feist-Burkhardt et al. 2008)

Shallow to middle shelf, muddy bottom
(Geyer & Gwinner 1986)

This paper

Gorazdze, PL

Late Anisian, Karchowice Formation, M.
Tr. (Feist-Burkhardt et al. 2008)

Shallow to middle shelf, detrital sands
(Feist-Burkhardt et al. 2008)

This paper

Strzelce Opolski, PL

Late Anisian, Karchowice Formation, M.
Tr. (Hagdorn 2011)

Shallow to middle shelf, detrital
sands with hexactinellid sponges and
hermatypic corals (Hagdorn 2011)

This paper

Felsbors, H

Late Anisian, Felsdbrs Formation, M. Tr.
(Vbros 2003)

Deep shelf, muddy bottom (Vbros 2003)

This paper

Recoaro, I

Early Anisian, Gracilis Formation, M. Tr.
(Feist-Burkhardt et al. 2008)

Shallow to middle shelf, mud bottom
(Feist-Burkhardt et al. 2008)

This paper

Soly, H

Olenekian, E. Tr. (Feist-Burkhardt et al.
2008)

Middle shelf, muddy bottom (Feist-
Burkhardt et al. 2008)

This paper

Dolomites, I.

Olenekian, E. Tr. (Broglio Loriga & Berti
Cavicchi 1972)

Shallow to middle shelf, muddy bottom
(Broglio Loriga & Berti Cavicchi 1972)

Broglio Loriga & Berti
Cavicchi (1972)

Kitakami Mountains, JP

Early Olenekian, Hiraiso Formation, E.
Tr. (Kashiyama & Oji 2004)

Shallow shelf, sandy bottom

(Kashiyama & Oji 2004)

Twitchett & Oji (2005)

md Alternacantha occulta Thuy & Meyer, 2013] known from well-preserved artieulated skeletons, are
ineluded in order to braeket divergenee times. Two new eharaeters are added to the set of eharaeters
proposed by Thuy et al. (2012); these appear as eharaeters 59-60 in the matrix, in eontinuation of the
original eharaeter numbering (Thuy et al. 2012):

59. Tentaele seales perpendieular to the axis of the arm and pointing towards midline of arm.

60. Position of the dorsalmost arm spine alternating between the arm segments.

The phylogenetie analysis was earried out using PAUP* 4.Ob 10 (PPC) (Swofford 2005), treating
all eharaeters as unordered and of equal weight. Charaeters were then reweighted by their resealed
eonsisteney index and the parsimony analysis repeated under the new weighting seheme. The tree
resulting from the analysis of the reweighed dataset is here used as a working hypothesis. Bootstrap
pereentages are based on 10000 fast (simple addition without braneh swapping) heuristie searehes in
PAUP*. Bremer support (Bremer 1994) was not ealeulated due to eomputing time limitations. Illustrated
trees were eonstrueted using TreeGraph 2 (Stover & Muller 2010).

Interpretation of assemblages

The taxonomie interpretation of dissoeiated ophiaeanthid lateral arm plates follows Thuy & Stohr
(2011) and, if possible, is performed using Reeent material for eomparison. For this purpose, lateral arm

THUYB., Fossil record of ophiacanthid brittle stars

Table 2. Locality details of previously published and new deep-sea ophiuroid assemblages (as studied
herein), including reference-supported details on the age and, whenever available, the stratigraphic unit,
as well as palaeodepth classification (see section Material and methods) and substrate interpretation.
References for previously published ophiuroid assemblages are given. Country acronyms: A = Austria;
D = Germany; F = France; NE Atlantic = northeast Atlantic; JP = Japan. Age acronyms: E = early; M =
middle; Cret. = Cretaceous; Jur. = Jurassic; Mioc. = Miocene; Oligoc. = Oligocene; Paleoc. = Paleocene.

Locality

Age

Palaeohabitat

References

Azumino City, JP

Bessho Formation, M. Mioc. (Ishida et al.
2009)

Bathyal, muddy bottom (Ishida et al. 2009)

Ishida et al. (2009)

Bad Freienwalde, D

Rupelian, “Septarienton”, Oligoc. (Bruckner
et al. 2003)

Shallow bathyal (Fechner 1996; Bruckner
et al. 2003)

This paper

Fakse, DK

Middle Danian, Faxe Formation, Tylocidaris
bruennichi Zone, Paleoc. (Donovan &
Jakobsen 2004)

Shallow to middle bathyal, azooxanthellate
coral reefs (Bemecker & Weidlich 2005)

Lauridsen et al.

2010; this paper

Blake Nose, NE Atlantic

Latest Aptian to earliest Albian, Hedbergella
trochoidea to Microhedbergella rischi
planktonic foraminifer zones, E. Cret.

(Huber & Leckie 2011)

Deep bathyal (Norris et al. 1998)

This paper

Carniol-Oppedette, F

Middle Aptian, Gargasian, E. Cret. (Ropolo
et al. 2006)

Shallow bathyal (Fries & Parize 2003)

This paper

Temberg, A

Late Valanginian, Verriicosum Zone, E. Cret.
(Lukeneder 2004)

Shallow bathyal (Lukeneder 2004)

This paper

Toueit near Chaudon, F

Bajocian-Bathonian boundary, M. Jur.
(Femandez-Lopez et al. 2009)

Middle bathyal (Femandez-Lopez et al.
2009)

This paper

Glasenbach Gorge, A

Late Sinemurian to Early Pliensbachian, E.
Jur. (Vortisch 1970)

Bathyal, probably middle bathyal (Bbhm
1992; Bbhm & Brachert 1993; Bernoulli &
Jenkyns 2009; microendolithic ichnofossil
evidence provided by M. Wisshak)

This paper

plates were extracted from a number of modem representatives of ophiacanthid taxa not illustrated by
Thuy & Stohr (2011), using conventional household bleach for maceration. Inconsistency of taxonomic
data - one of the major biases in large-scale palaeobiodiversity studies - was overcome by taxonomic
standardisation. In order to track depth distribution patterns through time, attempts were made to
identify evolutionary lineages on the basis of similarities in lateral arm plate morphology, in line with
the observation by Thuy & Stohr (2011) that the most closely similar lateral arm plates are generally
found in the most closely related species.

In addition to the age and palaeo-depth of first occurrences (F Os) of lineages, trends in relative abundance
and diversity through time and across the depth gradient are central themes in ophiacanthid evolution
considered in the present study. Spatial and temporal patterns in the relative abundance of members of
this family are explored using the ratio of the number of ophiacanthid lateral arm plates to the number
of those of non-ophiacanthids. Possible biases related to preservation potential of ophiacanthid lateral
arm plates are overcome using the lateral arm plates of other ophiuroids as a taphonomic control group.
Whenever possible, at least 300 ophiuroid lateral arm plates per assemblage are counted so as to assess
the relative abundance of the Ophiacanthidae, in line with standard procedures employed in other
micropalaeontological census approaches, in particular using foraminifera (e.g. Pfiaumann et al. 1996;
Fatela & Taborda 2002; Kucera 2007). Some samples, however, yielded fewer than 300 plates even
after intense sampling efforts. A particularly striking example is the Bathonian sample from Ea Pouza,
France, which yielded only 113 lateral arm plates, yet in excess of 100000 crinoid ossicles (Hess 2012).
In addition, it must be borne in mind that the number of arm segments, and thus of lateral arm plates, per
individual can vary between species. Relative abundance data from counts of fossil lateral arm plates
should therefore not be over-interpreted. They are here used as a tool to assess the general abundance
trends, which they can be assumed to refiect fairly accurately in spite of the above-mentioned issues.

European Journal of Taxonomy 48: 1-242 (2013)

Trends in ophiacanthid diversity through time are used as an additional souree of data to explore the evolution
of the family. Due to the heterogeneity of the ophiaeanthid fossil reeord, the relatively low speeies riehness
values per assemblage and the strong differenees in the number of ophiaeanthid speeimens per assemblage
(between 1 and 1343 speeimens), however, insights are limited and often should not be taken at faee value.
A major bias in eomparing the diversities of assemblages are differenees in sampling effort (number of
samples, individuals, habitat types, ete.), as in almost all palaeobiodiversity studies (e.g. Kroh 2007).

The main approaeh employed in the present study to explore the effeet of sampling bias is to lump the
assemblages studied in intervals of 5 Ma in order to reduee the effeet of differenees in habitat type, and
to plot the speeies riehness values along with the number of samples and lateral arm plates eounted
for eaeh individual. Straightforward interpretations on the basis of these plots are found to be both
expedient to explore the general, large-seale trends, and less prone to the pitfalls of method abuse (e.g.
Tipper 1979) due the above-mentioned peeuliarities of the data set at hand. In eontrast, rarefaetion - one
of the most eommonly employed, well-established teehniques to eompare samples of different sizes
(e.g. Adrain et al. 2000; Kroh 2007) - was of limited use only in the present study. The requirement that
samples are to be taken from a similar “habitaf ’ (Sanders 1968; Tipper 1979), and the extremely low
ophiaeanthid abundanees in most Triassie reeords preelude a meaningful applieation to the eomplete
data set. Rarefaetion analysis is used only to eompare seleeted assemblages in order to test large-seale
trends suggested by the 5 Ma interval diversity plot. Computing of the rarefaetion values is done using
the PAST software (Hammer et al. 2001) based on the algorithm of Krebs (1989).

Results

Ophiaeanthid lineages: palaeo-depths and dating first occurrences

A total of 122 ophiaeanthid speeies were identified from the samples studied herein (see Appendix 1);
55 of these are here formally deseribed as new, while another 21 speeies are most probably new as
well, but were not named here due to insuffieient material. The remaining 19 speeies, all previously
named, are reinterpreted. Based on a eareful eomparison with lateral arm plates (LAPs) of Reeent
ophiaeanthid speeies, and on the observation by Thuy & Stohr (2011) that LAP morphology generally
refleets phylogenetie relationships in ophiuroids, it is possible to identify a number of ophiaeanthid
lineages (Fig. 1), based on similarities in LAP morphology. These lineages represent groups of speeies
whieh share a number of distinetive features and thus are more elosely related to eaeh other than to any
other speeies. The generie assignment of the speeies in question is not always fully eonsistent, beeause
many extant ophiaeanthid genera are ill defined (O’Hara & Stohr 2006), and beeause most of the speeies
eonsidered are known exelusively from dissoeiated lateral arm plates. Thus, the term lineage is used
here to designate those groups of speeies that share similar LAP morphologies and thus almost eertainly
represent true elades. Onee identified, the individual lineages are systematieally traeed in time and in
eonneetion to palaeo-depth estimates.

The vast majority of the lineages are found in the Jurassie, in stark eontrast with the very restrieted
ophiaeanthid faunal speetrum in the Triassie. Only a third (33 per eent) of the lineages have a fossil
reeord at shelf depths in the Cretaeeous. Approximately half of the lineages have fossil reeords in
both shallow and deep settings at some point of their evolutionary history. In eight lineages, ineluding
extant ones, fossil oeeurrenees are restrieted to shallow-water deposits, and a single lineage is known
exelusively from deep-sea settings. The most intriguing observation, however, is that more than one-
third of the lineages identified first oeeur in deep-sea settings prior to being found in shelf sediments.
This is surprising given the overwhelming sampling bias that ean be expeeted from the number of shelf
assemblages studied whieh exeeeds that of deep-sea assemblages by an order of magnitude. Conversely,
the mueh greater eompleteness of the fossil reeord at shelf depths strongly suggests that the deep origin
of the lineages in question is a true signal rather than a sampling artefaet.

THUYB., Fossil record of ophiacanthid brittle stars

Mesozoic

Cenozoic

Triassic

Jurassic

Cretaceous

Paleogene

Neogene

•£=

(2!

-32

■D

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■O

Q-

3 a>
^ <u

‘c

03 ^
CD iS

I— ^

TO 2
” >

cQtSo

*05

bli

11
TO

-I

TO TO
o'c
TO^
'c C
O TO
OCO

c c
C TO TO

COt-

3 E
g- 3
< CD

-2

Eolaxoporus

■Lapidaster- Ophiologimus -

Ophiotoma

Ophiolimna

Geromura

Krohcoma

— Europacantha

Ophiotreta -
Ophiopristis

Ophiacantha

Ophiogaleus

Hanshessia

Alternacantha - Dermocoma - Dermacantha

Ishidacantha

Ophiomalleus

Inexpectacantha - Ophioleviathan

Ophiocamax - Reitneracantha
I

Sabinacantha - Ophiohamus -

Manfredura

Ophiojagtus

shallow record
deep record

Fig. 1. Ophiacanthid brittle star lineages and their fossil record in shallow (< 200 m palaeodepth, thick
grey lines) and deep (> 200 m palaeodepth, thick black lines) environments through time. Extant lineages
are indicated by the thin median line extending to the Holocene.

European Journal of Taxonomy 48: 1-242 (2013)

Calibrated phylogeny versus observed fossil record

In order to test whether the lineages whieh first oeeur at shelf depths are proof of a shallow origin, in line
with the assumption of onshore origination, the ophiaeanthid phylogeny by Thuy et al. (2012) is revised,
inelusive of a number of well-known fossil ophiaeanthids to determine the minimum ages of the key
nodes. Tree topology (Fig. 2) is basieally similar to that of the initial analysis by Thuy et al. (2012), with
a slightly lower resolution ineluding three triehotomies rather a single one. Most importantly, however,
the new tree eorroborates the size of the tentaele pore as one of the major eharaeters of phylogenetie
relevanee in the Ophiaeanthidae, separating the family into a large elade of small-pored taxa and a
number of large-pored, basal sister taxa. This is a erueial observation in view of the faet that tentaele
pore size ean be inferred from the morphology of dissoeiated LAPs, whieh ean thus be used to braeket
the minimum divergenee date of the small-pored elade. In addition, the new tree topology agrees with

O pentagona
O glacialis
O hexactis
O coriacea
O bairdi
O hirsuta
O duplicata
L gracilispina
D wright
A sp nov
O spatula
O scolopendrica
O laevipellis
O cataleimmoidus
O lineolata
H trochitophila
I acrobatica
O marginata
O troscheli
O tuberculosa
O bidentata
O punctata
O scorteus
O tylota
O discycia
O crinitum
O dipsacos
O vallda
O vltrea
O convolutus
O obstricta
Onanus
O eprae
O pectorale
O squamosa

O pentagona
O glacialis
O hexactis
O coriacea
O bairdi
O hirsuta
O duplicata
L gracilispina
O lineolata
O scolopendrica
O troscheli
O tuberculosa
O bidentata
O punctata
O scorteus
H trochitophila
O cataleimmoidus
O spatula
D wright
A sp nov
O laevipellis
O tylota
I acrobatica
O marginata
O discycia
O dipsacos
O crinitum
O valida
O vitrea
O obstricta
Onanus
O convolutus
O eprae
O pectorale
O squamosa

Fig. 2. Phylogeny of the Ophiaeanthidae. A. Majority rule eonsensus of 2572 most parsimonious trees
(182 steps length) resulting from the phylogenetie analysis of the full data set. B. Striet eonsensus
of nine most parsimonious trees (47.91375 steps length) resulting from the analysis of the reweighed
dataset (eharaeters reweighed by their maximum resealed eonsisteney index). Numbers above branehes
represent bootstrap support for the respeetive nodes (10000 replieates); numbers below branehes are
node frequeneies of the majority rule eonsensus tree.

THUYB., Fossil record of ophiacanthid brittle stars

the original one in showing a clade of ophiacanthids with thick disc plates (i.e. composed of the former
Ophioplinthacinae Paterson, 1985 and some former hemieuryalids) within the small-pored clade.

Differences between the original tree and the revised one pertain mainly to the position of a few genera.
Among the most notable is the position of Ophiocopa spatula Lyman, 1883, sister to the clade formed
by the Middle Jurassic Dermocoma wrighti Hess, 1964 and Alternacantha occulta Thuy & Meyer,
2013, rather than sister to the Early Jurassic Inexpectacantha acrobatica Thuy, 2011 as suggested by
the original tree. The new position of Ophiocopa Lyman, 1883 is corroborated by similarities in LAP
morphology (see below), in line with observations by Thuy & Stohr (2011) on the correlation between
LAP morphology and phylogenetic relationship. The Middle Jurassic Hanshessia trochitophila Thuy &
Meyer, 2013 and the Ophiophthalmus-Ophiocopa-Alternacantha-Dermocoma clade are unresolved
sister taxa to the large clade that comprises all remaining small-pored ophiacanthids with thick disc
plates. As predicted by Thuy & Schulz (in press), the Late Jurassic Ophiosternle crinitum (Quenstedt,
1876) is a member of the Ophioplinthaca-Ophiocamax-Ophiomitra clade. Finally, the Late Triassic
Leadagmara gracilispina Thuy, Ishida, Doi & Kroh, 2012, holds an even less basal position within
the large-pored ophiacanthids than suggested by the original tree. In fact, together with the extant
Ophiomedea duplicata Koehler, 1906 and Ophiopristis hirsuta (Lyman, 1875), it forms the direct sister
clade to the small-pored ophiacanthids.

In order to place the ophiacanthid fossil record into an evolutionary context, the tree chosen as
working hypothesis was transformed into an evolutionary tree using two key fossil occurrences as
main calibration points (Fig. 3 A). First, the oldest occurrence of an ophiacanthid which unquestionably
displays small tentacle pores are dissociated LAPs from Anisian (Middle Triassic) shelf deposits in
Hungary, described below as Europacanthapaciphila gen. et sp. nov., which astonishingly represent the
oldest fossil ophiacanthid remains known to date. This important discovery implies that the small-pored
ophiacanthids had already diverged by the Anisian at the latest, and that the large-pored taxa must be
even older. Secondly, dissociated LAPs from Pliensbachian deep-sea strata in Austria which display a
combination of characters exclusively found in members of the extant Ophiocamax-Ophiomitra clade,
imply that even the more derived members of the small-pored ophiacanthids with thick disc plates must
have diverged prior to the Pliensbachian. All other divergence times are estimated conservatively on the
basis of the oldest fossil occurrences of the respective genera and lineages. The resultant evolutionary
tree strongly suggests that almost the entire early cladogenesis in the Ophiacanthidae occurred in pre-
Jurassic times.

Next, the fossil record of the ophiacanthids other than those used as calibration points is compared
with the evolutionary tree in order to test whether the predicted origination times match the observed
first occurrence dates of the respective taxa in shelf deposits, in line with the hypothesis of onshore
origination, or not. Almost all taxa with a fossil record at shelf depths first occur in the Jurassic, i.e.
much later than predicted by the phytogeny. The pattern is particularly striking in large-pored taxa such
as Ophiologimus H.L. Clark, 1911, Ophiotoma Verrill, 1899 and Ophiolimna Verrill, 1899 whose first
occurrence dates at shelf depths post-date even the most conservative divergence date estimates by more
than 60 Ma. The long ghost lineages that result from the discrepancy between the predicted origination
and the first occurrence observed at shelf depths challenges the hypothesis of onshore origination.

Relative abundance patterns in the fossil record of ophiacanthids

While the Ophiacanthidae are here shown to have occurrences at shelf depths extending back to the
Middle Triassic, their fossil record is far from homogeneous in terms of relative abundance (Fig. 3).
LAP counts clearly show that ophiacanthids were extremely rare in the Triassic, accounting for less
than 4 percent in all brittle star assemblages studied. Intriguingly, the highest relative abundances in the
pre-Rhaetian Triassic are attained in deep-shelf assemblages (1.6 per cent at Felsoors and 3.4 per cent

European Journal of Taxonomy 48: 1-242 (2013)

Mesozoic

Triassic

Jurassic

1IIIIIIIIIIIII iiiiiiiiiiiiiiiiiiiiiiiiii

Leadagmara

rHimimim

Cretaceous

mil

Hanshessia

Cenozoic

Paleogene Neogene

Dermocoma

Alternacantha

Inexpectacantha

Ophiosternle

••

.. ^

250

200

150 100

age (Ma)

' Ophiomyxa

■ Ophioscloex

• Ophiologimus

■ Ophiotoma

• Ophiolimna

• Ophiopristis

• Ophiomedea

— Ophiotreta

— Ophientrema
j— Ophiacanthella
^ Ophialcaea

— Ophiacantha
j— Ophiogema
^ Ophiolebes

— Ophiophthalmus

— Ophiocopa

■ Ophiomitrella

■ Ophiosemnotes

• Ophioripa

' Ophiothamnus

• Ophioplinthaca

■ Ophiomitra

' Ophiocamax

• Ophiomoeris

■ Ophiohamus

■ Ophiochondrus
Ophiolamina
Ophiodictys
Ophiochondrella

100

■o

0 iS

Fig. 3. A. Evolutionary tree of the Ophiaeanthidae based on the reweighed dataset tree of Fig. 2B.
Calibration is based on nodes marked as 1 (oldest oeeurrenee of small tentaele pores, Europacantha
paciphila sp. nov. from the Anisian of Hungary) and 2 (oldest oeeurrenee of lateral arm plate morphology
exelusively found in the Ophiomitra-Ophiocamax elade, Reitneracantha dissidens sp. nov. from the late
Sinemurian to early Pliensbaehian of Austria), and on the first oeeurrenees of a number of extinet genera
(Leadagmara Thuy et al, 2012, Dermocoma Hess, 1964, Inexpectacantha Thuy, 2011). Thiek lines
indieate the observed fossil reeord of the aetual genus, doted lines denote the fossil reeord of a genus
within the same lineage (e.g. Lapidaster sp. nov. in Ophiologimus H.L. Clark, 1911), and thin lines are
the expeeted ranges. B. Relative abundanees of the Ophiaeanthidae in shallow (< 200 m palaeodepth,
small dots) and deep (> 200 m palaeodepth, asterisks) environments through time.

THUYB., Fossil record of ophiacanthid brittle stars

at Jushui; see Table 1 for locality details). In the Hettangian, abundance abruptly increased to more than
30 per cent and remained high throughout the Jurassic. Peak values (> 85 per cent) were reached in a
Bajocian shallow-shelf coral reef assemblage from France and a Callovian middle-shelf, muddy bottom
assemblage from India. Relative abundance values rapidly dropped again at the end of the Jurassic and
remained well below 20 per cent, up to the youngest (middle Miocene) assemblage studied in the present
paper. Clearly, the Jurassic was the time when the Ophiacanthidae were most abundant at shelf depths,
attaining relative abundances comparable to those observed in present-day bathyal settings (e.g. Clark
1911; Koehler 1922; Metaxas & Gifhn 2004). Interestingly, this trend seems to be independent of habitat
type. In fact, shallow-water coral reefs, sponge reefs, mud bottoms and hardgrounds/rocky shores all
show highest ophiacanthid abundances in the Jurassic, preceded in all cases by extremely low values in
the Triassic, and followed again by low values in the Cretaceous and Cenozoic. In contrast, in all deep-
sea assemblages studied, inclusive of the Pliensbachian one from Austria, the family accounts for at least
40 per cent of ophiuroid deep-sea communities throughout, in line with present-day relative abundance
of the family at bathyal depths (see above).

The main bias in relative abundance patterns is sampling completeness. Incompleteness of the fossil
record is inherent to palaeontology. Yet, attempts should be made to keep the data set used for studies
of relative abundance patterns as representative as possible in order to make certain that the patterns
observed are, indeed, due to shifts in depth distribution of taxa over time rather than the result of regional
migrations between shelf habitats. The Triassic record studied herein includes assemblages from the
Germanic Basin, the western margin of the Tethys Ocean, the South China terrane and the northwestern
margin of Panthalassa (Fig. 4). All yielded very low numbers of ophiacanthid LAPs, if any at all. In
addition to these new assemblages, a number of previously published Triassic ophiuroid occurrences
from various parts of the Triassic world oceans, including the northeastern margin of Panthalassa in
present-day North America, provide useful data (see caption of Fig. 4 for full list of references). In fact,
except for the Rhaetian assemblage from the Wombat Plateau (Kristan-Tollmann & Gramann 1992),
none of these previously published Triassic ophiuroid record includes ophiacanthids, not even the
extraordinarily thoroughly sampled Central European Muschelkalk Basin (e.g. Hess 1965a; Zatoh et al.
2008). Thus, the extremely low numbers of ophiacanthids at shelf depths during the Triassic appears to
be a real phenomenon that begs for an explanation.

The Jurassic record studied herein is strongly biased towards the Peri-Tethys, yet it also includes a
number of assemblages from the Malagasy Gulf in the Southern Hemisphere, situated in present-day
northwestern India (Scotese 1991). The ophiacanthid abundance patterns of the Malagasy assemblages
perfectly match those observed in the Peri-Tethyan area, suggesting that the Jurassic abundance maximum,
similar to the Triassic abundance minimum, is a real, global phenomenon. Similarly, Cretaceous and
younger abundance values also follow comparable trends in more than one palaeogeographical region.

Very low relative abundance values of ophiacanthids at shelf depths in the Triassic are at odds with the
prediction that most of the early cladogenesis of the family occurred at that time. The sudden, habitat
type-independent increase in abundance at shelf depths in the Jurassic, paralleled by similarly high
abundance values in coeval deep-sea assemblages, is intriguing. It can only be reconciled with the
hypothesis of onshore origination when assuming a sudden, massive proliferation of the family at shelf
depths long after the initial radiation and almost immediately followed by a similarly massive migration
into the deep sea. A much more likely scenario is a sudden large-scale invasion of shelf habitats in the
Jurassic as offshoots of previously diversified deep-sea ophiacanthid communities.

Ophiacanthid diversity through time

Among the 122 ophiacanthid species identified in the present study, 26 species are found in deep-sea
settings and the remaining 96 at shelf depths. No species occurs in both shallow and deep sediments.

European Journal of Taxonomy 48: 1-242 (2013)

More than two-thirds (34) of the shallow-water speeies are Jurassie in age, whereas only six are known
from the Triassie. At the same time, however, the Jurassie yielded more than 29 000 speeimens from
45 assemblages, eomparedto only 6051 speeimens from 16 assemblages of Triassie age, although both
time intervals are of largely eomparable duration (Ogg et al. 2008).

A more differentiated pieture emerges when speeies riehness values of assemblages lumped in 5 Ma
intervals is plotted together with the eorresponding numbers of samples and speeimens (Fig. 5). The
mid-Jurassie and uppermost Cretaeeous peaks in speeies riehness eoineide with peaks in sample and/
or speeimen numbers. Thus, ehanees are high that these are at least to a eonsiderable extent the result
of sampling artefaets. In eontrast, the terminal Triassie and lower Jurassie inerease in speeies riehness
is only weakly paralleled, if at all, by sample and speeimen numbers. Most importantly, the Oxfordian-
Kimmeridgian speeies ric hn ess maximum, the highest in the entire ophiaeanthid shallow-water fossil
reeord, eoineides with eomparatively low numbers of samples and speeimens, not signifieantly exeeeding
those of the more eompletely sampled Triassie intervals.

Fig. 4. Palaeogeographie reeonstruetion for the Middle Triassie [after Smith et al. (1994)] with positions
of eurrently known Triassie ophiuroid oeeurrenees (grey areas indieate emerged land). Round dots
indieate assemblages quantitatively assessed in this study (see Table 1 for details). 1. Fiseherwiese,
Oberseheffaeh, Sehillingstadt. 2. Gorazdze, Strzelee Opolski, Felsoors, Soly. 3. Alpe di Speeie, Romerlo,
Milieres, Reeoaro. 4. Kitakami Mountains. 5. Jushui. Squares indieate previously published Triassie
reeords. At the same positions as round dots 1-3: Baehmayer & Kollmann (1968), Broglio Loriga &
Berti Cavieehi (1972), Hess (1970a), Kutseher (1987b, 2000), Radwahski (2002), Salamon (2004) and
ophiuroid reeords revised by Hess (1965b). Squares: 6. Calzada & Gutierrez (1988). 7. Hess (1972b),
Kristan-Tollmann et al. (1979). 8. Twitehett et al. (2005). 9. Zonneveld (2001). 10. Kummel & Teiehert
(1970). 11. Runnegar (1969). 12. Kristan-Tollmann & Gramann (1992). At the same position as round
dot 5: Yang (1960), Feng (1985), Chen et al. (2004). Square 13. Ishida et al. (2011).

THUYB., Fossil record of ophiacanthid brittle stars

In order to test whether the Oxfordian-Kimmeridgian diversity peak is indeed a real phenomenon worth
explaining or not, rarefaction analysis was performed to allow for pairwise comparison of Oxfordian-
Kimmeridgian and Triassic assemblages from similar habitats. In all cases, Oxfordian-Kimmeridgian
species richness values exceed those of the Triassic samples when scaled down to the same sample size.
The greatest deviations are found for deep-shelf sponge reefs (3.70 at the Plettenberg, Germany versus 1
at Jushui, China; see Table 1 for locality details), followed by mid-shelf mud bottoms (2.93 in Savigna,
France versus 1 at Felsoors, Hungary; see Table 1 for locality details). These results lend support to
the initial observation that ophiacanthid diversity at shelf depths was much higher in the Jurassic than
in the Triassic, which strongly suggests that the early diversification of the family in the Triassic, as
predicted by the phytogeny (see above), did not occur at shelf depths. Considering the extremely small
sample sizes of most Triassic assemblages (e.g. only eight specimens for the mud-bottom assemblage),
however, caution must be exercised when interpreting the results.

Interestingly, the highest species richness values per assemblage were found in the lower Maastrichtian
deep shelf of Riigen, Germany (eight species), and the two deep-sea assemblages from Blake Nose (eight

250

200

150

100

Age (Ma)

Fig. 5. Diversity of ophiacanthid brittle stars, given as species richness per 5 Ma intervals, in shallow-
water (< 200 m palaeodepth) environments through time, together with corresponding numbers of
samples and of lateral arm plates (LAPs) counted (both ophiacanthids and non-ophiacanthids) per
interval. Note that the scale for specimen numbers is increased by factor 10^

European Journal of Taxonomy 48: 1-242 (2013)

species) and the Glasenbach Gorge (ten species), although in the last-named some of the ophiacanthid
diversity might be the result of faunal mixing in view of its slumping mass nature. When scaled to
the sample size of the Glasenbach Gorge assemblage employing rarefaction analysis, Riigen (7.40)
and Blake Nose (6.24) still show extraordinarily high species richness unmatched by any other of the
assemblages studied. These values are comparable with ophiacanthid diversities of present-day brittle
star communities in the deep sea (e.g. Clark 1911). Since Riigen is probably the deepest shelf assemblage
considered herein, the above observations suggest that deep environments yield the highest ophiacanthid
diversities throughout most of the ophiacanthid evolutionary history, at least since the Early Jurassic,
which is hardly reconcilable with the hypothesis of a shallow-water origin (Ricklefs & Schluter 1993).

Discussion

The present study documents several lines of evidence which strongly suggest that the Ophiacanthidae
originated in the deep sea, temporarily expanded to shelf depths and eventually became largely restricted
to the deep sea again:

1) more than one-third of the ophiacanthid lineages identified first occurred in the deep sea, in spite
of the much higher completeness of the fossil record at shelf depths;

2) the observed first occurrence dates at shelf depths in the basal large-pored ophiacanthid lineages
post-date the predicted originations by more than 60 Ma;

3) almost the entire early evolution of the Ophiacanthidae took place in the Early to Middle Triassic,
yet ophiacanthids were extremely rare at shelf depths until the Early Jurassic when relative abundances
suddenly increased to values typically observed at present-day bathyal depths;

4) fossil deep-sea assemblages, in contrast, displayed very high ophiacanthid relative abundances
throughout, at least since the Early Jurassic;

5) the diversity of the family was very low throughout most of the Triassic, and most probably
increased in the latest Triassic and Early Jurassic, reaching acme in the Eate Jurassic. These observations
are hardly reconcilable with the hypothesis of onshore origination of the family, which is thus rejected
here.

The conclusion is substantiated by extensive sampling of the Triassic shallow-water fossil record.
In combination with numerous previously published occurrences of articulated Triassic ophiuroids,
the samples based on dissociated lateral arm plates provide a fairly accurate picture of the Triassic
ophiacanthid fossil record at shelf depths. It seems unlikely that the representatives of the numerous
originally Triassic lineages which do not appear in shelf environments until the Jurassic were missed
out, all the more so in view of the fact that modem ophiuroid distributions at family level are in general
anything but patchy (Stohr et al. 2012). The Triassic record of the Ophiacanthidae is comparable to the
present-day distribution of the family at shelf depths consisting of very rare and patchy occurrences of
single species (e.g. Baker & Devaney 1981; O’Hara & Stohr 2006; Stohr 2011). In order to provide the
ultimate test of the conclusions reached here, however, Triassic deep-sea ophiuroid assemblages need
to be discovered and screened for ophiacanthids. Although unaltered, fossiliferous deep-sea sediments
of Triassic age are very rare; however, a few promising outcrops have been described (Guaiumi et al.
2007; Peckmann et al 2011), suggesting that the search for Triassic deep-sea ophiuroids is not an
inconceivable task.

Previously, the extensive fossil occurrences at shelf depths of a number of modem deep-sea groups have
commonly been considered as evidence for the long-proposed onshore-offshore trend in the evolution
of marine biodiversity (e.g. Moseley 1880; Wolf 1960; Madsen 1961; Clarke 1962; Hessler & Sanders
1967). The realisation that an originally deep-sea group temporarily invaded shelf environments
radically breaks with this paradigm. One of the very few authors to cast a comparably critical light
on the shallow-water fossil record of an extant deep-sea group was Voros (2005), who speculated that

THUYB., Fossil record of ophiacanthid brittle stars

post-Palaeozoic smooth brachiopods invaded shallow environments as offshoots of stable deep-sea
communities in times of suitable palaeoceanographic conditions. The potential of deep-sea groups to
contribute to shallow-water diversity has recently been demonstrated by Lindner et al. (2008), who
showed that Recent shallow-water stylasterid corals evolved from deep-sea ancestors at least three
times. Similar trends may thus be expected in other groups with both shallow and deep representatives.
The evidence presented herein, however, is unprecedented in departing from the usual unidirectional
assumptions invoking either onshore to offshore shifts or vice versa, but rarely a combination of both.
For the first time, a group is shown to originate in the deep-sea, expand to shallow environments and
gradually retreat again from the latter.

The model of temporary, large-scale shelf invasion by deep-sea groups provides new, potentially
insightful perspectives for a number of key aspects in marine (palaeo)biodiversity. It stresses the necessity
of taking into account the possibility of vertical shifts in distribution on macroevolutionary time scales
when exploring shallow-marine diversity. Studies of biogeographic patterns of species distributions, for
example, almost invariably ignore the possibility of shelf invasion by deep-sea groups (e.g. Goldberg
et al. 2005). The present study adds to the growing body of evidence that modem shallow-water
environments are not exclusively the result of in situ evolution but received considerable input from
deep-sea invaders (Lindner et al. 2008). Although, admittedly, adding the vertical migration component
presents the risk of making palaeobiodiversity analyses exceedingly complex, straightforward exclusion
of the potential contribution of deep-sea environments to shallow-water diversity is an oversimplification
that is no longer tenable.

The model of temporary expansions of deep-sea groups to shelf environments also calls for a fundamental
reappraisal of the role of the deep sea in macroevolutionary processes, away from the classic concept of
a sink basically accumulating species and lineages from shallow environments, as implicitly stated by
the onshore-offshore hypothesis (Jablonski et al. 1983). The conclusions drawn herein significantly add
to the growing body of evidence that deep-sea environments provided opportunities for the evolution
and diversification of groups that have subsequently invaded other environments (Lindner et al. 2008;
Moura et al. 2012). The deep-sea assemblages described herein also suggest that the deep sea provided
sufficient resilience against large-scale perturbations to sustain ophiacanthid diversities unmatched
by any shallow-water assemblage at least since the Early Jurassic. Clearly, the concept of the deep-
sea as a refuge for taxa retreating from shelf environments that is episodically swept by large-scale
palaeoceanographic perturbations such as Oceanic Anoxic Events (OAEs) (Jacobs & Eindberg 1998) is
untenable.

Finally, the evolutionary history of the Ophiacanthidae as reconstructed in the present study raises the
question as to what factors control macroevolutionary shifts in bathymetric distribution. So far, debates
have almost exclusively focused on the offshore retreat of groups, arguing for an increase in predation
pressure or the evolution of superior competitors (Vermeij 1977, 1987, 1995; Oji 1996; McClintock
et al. 1999). In this respect, the data presented here contribute little to the ongoing debates other than
to add yet another group to the list of organisms which gradually retreated from shallow depths in the
course of the Eate Mesozoic.

Much more intriguing is the large-scale, habitat-unspecific invasion of shelf environments around the
Triassic-Jurassic boundary. While the present study provides little insight into the actual factors that
controlled this deep- to shallow-water pattern, it is among the first to constrain the timing of such a
pattern using fossil evidence. The Rhaetian EAP assemblage described herein, in combination with
the array of previously published latest Triassic ophiuroid records (see caption of Fig. 4 for a full list
of references), suggest that the large-scale invasion of shelf environments started at the very end of
the Triassic. It can be speculated that the mass extinction at the Triassic-Jurassic boundary (Benton

European Journal of Taxonomy 48: 1-242 (2013)

1995) vacated a niche in shelf enviro nm ents whieh the ophiaeanthids then temporarily filled. Modem
ophiaeanthids are slow-moving suspension feeders (e.g. MeClintoek 1994; Metaxas & Giffin 2004),
eatehing prey using their long spines and tube feet, and often elinging to eoral or sponge hosts (Stohr
et al. 2012). Triassie ophiuroids, however, do not inelude any other long-spined forms whieh eould
have oeeupied the same niehe as the Ophiaeanthidae, unlike, for instanee, members of the modem
Ophiothrieidae whieh are the dominant long-spined, suspension-feeding ophiuroids in most present-day
tropieal to temperate shelf habitats (Jangoux & Lawrenee 1982).

An alternative explanation for the end-Triassie invasion of shelf environments might be sought in global-
seale ehanges in oeean eireulation mode. Many modem deep-sea groups are restrieted to a partieular,
eomparatively narrow depth range (Menzies et al. 1973), and limits in larval dispersal are among the key
faetors whieh eonstrain the bathymetrie range of organisms (Tyler & Young 1998; Young et al. 1997; Aquino-
Souza et al. 2008). It has reeently been shown that larvae of deep-sea eorals generally are retained within
water masses rather than migrating among them (Miller et al. 2011), whieh implies that vertieal migration of
organisms is most likely to oeeur when water masses are homogeneous along the depth gradient. Indeed, the
thermohaline eireulation whieh eonneets shallow-water Antaretie enviro nm ents with the deep Indian, Atlantie
and Paeifie oeeans through an isothermal water eolunm (Rogers 2000), has reeently been shown to have
played an essential role in the invasion of the deep sea by Antaretie shallow-water oetopuses (Stmgnell et al.
2008). The eold isothermal water eolumn is assumed to be among the key faetors eontrolling the enhaneed
eurybathy found among Southern Oeean invertebrates (e.g. Brey et al. 1996; Brandt et al. 2007), involving
both the submergenee of shallow taxa and the emergenee of deep ones. Conversely, in the warm, near-
isothermal water eolunm of the present-day Mediterranean, many taxa have a wider bathymetrie distribution
than e.g. in the thermally more strongly stratified Atlantie (Emig & Geistdoerfer 2004). Furthermore, Young
et al. (1997) doeumented that the larvae of northeast Atlantie and Mediterranean eehinoids were more likely
to survive deep-sea pressures at high temperatures than at low temperatures.

During mueh of the mid- and Late Mesozoie, the prevailing meehanism of deep-water formation was
halothermal eireulation, the sinking of warm, high-salinity surfaee waters at low latitudes (Home 1999).
As a eonsequenee, deep water masses were relatively warm (>10°C) during most of the later Mesozoie
(e.g. Huber et al. 2002), and world oeeans generally were mueh less strongly thermally stratified than the
present-day major oeean basins due to the eold (~ 4°C) deep-water masses that result from surfaee water
sinking at high latitudes. Interestingly, it has been suggested on the basis of ostraeod evidenee (Kozur
1972) and eireulation modelling (Kutzbaeh & Guetter 1990) that deep-water masses were eold during
most of the Triassie. Based on these observations, it may be speeulated that ophiaeanthids originated in
the pre-Jurassie, presumably eold deep sea, and were only eapable of very limited shallow-water invasion
until a hypothetieal major ehange in oeean eireulation mode around the Triassie-Jurassie boundary led
to inereased deep-water temperatures. As a eonsequenee, thermal stratifieation of the water eolumn
was attenuated, providing opportunities for enhaneed vertieal migration of taxa and possibly allowing
the Ophiaeanthidae to invade shelf environments on a mueh larger seale than during the Triassie. The
ophiaeanthid shallow-water fossil reeord suggests multiple independent invasions of shelf environments
by ophiaeanthid lineages throughout the Jurassie, rather than a single eolonisation event followed by in
situ diversifieation. This pattern is in line with the seenario of enhaneed vertieal migration potential over
a prolonged period, as would be expeeted from a global-seale ehange in deep-water eireulation mode.

Whatever the eauses, the temporary invasion of shelf environments by an originally deep-sea group,
as shown here for the Ophiaeanthidae, involves proeesses whieh are very unlikely to have affeeted the
evolutionary history of a single group without afifeeting many more. 1 thus prediet that future studies,
whieh should systematieally traee the fossil reeord of modem deep-sea groups and eompare it with
ealibrated phytogenies, will show that temporary expansion to shelf environments was a widespread
phenomenon among modem deep-sea groups.

THUYB., Fossil record of ophiacanthid brittle stars

Systematic palaeontology

Class Ophiuroidea Gray, 1840
Order Ophiurida Muller & Troschel, 1840
Family Ophiacanthidae Ljungman, 1867

Genus Eolaxoporus gen. nov.

um:lsid:zoobank.org:act:6C93137E-586A-405A-B553-2359C7534CCE

Type species

Eolaxoporus hagdorni sp. nov. by present designation.

Other species included

Eolaxoporus imminens sp. nov.

Diagnosis

Ophiacanthid with lateral arm plates of rectangular outline displaying large tentacle notches; well-
developed constriction, outer surface without conspicuous ornamentation; two spurs on the outer
proximal and inner distal edges; spine articulations with near-parallel, proximally widely separated
dorsal and ventral lobes connected distally by sigmoidal fold; tongue-shaped, dorso-proximalwards
bent ridge devoid of kinks and widened parts on the inner side.

Etymology

Name composed of Eos, the Greek goddess of the dawn, laxus, Eatin for “wide”, and porus, Eatin for
“pore”, in allusion to the fact that this genus represents one of the oldest members of the large-pored
ophiacanthid lineages; gender masculine.

Remarks

Small dissociated lateral arm plates with conspicuously large tentacle notches, a well-developed
constriction resulting in an elevated distal part, and spine articulations composed of proximally widely
separated dorsal and ventral lobes connected distally by a sigmoidal fold are the commonest and
stratigraphically most widely distributed ophiacanthid remains in Triassic shallow-water deposits. The
peculiar structure of the spine articulations seems misleading at first, but the presence of a sigmoidal fold
(as defined by Martynov 2010) undoubtedly places the present EAP type in the Ophiacanthidae. The size
of the tentacle notches implies that the corresponding tentacle pores were large as defined by Thuy et al.
(2012). This refers the present EAP type among the basal, large-pored ophiacanthid lineages formerly
united as the subfamily Ophiotominae Paterson, 1985 (Paterson 1985).

Indeed, there is a certain resemblance to the EAPs of extant Ophiologimus and, on account of the
presence of spurs on the outer proximal and inner distal edges, even a closer match with the EAPs of
extinct Lapidaster gen. nov. The structure of the spine articulations, however, differs fundamentally.
A new genus, Eolaxoporus gen. nov., is thus erected here to accommodate the EAP type in question.
Phylogenetic relations with other large-pored ophiacanthid lineages, however, remain elusive until
articulated specimens of this new genus are discovered.

The EAPs described as Ophiacanthal binitorulosa Kristan-Tolhnann, Tolknann and Hamedani, 1979 from
the Rhaetian of Iran, are probably assignable to Eolaxoporus gen. nov, in particular in view of the near¬
parallel dorsal and ventral lobes of the spine articulations. In the absence of SEM-supported re-examination of
the type material, however, assignment to Eolaxoporus gen. nov. must be treated as questionable. On the basis
of the drawings in Kristan-Tollmann et al. (1979), it cannot be decided whether the EAPs of O. ? binitorulosa

European Journal of Taxonomy 48: 1-242 (2013)

display a sigmoidal fold or not; this means that that species cannot even be considered as an unquestionable
ophiacanthid record. The LAPs figured by Kristan-Tollmann & Gramann (1992) as Ophiacanthal binitorulosa
from the Rhaetian of the Exmouth Plateau are too poorly preserved to be identifiable.

Eolaxoporus sp.

Fig. 6: 1

Material examined

MHl 2083/1 (dissociated LAP) from the uppermost Anisian (middle Triassic) Trochitenkalk of
Oberscheffach, Germany.

Description

MHl 2083/1 is a dissociated, very small, median LAP of near-rectangular outline; approximately 1.5
times wider than high; dorsal edge concave as a result of a well-developed constriction; distal edge
slightly convex; ventro-distal tip of LAP slightly protruding; proximal edge concave, too poorly
preserved for spurs to be discernible; no conspicuous ornamentation seen on outer surface; mesh size of
stereom on outer surface unknown. Four large, ear-shaped spine articulations on slightly elevated distal
part of LAP; dorsal and ventral lobes of spine articulations proximally widely separated, horizontally
elongate, nearly parallel and slightly arched concentrically; slight dorsalward increase in the size of the
spine articulations. Ventral edge of LAP with large, slightly concave tentacle notch.

Inner side of LAP with large, well-defined, bent ridge; dorsal tip of ridge rounded, not widened, pointing
dorso-proximalwards; ventral tip of ridge separated from ventral edge of LAP; inner side of distal edge
of LAP with two large, poorly defined, slightly prominent spurs, one near the dorso-distal tip and the
second near the ventro-distal tip of the LAP.

Remarks

The single LAP described above is poorly preserved. Yet, it is an important specimen since it is
unambiguously assignable to Eolaxoporus gen. nov. on account of the general shape of the LAP, the
constriction, the highly distinctive shape of the spine articulations and of the ridge on the inner side, and
the very large tentacle notch, and thus documents the presence of the genus in strata as old as Anisian.
The specimen shows closest similarities to E. hagdorni sp. nov. but its poor preservation precludes any
more detailed comparison on the species level.

Eolaxoporus hagdorni sp. nov.

um:lsid:zoobank.org:act:B382D3C8-B7DC-442C-AAQ6-CF761442DQDC

Fig. 6: 2-4

Diagnosis

Species of Eolaxoporus gen. nov. with small LAPs displaying a low height/width ratio; two moderately
well-defined spurs on outer proximal and inner distal edges, close to dorsal and ventral edges, respectively;
up to four near-horizontal spine articulations; ridge on inner side relatively short and wide.

Etymology

Named in honour of Hans Hagdom, who generously provided most of the Triassic samples used in the
present study, including those that yielded the type material of the present species.

Type material

Holotype

MHl 2084/1.

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 6. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b) views.
1. Eolaxoporus sp. from the latest Anisian (Middle Triassie) of Oberseheffaeh, Germany, MHI 2083/1,
median LAP. 2-4. Eolaxoporus hagdorni gen. et sp. nov. from the late Camian (Late Triassie) of Jushui,
China. 2. MHI 2084/1 (holotype), proximal LAP. 3. MHI 2085/1 (paratype), median LAP. 4. MHI
2086/1 (paratype), distal LAP. 5. Eolaxoporus sp. nov. innom. from the early Camian (Late Triassie)
of Milieres, Italy; GZG.INV.78500, proximal to median LAP. 6-8. Eolaxoporus imminens gen. et sp.
nov. from the late Sinemurian to early Pliensbaehian (Early Jurassie) of the Glasenbaeh Gorge, Austria.
6. NHMW 2012/0137/0001 (holotype), proximal LAP. 7. NHMW 2012/0137/0002 (paratype), median
LAP. 8. NHMW 2012/0137/0003 (paratype), distal LAP. One eommon seale bar per speeies is given.

European Journal of Taxonomy 48: 1-242 (2013)

Paratypes

MHl 2085/1 and MHl 2086/1.

Type locality and horizon

Jushui, Sichuan, China; marly beds in the upper Hanwang Formation, late Camian, Late Triassie.

Additional material

MHl 2087/1-35 (35 dissoeiated LAPs from sample C30); MHl 2088/1-11 (11 dissoeiated LAPs from
sample C36); MHl 2089/1 (1 dissoeiated LAP from sample C33).

Description

Holotype

MHl 2084/1 is a dissoeiated, small, proximal LAP of reetangular outline; slightly wider than high; dorsal
edge strongly eoneave as a result of a well-developed eonstrietion; ventral fifth of LAP very weakly
protruding ventro-proximalwards; ventro-distal tip of LAP protruding; distal edge straight to slightly
eoneave; proximal edge with eentral noteh and two large, moderately well-defined, slightly prominent
yet strongly protruding spurs, one in the middle of the dorsal half of the proximal edge, the seeond
in the middle of the ventral half; outer surfaee laeking eonspieuous ornamentation; stereom of outer
surfaee eoarsely meshed in a vertieal band along the midline of the LAP, beeoming more finely meshed
towards the proximal edge and towards the spine artieulations. Four ear-shaped spine artieulations on
elevated distal part of LAP; slight dorsalward inerease in size of spine artieulations and in size of gaps
separating them; dorsal and ventral lobes of spine artieulations nearly parallel, horizontally elongate,
separated proximally by small knobs, eonneeted distally by sigmoidal fold. Ventral edge of LAP with
large, eoneave tentaele noteh.

Inner side of LAP with large, prominent, sharply defined, relatively short, tongue shaped, arehed ridge;
dorsal tip of ridge round, not widened, pointing dorso-proximalwards; ventral tip of ridge widest,
sharply defined rather than merged with ventral edge of LAP; inner side of distal edge with two large,
well-defined, prominent but not protruding spurs eomposed of slightly denser stereom, one near dorso-
distal tip of LAP, the seeond near ventro-distal tip. Inner side of tentaele noteh with eoarsely meshed,
slightly horizontally stretehed stereom. No perforations diseemible.

Paratype supplements and variation

MHl 2085/1 is a median dissoeiated LAP of reetangular outline; approximately 1.5 times wider than
high; morphologieally matehing the holotype; spurs on proximal edge less well defined. Four nearly
equal-sized spine artieulations.

Inner side well in agreement with that of holotype; spurs on distal edge less well defined.

MHl 2086/1 is a dissoeiated distal LAP; twiee wider than high; eonstrietion less well developed than in
holotype, thus distal part of LAP less strongly elevated; spurs on proximal edge almost indiseemible.
Three nearly equal-sized spine artieulations. Ventral edge of LAP with relatively large, gently eoneave
tentaele noteh.

Inner side with small, prominent, sharply defined, tongue-shaped knob; two large, poorly defined spurs
eomposed of denser stereom on inner distal edge.

Remarks

These LAPs ean be easily distinguished from the other LAP types assignable to Eolaxoporus n. gen.
on aeeount of the vertieal spine artieulations, in eombination with a wide ridge on the inner side and
two weakly protruding spurs, the dorsal one of whieh is elose to the dorso-proximal tip of the LAP. It

THUYB., Fossil record of ophiacanthid brittle stars

displays the highly distinctive combination of characters of Eolaxoporus gen. nov. best and is thus here
described as its type species.

Occurrence

Late Camian of Sichuan, China.

Eolaxoporus sp. nov. innom.
Fig. 6: 5

Material examined

GZG.INV.78500 (dissociated LAP) from the Cassian Formation, early Camian of Milieres, Italy.

Description

GZG.INV.78500 is a dissociated, small, proximal to median LAP; slightly wider than high; dorsal and
distal edges nearly straight; proximal edge gently concave except for very large, conspicuous, strongly
protmding, moderately well-defined, prominent and slightly angular spur almost in the middle of the
proximal edge and composed of slightly more densely meshed stereom; second much smaller and
much less well defined, weakly prominent and non-protmding spur close to ventro-proximal edge of
LAP; ventral fifth of LAP strongly protmding ventro-proximalwards; ventro-distal tip of LAP strongly
protmding ventralwards, tongue-shaped; outer surface with moderately coarsely meshed stereom. Four
moderately large, nearly equal-sized and equidistant spine articulations freestanding on slightly elevated
distal portion of LAP; dorsal and ventral lobes of near-equal size, parallel, horizontal, widely separated
proximally; gap between spine articulations and distal edge of LAP relatively narrow. Ventral edge of
LAP with large, deeply incised, concave tentacle notch.

Inner side of LAP with very small, conspicuously slender, sharply defined, prominent, dorso-
proximalwards bent ridge; two rather poorly defined, weakly prominent, round spurs on inner side of
distal edge of LAP; inner side of tentacle notch very large. No perforations and furrow discernible.

Remarks

This single LAP displays all diagnostic characters of Eolaxoporus gen. nov. Within this genus, it is
unique in having a strongly protmding, slightly angular dorsal spur almost in the centre of the proximal
edge, and a very small, slender ridge on the inner side. The LAP in question certainly belongs to a new
species which, in the absence of more material, cannot be described formally for now.

Eolaxoporus imminens sp. nov.

urn:lsid:zoobank.org:act:698BEA08-2562-4B83-9062-C09DC982E9A3

Fig. 6: 6-8

Diagnosis

Species of Eolaxoporus gen. nov. with moderately small LAPs displaying a relatively high height/width
ratio; very poorly defined spurs on outer proximal edge; up to five, strongly oblique spine articulations;
ridge on inner side of LAP relatively long and slender.

Etymology

Species name formed after imminere, Latin for “reaching” or “hanging over”, in reference of the species
being the only known Jurassic species of the otherwise exclusively Triassic Eolaxoporus gen. nov.

European Journal of Taxonomy 48: 1-242 (2013)

Type material
Holotype

NHMW 2012/0137/0001.

Paratypes

NHMW 2012/0137/0002 and NHMW 2012/0137/0003.

Type locality and horizon

Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbaehian, Early Jurassie.

Additional material

NHMW 2012/0137/0004 (6 dissoeiated LAPs).

Description

Holotype

NHMW 2012/0137/0001 is a dissoeiated, small, proximal LAP; slightly higher than wide; ventro-distal
tip of LAP not protruding; dorsal edge strongly eoneave as a result of a well-developed eonstrietion;
distal edge gently eonvex; proximal edge strongly eoneave, with two small, very poorly defined, slightly
prominent spurs, one in the middle of the proximal edge, protruding, the seeond one near the ventro-
proximal tip of the LAP, not protruding; outer surfaee without eonspieuous ornamentation; finely meshed
stereom, beeoming slightly more finely meshed towards proximal edge and towards spine artieulations.
Five large, ear-shaped spine artieulations on elevated distal part of LAP; dorsalward inerease in size of
spine artieulations and, a little less strongly, in gaps separating them; spine artieulations eomposed of
near-parallel, eoneentrieally arehed dorsal and ventral lobes, tilted and therefore dorso-proximally rather
than proximally widely separated, eonneeted distally by sigmoidal fold. Ventral edge straight to slightly
eonvex, tentaele noteh not visible in external view.

Inner side of LAP with rather narrow, well-defined, finger-shaped, arehed ridge, best defined and slightly
widened at dorsal and ventral tips; dorsal tip of ridge rounded, pointing dorso-proximalwards; ventral
tip sharply separated from thiekened ventral edge of LAP; small, moderately well-defined, slightly
prominent spur on inner side of ventro-distal tip of LAP; no other spur diseemible on inner side of distal
edge. Tentaele noteh very large. No perforations diseemible.

Paratype supplements and variation

NHMW 2012/0137/0002 is a dissoeiated median LAP of reetangular outline; dorsal edge strongly
eoneave; ventro-distal tip of LAP slightly protmding; proximal edge of LAP slightly eoneave with
moderately large, poorly defined, prominent spurs, one in the middle of the proximal edge, bluntly
protmding, the seeond one elose to the ventro-proximal tip of the LAP. Five spine artieulations, similar
to those of holotype. Ventral edge of LAP with large, but weakly eoneave tentaele noteh.

Inner side similar to that of holotype.

NHMW 2012/0137/0003 is a dissoeiated distal LAP of reetangular outline; almost twiee wider than
high; dorsal edge slightly less eoneave than in holotype; ventral spur on proximal edge moderately well
defined, prominent; no spur diseemible in eentre of proximal edge. Four spine artieulations, similar to
those of holotype. Ventral edge of LAP slightly eoneave; tentaele noteh not visible in external view.
Inner side with narrow, bent, well-defined ridge; dorsal and ventral tips best defined and widest; dorsal
tip pointing dorso-proximalwards; inner side of ventro-distal tip with large, prominent, well-defined,
horizontally elongate spur; no other spur diseemible on inner side of distal edge. Tentaele noteh very
large. No perforations visible.

THUYB., Fossil record of ophiacanthid brittle stars

Remarks

These LAPs display the highly distinctive combination of characters typically found in Eolaxoporus
gen. nov., although the oblique spine articulations are unusual. Nevertheless, this LAP type appears best
placed in Eolaxoporus gen. nov. and can be easily differentiated from its congeners on account of the
oblique spine articulations and the very poorly developed spurs on the outer proximal and inner distal
edges.

Occurrence

Late Sinemurian to early Pliensbachian of Austria.

Genus Lapidaster gen. nov.

um:lsid:zoobank.org:act:C21FF4FC-5361-44D5-ACC9-6AD5907BAC9Q

Type species

Lapidaster hystricarboris sp. nov., by present designation.

Other species included

Lapidaster caeloscopus sp. nov., Lapidaster coreytaylori sp. nov., Lapidaster etteri sp. nov., Sinosura
fasciata Kutscher & Villier, 2003, Lapidaster lukenederi sp. nov., Lapidaster mastodon sp. nov.,
Lapidaster mathcore sp. nov., Lapidaster wolfii sp. nov. and Lapidaster varuna sp. nov.

Diagnosis

Ophiacanthid with lateral arm plates displaying large tentacle notches; spine articulations not positioned
on elevated ridge and not sunken into depressions or notches; ventral portion of lateral arm plate
protruding ventro-proximally; generally single, poorly to moderately defined, spur on outer proximal
and inner distal edge of lateral arm plate; inner side with single, well-defined ridge generally separated
by rounded kink into dorsal and ventral halves.

Etymology

Name composed of lapis, Latin for “rock”, and aster, Greek for “star”, in reference to three species of
the genus being named after rockstars; gender masculine.

Remarks

Lateral arm plates with a conspicuous, large tentacle notch combined with a strongly protruding ventro-
proximal portion of the plate and spine articulations which are neither on an elevated vertical ridge nor
sunken in depressions of the distal plate edge are a common and morphologically diverse component of
many Jurassic and Cretaceous ophiuroid assemblages (see below for details of distribution). The large
ventral notches of the LAPs imply that the forms they belong to had large tentacle pores as defined by
Thuy et al. (2012), which places them among the basal, large-pored ophiacanthid lineages formerly
united as the subfamily Ophiotominae (Paterson 1985). Indeed, there are striking morphological
similarities between the LAPs of the fossils considered here and those of extant Ophiologimus H.L.
Clark, 1911 (Fig. 11: 1), in particular with regard to the development of the tentacle notch and the
ventro-proximal portion of the plate, and the position and arrangement of the spine articulations. There
are superficial similarities to the LAPs of extant Ophiotoma Verrill, 1899. In that genus, however, the
spine articulations generally are slightly sunken into depressions of the distal plate edge, and the ridge
on the inner side of the plate displays two kinks instead of one.

As clearly shown by Thuy & Stohr (2011), the greater the similarity between LAP morphologies, the
more closely related the species in question are. In the present case, the above-mentioned fossil LAPs

European Journal of Taxonomy 48: 1-242 (2013)

are so similar to the LAPs of Ophiologimus that they, indeed, belong to Ophiologimus or at least to a
very elosely related genus. The latter possibility is preferred here sinee the fossil LAPs differ, albeit
only slightly, from those of Ophiologimus in generally displaying a spur on the outer proximal and inner
distal plate edges. Thus, Lapidaster gen. nov. is ereeted here to aeeommodate dissoeiated fossil LAPs
whieh are most elosely similar to those of Ophiologimus. The great similarities in LAP morphology,
however, strongly suggest that Ophiologimus and Lapidaster gen. nov. are sister taxa, although definite
proof for the existenee of an Ophiologimus-Lapidaster lineage ean solely be gleaned from artieulated
speeimens of Lapidaster gen. nov.

Lapidaster caeloscopus sp. nov.

um:lsid:zoobank.org:aet:C670AEE6-65DA-49F5-B098-A8ElE372Q63A

Fig. 7: 1-3

Diagnosis

Speeies of Lapidaster with small, elongate EAPs of trapezoid outline, well-developed eonstrietion and
strongly enlarged dorsalmost spine artieulation pointing dorsally.

Etymology

Name eomposed of caelum, Eatin for “sky”, and scopus, Eatin for “targef’, in referenee to the large,
dorsally pointing, or “skygazing”, dorsalmost arm spine artieulation in this speeies.

Type material
Holotype

NHMW 2012/0137/0005.

Paratypes

NHMW 2012/0137/0006 and NHMW 2012/0137/0007.

Type locality and horizon

Glasenbaeh Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbaehian, Early Jurassie.

Additional material

NHMW 2012/0137/0008 (12 dissoeiated EAPs).

Description

Holotype

NHMW 2012/0137/0005 is a dissoeiated, very small, proximal EAP, somewhat wider than high, of
irregularly reetangular to trapezoid outline, with slightly eoneave dorsal edge as a result of a weak
eonstrietion; slightly eoneave distal edge; ventral fifth of EAP protruding ventro-proximal wards; ventro-
distal tip of EAP very large, tongue shaped, strongly protruding ventro-distalwards; proximal edge of
EAP almost straight to slightly eoneave, exeept for sharp kink in ventral quarter; the latter ventrally
bordered by well-defined, elongate, lens-shaped and strongly prominent spur; outer surfaee with finely
to moderately eoarsely meshed stereom, with trabeeulae not merged into vertieal striation. Three ear¬
shaped spine artieulations; eonspieuously wide gap between spine artieulations and distal edge of EAP;
very strong dorsalward inerease in size of spine artieulations; dorsalmost spine artieulation more than
twiee larger than ventralmost one, eonspieuously pointing dorsalwards; dorsal and ventral lobes of
spine artieulations forming eontinuous volute; dorsal gap between spine artieulations slightly larger
than ventral one. Ventral edge of EAP with very large, eoneave tentaele noteh.

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 7. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b)
views. 1-3. Lapidaster caeloscopus gen. et sp. nov. from the late Sinemurian to early Pliensbaehian
(Early Jurassie) of the Glasenbaeh Gorge, Austria. 1. NHMW 2012/0137/0005 (holotype), proximal
LAP. 2. NHMW 2012/0137/0006 (paratype), median LAP. 3. NHMW 2012/0137/0007 (paratype), distal
LAP 4-6. Lapidaster hystricarboris gen. et sp. nov. from the early Pliensbaehian (Early Jurassie) of
Bloekley, Great Britain. 4. GZG.1NV.78501 (holotype), proximal LAP. 5. GZG.INV.78502 (paratype),
median LAP. 6. GZG.INV.78503 (paratype), distal LAP. 7-8. Lapidaster fasciatus (Kutseher & Villier,
2003) eomb. nov. from the middle Toareian (Early Jurassie) of Le Clapier, Franee. 7. GZG.INV.78505,
proximal LAP. 8. GZG.INV.78506, distal LAP. One eommon seale bar per speeies is given.

European Journal of Taxonomy 48: 1-242 (2013)

Inner side of LAP unfortunately partially obseured by sediment; ridge diseemible, well defined,
prominent, nearly straight to slightly bent, narrow, small and eonspieuously short, hardly reaehing
horizontal midline of LAP, ventral tip of ridge well defined, not merged with slightly thiekened ventral
part of LAP; inner side of ventro-distal tip of LAP thiekened into large, prominent, elongate and slightly
protruding spur eomposed of dense stereom. Inner side of large tentaele noteh obseured by sediment;
presenee of possible perforations on inner side indeterminable.

Paratype supplements and variation

NHMW 2012/0137/0006 is a dissoeiated median LAP, approximately twiee wider than high, of trapezoid
outline; ventro-distal tip of LAP very large and strongly protruding; dorsal edge elearly eoneave as a
result of the eonstrieted outer surfaee; distal edge oblique, straight to slightly eonvex; dorsal four-fifths
of proximal edge evenly eonvex; ventral fifth of proximal edge separated from the latter by sharp kink,
ventrally bordered by moderately well-defined, prominent, elongate spur. Three spine artieulations;
dorsal ward inerease in size mueh weaker than in holotype; dorsalmost spine artieulation slightly larger
than remaining two, pointing dorsalwards; eonspieuously wide gap between row of spine artieulations and
distal edge of LAP, as in holotype. Ventral edge of LAP with very large, gently eoneave tentaele noteh.
Inner side of LAP largely obseured by sediment; ridge similarly short as in holotype; inner side of
ventro-distal tip of LAP with large, oval, strongly prominent spur eomposed of dense stereom.

NHMW 2012/0137/0007 is a dissoeiated distal LAP, more than twiee wider than high, with strongly
eoneave dorsal edge indieating a strong eonstrietion; proximal edge undulose, with eentral eonvex part
and ventral quarter sharply separated by kink; the latter bordered by relatively large, yet poorly defined,
elongate, prominent spur. Two spine artieulations, one near the ventral edge of the LAP, the seeond in
the middle of the LAP, slightly larger than the ventral one. Ventral edge of LAP almost straight, exeept
for large, yet only weakly eoneave tentaele noteh.

Inner side with very small, short, knob-like, prominent and well-defined ridge, widest ventrally and not
merged with ventral part of LAP.

Remarks

The very small, dissoeiated LAPs of Lapidaster caeloscopus sp. nov. are unique in displaying a strongly
enlarged dorsalmost spine artieulation whieh points dorsally. The irregular trapezoid outline of the
LAPs, as well as the very short ridge on the inner side, are further eharaeters whieh elearly set the LAPs
of L. caeloscopus sp. nov. apart from any other known type of LAPs. Greatest similarities are shared
with the LAPs of Lapidaster lukenederi sp. nov. (see below) from the Valanginian of Austria, espeeially
on aeeount of the eonstrietion, the rather thin plate arehiteeture, the small size, and the height/width
ratio of the proximal LAPs, whieh is indieative of elongated arm segments, a typieally paedomorphie
eharaeter (Stohr 2005). In eontrast, similarities to the distal LAPs of Reitneracantha dissidens sp. nov.,
whieh oeeur in the same samples, are merely superfieial and limited to the enlarged dorsally pointing
spine artieulations found in both speeies. Almost all other eharaeters, in partieular the development of
the tentaele noteh, the outer surfaee ornamentation and the morphology of the spine artieulations elearly
differ in both speeies.

Assignment to Lapidaster gen. nov. is suggested here on aeeount of the general Ophiologimus-\fks
LAP morphology (very large tentaele noteh, ventro-proximalwards protruding ventral portion of LAP,
strongly protruding ventro-distal tip of LAP, spine artieulations neither sunken in depressions nor
positioned on strongly elevated ridge), eombined with the presenee of a well-developed spur on the
outer proximal and inner distal edges of the LAP.

Occurrence

Late Sinemurian to early Pliensbaehian of Austria.

THUYB., Fossil record of ophiacanthid brittle stars

Lapidaster hystricarboris sp. nov.

um:lsid:zoobank.org:act:FBF92Q66-FE54-4400-867E-FE2E3845307A

Fig. 7: 4-6

Diagnosis

Species of Lapidaster gen. nov. with relatively large EAPs displaying a very finely striated outer surface
and up to six spine articulations increasing in size dorsalwards.

Etymology

Name derived from Hystrix, a genus of porcupine, and arbor, Eatin for “tree”, in honour of Steven
Wilson, Richard Barbieri, Gavin Harrison and Colin Edwin of Porcupine Tree whose music was a fertile
source of inspiration whenever the creative process of the present study threatened to come to a halt.

Type material

Holotype

GZG.INV.78501.

Paratypes

GZG.INV.78502 and GZG.INV.78503.

Type locality and horizon

Blockley, near Cheltenham, Great Britain; shell lenses in clay matrix, Davoei Zone, early Pliensbachian,
Early Jurassic.

Additional material

GZG.INV.78504 (41 dissociated EAPs).

Description

Holotype

GZG.INV.78501 is a dissociated, medium-sized, proximal lateral arm plate, almost twice higher than
wide, with rounded outline, ventral quarter of plate protruding ventro-proximalwards; conspicuous,
tongue-like ventro-distal protrusion; dorsal edge of EAP strongly convex; proximal edge gently concave,
with single poorly defined, slightly protruding spur close to ventro-proximal tip of the EAP, no other
spurs discernible on outer proximal edge; distal edge gently convex; no constriction. Outer surface
with irregular vertical striation consisting of very fine ridges separated by narrow bands of fenestrate
stereom; ridges irregularly converging on ventral half of outer surface; striation rapidly grading into
fine granulation followed by finely meshed stereom towards the proximal edge of the EAP; striation
sharply separated from three ventralmost spine articulations, and confiuent with the proximal edges of
the three dorsal spine articulations, with conspicuous overlap of the striation onto the proximal edge of
the dorsalmost spine articulation. Six large, ear-shaped spine articulations freestanding in continuous
vertical row close to distal edge of EAP; dorsal and ventral lobes forming continuous volute; dorsalward
increase in size of spine articulations and gaps separating them. Ventral edge of EAP with large,
conspicuous, evenly concave tentacle notch.

Inner side of EAP with single thin, well-defined, prominent, oblique ridge, slightly widening towards its
rounded dorsal tip; dorsal half of ridge nearly straight, not reaching dorsal or proximal edges of EAP,
ventral half gently bent, poorly defined and confiuent with thickened ventral quarter of EAP; irregular
set of perforations on inner side of EAP, hardly discernible as vertical row corresponding to spine
articulations; distal edge of EAP thinning distalwards; inner side of ventro-distal protrusion with well-

European Journal of Taxonomy 48: 1-242 (2013)

defined, prominent knob, eorresponding to poorly developed spur on outer proximal edge of the LAP.
Inner side of tentaele noteh with eoarsely retieulate stereom reminiseent of horizontally stretehed glue.

Paratype supplements and variation

GZG.1NV.78502 is a dissoeiated median lateral arm plate, slightly higher than wide; overall morphology
agreeing well with holotype. Dorsal edge nearly straight, ventro-distal tip of LAP hardly protruding;
proximal edge of LAP strongly eoneave, with large, poorly defined and barely prominent and protruding
spur near ventro-proximal tip of plate, and small, sharply defined, prominent and slightly protruding
dorsal spur. Vertieal striation on outer surfaee separated from three ventral spine artieulations, eonfiuent
with proximal edge of two dorsal spine artieulations. A total of five large spine artieulations with elear
dorsalward inerease in size and gaps separating them. Dorsalmost spine artieulation, as in holotype, with
elear onlap of striation onto proximal edge.

Inn er side of LAP in agreement with morphology of holotype; no perforations diseemible. Very poorly
defined, barely prominent spur in the eentre of the inner distal edge of the LAP; spur on inner side of
ventro-distal tip of LAP poorly developed, slightly prominent.

GZG.INV.78503 is a dissoeiated distal lateral arm plate, approximately 1.5 times wider than high. Dorsal
edge oblique and straight to very gently eonvex; ventro-distal tip of LAP slightly protruding; proximal edge
of LAP with very well-defined, prominent and elearly protruding spur in eentre and seeond, poorly defined
and slightly prominent spur elose to ventro-proximal tip of LAP. Vertieal striation on outer surfaee separated
from three ventral spine artieulations, slightly eonfiuent with single dorsalmost spine artieulation. A total of
four, near-equal sized spine artieulations, the dorsalmost separated from the remainder by a slightly larger gap.
Inner side well in agreement with holotype. Two well-defined, prominent spurs on inner distal edge of
LAP, eorresponding to spurs on outer proximal edge. Single irregular perforation on inner side. Tentaele
noteh eonspieuously large, very similar to noteh observed in holotype.

Remarks

The large size of the LAPs of Lapidaster hystricarboris sp. nov. and their high number of spine
artieulations differentiaties them from almost all other LAP types assigned to this new genus. Greatest
similarities are shared with the LAPs of Lapidaster wolfii sp. nov. In the latter, however, the spine
artieulations laek the dorsalward inerease in size, and the vertieal striation of the outer surfaee is very
eoarse, yet faint, in eontrast to the well-developed, fine striation observed in L. hystricarboris sp. nov.
There is a eertain resemblanee with the LAPs deseribed as Ophiacanthal rugosa Kutseher & Jagt, 2000
by Kutseher & Jagt (2000) from the early Maastriehtian of Germany and Denmark, and here re-assigned
to Ophiologimus (see below). The LAPs of L. hystricarboris sp. nov., however, differ in displaying
a spur on the outer proximal and inner distal edges, and in having a eontinuous ridge on the inner
side rather than two separate knob-like struetures. Lapidaster hystricarboris sp. nov. best exemplifies
the great similarities, along with slight yet diagnostie dififerenees, between Lapidaster gen. nov. and
Ophiologimus, and is therefore ehosen as the type speeies of the former.

Occurrence

Early Pliensbaehian of Great Britain.

Lapidasterfasciatus (Kutseher & Villier, 2003) eomb. nov.

Fig. 7: 7-8

Sinosura fasciata Kutseher & Villier, 2003: 185, pi. 3 fig. 9, pi. 4 figs 1-2.

Sinosura schneideri - Kutseher 1996: p. 9, pi. 2 figs 6-8 (material ineorreetly assigned to Sinosura
Schneider iY^utschQX, 1987).

THUYB., Fossil record of ophiacanthid brittle stars

Diagnosis

Species of Lapidaster gen. nov. with small- to medium-sized LAPs displaying an irregular, coarse
vertical striation, a relatively short ridge on the inner side, and up to four spine articulations composed
of confluent dorsal and ventral lobes.

Material examined

GZG.INV.78505, GZG.INV.78506 and GZG.INV.78507-1 (16 dissociated LAPs) from the Middle
Toarcian ofLe Clapier, France; GZG.INV.78507-2 (8 dissociated LAPs) from the Gausses, France; type
material of Kutscher & Villier (2003) from the late Toarcian of Sainte-Verge, France; original material
of Kutscher (1996) from the Toarcian/Aalenian of Quedlinburg, Germany.

Description

Relatively small LAPs, proximal ones slightly higher than wide, median ones slightly wider than high
and distal ones nearly twice wider than high, with gently convex distal edge; dorsal edge slightly convex
(proximal LAPs) to slightly concave (distal LAPs); ventral flfth to quarter of LAP protruding ventro-
proximalwards; ventro-distal tip of LAP pointed, protruding; proximal edge irregularly concave, with
poorly (in proximal LAPs) to well-deflned (in distal LAPs), obliquely elongate, slightly prominent spur
near ventro-proximal tip, composed of slightly denser stereom; outer surface with coarsely meshed
stereom, with trabeculae merging into irregular but well-developed vertical striation. Three (distal
LAPs) to four (proximal LAPs) moderately large, ear-shaped spine articulations, with dorsal and ventral
lobes forming continuous volute; dorsalward increase in size of spine articulations, with dorsalmost
one, however, smaller than second dorsalmost; dorsalward increase in size of gaps separating spine
articulations; two to three ventral spine articulations separated from striated outer surface by irregular,
confluent areoles of slightly more flnely meshed stereom; dorsalmost spine articulation embedded in
striated outer surface. Ventral edge of LAP with large, deeply concave tentacle notch.

Inner side of LAP with sharply deflned, rather narrow ridge, dorsal portion of which oblique and slightly
bent, not widened dorsally and not approaching dorsal or proximal edges of LAP; ventral portion of
ridge separated from dorsal one by slightly rounded kink, very short, rapidly merging into thickened
ventral part of LAP; inner side of ventro-distal tip of LAP with small, moderately well-deflned, slightly
prominent spur. Inner side of large tentacle notch with coarsely reticulate, horizontally stretched stereom.

Remarks

These LAPs seem to be identical with those described and illustrated by Kutscher (1996) from the
Toarcian and Aalenian of Germany and assigned to Sinosura schneideri Kutscher, 1987. Similar LAPs
from the Toarcian of France have subsequently been described by Kutscher & Villier (2003), who
reassigned them to their new species Sinosura fasciata Kutscher & Villier, 2003. The genus Sinosura
Hess, 1964 was introduced by Hess (1964) to accommodate fossil ophiuroid species with fragile LAPs
displaying a vertical striation, a wide gap between the spine articulations and the distal edge of the
LAP and well-developed spine articulations. Superflcially, the LAPs described by Kutscher (1996) and
Kutscher & Villier (2003) fit this diagnosis. However, an examination of the type material of Sinosura
brodiei (Wright, 1866), the type species of the genus, from the Pliensbachian of Great Britain, as well as
of additional, exceptionally well-preserved material from the Pliensbachian of France (Thuy et al. 2011)
has revealed a fundamental difference in spine articulation morphology. While the spine articulations
in S. brodiei are of the ophioleucinid type as described by Martynov (2010), those of Sinosura fasciata
are ear-shaped with a sigmoidal fold, as typically found in the Ophiacanthidae (Martynov 2010). On
the basis of the clearly ophiacanthid spine articulation structure in combination with the generally
Ophiologimus-\ikQ morphology and the presence of a spur on the outer proximal and inner distal edges,
Sinosura fasciata is here transferred to Lapidaster gen. nov.

European Journal of Taxonomy 48: 1-242 (2013)

Lapidasterfasciatus comb. nov. differs fromL. hystricarboris sp. nov. andL. wolfii sp. nov. in displaying
a much lower number of spine articulations. Lapidaster lukenederi sp. nov. and L. etteri sp. nov. both
have constricted LAPs in contrast to L. fasciatus comb, nov., and in Z. coreytaylori sp. nov. the trabeculae
of the outer surface stereom are very thick and not merged into vertical stripes. Greatest similarities are
shared with L. mastodon sp. nov. and L. varuna sp. nov. In the former, however, the LAPs have a much
less strongly protruding ventro-distal tip, generally no more than three spine articulations, separated
ventral and dorsal lobes of the spine articulations, and a more rounded overall aspect. In L. varuna sp.
nov., the ridge on the inner side of the LAP is longer, and the vertical striation on the outer surface is
much less developed.

Occurrence

Middle and Late Toarcian of France; Toarcian/Aalenian of Germany.

Lapidaster sp. nov. innom. 1
Fig. 8: 1

p.p. Ophiacanthal toarcensis - Hess 1962: 649 (Schicht C) (original specimen incorrectly assigned to
Ophiacanthal toarcensis Hess, 1962).

Material examined

NHMB Ml 1208 (dissociated LAP) from the late Toarcian of Seewen, Switzerland, the original material
of Hess (1962).

Description

Single dissociated, median to proximal LAP, slightly wider than high, dorsal edge nearly straight,
distal edge strongly convex; ventral fifth protruding ventro-proximalwards; ventro-distal tip of LAP
large, rounded, protruding; proximal edge concave, with large, strongly protruding, sharply defined,
horizontally elongate, lens-shaped, prominent spur in the middle, and with second horizontally elongated,
lens-shaped but slightly smaller, less well-defined, less prominent and protruding spur close to ventro-
proximal tip of LAP; outer surface with very slight constriction, and with coarsely meshed stereom;
trabeculae of outer surface stereom showing weak tendency to merge into short, irregular vertical stripes
close to row of spine articulations. Four small spine articulations, ventralmost slightly smaller than other
three; dorsal and ventral lobes separated by small, round knob; strong dorsal increase in size of gaps
separating spine articulations; two ventral spine articulations separated from coarsely meshed outer
surface stereom by faint, irregular, confiuent areoles; two dorsal spine articulations embedded in outer
surface stereom. Ventral edge of LAP with large, moderately deep tentacle notch.

Inner side of LAP with sharply defined, dorsal portion of which straight to slightly bent, not widened
dorsally and not approaching ventral or dorsal edges of LAP; ventral portion of LAP separated from
dorsal one by rounded kink, very short and sharply defined, not merging with ventral part of LAP; inner
distal edge with two large, well-defined, horizontally elongate, prominent spurs composed of dense
stereom, ventral one of which slightly protruding. Inner side of tentacle notch moderately large and with
coarsely meshed, slightly horizontally stretched stereom. No perforations discernible on inner side.

Remarks

Among the original material of Ophiacanthal toarcensis Hess, 1962 from the Toarcian of Switzerland,
here reassigned to Dermocoma Hess, 1964 (see below), is a single LAP which obviously does not belong
to that species. A detailed re-examination of that plate has revealed that it is a species of Lapidaster gen.
nov., on account of its Ophiologimus-\ikQ morphology and the presence of spurs on the outer proximal
and inner distal edges. The unusually small spine articulations composed of separated dorsal and ventral

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 8. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b) views.
1. Lapidaster sp. nov. innom. 1 from the late Toareian (Early Jurassie) of Seewen, Switzerland; NHMB
Ml 1208, proximal to median LAP. 2-4. Lapidaster wolfii gen. et sp. nov. from the Bajoeian-Bathonian
boundary (Middle Jurassie) of Touert, Franee. 2. GZG.INV.78508 (holotype), proximal LAP. 3. GZG.
INV.78509 (paratype), median LAP. 4. GZG.INV.78510 (paratype), distal LAP. 5-7. Lapidaster varuna
gen. et sp. nov. from the Callovian of Jumara, India. 5. GZG.INV.78511 (holotype), proximal LAP.
6. GZG.INV.78512 (paratype), median LAP. 7. GZG.INV.78513 (paratype), distal LAP. One eommon
seale bar per speeies is given.

European Journal of Taxonomy 48: 1-242 (2013)

lobes, as well as the presenee of a seeond, strongly developed spur in the eentre of the outer proximal
and inner distal edges sets the LAP in question quite apart from other LAP types assigned to Lapidaster
gen. nov. It unquestionably represents a distinet, undeseribed speeies. Unfortunately, only a single LAP
is eurrently known, whieh preeludes the formal deseription of a new speeies.

Lapidaster wolfii sp. nov.

um:lsid:zoobank.org:aet:ECF21B65-FADl-488C-8343-QC5C3E192B74

Fig. 8: 2-4

Diagnosis

Speeies of Lapidaster gen. nov. with moderately large EAPs showing eoarsely meshed stereom with
trabeeular merging into a very weak vertieal striation; up to six large, equal-sized spine artieulations.

Etymology

Speeies named in honour of my friend and former band-mate Wolfgang (“Wolfi”) Prebeek, for eheering
up moments of frustration, in partieular during the eourse of the present study.

Type material

Holotype

GZG.1NV.78508.

Paratypes

GZG.1NV.78509 and GZG.1NV.78510.

Type locality and horizon

Touert near Chaudon, Franee; marl bed at the Bajoeian-Bathonian boundary. Middle Jurassie.

Description

Holotype

GZG.1NV.78508 is a dissociated, small, proximal lateral arm plate, slightly higher than wide, of
irregularly angular aspect; ventral quarter of EAP protruding ventro-proximalwards; ventro-distal tip
of EAP slightly protruding; dorsal and distal edges of EAP nearly straight; proximal edge slightly
undulose, with very faint, almost indiscernible spur close to ventro-proximal tip. Outer surface with
coarsely reticulate stereom with trabeculae tending to merge into a very faint, irregular vertical ridges,
rapidly grading into finely meshed stereom close to distal edge of EAP; reticulate stereom separated
from three ventral spine articulations, and slightly confluent with proximal edge of three dorsalmost
spine articulations. Six, large, ear-shaped spine articulations with dorsal and ventral lobes forming a
continuous volute, freestanding in continuous vertical row close to distal edge of EAP, equal in size but
with slight dorsalward increase in size of gaps separating them. Ventral edge of EAP with large, concave
tentacle notch.

Inner side of EAP with single relatively thin, sharply deflned, prominent, oblique ridge, of nearly
constant width and with rounded dorsal tip: dorsal half of ridge slightly bent dorsalwards; ventral half
separated from dorsal one by rounded kink and confluent with thickened ventro-proximal edge of EAP.
No perforations discernible. Inner distal edge thinning distalwards; ventro-distal tip thickened into an
irregular, oblique, poorly deflned, prominent spur. Inner side of tentacle notch with coarsely reticulate
stereom, slightly stretched horizontally.

THUYB., Fossil record of ophiacanthid brittle stars

Paratype supplements and variation

GZG.INV.78509 is a dissociated median lateral arm plate, slightly higher than wide. Overall morphology
well in agreement with that of holotype. Proximal edge of LAP strongly undulose, with large, relatively
well-defined, slightly prominent spur on ventro-proximal tip, composed of denser stereom. Striation on
outer surface slightly better developed than in holotype. A total of five spine articulations of equal size,
poorly preserved, with slight increase in size of the gaps separating them.

Morphology of inner side of LAP as in holotype. Ventro-distal spur more clearly defined and slightly
more prominent than in holotype.

GZG.INV.78510 is a dissociated distal lateral arm plate, wider than long, of rounded triangular aspect,
with slightly convex dorsal and distal edges, and slightly undulose proximal edge; ventral quarter
slightly protruding ventro-proximal wards; outer surface with coarsely reticulate stereom, with trabeculae
showing hardly any tendency to develop into vertical striation; ventro-proximal tip of LAP poorly
preserved. Three spine articulations of equal size, gap between dorsal and median spine articulation
slightly larger than gap between median and ventral ones.

Morphology of inner side well in agreement with holotype and other paratype. Oblique ventro-distal
spur large, sharply defined and strongly prominent, suggesting equally well-developed counterpart on
outer ventro-proximal edge not observable due to insufficient preservation of the LAP. Tentacle notch
large and conspicuous.

Remarks

The present species most closely resembles Lapidaster hystricarboris sp. nov. from which it differs,
however, in displaying a much coarser and less well-developed vertical striation on the outer surface of
the LAPs, as well as a slightly smaller dorsalward increase in the size of the gaps separating the spine
articulations. It is thus described here as a new species. Assignment to Lapidaster gen. nov. is based on
the strikingly Ophiologimus-like LAP morphology and the presence of a spur, albeit weakly developed,
on the outer proximal and inner distal edges of the LAPs.

Occurrence

Bajocian-Bathonian boundary beds of France.

Lapidaster varuna sp. nov.

urn:lsid:zoobank.org:act:6E723392-8565-4F6C-84C5-B6FEBElA69CB

Fig. 8: 5-7

Diagnosis

Species of Lapidaster gen. nov. with relatively large LAPs displaying a weakly to moderately well-
developed vertical striation, a long ridge on the inner side reaching the dorsal edge of the LAP, and up
to four spine articulations composed of confiuent dorsal and ventral lobes.

Etymology

Species named after Varuna, the god of the oceans in Hindu mythology, in reference to the cultural
background prevailing in the area of the type locality in Kachchh, India.

Type material

Holotype

GZG.INV.7851L

European Journal of Taxonomy 48: 1-242 (2013)

Paratypes

GZG.1NV.78512 and GZG.1NV.78513.

Type locality and horizon

Jumara, Kachchh, India; sample 117, upper Chari Formation, Callovian, Middle Jurassie.

Additional material

GZG.1NV.78514 (78 dissoeiated LAPs) from sample 117; GZG.1NV.78515 (14 dissoeiated LAPs) from
sample 119; GZG.1NV.78516 (12 dissoeiated LAPs) from sample 121.

Description

Holotype

GZG.1NV.78511 is a dissoeiated, medium-sized, median to proximal LAP, slightly wider than
high; dorsal and distal edges straight to slightly eonvex; ventral quarter of LAP protruding ventro-
proximalwards; ventro-distal tip of LAP strongly protruding, tongue shaped; proximal edge evenly
eoneave, with small, rather poorly defined and slightly prominent spur near ventro-proximal tip of LAP;
outer surfaee eonsisting of eoarsely meshed stereom with trabeeulae merging into irregular vertieal
striation, espeeially near spine artieulations; eoarsely meshed stereom rapidly grading into mueh more
finely meshed stereom near proximal edge of LAP Three equal-sized spine artieulations near distal edge
of LAP, ventral and dorsal lobes forming eontinuous volute; two ventral spine artieulations surrounded
by irregular areole of finely meshed stereom; dorsalmost spine artieulation embedded in striated to
eoarsely meshed stereom, separated from two ventral spine artieulations by slightly larger gap. Ventral
edge of LAP with large, very deep and eoneave tentaele noteh.

Inner side of LAP with sharply defined, prominent and relatively narrow ridge, dorsal portion of whieh
oblique, nearly straight, with slightly widened, round tip, almost reaehing dorso-proximal eomer of LAP;
ventral portion of ridge separated from dorsal one by slightly round kink, mueh less sharply defined and
rapidly merging into thiekened ventral part of LAP. Inner distal edge of LAP thinning out distalwards,
with small, sharply defined, lens-shaped spur eomposed of eompaet stereom on inner ventro-distal tip
of LAP. Inner side of tentaele noteh with eoarsely meshed and slightly horizontally stretehed stereom,
dorsally bordered by large, irregular perforation.

Paratype supplements and variation

GZG.INV.78512 is a dissoeiated proximal LAP, nearly as wide as high; dorsal and distal edges gently
eonvex; ventral quarter of LAP and ventro-distal tip largely missing; spur on outer proximal edge slightly
protruding, otherwise well in agreement with eorresponding spur observed on holotype; outer surfaee
with eoarsely meshed stereom merged into faint vertieal striation. Four spine artieulations, ventralmost
smaller than remaining three; dorsalward inerease in size of gaps separating spine artieulations; three
ventral spine artieulations surrounded by irregular areole.

Inner side of LAP well in agreement with that of holotype; dorsal portion of ridge slightly shorter, not
approximating dorso-proximal eomer of LAP.

GZG.INV.785I3 is a dissoeiated distal LAP, approximately twiee wider than high; dorsal edge slightly
eoneave; distal edge straight; ventral fifth of LAP protmding ventro-proximalwards; ventro-distal tip
of LAP strongly protmding, tongue shaped; proximal edge nearly straight, with sharp kink in ventral
quarter, marked by well-defined, elongate, slightly prominent and protmding spur eomposed of very
dense stereom; outer surfaee with eoarsely meshed stereom with trabeeulae showing only very faint
tendeney to merge into vertieal striation. Three spine artieulations, middle one slightly larger than
ventral and dorsal ones. Tentaele noteh large and moderately deep.

THUYB., Fossil record of ophiacanthid brittle stars

Inner side well in agreement with than of holotype; dorsal portion of ridge not reaching dorso-proximal
comer of LAP, not widened at dorsal tip.

Remarks

These LAPs display a striking similarity to those of extant Ophiologimus hexactis H.L. Clark, 1911,
but differ in having a spur on the outer proximal and inner distal edges. Although this spur is rather
poorly developed, the present LAPs are assigned to Lapidaster gen. nov. Within this genus, closest
similarities are shared with Lapidaster fasciatus comb, nov., in which, however, the LAPs have a much
better-developed vertical striation and a slightly shorter ridge on the inner side. These differences, even
if seemingly small, are considered sufficient for distinction at the species level, in accordance with
the observations of Thuy & Stohr (2011) on the spectmm of possible differences in LAP morphology
between congeneric species. The present LAPs are therefore described as a new species.

Occurrence

Callovian of India.

Lapidaster etteri sp. nov.

um:lsid:zoobank.org:act:DFBC69CF-37Fl-4D39-A8F3-D8DA467Q8DQ5

Fig. 9: 1-5

p.p. Ophiopholisl trispinosa Hess, 1965a: 1067, 1075, figs 16, 38-40 (non figs 36-37, referable to
Ishidacantha trispinosa (Hess, 1965) comb, nov.)

Diagnosis

Species of Lapidaster gen. nov. with relatively large LAPs showing a weak constriction, a widened
dorsal tip of the ridge on the inner side and a thickened ventral part.

Etymology

Species named in honour of Walter Etter (Naturhistorisches Museum Basel, Switzerland), who
generously provided access to the original material of Hans Hess’s pioneering studies on ophiuroid
micropalaeontology, inclusive of the type material of the new species.

Type material

Holotype

NHMBM11209.

Paratypes

NHMB M11210, NHMB M11211, NHMB M11212 andNHMB M11213.

Type locality and horizon

Longecombe, France; Renggeri Member, Barschwil Formation, early Oxfordian, Late Jurassic.

Additional material

304 dissociated LAPs from Longecombe, France, the original material of Hess (1965a); 7 dissociated
LAPs from Chapois, France, the original material of Hess (1965a).

European Journal of Taxonomy 48: 1-242 (2013)

Fig. 9. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b)
views and artieulated arm fragments. 1-5. Lapidaster etteri gen. et sp. nov. from the early Oxfordian
(Late Jurassie) ofLongeeombe, Franee. 1. NHMB Ml 1209 (holotype), proximal LAP. 2. NHMB 11210
(paratype), median LAP 3. NHMB Ml 1211 (paratype), distal LAP. 4. NHMB Ml 1212 (paratype), distal
arm fragment in lateral view. 5. NHMB Ml 1213 (paratype), distal arm fragment in dorsal (a) and ventral
(b) views. 6-8. Lapidaster mastodon gen. et sp. nov. from the late Oxfordian (Late Jurassie) of the
Plettenberg, Germany. 6. GZG.INV.78517 (holotype), proximal LAP 7. GZG.INV.78518 (paratype),
median LAP. 8. GZG.INV.78519 (paratype), distal LAP. One eommon seale bar per speeies is given,
exeept for 4 and 5.

THUYB., Fossil record of ophiacanthid brittle stars

Description

Holotype

NHMB Ml 1209 is a dissociated, medium-sized proximal lateral arm plate, slightly wider than long,
with strongly concave proximal edge and strongly convex distal edge; ventro-proximal quarter of
LAP protruding ventro-proximalwards; slight constriction, resulting in slightly concave dorsal edge;
horizontal, elongate, moderately well-defined and prominent spur close to ventro-proximal tip of LAP.
Outer surface with coarsely reticulate stereom with thickened trabeculae; trabeculae without tendency
to develop into vertical striation; coarsely reticulate stereom evenly surrounding all spine articulations,
grading into finely meshed stereom close to proximal edge. Four large, ear-shaped spine articulations,
freestanding in continuous row close to distal edge of LAP, dorsal and ventral lobes forming continuous
volute in all spine articulations; proximal edge of dorsalmost spine articulation overlapped by finely
reticulate stereom; ventralmost and dorsalmost spine articulations smaller than two median ones;
dorsalward increase in size of gaps separating spine articulations. Ventral edge of LAP with large,
conspicuous and gently concave tentacle notch.

Inner side of LAP with sharply defined, narrow, prominent ridge; dorsal half of ridge oblique and nearly
straight, with rounded tip nearly twice wider than remaining dorsal half of ridge and not reaching dorsal
or proximal edges of LAP; ventral half of ridge slightly wider than dorsal half, separated from the latter
by rounded kink, less sharply defined and prominent than dorsal half but not confiuent with thickened
ventral edge of LAP. Single irregular perforation discernible on inner side of LAP near tentacle notch.
Small, moderately well-defined, prominent and slightly oblique ridge on inner side of ventro-distal tip
of LAP. Inner side of tentacle notch with coarsely reticulate and horizontally stretched stereom.

Paratype supplements and variation

NHMB Ml 1210 is a dissociated median lateral arm plate, wider than high. Overall morphology well
in agreement with that of holotype. Constriction stronger than in holotype, resulting in clearly concave
dorsal edge of LAP. Spur near ventro-proximal edge of LAP poorly defined, hardly discernible. Three
spine articulations in continuous row; median spine articulation slightly larger than others. Ventral edge
of LAP with large, conspicuous tentacle notch.

Inner side with well-defined, narrow, prominent ridge; dorsal half of ridge strongly oblique, straight,
with slightly widened dorsal tip; ventral half of ridge wider than dorsal one but less well-defined, not
confiuent with thickened ventral edge of LAP. Small, very poorly defined and barely prominent spur on
inner side of ventro-distal edge.

NHMB M11211isa dissociated distal LAP, almost three times wider than high, of rectangular to bar¬
like outline; distal edge gently convex, proximal edge concave; slight constriction, resulting in very
gently concave dorsal edge and clearly concave ventral edge of LAP; no spurs discernible on outer
proximal edge. Two spine articulations, nearly equal in size. Large tentacle perforation near ventral
spine articulation.

Inner side with two very small, irregular, diffuse, slightly prominent and widely separate knobs. Large
tentacle perforation in centre of distal half of LAP.

NHMB M11212 is a median arm fragment composed of two articulated segments. LAPs well in
agreement with type specimens; ventral arm plates T shaped, with narrow proximal half, concave lateral
edges, distal half almost three times wider than proximal half, distal edge straight to slightly concave.
Tentacle openings clearly larger than half the width of the ventral arm plates. Dorsal arm plates very
thin, wedge shaped, with strongly acute proximal angle, outline of distal edge not clearly discernible.
Single arm spine preserved, attached to ventral spine articulation, conical, with coarse outer surface,
broken tip but probably not much longer than half the width of a LAP.

European Journal of Taxonomy 48: 1-242 (2013)

NHMB Ml 1213 are two distal arm fragments eomposed of five intaet arm segments. One LAP preserving
two arm spines in plaee, ventral one broken, dorsal one intaet, shorter than half the width of a LAP,
eonspieuously elaw shaped with point faeing ventralwards.

Remarks

When Hess (1965a) deseribed a new speeies, Ophiopholisl trispinosa, on the basis of dissoeiated LAPs
and artieulated arm fragments from the Oxfordian of Franee, he lumped two entirely different LAP
types under a single speeies. A re-examination of the original material has now revealed that one type,
figured in the original deseription (Hess 1965a: figs 16, 38-40) along with the seeond type, bears a
striking similarity to the LAPs of extant Ophiologimus. The presenee of a spur on the outer proximal and
inner distal edges plaees this type of LAPs in Lapidaster gen. nov. In view of the faet that the holotype
of O. ? trispinosa is a LAP of the seeond type (see below for a detailed reassessment), however, the
speeies name eannot be used for the LAPs assigned to Lapidaster gen. nov. The latter are therefore here
deseribed as a new speeies. Greatest similarities are shared with the LAPs of Lapidaster lukenederi sp.
nov., espeeially on aeeount of the slight eonstrietion. The LAPs of Lapidaster etteri sp. nov., however,
differ in being more markedly thiekened near their ventral edge and in having a better-developed spur
on the outer proximal and inner distal edges and a dorsally widened tip of the ridge on the inner side.

Lapidaster etteri sp. nov. is the sole speeies of the genus of whieh arm spines and ventral and dorsal
arm plates are available. Hook-shaped spines on distal arm segments, as observed in the artieulated arm
fragments of L. etteri sp. nov. deseribed above are eommonly found in extant speeies of Ophiologimus
(e.g. O’Hara & Stohr 2006; Martynov 2010). In addition, tentaele pores of the distalmost arm segments
developed as within-plate perforations rather than between-plate openings, as observed in L. etteri sp.
nov., are regularly seen in extant speeies of Ophiologimus. The hook-shaped arm spines and within-plate
tentaele openings in distalmost arm segments provide additional evidenee for the elose ties between
both genera.

Occurrence

Early Oxfordian of Franee.

Lapidaster mastodon sp. nov.

um:lsid:zoobank.org:aet:6040E02F-5B0D-4F78-8772-BC23B55BEBD9

Fig. 9: 6-8

Diagnosis

Speeies of Lapidaster gen. nov. with moderately large EAPs displaying a round, siekle-shaped outline;
up to three spine artieulations in proximal EAPs.

Etymology

Speeies named in honour of Brent Hinds, Brann Bailor, Bill Kelliher and Troy Sanders of the roekgroup
Mastodon, whose musie was indispensable during lengthy nightly sessions at the seanning eleetron
mieroseope.

Type material

Holotype

GZG.1NV.78517.

Paratypes

GZG.1NV.78518 and GZG.1NV.78519.

THUYB., Fossil record of ophiacanthid brittle stars

Type locality and horizon

Plettenberg near Balingen, southern Germany; clay pockets between sponge associations in the lowest
bed exposed at the quarry, Bimammatum Zone, Late Oxfordian, Late Jurassic.

Additional material

GZG.INV.78520 (194 dissociated LAPs) from the Late Oxfordian of Plettenberg near Balingen; GZG.
INV.78521 (2 dissociated LAPs) from the Early Kimmeridgian of Geisingen, southern Germany.

Description

Holotype

GZG.INV.78517 is an isolated, small proximal LAP, of equal height and width, with siclde-shaped
outline; ventral third of LAP protruding; ventro-distal tip of LAP only slightly so; proximal edge strongly
concave, distal and dorsal edges convex; dorso-proximal and ventro-proximal tips of LAP pointed; no
constriction; poorly defined but slightly prominent and protruding spur in ventral third of proximal edge,
composed of slightly denser stereom than remaining edge. Outer surface with finely reticulate stereom;
trabeculae showing tendency to merge into irregular vertical stripes, especially in ventral half of outer
surface; reticulate stereom grading into finely meshed stereom towards proximal edge; dorsalmost
spine articulation directly surrounded by reticulate stereom; two ventral spine articulations surrounded
by slightly sunken areole of more finely meshed stereom, encompassed by reticulate stereom of outer
surface. Three large, ear-shaped spine articulations freestanding in continuous row near distal edge,
of equal size, dorsal gap larger than ventral one; dorsal and ventral lobes separated in all three spine
articulations by irregularly crenulate central proximal knob. Ventral edge of LAP with large, gently
concave tentacle notch.

Inner side of LAP with moderately large, well-defined and prominent ridge; dorsal half of ridge oblique
and nearly straight, not reaching dorsal or proximal edges of LAP, with slightly widened dorsal tip;
ventral half of ridge confluent with thickened ventral edge of LAP, less prominent than dorsal one,
separated from the latter by a rounded kink; no perforations discernible on inner side; inner side of
ventro-distal tip of LAP with large, well-deflned, round, prominent spur. Inner side of tentacle notch
with horizontally stretched stereom.

Paratype supplements and variation

GZG.INV.78518 is a dissociated median LAP, slightly wider than high, differing from holotype in
having a slightly better-deflned spur on the ventral third of the outer proximal edge, and in addition a
very poorly deflned, almost indiscernible spur in the middle of the outer proximal edge. Inner side well
in agreement with holotype morphology.

GZG.INV.78519 is a dissociated distal LAP, approximately twice wider than high; dorsal edge straight
to very slightly concave; only very small ventral portion of LAP protruding ventro-proximal wards.
Proximal edge with well-deflned, prominent and slightly protruding spur near ventro-proximal tip of
LAP; second, smaller, less well-deflned but clearly protruding spur in the middle of the proximal edge.
Three spine articulations; dorsal gap between spine articulations only slightly larger than ventral one.
Tentacle notch large but shallow.

Inner side with sharply deflned, prominent, oblique and nearly straight ridge, widest ventrally, with
short ventro-proximalwards pointing protrusion. Inner side of ventro-distal tip of LAP with large, well-
deflned and prominent spur. Tentacle notch wide, with slightly horizontally stretched stereom, dorsally
bordered by single irregular perforation.

European Journal of Taxonomy 48: 1-242 (2013)

Remarks

The round, sickle-shaped outline, the unusually weakly protruding ventro-distal tip of the LAPs, and the
low number of spine articulations (three in proximal segments) are a combination of characters which is
unique among the LAP types assignable to Lapidaster gen. nov. It is therefore here described as a new
species within this genus. At least in terms of LAP morphology, however, Lapidaster mastodon sp. nov.,
L. fasciatus comb. nov. and L. varuna sp. nov. appear to be very closely related.

From a palaeoecological perspective, both known occurrences of Lapidaster mastodon sp. nov. are from
clayey crevasse infills within sponge reefs and from clay levels interbedded with sponge reefs. It thus
seems to be the sole species known of the genus which is exclusively found associated with sponge
build-ups rather than on muddy bottoms.

Occurrence

Late Oxfordian to early Kimmeridgian of Germany.

Lapidaster sp. nov. innom. 2
Fig. 10: 4

Material examined

GZG.INV.78522 (dissociated LAP) from the Lacunosa Marls, early Kimmeridgian, Late Jurassic, of
Geisingen, southern Germany.

Description

GZG.INV.78522 is a dissociated, small, proximal to median LAP; approximately 1.5 times wider than
high; dorsal edge strongly concave as a result of a well-developed constriction; distal edge convex;
proximal edge concave, with two well-defined, prominent spurs; ventral spur slender, strongly
horizontally elongate, proximally pointed, non protruding; dorsal spur round, smaller, more strongly
prominent, protruding; coarsely meshed stereom with thickened trabeculae on distal two-thirds of outer
surface, replaced by finely meshed stereom on proximal third of outer surface. Three moderately large,
equidistant, very poorly preserved spine articulations. Ventral edge of LAP with very large, but rather
shallowly concave, tentacle notch.

Inner side of LAP with large, sharply defined, conspicuous, prominent ridge composed of straight, oblique
dorsal half with non-thickened dorsal tip, and ventro-proximally bent, slightly broader ventral part; both
parts of ridge connected by angular kink; one moderately large, well-defined, weakly prominent spur
composed of densely meshed stereom on inner side of distal edge of LAP; second less well-defined, but
larger and more prominent spur on inner side of ventro-distal tip of LAP; inn er side of tentacle notch
with coarsely meshed, horizontally elongate stereom. Single, moderately large perforation dorsally
bordering tentacle notch.

Remarks

This LAP is strikingly similar to those of Lapidaster coreytaylori sp. nov. and L. mathcore sp. nov. with
respect to general morphology, the outer surface stereom and the shape of the ridge on the inner side. It
clearly belongs to the same group within Lapidaster gen. nov. as the two last-named species. The well-
developed second spur on the outer proximal and inner distal edges sets the present LAP apart from
those of Lapidaster coreytaylori sp. nov. and L. mathcore sp. nov. The LAP in question most probably
represents a new species, the formal description and naming of which, however, cannot be based on a
single, imperfectly preserved specimen.

THUYB., Fossil record of ophiacanthid brittle stars

-• '4“»virai5SfeS

MMmk

Fig. 10. Fossil lateral arm plates (LAPs) of ophiacanthid brittle stars in external (a) and internal (b) views.
1-3. Lapidaster lukenederi gen. et sp. nov. from the late Valanginian (Early Cretaceous) of the Temberg
Nappe, Austria. 1. NHMW 2012/0138/0001 (holotype), proximal LAP. 2. NHMW 2012/0138/0002
(paratype), median LAP. 3. NHMW 2012/0138/0003 (paratype), distal LAP. 4. Lapidaster sp. nov.
innom. 2 from the early Kimmeridgian (Late Jurassic) of Geisingen, Germany; GZG.INV.78522,
proximal to median LAP. 5-7. Lapidaster coreytaylori gen. et sp. nov. from the middle Aptian (Early
Cretaceous) of Camiol, France. 5. GZG.INV.78523 (holotype), proximal LAP. 6. GZG.INV.78524
(paratype), median LAP. 7. GZG.1NV.78525 (paratype), distal LAP. 8-10. Lapidaster mathcore gen. et
sp. nov. from the middle Albian (Early Cretaceous) of Folkestone, Great Britain. 8. GZG.INV.78528
(holotype), proximal LAP. 9. GZG.INV.78529 (paratype), median LAP. 10. GZG.INV.78530 (paratype),
distal LAP. One common scale bar per species is given.

European Journal of Taxonomy 48: 1-242 (2013)

Lapidaster lukenederi sp. nov.

um:lsid:zoobank.org:act:7E64C5B3-CAFF-4342-AD67-DDB05F3Q50EB

Fig. 10: 1-3

Diagnosis

Species of Lapidaster gen. nov. with small FAPs displaying a low height/width ratio and a well-
developed constriction; ventral portion of FAP not thickened; spur on the outer proximal and inner distal
edges very poorly defined; dorsal part of ridge on inner side not widened.

Etymology

Named in honour of Alexander Fukeneder (Naturhistorisches Museum Wien, Vienna), who collected
and generously provided the residues yielding the type material of the new species.

Type material
Holotype

NHMW 2012/0138/0001.

Paratypes

NHMW 2012/0138/0002 and NHMW 2012/0138/0003.

Type locality and horizon

KBl-A section of Fukeneder (2004) in the Temberg Nappe, Austria; Verrucosum Zone, late Valanginian,
Early Cretaceous.

Additional material

NHMW 2012/0138/0004 (88 dissociated FAPs).

Description

Holotype

NHMW 2012/0138/0001 is a dissociated, small, proximal to median FAP, approximately 1.5 times wider
than high, with gently convex distal edge; dorsal edge clearly concave, indicating a slight constriction
of the outer surface; ventral fifth of FAP protruding ventro-proximalwards; ventro-distal tip of FAP
not conspicuously large, slightly protruding ventro-distalwards; proximal edge of FAP angular, with
small very faint, hardly discernible, spur-like structure near ventro-proximal tip of FAP; outer surface
with coarsely meshed stereom; trabeculae of outer surface stereom showing no tendency to merge into
vertical striation. Four relatively small spine articulations, ventralmost slightly smaller than remaining
three; very small dorsalward increase in size of gaps separating spine articulations; dorsal and ventral
lobes composing volute connected by very short, markedly narrow ridge proximally; dorsalmost spine
articulation pointing dorsalwards; all spine articulations embedded in outer surface stereom. Ventral
edge of FAP with moderately large, gently concave tentacle notch.

Inner side of FAP with relatively narrow, well-defined ridge, dorsal portion of which nearly straight,
widest in middle part, with narrow tip not reaching dorsal and distal edges of FAP; ventral portion of
ridge separated from dorsal one by kink, shorter, wider, less well defined but not confiuent with ventral
part of FAP; ventral part of FAP not thickened; ventro-distal tip of FAP with barely discernible spur
composed of slightly denser stereom; inner side of tentacle notch with coarsely meshed stereom, hardly
stretched horizontally. No perforations visible on inner side.

THUYB., Fossil record of ophiacanthid brittle stars

Paratype supplements and variation

NHMW 2012/0138/0002 is a dissociated median LAP, approximately twice wider than high; ventro-
distal tip of LAP slightly larger than in holotype; dorsal edge strongly concave, indicating well-developed
constriction; proximal edge gently concave with small, very poorly defined, barely visible spur close to
ventro-proximal tip of LAP; outer surface with coarsely meshed stereom with very weak tendency of
trabeculae to merge into irregular vertical striation. Three equal-sized spine articulations, separated by
equal-sized gaps.

Inner side of LAP generally well in agreement with that of holotype; dorsal portion of ridge straight,
slightly widened dorsally; ventral portion of ridge wider, very short, poorly defined but not confiuent
with ventral part of LAP; no spur discernible on inner side of ventro-distal tip of LAP

NHMW 2012/0138/0003 is a dissociated distal plate, more than twice wider than high; both dorsal and
ventral edges concave as a result of the constriction; no spur discernible on proximal edge of LAP. Three
equal-sized spine articulations near distal edge of LAP, separated by equal-sized gaps. Ventral edge of
LAP with large, gently concave tentacle notch.

Inner side with moderately well-defined ridge, oblique and slightly bent, relatively wide, short; no
kink separating ridge into dorsal and ventral portions; ventral tip of ridge widest, best defined; no spur
discernible on inner side of ventro-distal tip of LAP.

Remarks

These LAPs share greatest similarities with those of Lapidaster etteri sp. nov., especially with regard to
the constriction and the height/width ratio of the proximal LAPs. In the latter, however, the the ventral
part is more strongly thickened, the dorsal tip of the ridge on the inner side is widened, and the spur on
the outer proximal and inner distal edges is slightly better defined.

Occurrence

Late Valanginian of Austria.

Lapidaster coreytaylori sp. nov.

um:lsid:zoobank.org:act:EC3622FF-FE17-43EF-8626-827QBAlF7C38

Fig. 10: 5-7

Diagnosis

Species of Lapidaster gen. nov. with moderately large EAPs with coarsely meshed stereom in a broad
band of the outer surface displaying conspicuously thick trabeculae; ventral portion moderately narrow
and strongly protruding ventro-proximal wards; spur on outer proximal edge slender, horizontally
elongate and proximally pointed, paralleled by a well-defined spur on the inner distal edge; dorsal part
of the ridge on the inner side straight.

Etymology

Species named in honour of Corey Taylor, lead vocalist of the rockgroup Slipknot and Stone Sour, for
lending a powerful voice during moments of despair in the course of the present study.

Type material

Holotype

GZG.INV.78523.

Paratypes

GZG.INV.78524, GZG.INV.78525 and GZG.INV.78526.

European Journal of Taxonomy 48: 1-242 (2013)

Type locality and horizon

Camiol, France; Furcatus Zone, middle Aptian, Early Cretaeeous.

Additional material

GZG.1NV.78527 (51 dissoeiated LAPs).

Description

Holotype

GZG.1NV.78523 is a dissoeiated medium-sized, proximal LAP; approximately 1.5 times wider than
high; distal edge eonvex; dorsal edge elearly eoneave as a result of a eonstrietion of the outer surfaee;
ventral quarter of LAP relatively narrow, strongly protruding ventro-proximalwards; ventro-distal tip
of LAP very large, tongue shaped and eonspieuously protruding; proximal edge separated by sharp
kink into dorsal and ventral portion; kink bordered by large, eonspieuous, sharply defined, prominent,
horizontally strongly elongate and proximally pointed spur eomposed of dense stereom; eoarsely
meshed stereom on distal two-thirds of outer surfaee; trabeeulae of outer surfaee stereom thiek but with
no tendeney to merge into vertieal striation; eoarsely meshed stereom of outer surfaee replaeed by more
finely meshed stereom in proximal third of outer surfaee. Four ear-shaped spine artieulations freestanding
on very weakly elevated distal portion of LAP with slight dorsalward inerease in size of gaps separating
them; seeond dorsalmost spine artieulation slightly larger than remaining three; dorsal and ventral lobes
forming eontinuous volute; all four spine artieulations surrounded by irregular, eonfiuent areoles of
finely meshed stereom. Ventral edge of LAP with extremely large, deeply eoneave tentaele noteh.

Inner side of LAP with large, sharply defined ridge separated by angular kink into dorsal and ventral
portions; dorsal portion oblique, straight, with elearly widened dorsal tip in eontaet with dorsal edge of
LAP; ventral portion straight, forming an almost right angle with dorsal portion and approximately as
long as the latter, with thiekened, horizontally elongate ventral tip; inner side of ventro-distal tip of LAP
thiekened with moderately well-defined, round, slightly prominent spur eomposed of dense stereom.
Inner side of large tentaele noteh with eoarsely meshed and slightly horizontally stretehed stereom
dorsally bordered by large, irregular perforation.

Paratype supplements and variation

GZG.INV.78524 is a dissoeiated median LAP, twiee wider than high; proximal edge with sharp kink
similar to that observed in holotype, bordered by moderately well-defined, elongated and prominent
spur; seeond spur in dorsal half of proximal edge, slightly smaller than ventral spur and protruding, but
similarly well defined, prominent and elongate. Outer surfaee with eoarsely meshed stereom, with thiek
trabeeulae showing no tendeney to merge into a vertieal striation. Three spine artieulations separated by
equal-sized gaps; middle spine artieulation slightly larger than remaining two. Ventral edge of LAP with
extremely large, gently eoneave tentaele noteh.

Inner side of LAP with thin, moderately well-defined ridge eomposed of two portions separated by kink;
dorsal portion narrow, with slightly wider dorsal tip; ventral portion of ridge forming aeute angle with
dorsal one, nearly as long as the latter but wider and less well defined, eonfiuent with ventral edge of
LAP.

GZG.INV.78525 is a dissoeiated distal LAP, approximately 2.5 times wider than high; ventro-distal tip
eonspieuously protruding; proximal edge eoneave, with poorly defined, elongate and slightly prominent
spur in ventral half; seeond spur in dorsal half smaller, similarly poorly defined, prominent and slightly
protruding. Three spine artieulations, ventralmost of whieh slightly smaller than remaining two. Ventral
edge of LAP eoneave as a result of a elear eonstrietion of the outer surfaee, and with large, eoneave
tentaele noteh.

THUYB., Fossil record of ophiacanthid brittle stars

Inner side of LAP with two moderately well-defined, prominent and slightly elongated spurs on dorso-
distal and ventro-distal tips, respectively, dorsal one of which slightly protrudes; ridge on inner side of
LAP hardly discernible as a result of insufficient preservation.

GZG.INV.78526 is a dissociated distalmost LAP, rod-like in outline, more than three times wider than
high, with concave dorsal and ventral edges. Two small equal-sized spine articulations. No tentacle
notch on ventral edge of LAP; tentacle perforation distally bordering ventral spine articulation. Inner
side of LAP insufficiently preserved.

Remarks

These LAPs reveal striking similarities to those of Lapidaster mathcore sp. nov. and with the single
unnamed LAP from the Kimmeridgian of Germany described above. It differs from the former in
displaying a slightly wider ventral portion of the LAPs, coarsely meshed stereom on two-thirds rather
than half of the outer surface, a slender, horizontally strongly elongate and proximally pointed spur,
and a straight dorsal half of the ridge on the inner side with a more markedly widened dorsal tip. These
LAPs, L. mathcore sp. nov. and the unnamed Jurassic specimen form one of the groups of similar
species in terms of LAP morphology within Lapidaster gen. nov. . Another example of such a group of
morphologically similar LAPs includes L.fasciatus comb. nov. , L. mastodon sp. nov. andL. varuna sp.
nov. Whether these groups are all assignable to Lapidaster gen. nov. or, in contrast, represent different
closely related genera remains to be tested.

Occurrence

Middle Aptian of France.

Lapidaster mathcore sp. nov.

um:lsid:zoobank.org:act:13487QA5-8900-4C8F-97E4-8D098266865D

Fig. 10: 8-10

Diagnosis

Species of Lapidaster gen. nov. with moderately large LAPs with coarsely meshed stereom in a narrow
band of the outer surface displaying conspicuously thick trabeculae; ventral portion very narrow and
strongly protruding ventro-proximalwards; spur on outer proximal edge oval, slightly horizontally
elongate, not pointed proximally, paralleled by a well-defined spur on the inner distal edge; dorsal part
of ridge on the inner side bent proximally.

Etymology

Species named after “Mathcore”, a music geme that has been among my most infiuential sources of
inspiration in understanding and expressing complexity.

Type material

Holotype

GZG.INV.78528.

Paratypes

GZG.INV.78529 and GZG.INV.78530.

Type locality and horizon

Folkestone, Great Britain; level 2 of Young et al. (2010), Loricatus Zone, middle Albian, Early
Cretaceous.

European Journal of Taxonomy 48: 1-242 (2013)

Additional material

GZG.1NV.78531 (5 dissociated LAPs).

Description

Holotype

GZG.1NV.78528 is a dissociated, moderately large, proximal LAP; nearly 1.5 times wider than high;
distal edge convex; dorsal edge slightly concave as a result of a weakly developed constriction; ventral
quarter of LAP very narrow, strongly protruding ventro-proximalwards; ventro-distal tip of LAP very
large, tongue shaped and conspicuously protruding; proximal edge separated by sharp kink into dorsal
and ventral portion; large, conspicuous, sharply defined, prominent and slightly elongated, oval spur
composed of more densely meshed stereom at some distance from kink separating proximal edge;
coarsely meshed stereom in distal half of outer surface; trabeculae of outer surface stereom thick, no
tendency to merge into vertical striation; coarsely meshed stereom of outer surface replaced by more
finely meshed stereom in proximal half of outer surface. Four ear-shaped spine articulations, with slight
dorsalward increase in size of gaps separating them; second dorsalmost spine articulation slightly larger
than remaining three; dorsal and ventral lobes forming continuous volute; all four spine articulations
surrounded by irregular, confiuent areoles of finely meshed stereom. Ventral edge of LAP with extremely
large, deeply concave tentacle notch.

Inner side of LAP with large ridge separated by kink into sharply defined dorsal and less well-defined
ventral portions; dorsal portion oblique, bent proximally, with weakly widened dorsal tip; ventral portion
straight, forming a slightly obtuse angle with dorsal portion and approximately as long as the latter, with
slightly thickened ventral tip not confiuent with ventral portion of LAP; inner side of ventro-distal tip
of LAP thickened with moderately well-defined, round, slightly prominent spur composed of dense
stereom. Inner side of large tentacle notch with coarsely meshed and slightly horizontally stretched
stereom dorsally bordered by large, irregular perforation.

Paratype supplements and variation

GZG.INV.78529 is a dissociated median LAP; well in agreement with holotype but slightly less well
preserved; ventral portion of LAP smaller, slightly less strongly protruding ventro-proximalwards;
proximal edge with spur on ventral portion similar to that observed on holotype; second much smaller,
but similarly well-defined, spur in dorsal half of proximal edge. Three spine articulations similar to those
observed on holotype. Tentacle notch very large but not as deeply concave as in holotype.

Ridge on inner side poorly preserved but superficially similar to that of holotype.

GZG.1NV.78530 is a dissociated distal LAP; less well preserved than holotype; large spur in the middle
of the ventral portion of the LAP probably similar to that of holotype; second small, slightly protruding,
very poorly preserved spur in dorsal half of proximal edge; coarsely meshed stereom on distal two-
thirds of outer surface, replaced by finely meshed stereom on proximal third of outer surface. Three
very poorly preserved spine articulations. Tentacle notch very large and almost as deeply incised as in
holotype.

Ridge on inner side similar to that of holotype but with straight dorsal half and very poorly defined
ventral half

Remarks

These LAPs are remarkably similar to those of Lapidaster coreytaylori sp. nov. from slightly older
deep-sea sediments in France. They can be unambiguously distinguished from the latter on account of
the size of the ventral LAP portion, the extent of the coarsely meshed stereom on the outer surface, the
shape and position of the spur on the ventral portion of the outer proximal edge, and the shape of the
ridge on the inn er side.

Occurrence

Middle Albian of Great Britain.

THUYB., Fossil record of ophiacanthid brittle stars

Genus Ophiologimus YL.L. Clark, 1911

Type species

Ophiologimus hexactis H.L. Clark, 1911, by original designation.

Diagnosis

LAPs with large, eonspieuous tentaele notehes; spine artieulations not on elevated ridge and not
sunken into depressions or notehes; ventral portion of lateral arm plate strongly protruding ventro-
proximalwards; generally no spurs on outer proximal and inner distal edges of LAP.

Remarks

The LAPs of extant speeies of Ophiologimus are eharaeterised by very large, generally deeply ineised
tentaele notehes, the absenee of a strong eonstrietion or a strongly elevated distal portion, the moderately
large, freestanding spine artieulations and the relatively simple ridge on the inner side devoid of strongly
widened parts. Closest similarities are shared with the LAPs of extinet Lapidaster gen. nov., whieh differ
mainly in the possession of at least one spur on the outer proximal and inner distal edges. As diseussed
above, it seems highly probable that Ophiologimus and Lapidaster gen. nov. eome from a single lineage,
in view of the striking similarities in LAP morphology displayed by both genera.

Ophiologimus martynovi sp. nov.

um:lsid:zoobank.org:aet:FQ5FA7AB-4BE9-43BE-BlDl-693D08CAE2D2

Fig. 11:2-4

Diagnosis

Speeies of Ophiologimus with large EAPs; well-developed vertieal striation eomposed of overlapping
lamellae at least in proximal EAPs; up to three large, ear-shaped spine artieulations; ventral lobe
more slender than dorsal one and projeeting ventro-distalwards beyond latter; inner side of EAP with
moderately wide, straight, oblique ridge ventrally not merged with ventral portion of EAP; tentaele
noteh very deeply ineised.

Etymology

Speeies named in honour of Alexander Martynov, who generously provided SEM pietures of lateral arm
plates of Reeent speeies of Ophiologimus for eomparison.

Type material

Holotype

GZG.INV.78532.

Paratypes

GZG.INV.78533 and GZG.INV.78534.

Type locality and horizon

Blake Nose, borehole ODP 171B 1049C 12x6, tropieal northeast Atlantie; latest Aptian to earliest Albian,
Hedbergella trochoidea to Microhedbergella rischi planktonie foraminifer zones. Early Cretaeeous.

European Journal of Taxonomy 48: 1-242 (2013)

Fig. 11. Lateral arm plates (LAPs) of fossil and Reeent ophiaeanthid brittle stars in external (a) and
internal (b) views. 1. Ophiologimus hexactis H.L. Clark, 1911, Reeent, median LAP in external view.
2-4. Ophiologimus martynovi sp. nov. from the latest Aptian to earliest Albian (Early Cretaeeous) of Blake
Nose, NE Atlantie. 2. GZG.INV.78532 (holotype), proximal EAP. 3. GZG.INV.78533 (paratype), median
EAP. 4. GZG.INV.78534 (paratype), distal EAP. 5-6. Ophiologimus aiodipius sp. nov. from the latest
Aptian to earliest Albian (Early Cretaeeous) of Blake Nose, NE Atlantie. 5. GZG.1NV.78536 (holotype),
proximal EAP. 6. GZG.1NV.78537 (paratype), median EAP. 7-8. Ophiologimus rugosus (Kutseher &
Jagt, 2000) eomb. nov. from the early Maastriehtian (Eate Cretaeeous) of Rtigen, Germany. 7. GZG.
INV.78539, proximal EAP. 8. GZG.INV.78540, median EAP. One eommon seale bar per speeies is given.

Additional material

GZG.INV.78535 (45 dissociated LAPs).

THUYB., Fossil record of ophiacanthid brittle stars

Description of holotype
Holotype

GZG.INV.78532 is a dissoeiated, large proximal LAP; nearly as high as wide; dorso-proximal tip
fragmentary; outline of dorsal edge not determinable; distal edge gently eonvex; proximal edge irregularly
eoneave, devoid of spurs; ventral third of LAP strongly protruding ventro-proximalwards; ventro-distal
tip of LAP strongly protruding ventralwards, tongue shaped; outer surfaee with well-developed, rather
irregular, eoarse vertieal striation eomposed of overlapping lamellae with proximalward deerease in
size and replaeed by moderately eoarsely to finely meshed stereom in proximal half of outer surfaee.
Three large, equal-sized and equidistant, ear-shaped, nearly round spine artieulations freestanding on
non-elevated distal portion of LAP; dorsal and ventral lobes merged into eontinuous volute; ventral
lobe more slender and smaller than dorsal one, ventro-distalwards projeeting beyond dorsal lobe; gap
between spine artieulations and distal edge of LAP inereasing in width ventralwards. Ventral edge of
LAP with very large, deeply ineised, eoneave tentaele noteh.

Inner side of LAP with large, sharply defined, prominent, oblique, straight ridge with very weakly
widened, round dorsal and ventral tips; no kinks, knobs or extensions; no spurs on inner side of distal
edge of LAP; inner side of tentaele noteh very large, with eoarsely meshed, horizontally elongate
stereom. No perforations or furrow diseemible.

Paratype supplements and variation

GZG.INV.78533 is a dissoeiated median LAP; approximately 1.5 times higher than wide; elosely similar
to holotype; outer surfaee with eoarsely meshed stereom, trabeeulae not merged into vertieal striation;
eoarsely meshed stereom replaeed by more finely meshed stereom near proximal edge of LAP. Three
spine artieulations similar to those observed on holotype. Tentaele noteh large and eonspieuous but not
as deep as in holotype. Ridge on inner side similar to that of holotype.

GZG.INV.78534 is a dissoeiated distal LAP; almost twiee wider than high; dorsal edge slightly eoneave
as a result of a weak eonstrietion; outer surfaee with eoarsely meshed stereom; few trabeeulae merged
into very weak, almost indiseemible vertieal striation in distal half of outer surfaee; eoarsely meshed
stereom replaeed by more finely meshed one towards proximal edge of LAP. Three spine artieulations
similar to those observed on holotype; ventral spine artieulation slightly smaller than remaining two.
Tentaele noteh not as deep as in holotype but large, eonspieuous, eoneave.

Ridge on inner side of LAP with strongly widened ventral tip; dorsal part of ridge straight, slender and
oblique.

Remarks

These LAPs display the distinetive eombination of eharaeters typieally found in LAPs of Ophiologimus,
thus warranting assignment to this genus. Closest similarities are shared with the LAPs of Ophiologimus
rugosus (Kutseher & Jagt, 2000) eomb. nov. (see below) in partieular with respeet to the outer surfaee
vertieal striation and the deeply ineised tentaele noteh. The LAPs of O. rugosus eomb. nov., however,
display up to seven, rather than three, spine artieulations as well as two widely separate knobs or short
ridges rather than a single large one on the inner side.

Occurrence

Latest Aptian to earliest Albian of the tropieal northeast Atlantie.

European Journal of Taxonomy 48: 1-242 (2013)

Ophiologimus aiodipius sp. nov.

um:lsid:zoobank.org:act:C014CC2C-6QE3-43F6-BlD6-2QF641QE6A97

Fig. 11:5-6

Diagnosis

Species of Ophiologimus with large EAPs displaying coarsely meshed stereom on outer surface;
trabeculae of coarsely meshed stereom merged into short, irregular vertical stripes close to spine
articulations; up to four lenticular, oblique spine articulations; ridge on inner side of EAPs very slender;
ventral part of ridge merged with ventral portion of EAP and connected with dorsal part of ridge by
gently rounded kink; tentacle notch rather shallow.

Etymology

Species name derived from lODP, Integrated Ocean Drilling Program, under which the samples yielding
the type material were recovered.

Type material

Holotype

GZG.1NV.78536.

Paratypes

GZG.1NV.78537.

Type locality and horizon

Blake Nose, borehole ODP 171B 1049C 12x5, tropical northeast Atlantic; latest Aptian to earliest Albian,
Hedbergella trochoidea to Microhedbergella rischi planktonic foraminifer zones. Early Cretaceous.

Additional material

GZG.1NV.78538 (33 dissociated EAPs).

Description

Holotype

GZG.1NV.78536 is a dissociated, large, proximal EAP; slightly wider than high; dorsal edge straight;
distal edge convex; proximal edge concave, devoid of spurs; ventral fifth of EAP strongly protruding
ventro-proximalwards; ventro-distal tip of EAP slightly protruding; outer surface with coarsely meshed
stereom; trabeculae merging into short, irregular, vertical stripes close to spine articulations; coarsely
meshed stereom replaced by finely meshed stereom in narrow band along proximal edge of EAP.
Four large, lenticular, oblique, slightly elongate, nearly equal-sized and equidistant spine articulations
freestanding on non-elevated distal portion of EAP; dorsal and ventral lobes merged by sharp, acute
kink proximally into continuous volute; gap between spine articulations and distal edge of EAP narrow,
slightly increasing in width ventralwards. Ventral edge of EAP with very large, moderately deeply
incised, concave tentacle notch.

Inner side of EAP with large, very slender ridge; dorsal part of ridge straight, oblique; ventral part almost
vertical, merged with ventral portion of EAP and connected with dorsal part by gently rounded kink;
no spurs on inner side of distal edge of EAP; inner side of tentacle notch very large. No perforations or
furrow discernible.

Paratype supplements and variation

GZG.1NV.78537 is a dissociated distal EAP; approximately twice wider than high; well in agreement
with holotype; outer surface with very coarsely meshed stereom; trabeculae merged into shorter and

THUYB., Fossil record of ophiacanthid brittle stars

even less regular vertical stripes than in holotype. Three spine articulations similar to those observed in
holotype but with dorsalward increase in size. Ventral edge of LAP with very large, but shallow tentacle
notch.

Ridge on inner side of LAP straight, oblique, slender, merged ventrally with ventral portion of LAP.

Remarks

These LAPs are unambiguously assignable to Ophiologimus on account of the very large tentacle notch
combined with the spine articulations freestanding on the non-elevated distal portion of the LAP and
the simple ridge on the inner side devoid of conspicuously thickened parts. Among the fossil LAP types
assigned to this genus, the above is unique in combining a coarsely meshed outer surface stereom with
lenticular, oblique spine articulations and a continuous ridge on the inner side with the ventral part
merged with the ventral portion of the LAP.

Occurrence

Latest Aptian to earliest Albian of the tropical northeast Atlantic.

Ophiologimus rugosus (Kutscher & Jagt, 2000) comb. nov.

Fig. 11:7-8

Ophiacanthal rugosa Kutscher & Jagt, 2000 in Jagt 2000: 11, pi. 13 fig. 1.

Ophiacanthal rugosa Kutscher & Jagt, 2000: 63, pi. 25 fig. 7.

Ophiacantha? n. sp. - Jagt 1999a: 200, pi. 2 fig. 5.

Diagnosis

Species of Ophiologimus with large LAPs displaying well-developed vertical constriction on outer
surface composed of coarse, strongly overlapping lamellae; up to seven large, ear-shaped spine
articulations; ventral portion of LAP relatively narrow; inner side of LAP with two widely separate short
ridges or knobs; tentacle notch deeply incised.

Material examined

GZG.INV.78539 and GZG.INV.78540 (leg. Manfred Kutscher) 50 dissociated LAPs, original material
listed by Kutscher & Jagt (2000); dissociated LAP (NHMM JJ 10600/12e) from the upper Campanian
Zeven Wegen Member (Gulpen Formation) of Haccourt, northeast Belgium, the original material of Jagt
( 2000 ).

Description

Relatively large LAPs, proximal ones nearly 1.5 times higher than wide, distal ones slightly wider than
high; ventral fifth (proximal LAPs) to third (distal LAPs) strongly protruding ventro-proximalwards;
ventro-distal tip of LAPs tongue shaped, conspicuously protruding; dorsal edge straight to slightly
concave as a result of a very weak constriction; distal edge evenly convex; proximal edge undulose,
with convex central part and protruding ventral fifth to quarter, separated by kink; no spurs on proximal
edge; outer surface with conspicuous irregular striation composed of broad, fiattened, distalwards
slightly overlapping stripes loosely following outline of proximal edge of LAP; striation restricted
to central band, proximally bordered by band of very finely meshed stereom and distally bordered
by confiuent areoles of finely meshed stereom surrounding all spine articulations. Four (distal LAPs)
to seven (proximal LAPs) relatively large, ear-shaped, equal-sized spine articulations; dorsalward
increase in size of gaps separating spine articulations; dorsal and ventral lobes forming continuous

European Journal of Taxonomy 48: 1-242 (2013)

volute in all spine artieulations. Ventral edge of LAPs with extremely large, deeply eoneave tentaele
noteh.

Inner side of LAPs with two separate ridges or knobs; ventral ridge eonsisting of a short, prominent
dorsalward protrusion of the slightly thiekened ventral portion of the LAP, with well-defined, widened,
rounded dorsal tip; seeond ridge near eentre of inner proximal edge of the LAP, eonsisting of a well-
defined, prominent, reversed V-shaped knob with a ventro-proximally pointing braneh and slightly
shorter and narrower ventro-distal ward pointing braneh; in distal LAPs poorly defined and only slightly
prominent eonneetion between both ridge-like struetures; inner side of ventro-distal tip of LAP strongly
protruding but not thiekened and devoid of spurs. Inner side of tentaele noteh with eoarsely meshed,
horizontally stretehed stereom. Very faint, irregular vertieal row of small perforations on inner side of
proximal LAPs.

Remarks

This speeies was originally deseribed by Kutseher & Jagt {in Jagt 2000) on the basis of dissoeiated
LAPs from the early Maastriehtian of Germany and Denmark and tentatively assigned to the genus
Ophiacantha. Reassessment of the type speeimens has revealed that the speeies is assignable to
Ophiologimus. Within this genus, it is unambiguously reeognisable on aeeount of the high number of
spine artieulations.

Occurrence

Late Campanian of northeast Belgium and early Maastriehtian of northeast Germany and Denmark.

Genus OphiotomaYQuiW, 1899

Type species

Ophiotoma coriacea Lyman, 1883, by monotypy.

Diagnosis

LAPs devoid of eonstrietion or strongly elevated or bulging distal portion; spine artieulations free
standing or in shallow notehes of the slightly elevated distal edge; ventral portion of LAP very large,
protruding ventro-proximalwards; tentaele noteh large, inner side of tentaele noteh in proximal LAPs
at least as wide as one-third of the total ventral LAP edge width; outer surfaee eommonly with vertieal
striation; no eonspieuous spurs on outer proximal and inner distal edges; ridge on inner side of LAP
generally with widened dorsal tip.

Remarks

The LAPs of extant speeies of Ophiotoma (Fig. 12: 1-3) are eharaeterised by the laek of a eonstrietion
and of a bulging or strongly elevated distal portion, as well as a large, strongly protruding ventral portion
bordering a large tentaele noteh. The spine artieulations are generally in shallow notehes or depressions
of the slightly elevated distal LAP edge, whieh differentiates them from the LAPs of Ophiologimus
(see above). Superfieial similarities exist to the LAPs of extant speeies of Ophiolimna Verrill, 1899 (see
below). In these, however, the spine artieulations are proximally slightly overlain by the eoarse vertieal
striation of the outer surfaee and merged with the latter by a eonneeting ridge.

The ophiaeanthid fossil reeord ineludes only very few dissoeiated LAP types whieh eonvineingly
mateh the diagnosis of Ophiotoma. Given their seareity and limited eurrently known diversity, these
fossil LAP types are here assigned to the extant genus Ophiotoma. The diseovery of artieulated
speeimens with the LAP types in question, however, are very likely to reveal differenees in general
skeletal morphology whieh imply distinetion at the generie level. Irrespeetive of generie plaeement

THUYB., Fossil record of ophiacanthid brittle stars

issues, the striking morphological similarities shared by the fossil LAPs and those of Ophiotoma
strongly suggest close phylogenetic ties, which is the relevant aspect for the scope of the present
study.

The LAPs of Ophiotoma, especially the fossil ones, share an intriguing similarity with those assigned to
extinct Dermocoma Hess, 1964 (see below), in particular on account of the strongly protruding ventral
portion of the LAPs, the absence of a constriction and a bulging distal portion, the position of the spine
articulations and the shape of the ridge on the inner side of the LAPs. The LAPs of Dermocoma tend to
differ from those of Ophiotoma in displaying large and strongly protruding spurs on their outer proximal
and inner distal edges. However, since both genera include species which deviate from this pattern, the
latter cannot be taken as a rule. The only unambiguous character to distinguish the LAPs of Ophiotoma
and Dermocoma is the size of the tentacle notch.

Ophiotoma sp. nov. innom.

Fig. 12: 4

Material examined

NHMW 2012/0137/0009 (dissociated LAP) from the late Sinemurian to early Pliensbachian of the
Glasenbach Gorge, Austria.

Description

NHMW 2012/0137/0009 is a dissociated, small, proximal to median LAP, slightly wider than high;
dorsal edge nearly straight; distal edge oblique, nearly straight to slightly convex; proximal edge
strongly concave, devoid of spurs; ventral third of LAP strongly protruding ventro-proximalwards;
distal portion of LAP not bulging and not elevated; outer surface almost entirely covered by fine,
regular, vertical striation composed of thin distally slightly overlapping lamellae. Four ear-shaped,
equi-distant spine articulations in tight, shallow notches of the the distal edge only very slightly
interrupting the vertical striation; ventralmost spine articulation slightly smaller than remaining three;
moderately large and ventrally increasing gap between spine articulations and distal edge of LAP;
dorsal and ventral lobes of spine articulations forming continuous volute. Ventral edge of LAP with
very large, concave tentacle notch.

Inner side of LAP: ridge very narrow, well defined, prominent, evenly bent, with widened dorsal tip
reaching dorso-proximal comer of LAP; ventral tip pointing ventro-proximalwards, merging with
ventral portion of LAP; no spurs discernible on inner side of distal edge of LAP; inner side of tentacle
notch slightly wider than one-third of the ventral edge width of the LAP. Presence of perforations on the
inner side not determinable on account of insufficient preservation.

Remarks

The single known LAP is characterised by the very large tentacle notch, the absence of a constriction or
strongly elevated distal portion, and the spine articulations in shallow notches and devoid of connecting
ridges with the outer surface ornament. This combination of characters strongly suggests assignment to
Ophiotoma or at least to the fossil LAP types placed in Ophiotoma for the reasons discussed above. The
LAP in question shows closest similarities to those of Ophiotoma charlottae sp. nov. (see below), but
differs in having its outer surface almost entirely covered by vertical striation. In Ophiotoma vadosa sp.
nov. the spine articulations show a strong dorsalward increase in size and in the gaps separating them.
The LAP from the Glasenbach Gorge belongs to an undescribed species, but in view of the fact that a
single specimen is available, any formal description is premature.

European Journal of Taxonomy 48: 1-242 (2013)

Fig. 12. Lateral arm plates (LAPs) of fossil andReeent ophiaeanthid brittle stars in external (a) and internal
(b) views. 1. Ophiotoma assimilis Koehler, 1904, Reeent, proximal LAP. 2-3. Ophiotoma megatreta
(H.L. Clark, 1911), Reeent. 2. Pro xim al LAP. 3. Median LAP. 4. Ophiotoma sp. nov. innom. from
the late Sinemurian to early Pliensbaehian (Early Jurassie) of the Glasenbaeh Gorge, Austria; NHMW
2012/0137/0009, median LAP. 5-7. Ophiotoma vadosa sp. nov. from the early Pliensbaehian (Early
Jurassie) of Bloekley, Great Britain. 5. GZG.INV.78541 (holotype), proximal EAP 6. GZG.INV.78542
(paratype), median EAP. 7. GZG.1NV.78543 (paratype), distal EAP. 8-10. Ophiotoma charlottae sp. nov.
from the early Kimmeridgian of the Pointe du Chay, Franee. 8. GZG.1NV.78545 (holotype), proximal
EAP. 9. GZG.INV.78546 (paratype), proximal to median EAP. 10. GZG.INV.78547 (paratype), distal
EAP. One eommon seale bar per speeies is given.

THUYB., Fossil record of ophiacanthid brittle stars

Ophiotoma vadosa sp. nov.

um:lsid:zoobank.org:act:698A06E5-BC2D-4729-8C41-15F2EBBFEB3E

Fig. 12: 5-7

Diagnosis

Species of Ophiotoma with relatively large EAPs displaying large, conspicuous, tongue-shaped and strongly
protruding ventro-distal tip; two small, but comparatively well-developed spurs on the outer proximal and
inner distal edges; up to six spine articulations displaying strong dorsalward increase in size and in the size of
the gaps separating them; dorsal tip of the ridge on the inner side of the proximal EAPs only slightly enlarged.

Etymology

From vadosus, Eatin for “shallow”, in reference to the relatively shallow (mid-shelf) water depth
assumed for the palaeohabitat of the species.

Type material

Holotype

GZG.INV.78541.

Paratypes

GZG.INV.78542 and GZG.INV.78543.

Type locality and horizon

Blockley, near Cheltenham, Great Britain; shell lenses in clayey matrix, Davoei Zone, early Pliensbachian,
Early Jurassic.

Additional material

GZG.INV.78544 (20 dissociated EAPs) from Blockley, Great Britain; 175 dissociated EAPs from the
late Pliensbachian of Seewen, Switzerland, the original material of Hess (1962).

Description

Holotype

GZG.INV.78541 is a dissociated, large, proximal EAP; dorsal and distal edges slightly convex; proximal
edge undulose, with small, well-defined, oval, prominent spur positioned in the centre of protruding part
of proximal EAP edge; second slightly larger but much less well-defined spur in the middle of the ventral
half of the proximal edge; ventral third to quarter of EAP strongly protruding ventro-proximalwards;
ventro-distal tip of EAP large, strongly protruding, tongue shaped; distal portion of EAP neither bulging
nor elevated; outer surface with well-developed, regular vertical striation composed of thin, distalwards
slightly overlapping lamellae, replaced by finely meshed stereom on ventral portion of EAP and near
proximal edge. Six ear-shaped spine articulations in notches of distal edge; strong dorsalward increase
in size of spine articulations and of gaps separating them; no connecting ridge with striation of outer
surface; dorsal and ventral lobes of spine articulations separated by very small incision proximally; large
and ventrally strongly increasing gap between spine articulations and distal edge. Ventral edge with very
large, deeply concave, conspicuous tentacle notch, exacerbated by strongly protruding ventro-distal tip
of EAP.

Inner side of EAP with large, sharply defined, prominent, bent ridge; dorsal tip of ridge only very
slightly widened, pointing dorsalwards; ventral tip of ridge merged with ventral portion of EAP; inner
side of distal edge of EAP with two spurs, dorsal one of which small, round, poorly defined, very slightly
prominent but not protruding; ventral spur much larger, better defined, prominent, lenticular; inner side
of tentacle notch slightly wider than one-third of the total ventral EAP edge width. Irregular vertical row

European Journal of Taxonomy 48: 1-242 (2013)

of perforations, ventralmost of which dorsally bordering tentacle notch, moderately large; remaining
perforations minute; row of perforations distally bordered by poorly defined, slightly prominent ridge.

Paratype supplements and variation

GZG.1NV.78542 is a dissociated median LAP, nearly as high as wide; of rectangular to trapezoid outline;
dorsal and distal edges oblique, straight; proximal edge slightly undulose, with two small, poorly defined,
slightly prominent and very slightly protruding spurs; ventral fifth of LAP protruding; outer surface with
vertical striation becoming slightly irregular in ventral half of LAP; striation replaced by finely meshed
stereom close to proximal edge of LAP Four spine articulations in moderately deep notches of distal
edge; very weak dorsalward increase in size of spine articulations and of gaps separating them; narrow
but ventrally increasing gap between spine articulations and distal edge of LAP Ventral edge of LAP
convex with moderately large, weakly concave tentacle notch.

Inner side with large, sharply defined ridge; dorsal tip of ridge slightly widened, ventral tip separated
from ventral portion of LAP; inner side of distal edge of LAP with two small, moderately well-defined,
slightly prominent spurs; inner side of tentacle notch slightly smaller than one-quarter of the total ventral
edge of the LAP. Poorly defined, irregular perforation halfway between ridge and distal edge of LAP.

GZG.INV.78543 is a dissociated distal LAP, approximately 1.5 times wider than high, of rectangular
outline; well in agreement with other paratype; ventral portion of LAP hardly protruding.

Inner side of LAP with sharply defined, prominent, bone-shaped ridge; dorsal and ventral tips of ridge
strongly widened.

Remarks

These LAPs show a certain resemblance with LAPs assigned to Dermocoma (see below), in particular
on account of the relatively deep notches holding the spine articulations and the spurs on the outer
proximal and inner distal edges. These similarities, however, are superficial at most. In fact, the very
large tentacle notches clearly preclude assignment to Dermocoma. Among the large-pored ophiacanthid
lineages, greatest similarities are shared with the LAPs of extant Ophiotoma and the fossil LAP types
assigned to that genus. Thus, in spite of the rather atypically well-developed spurs on the outer proximal
and inner distal edges, the above-described LAPs are assigned to Ophiotoma. Within this genus, the
LAPs in question are highly distinctive on account of the spurs and their very large, conspicuous,
tongue-shaped ventro-distal tip, which is why they are described as a new species.

Occurrence

Early Pliensbachian of Great Britain and Late Pliensbachian of Switzerland.

Ophiotoma charlottae sp. nov.

um:lsid:zoobank.org:act:BFA9592E-7CEA-4B12-B2FQ-45ElE27B7EF6

Fig. 12: 8-10

Diagnosis

Species of Ophiotoma with comparatively small EAPs displaying a large, nearly rectangular and strongly
protruding ventral portion (third of a proximal EAP); four to five equal-sized spine articulations; outer
surface with striation restricted to relatively narrow band close to spine articulations and composed of
thin lamellae separated by single rows of small stereom pores; inner side with main, central bone-shaped
ridge and second ridge on ventral portion of EAP; very large, single perforation bordering ventral tip of
main ridge, occasionally dorsally accompanied by second vertically elongate ridge.

THUYB., Fossil record of ophiacanthid brittle stars

Etymology

Species named in honour of Charlotte Bmneau for introducing me to Alexandre Jardin’s wonderful L lie
des gauchers.

Type material

Holotype

GZG.INV.78545.

Paratypes

GZG.INV.78546 and GZG.INV.78547.

Type locality and horizon

Pointe du Chay near La Rochelle, France; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late
Jurassic.

Additional material

GZG.INV.78548 (3 dissociated LAPs).

Description

Holotype

GZG.INV.78545 is a dissociated, small, proximal LAP; approximately 1.5 times higher than wide;
slightly convex dorsal and distal edges; proximal edge gently concave with very slight central protrusion;
no spurs discernible on proximal edge; small, poorly defined, shallow depression in the middle of
the proximal edge; ventral third nearly rectangular, strongly protruding ventro-proximalwards; no
constriction; distal portion of LAP neither bulging nor elevated; outer surface with fine, regular vertical
striation composed of thin lamellae separated by single rows of small stereom pores; striation replaced
by finely meshed stereom in proximal third of outer surface and on most of the ventral portion of the
LAP. Four ear-shaped, equal-sized spine articulations in shallow notches of the distal edge, moderately
deeply incising the vertical striation of the outer surface; slight dorsalward increase in size of gaps
separating the spine articulations; dorsal and ventral lobes separated by a small knob; almost no gap
between spine articulations and distal edge of LAP. Ventral edge of LAP with very large, slightly angular
tentacle notch.

Inner side of LAP with large but comparatively short, sharply defined, prominent, bone-shaped main
ridge; dorsal portion of ridge oblique, with strongly widened dorsal tip; ventral portion with similarly
widened ventral tip, well defined but not as sharply and prominently as dorsal tip; second less well-
defined, less prominent but slightly wider, proximally bent ridge proximally bordering the inner side
of the tentacle notch, in direct continuation of the ventral portion of the main ridge but separated from
the latter; no spurs on the inner side of the distal edge of the LAP; inner side of the tentacle notch
with coarsely meshed, horizontally stretched stereom, almost as wide as half of the total ventral LAP
edge width. Single very large perforation distally bordering the tip of the ventral portion of the main
ridge; second smaller, vertically elongate perforation above large one. Ventro-distal edge of ventral LAP
portion with prominent ridge.

Paratype supplements and variation

GZG.INV.78546 is a proximal LAP; well in agreement with holotype. Vertical striation on outer surface
extending to a slightly larger area close to spine articulations and on dorsal edge of ventral portion of
LAP. Five spine articulations, of equal size and nearly equi-distant.

Inner side very well in agreement with that of holotype. Vertically elongate perforation lacking.

European Journal of Taxonomy 48: 1-242 (2013)

GZG.1NV.78547 is a median LAP; nearly as high as wide; well in agreement with holotype; ventral
quarter of LAP strongly protruding ventro-proximalwards; shallow, poorly defined depression in the
eentre of the proximal edge slightly larger. Five equal-sized, nearly equi-distant spine artieulations
shallowly ineising the vertieal striation of the outer surfaee.

Inner side with well-defined, bone-shaped main ridge well in agreement with that of holotype; no seeond
ridge on inner side of ventral portion of LAP diseemible; inner side of tentaele noteh with eoarsely
meshed, horizontally stretehed stereom, nearly as wide as half of the total ventral LAP edge width.
Single large perforation bordering ventral tip of main ridge; no seeond, elongate perforation. Ventro-
distal edge of ventral LAP portion with poorly defined, slightly prominent knob.

Remarks

These LAPs display the highly distinetive eharaeters of the LAPs of extant speeies of Ophiotoma, in
partieular the very large tentaele notehes, the spine artieulations in shallow depressions or notehes of the
non-bulging, non-elevated distal edge, the large and strongly protruding ventral portion, and the widened
dorsal tip of the ridge on the inner side. The LAPs in question thus seem best aeeommodated in Ophiotoma,
aeknowledging, however, that the diseovery of artieulated speeimens might reveal substantial differenees
in general skeleton morphology warranting separation at the generie level. The shape of the large, ventral
portion of the LAPs, the large perforation and the distinetly bone-shaped ridge on the inner side, and the
development and spatial extent of the vertieal striation on the outer surfaee unmistakably eharaeterise the
above-deseribed LAPs, whieh is why they are here deseribed as a new speeies of Ophiotoma.

Occurrence

Early Kimmeridgian of France.

Ophiotoma incredibilis sp. nov.

um:lsid:zoobank.org:aet:768EE8E5-D636-4D23-964Q-6D22A392265B

Fig. 13: 1-3

Diagnosis

Speeies of Ophiotoma with large EAPs displaying a low height/width ratio; outer surfaee with well-
developed vertieal striation; up to four relatively small spine artieulations in shallow notehes of the
non-elevated distal portion of the EAP; ridge on inner side devoid of thickened parts, composed of two
separated parts: a long, oblique, nearly straight, dorso-proximally pointing dorsal one and a shorter
ventro-proximally pointing ventral one.

Etymology

From incredibilis, Eatin for “unbelievable”, referring to the surprisingly emotional reactions some
colleagues showed when confronted with the discovery of the Blake Nose deep-sea ophiuroid assemblage.

Type material

Holotype

GZG.1NV.78549.

Paratypes

GZG.1NV.78550 and GZG.1NV.7855L

Type locality and horizon

Blake Nose, borehole ODP 17 IB 1049A20x5, tropical northeast Atlantic; latest Aptian to earliest Albian,
Hedbergella trochoidea to Microhedbergella rischi planktonic foraminiferal zones. Early Cretaceous.

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 13. Lateral arm plates (LAPs) of fossil and Reeent ophiaeanthid brittle stars in external (a) and
internal (b) views. 1-3. Ophiotoma incredibilis sp. nov. from the latest Aptian to earliest Albian (Early
Cretaeeous) of Blake Nose, NE Atlantie. 1. GZG.INV.78549 (holotype), proximal EAR 2. GZG.
INV.78550 (paratype), median EAP. 3. GZG.INV.78551 (paratype), distal EAR 4. Ophiolimna antarctica
(Eyman, 1879), Reeent, proximal EAR 5-6. Ophiolimna perfida (Koehler, 1904), Reeent. 5. Proximal
EAP. 6. distal EAP. 7-8. Ophiolimna tiamatia sp. nov. from the late Sinemurian to early Pliensbaehian
(Early Jurassie) of the Glasenbaeh Gorge, Austria. 7. NHMW 2012/0137/0010 (holotype), proximal
EAP. 8. NHMW 2012/0137/0011 (paratype), median EAP. 9-12. Ophiolimna malagasica sp. nov.
from the Bathonian (Middle Jurassie) of Jumara, India. 9. GZG.INV.78553 (holotype), proximal EAP.
10. GZG.INV.78554 (paratype), median EAP. 11. GZG.INV.78555 (paratype), median EAP. 12. GZG.
INV.78556 (paratype), distal EAP. One eommon seale bar per speeies is given.

European Journal of Taxonomy 48: 1-242 (2013)

Additional material

GZG.1NV.78552 (26 dissociated LAPs).

Description

Holotype

GZG.INV.78549 is a dissociated, very large, proximal LAP; slightly wider than high; dorsal edge
straight; distal edge convex; proximal edge irregularly concave, devoid of spurs; ventral third to quarter
strongly protruding ventro-proximalwards; ventro-distal tip of LAP weakly protruding, tongue shaped;
outer surface with well-developed, rather regular vertical striation composed of coarse, overlapping
lamellae replaced by finely meshed stereom in very narrow band along the proximal edge of the LAP
Four relatively small, ear-shaped spine articulations in shallow notches of the non-elevated distal edge
of LAP; very weak dorsalward increase in size of spine articulations and of gaps separating them;
notches of spine articulations deeply incising vertical striation of outer surface; dorsal and ventral lobes
of spine articulations proximally separated by very small notch; gap between spine articulations and
distal edge of LAP narrow, with ventralward increase in width. Ventral edge of LAP with large, deeply
concave tentacle notch.

Inner side of LAP with two sharply defined, prominent, very slender ridges separated by poorly defined,
very weakly prominent connection; dorsal ridge oblique, nearly straight except for ventrally pointing
ventral tip; ventral ridge much shorter, nearly straight, ventro-proximally pointing; inner side of distal
edge of LAP devoid of spurs; inner side of tentacle notch large, well defined, with coarsely meshed,
horizontally elongate stereom, slightly narrower than one-third of the total ventral LAP edge width. No
perforations or furrow discernible.

Paratype supplements and variation

GZG.1NV.78550 is a dissociated median to proximal LAP; almost 1.5 times wider than high; dorso-
proximal tip fragmentary; very well in agreement with holotype; vertical striation on outer surface
slightly finer and slightly less regular. Three spine articulations similar to those observed on holotype
but of equal size.

Inner side well in agreement with holotype; ridges slightly better preserved, completely separate. Single
small perforation dorsally bordering tentacle notch.

GZG.1NV.78551 is a dissociated distal LAP; twice higher than wide; dorsal edge slightly concave as
a result of a very weak constriction; vertical striation on outer surface less well developed than in
holotype. Three spine articulations similar to those observed on the holotype.

Inner side of LAP with small, slender ridge composed of slightly bent, oblique, dorso-proximally
pointing dorsal part and shorter ventro-proximally pointing ventral part separated from the dorsal one
by a gently rounded kink; sharply defined, prominent, round knob distally bordering the ridge.

Remarks

These LAPs are characterised by a well-developed outer surface vertical striation, a strongly ventro-
proximally protruding ventral portion, and the absence of a strongly elevated or bulging distal portion.
The genera Ophiologimus and Lapidaster gen. nov. can be excluded since the spine articulations are
in shallow notches rather than freestanding. The LAPs of Dermocoma display a continuous spine
articulation volute rather than dorsal and ventral lobes separated proximally by a small notch.

Among the genera with LAPs displaying strongly protruding, generally large ventral portions, closets
affinities are shared with Ophiotoma and Dermacantha gen. nov. The LAPs of the latter, although with
similarly low height/width ratio, generally display spurs on the outer proximal and inner distal edges and
a smaller tentacle notch. The above-described LAPs are thus assigned to Ophiotoma, acknowledging.

THUYB., Fossil record of ophiacanthid brittle stars

however, that the height/width ration is atypically low and the tentacle notch unusually small.
Nevertheless, assignment to Ophiotoma is favoured for now.

Occurrence

Latest Aptian to earliest Albian of the tropical northeast Atlantic.

Genus OphiolimnaNoniW, 1899

Type species

Ophiolimna bairdi Lyman, 1883, by original designation.

Diagnosis

LAPs with at least part of their outer surface covered by a well-developed, coarse vertical striation
composed of broad, overlapping lamellae; spine articulations sunken into notches of the distal edge and
partly overlapped by the strongly undulose distalmost lamella and connected with the latter by the large,
tongue-shaped ventral lobe of the spine articulations; inner side with central ridge, commonly with
widened or bifurcated dorsal tip, and ventral ridge, in direct continuation of central ridge or connected
with the latter.

Remarks

The LAPs of extant Ophiolimna (Fig. 13: 4-6) are among the most distinctive of the currently known
ophiacanthids. The well-developed, coarse vertical striation of the outer surface consisting of broadly
overlapping lamellae, and the spine articulations overlapped by the undulose distalmost lamella and
connected with the latter by the large, tongue-like ventral lobes of the spine articulations are found in
no other type of ophiacanthid LAP morphology. There is, however, a superficial resemblance with the
LAPs of extant Ophioconis Liitken, 1869, currently assigned to the Ophiodermatidae Ljungman, 1867
(Stohr & O’Hara 2007), as already pointed out by Martynov (2010). However, the LAPs of the two
genera can easily be told apart on the basis of the ridges on the inner side of the proximal LAPs: while
in Ophiolimna there is one large, central ridge with a second ventral one indirect continuation of the
former, Ophioconis displays three round knobs instead of true ridges. Ophiolimna and Ophiotoma share
a very similar development of the ridges on the inn er side of the LAPs, which underpins their close
phylogenetic ties.

The ophiacanthid fossil record includes a number of rare occurrences, from both shallow- and deep¬
water settings, of dissociated LAP types which closely recall the LAPs of extant Ophiolimna. In fact,
they fit the LAP-morphological diagnosis of Ophiolimna so well that they almost certainly belong to
Ophiolimna or at least to a very closely related genus.

Ophiolimna tiamatia sp. nov.

um:lsid:zoobank.org:act:89A5AD8F-A02B-47Cl-8238-E21F29FlF526

Fig. 13: 7-8

Diagnosis

Species of Ophiolimna with moderately large LAPs of rectangular outline; outer surface with relatively
fine vertical striation; comparatively small spine articulations deeply sunken into notches of distal edge;
inner side of proximal LAPs with large central ridge displaying slightly widened dorsally pointing
dorsal tip.

European Journal of Taxonomy 48: 1-242 (2013)

Etymology

Species named after Tiamat, primordial goddess of the ocean and chaos monster in Babylonian mythology,
in reference to the fact that this species is the oldest currently known occurrence of the Ophiolimna
lineage and, on account of its deep-water origin, thus challenges the widely accepted concepts of the
macroevolutionary significance of deep-water habitats.

Type material
Holotype

NHMW 2012/0137/0010.

Paratypes

NHMW 2012/0137/0011.

Type locality and horizon

Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbachian, Early Jurassic.

Additional material

NHMW 2012/0137/0012 (54 dissociated LAPs).

Description

Holotype

NHMW 2012/0137/0010 is a dissociated, medium-sized, proximal LAP of rectangular outline;
approximately 1.5 times higher than wide; dorsal edge pointed, with strongly obtuse angle; distal edge
convex; proximal edge unevenly concave, devoid of spurs; ventral portion of LAP slightly protruding
ventro-proximalwards, accounting for less than a seventh of total LAP height; ventro-distal tip of LAP
very slightly protruding, rounded; outer surface with very regular vertical striation composed of broadly
overlapping lamellae, with strong proximalward decrease in size; lamellae replaced by finely meshed
stereom in proximalmost third of outer surface and on ventral portion of LAP. Seven small, ear-shaped
and nearly equal-sized spine articulations in deep notches of the distal edge and partly overlapped by the
undulose distalmost lamella; ventral lobes of spine articulations strongly increasing in size dorsalwards,
conspicuously tongue shaped and connected with the distalmost lamella in all but the two ventralmost
spine articulations; dorsalward increase in size of the gaps separating spine articulations; narrow gap
between the four ventral spine articulations and the distal edge of the LAP. Ventral edge of LAP with
large, concave tentacle notch.

Inner side of LAP with large, sharply defined and prominent central ridge composed of an oblique,
relatively narrow median part, a widened, dorsally pointing dorsal part, and a ventro-proximally bent,
slightly less well-defined and relatively narrow ventral part; second small, inconspicuous, poorly defined
and weakly prominent, proximally pointing ridge near ventro-proximal tip of LAP; inner side of distal
edge of LAP devoid of spurs; inner side of tentacle notch distally bordered by slightly thickened ventro-
distal edge of LAP. Very shallow vertical furrow dorsally bordering tentacle notch with single, very
small perforation near ventralmost tip of furrow; no other perforations discernible.

Paratype supplements and variation

NHMW 2012/0137/0011 is a dissociated median LAP of trapezoid outline; nearly as high as wide; dorsal
edge straight. Live equal-sized spine articulations; ventral lobe large, conspicuously tongue shaped and
connected with distalmost lamella in all spine articulations; slight dorsalward increase in size of ventral
lobes; strong dorsalward increase in size of gaps separating spine articulations. Ventral edge of LAP
oblique, tentacle notch not discernible, possibly on account of insufficient preservation.

THUYB., Fossil record of ophiacanthid brittle stars

Inner side of LAP with central ridge well in agreement with that of holotype; dorsal tip only very slightly
widened; no second, ventral ridge discernible; inner side of tentacle notch large but poorly defined.
Vertical furrow dorsally bordering tentacle notch very faint, almost indiscernible.

Remarks

Although at first sight these LAPs appear rather atypical of the Ophiacanthidae, their spine articulations
are overlapped by the distalmost lamella of the outer surface striation, and the ventral lobes of the spine
articulations are large, tongue like and connected with the distalmost lamella, which, together with the
well-developed ridges on their inner side, unambiguously places them in the Ophiolimna lineage. There
is a superficial resemblance with the similarly rectangular LAPs of the extinct ophioleucinid Eirenura
Thuy, 2011. In the latter, however, the outer surface is only faintly striated, the dorsal tip of the ridge is
not widened, and, most importantly, the spine articulations are rhombic rather than ear-shaped and lack
the tongue-shaped ventral lobe.

The comparatively small and deeply sunken spine articulations and the slightly widened dorsal tip of the
central ridge on the inner side are highly distinctive features of the above-described LAPs, precluding
confusion with any other LAP type assigned to Ophiolimna. Thus, the LAP type in question is described
here as a new species.

Occurrence

Late Sinemurian to early Pliensbachian of Austria.

Ophiolimna malagasica sp. nov.

um:lsid:zoobank.org:act:158198F0-5105-4FD2-94F3-F79984D38A0E

Fig. 13: 9-12

Diagnosis

Species of Ophiolimna with tiny LAPs displaying pointed, strongly ventro-proximalwards protruding
ventral portion (accounting for at least one-third of the total height of proximal LAPs); outer surface
almost entirely covered by relatively coarse vertical striation; up to six relatively large spine articulations
separated from distal edge of LAP by very narrow gap; inner side with spoon-shaped central ridge with
strongly widened, round dorsal tip, and second ventral, triangular ridge.

Etymology

Name formed after the Malagasy Gulf which formed a southerly extension of the Tethys between Africa
and India in Jurassic times, in reference to the origin of the type material.

Type material

Holotype

GZG.INV.78553.

Paratypes

GZG.INV.78554, GZG.INV.78555 and GZG.INV.78556.

Type locality and horizon

Jumara, Kachchh, India; sample 24, Patcham Formation, late Bathonian, Middle Jurassic.

European Journal of Taxonomy 48: 1-242 (2013)

Additional material

GZG.1NV.78557 (5 dissociated LAPs) from sample 24; GZG.1NV.78558 (13 dissoeiated LAPs) from
sample 15; GZG.INV.78559 (6 dissoeiated LAPs) from sample 31; GZG.INV.78560 (8 dissoeiated
LAPs) from sample 89.

Description

Holotype

GZG.1NV.78553 is a dissoeiated, minute, very fragile, proximal LAP; eonsiderably higher than wide;
dorsal edge fragmentary; distal edge slightly eonvex; preserved portion of proximal edge undulose,
devoid of spurs; ventral portion of LAP pointed, strongly protruding ventro-proximal wards, aeeounting
for at least one-third of the total LAP height; outer surfaee almost entirely eovered by eoarse, regular,
vertieal striation eomposed of broad, overlapping lamellae deereasing in size distalwards and replaeed
by finely meshed stereom only at the very proximal edge of the LAP Six relatively large, ear-shaped,
equi-distant spine artieulations in notehes of the distal edge, overlapped by the undulose distalmost
lamella; ventral lobe large, eonspieuously tongue shaped and eonneeted with the distalmost lamella in
all spine artieulations; strong dorsal ward inerease in size of spine artieulations; very narrow gap between
spine artieulations and distal edge of LAP Ventral edge of LAP strongly oblique on aeeount of the
pointed ventral portion, with large, eoneave tentaele noteh.

Inner side of LAP with eonspieuous, sharply defined, prominent, spoon-shaped eentral ridge displaying
strongly widened, round and proximally pointing dorsal tip and very slightly widened ventro-distally
pointing ventral tip; seeond sharply defined, strongly prominent, triangular ridge elose to the eentre
of the ventro-distal edge of the LAP; no spurs diseemible on inner side of distal edge of LAP. No
perforations diseemible.

Paratype supplements and variation

GZG.1NV.78554 is a dissoeiated median LAP; nearly as wide as high, dorso-proximal edge strongly
fragmentary; ventral third to quarter strongly protmding ventro-proximal wards; lamellae of outer surfaee
vertieal striation very eoarse. Four equidistant spine artieulations with slight dorsalward inerease in size.
Inner side well in agreement with that of holotype; dorsal tip of eentral ridge less strongly widened.

GZG.1NV.78555 is a dissoeiated distal LAP of rounded reetangular outline, slightly wider than high;
dorsal edge straight; proximal edge intaet, slightly undulose, devoid of spurs; ventral portion of LAP
hardly protmding ventro-proximalwards. Four equidistant and nearly equal-sized spine artieulations
in notehes of distal edge. Ventral edge of LAP eonvex with small, eoneave tentaele noteh next to
ventralmost spine artieulation.

Inner side of LAP largely obseured by sediment; dorsal tip of eentral ridge diseemible, only slightly
widened, proximalwards pointing; no ventral ridge diseemible.

GZG.1NV.78556 is a dissoeiated median LAP; proximal edge eompletely intaet, slightly undulose with
narrow band of finely meshed stereom, otherwise well in agreement with other type speeimens.

Remarks

The tiny LAPs deseribed above are so strikingly similar to those of extant speeies of Ophiolimna,
showing all the diagnostie LAP-morphologieal eharaeters of the genus, that assignment to Ophiolimna
seems unquestionable. Among the speeies assigned to Ophiolimna, the elosest similarities are shared
with Ophiolimna kucerai sp. nov. (see below). In the latter, however, the LAPs are larger and display a
larger gap between the spine artieulations and the distal edge.

Occurrence

Middle Bathonian to Callovian of India.

THUYB., Fossil record of ophiacanthid brittle stars

Ophiolimna lisae sp. nov.

um:lsid:zoobank.org:aet:53A4D340-3462-4B83-B996-14E4D2A3FQ71

Fig. 14: 1-3

Diagnosis

Speeies of Ophiolimna with large LAPs displaying a large, eonspieuous, straight, oblique, golf elub-
shaped eentral ridge with strongly widened, ventro-proximally pointing dorsal tip; seeond ventral, short
ridge almost direetly bordering ventral tip of eentral ridge.

Etymology

Speeies named in honour of my friend Lisa Walz, who would always find eneouraging words to eheer
up moments of despair, ineluding those aeeompanying the terminal phase of this study.

Type material

Holotype

GZG.INV.78561.

Paratypes

GZG.INV.78562, GZG.INV.78563 and GZG.INV.78564 from the upper Kimmeridgian Amaral
Formation of Traneoso, Portugal

Type locality and horizon

Pointe du Chay near La Roehelle, Franee; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late
Jurassie.

Additional material

GZG.INV.78565 (78 dissoeiated LAPs) from the upper Kimmeridgian Amaral Formation of Traneoso,
Portugal.

Description

Holotype

GZG.INV.78561 is a dissoeiated, large, proximal one; higher than wide; dorsal and distal edges eonvex;
proximal edge eoneave and slightly angular, devoid of spurs but with narrow band of very finely
meshed stereom; ventral seventh of LAP only weakly protruding ventro-proximalwards; outer surfaee
almost entirely eovered by eoarse, regular vertieal striation eomposed of broad, overlapping lamellae
deereasing in size proximalwards and replaeed by densely meshed stereom in narrow area bordering
the eentral part of the finely meshed band at the proximal edge of the LAP. Six large, ear-shaped spine
artieulations in relatively deep notehes of the distal edge, overlapped by the strongly undulose distalmost
lamella and eonneeted with the latter by the large, eonspieuously tongue-shaped ventral lobes of the
spine artieulations; dorsalward inerease in the size of the spine artieulations and of the gaps separating
them; no gap between spine artieulations and distal edge of LAP. Tentaele noteh almost indiseernible in
external view.

Inner side of LAP with large, eonspieuous, sharply defined, prominent, oblique, straight, golf elub-
shaped eentral ridge; dorsal tip of ridge strongly widened, pointing ventro-proximal wards; seeond
ventral, well-defined and prominent but short ridge almost direetly bordering ventral tip of eentral ridge
but nevertheless sharply separated from the latter; no spurs on inner side of distal edge of LAP; inner

European Journal of Taxonomy 48: 1-242 (2013)

Fig. 14. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b) views.
1-3. Ophiolimna lisae sp. nov. from the early Kimmeridgian of the Pointe du Chay (1), Franee, and the
late Kimmeridgian of Traneoso, Portugal (2-3). 1. GZG.1NV.78561 (holotype), proximal LAP. 2. GZG.
1NV.78562 (paratype), proximal LAP. 3. GZG.1NV.78563 (paratype), median LAP. 4-7. Ophiolimna
kucerai sp. nov. from the latest Aptian to earliest Albian (Early Cretaeeous) of Blake Nose, NE Atlantie.
4. GZG.1NV.78566 (holotype), proximal EAP 5. GZG.1NV.78567 (paratype), median EAP 6. GZG.
INV.78568 (paratype), distal EAP. 7. GZG.INV. 78569 (paratype), proximal EAP. 8-10. Geromura
touertensis gen. et sp. nov. from the Bajoeian-Bathonian boundary of Touert, Franee. 8. GZG.1NV.78571
(holotype) median to proximal EAP. 9. GZG.INV. 78572 (paratype), proximal EAP. 10. GZG.INV. 78573
(paratype), distal EAP. One eommon seale bar per speeies is given.

THUYB., Fossil record of ophiacanthid brittle stars

side of tentacle notch large, obscured by sediment. Broad, shallow vertical furrow dorsally bordering
tentacle notch with series of irregular, medium-sized perforations, with dorsalward increase in gaps
separating perforations.

Paratype supplements and variation

GZG.INV.78562 is a dissociated proximal LAP, fragmentary, ventral portion of LAP missing; originally
larger and higher than holotype; otherwise well in agreement with holotype.

GZG.INV.78563 is a dissociated median LAP; nearly as high as wide, of rounded aspect; generally well
in agreement with holotype. Four large, ear-shaped spine articulations with dorsalward increase in size
of gaps separating them.

Inner side of LAP with large, conspicuous central ridge, similar to that of holotype but slightly bent
rather than straight; ventral ridge similar to that of holotype; inner side of tentacle notch large, bordered
distally by thin, moderately well-defined ridge. Broad, shallow vertical furrow dorsally bordering
tentacle notch with series of irregular, medium-sized perforations, distally bordered by poorly defined
and dorsally fading ridge.

GZG.INV.78564 is a dissociated distal LAP; slightly wider than high; well in agreement with holotype.
Four spine articulations, dorsalmost of which invisible in external view.

Inner side of LAP with large, conspicuous central ridge, similar to that of holotype but slightly bent and
merged with ventral ridge; inner side of tentacle notch large and distally bordered by prominent, well-
defined ridge. Broad, shallow, poorly defined vertical furrow dorsally bordering tentacle notch with series
of irregular, medium-sized perforations, distally bordered by poorly defined and dorsally fading ridge.

Remarks

The highly distinctive outer surface striation and spine articulation morphology leave no doubt as to
the assignment of these LAPs to the genus Ophiolimna. On account of its large size and the shape and
arrangement of the ridges on its inner side, the LAPs in question are incompatible with any currently
known species of Ophiolimna.

Occurrence

Early Kimmeridgian of France and late Kimmeridgian of Portugal.

Ophiolimna kucerai sp. nov.

um:lsid:zoobank.org:act:736B12D4-3C48-4CE3-A6B4-FA0BlCE9BDCE

Fig. 14: 4-7

Diagnosis

Species of Ophiolimna with small EAPs; ventral third to quarter strongly protruding ventro-
proximalwards; up to five moderately large spine articulations; relatively wide gap between spine
articulations and distal edge of EAP; inner side with nearly straight, oblique, spoon-shaped dorsal ridge
displaying strongly widened, round dorsal tip, and second, ventral, much shorter, nearly straight, ventro-
proximally pointing ridge.

Etymology

Species named in honour of Michal Kucera for generously providing the samples yielding the type
material of the species, and for the very fruitful and encouraging discussions on the potential of
ophiuroids as a model to explore the evolutionary history of modem deep-sea benthos.

European Journal of Taxonomy 48: 1-242 (2013)

Type material

Holotype

GZG.1NV.78566.

Paratypes

GZG.1NV.78567, GZG.1NV.78568 and GZG.INV.78569.

Type locality and horizon

Blake Nose, borehole ODP 17 IB 1049A20x5, tropieal northeast Atlantie; latest Aptian to earliest Albian,
Hedbergella trochoidea to Microbedbergella rischi planktonie foraminifer zones, Early Cretaeeous.

Additional material

GZG.1NV.78568 (752 dissoeiated LAPs).

Description

Holotype

GZG.1NV.78566 is a dissoeiated, small, proximal LAP; dorsal edge oblique, very weakly eoneave;
distal edge irregularly undulose; proximal edge devoid of spurs, with large, slightly thiekened, very
poorly defined eentral part; ventral quarter strongly protruding ventro-proximalwards; outer surfaee
with well-developed, eoarse, regular vertieal striation eomposed of broad, overlapping lamellae replaeed
by finely meshed stereom in very narrow band along proximal edge. Five moderately large, nearly
equi-distant, ear-shaped spine artieulations in relatively deep notehes of weakly elevated distal edge of
LAP; overlapped by the undulose distalmost lamella and eonneeted with the latter by the moderately
large, tongue-shaped ventral lobes of the spine artieulations; dorsalward inerease in the size of the spine
artieulations; gap between spine artieulations and distal edge of LAP relatively wide. Ventral edge of
LAP with moderately large, eoneave tentaele noteh.

Inner side of LAP with sharply defined, prominent, very slender, relatively long, oblique, nearly straight,
spoon-shaped dorsal ridge with strongly widened, round dorsal tip; seeond mueh shorter, slightly wider,
ventro-proximalwards pointing ridge on ventral portion of LAP; inner side of distal edge of LAP devoid
of spurs; inner side of tentaele noteh moderately large. No perforations or furrow diseemible.

Paratype supplements and variation

GZG.1NV.78567 is a dissoeiated proximal LAP, ventro-proximal part strongly fragmentary; very well
in agreement with holotype. Five spine artieulations similar to those observed on holotype but slightly
larger, with stronger dorsal inerease in size, and with larger and thieker lip-shaped ventral lobe eonneeted
with the distalmost lamella.

GZG.1NV.78568 is a dissoeiated median LAP; approximately 1.5 times wider than high; dorsal edge
very weakly eoneave as a result of a slight eonstrietion; vertieal striation on outer surfaee less regular
than in holotype and eomposed of finer lamellae. Four spine artieulations similar to thos observed on
holotype; dorsalmost and ventralmost spine artieulations slightly smaller than remaining two.

Inner side of LAP with single ridge eomposed of oblique, near-straight dorsal part with very weakly
widened dorsal tip, and mueh shorter, slightly wider ventral part; both parts of ridge eonneeted by
rounded kink.

GZG.1NV.78569 is a dissoeiated distal LAP; more than twiee wider than high. Three spine artieulations
similar to those observed on holotype.

Inner side largely obseured by sediment; slender, oblique, near-straight dorsal part of ridge diseemible.

THUYB., Fossil record of ophiacanthid brittle stars

Remarks

These LAPs are unambiguously assignable to Ophiolimna on account of the highly distinctive spine
articulation morphology and the outer surface striation. Within this genus, greatest similarities are shared
with the LAPs of Ophiolimna malagasica sp. nov. (see above), which, however, are smaller and display
six rather than five spine articulations separated by a much narrower gap from the distal edge of the LAP

Occurrence

Latest Aptian to earliest Albian of the tropical northeast Atlantic.

Genus Geromura gen. nov.

um:lsid:zoobank.org:act:10BE3FAB-5984-4759-8DFl-172F60DE98CA

Type species

Geromura teckliformis sp. nov., by present designation.

Other species included

Geromura touertensis sp. nov.

Diagnosis

Ophiacanthid genus with relatively small and extremely elongate FAPs, proximal ones at least twice
wider than high; well-developed constriction; relatively small spine articulations of rugged appearance,
freestanding on slightly elevated distal part of FAP; very large tentacle notch; two separate knobs on
inner side at least in median to distal FAPs.

Etymology

Genus named in honour of Gero Moosleitner, who introduced me to the spectacular site at the Glasenbach
Gorge near Salzburg, Austria, and who generously provided a major part of the samples used in this
study, including those yielding the original material of the type species of the genus; from our a, Greek
for “tail”, a commonly used suffix for ophiuroid names, gender feminine.

Remarks

The Mesozoic ophiuroid fossil record includes a highly peculiar type of dissociated FAPs which is
characterised by its extraordinary width. In fact, even proximal FAPs of the type in question are more
than twice wider than high, a ratio which, in most other ophiuroid lineages, is only found in the very
distalmost FAPs. Other distinctive characters of such FAP type are the relatively small, freestanding,
ear-shaped spine articulations composed of irregular, rough dorsal and ventral lobes, a very large
tentacle notch implying a large tentacle pore as defined by Thuy et al. (2012), a strong constriction, and
two separate knobs on the inner side at least of the median to distal FAPs. The last-named character
precludes confusion with the FAPs of Lapidaster gen. nov. and Ophiologimus, which share the greatest
similarities with the FAP type in question. A new genus, Geromura gen. nov., is therefore introduced
here to accommodate the peculiar type of FAPs in question. In spite of their rugged and rather atypical
appearance, the spine articulations of Geromura gen. nov. display a sigmoidal fold, which unambiguously
places them in the Ophiacanthidae.

The phylogenetic position of Geromura gen. nov. remains elusive as long as no articulated specimens
are known on the basis of which a complete character analysis could be performed. It is very likely,
however, that it shares greatest phylogenetic ties with the other large-pores lineages, in particular the
Lapidaster-Ophiologimus lineage (see above) as suggested by the close similarities in FAP morphology.
Interestingly, Geromura gen. nov. is currently known exclusively from deep-water deposits.

European Journal of Taxonomy 48: 1-242 (2013)

Geromura touertensis sp. nov.

um:lsid:zoobank.org:act:83E97048-lF4F-447A-927A-EA58AE3B4973

Fig. 14: 8-10

Diagnosis

Species of Geromura gen. nov. with moderately large EAPs, at least twice wider than high; displaying
two conspicuous, well-defined and strongly protruding spurs on the outer proximal edge paralleled
by two poorly defined areas of densely meshed stereom on the inner distal edge; up to three spine
articulations; single large knob in proximal EAPs, divided into two widely separate, smaller knobs in
median and distal EAPs.

Etymology

Species named after its type locality Ee Touert near Chaudon-Norante, Alpes-de-Haute-Provence,
France.

Type material

Holotype

GZG.1NV.78571.

Paratypes

GZG.1NV.78572 and GZG.1NV.78573.

Type locality and horizon

Ee Touert near Chaudon, France; marl bed at the Bajocian-Bathonian boundary. Middle Jurassic.

Description

Holotype

GZG.1NV.78571 is a dissociated, moderately large median to proximal EAP; slightly more than twice
wider than high; dorsal edge strongly concave as a result of a well-developed constriction; distal edge
nearly straight; ventro-distal tip of EAP strongly protruding; proximal edge wavy, with two moderately
large, well-defined, prominent, horizontally elongate and conspicuously protruding spurs composed of
densely meshed stereom; ventral spur larger and more strongly protruding than dorsal one; outer surface
with very coarsely meshed stereom, replaced by finely meshed stereom in a narrow band along the
proximal edge of the EAP; intersections of trabeculae thickened into granules. Two relatively small,
rugged, ear-shaped spine articulations, freestanding on slightly elevated distal edge, not in notches
or depressions; ventral and dorsal lobes forming nearly circular volute; nerve opening large, ventro-
distally bordering sigmoidal fold; dorsal spine articulation slightly larger than ventral one; very large
gap separating spine articulations and distal edge of EAP. Ventral edge of EAP concave, with very large,
concave tentacle notch.

Inner side of EAP with two widely separate, sharply defined and prominent knobs; the proximal knob
three times larger than distal one, nearly triangular; distal knob rounded; inner side of distal edge of EAP
with poorly defined, slightly prominent knobs composed of densely meshed stereom, one knob in the
dorso-distal comer, the other in the ventro-distal comer. Inner side of tentacle notch with very coarsely
meshed and horizontally stretched stereom. No perforations discernible on inner side.

Paratype supplements and variation

GZG.INV.78572 is a dissociated proximal EAP; twice wider than high; generally well in agreement
with holotype; dorso-proximal tip fragmentary. Three spine articulations, with very slight dorsalward
increase in size; ventral gap larger than dorsal gap.

THUYB., Fossil record of ophiacanthid brittle stars

Inner side with single, large, sharply defined, prominent, nearly wedge-shaped knob.

GZG.INV.78573 is a dissociated distal LAP; rod shaped; almost three times as wide as high; spurs on
proximal edge strongly protruding, nearly equal sized. Two spine articulations, ventral one slightly
smaller than dorsal one. Ventral edge of LAP evenly concave, tentacle opening developed as perforation
ventrally bordering the ventral spine articulation.

Inner side with two sharply defined, rounded, prominent and widely separated knobs; proximal knob
approximately three times larger than distal one. Very large tentacle notch in the middle of the distal
third of the inn er side.

Remarks

These LAPs can be unmistakably distinguished from those of its congener Geromura teckliformis
sp. nov. (see below) on account of the two well-developed and strongly protruding spurs on the outer
proximal edge paralleled by less well-defined, slightly prominent spurs on the inner distal edge, as
well as the lower number of spine articulations. The transformation of two separate knobs into a single
larger one from median to proximal LAPs is remarkable. In fact, it suggests that the development of
the knobs on the inner side is primarily controlled by biomechanical constraints imposed by the height/
width ration of the LAPs. This is corroborated by G. teckliformis sp. nov. in which all LAPs, including
the proximal ones, have a significantly lower height/width ratio than those of G. touertensis sp. nov.,
and at the same time invariably display two widely separated knobs. Supportive evidence furthermore
comes from the distalmost LAPs of Lapidaster etteri sp. nov. (see above). With a height/width ratio of
1:3 and thus comparable to that of most LAPs of species of Geromura gen. nov., the distalmost LAPs of
Lapidaster etteri sp. nov. display two widely separate knobs rather than a single knob or ridge.

Because elongate arm segments are a typically juvenile character (Stohr 2005), it appears probable
that Geromura gen. nov. developed from an ancestor of the Lapidaster-Ophiologimus lineage via
paedogenesis. The strong elongation of the arm segments entailed the transformation of a single knob
or ridge on the inner side of the LAPs into two widely separate knobs. It cannot be ruled out that this
process occurred more than once, which would imply that Geromura gen. nov. is an artificial grouping
of superficially similar but independently evolved LAP morphologies. The strong similarities in spine
articulation morphology, however, endorse the concept of Geromura gen. nov. as a single lineage, since
there is no evidence that a decrease in height/width ratio entails any changes in the structure of the spine
articulations.

Occurrence

Bajocian-Bathonian of France.

Geromura teckliformis sp. nov.

um:lsid:zoobank.org:act:FFC94DlF-2BB4-4CAF-AF61-7E7CQD60FlCA

Fig. 15: 1-3

Diagnosis

Species of Geromura with moderately large LAPs, at least 3.5 times wider than high; two poorly
defined and non-protruding spurs on the outer proximal edge paralleled by very weakly developed
spurs composed of slightly more densely meshed stereom on the inner distal edge; up to five spine
articulations; two widely separate knobs on inner side of all LAPs.

European Journal of Taxonomy 48: 1-242 (2013)

Etymology

Name derived from “Teekel”, the German sausage dog, in referenee to the extremely elongate LAPs of
the speeies.

Type material
Holotype

NHMW 2012/0138/0005.

Paratypes

NHMW 2012/0138/0006 and NHMW 2012/0138/0007.

Type locality and horizon

KBl-A seetion of Lukeneder (2004) in the Temberg Nappe, Austria; Verrucosum Zone, late Valanginian,
Early Cretaeeous.

Additional material

NHMW 2012/0138/0008 (123 dissoeiated LAPs).

Description

Holotype

NHMW 2012/0138/0005 is a dissoeiated, medium-sized, proximal LAP; rod shaped, approximately
3.5 times wider than high; dorsal edge eoneave as a result of a well-developed eonstrietion; distal edge
nearly straight; ventro-distal tip of LAP strongly protruding, tongue shaped; proximal edge irregularly
eoneave, with two small, poorly defined, horizontally elongate, slightly prominent but not protruding
spurs eomposed of slightly more densely meshed stereom; outer surfaee with very eoarsely meshed
stereom, replaeed by finely meshed stereom in a narrow band along the proximal edge of the LAP;
interseetions of trabeeulae not thiekened into granules. Five small, round to slightly ear-shaped, equi¬
distant spine artieulations of rugged appearanee, freestanding on elevated distal portion of LAP;
ventralmost spine artieulation slightly smaller than remaining four; dorsalmost spine artieulation on
dorsal edge of LAP, hardly diseemible in external view; ventral and dorsal lobes of spine artieulations
forming nearly eireular volute with very small sigmoidal fold and very small nerve opening; gap between
spine artieulations and distal edge of LAP very wide, almost twiee wider than spine artieulations. Ventral
edge of LAP gently eonvex exeept for very large, eoneave tentaele noteh.

Inner side of LAP with two very small, sharply defined, prominent, round and widely separate knobs
eomposed of finely meshed stereom; inner side of distal edge of LAP with two very weakly defined,
non-prominent and non-protruding spurs eomposed of slightly more densely meshed stereom. No
perforations diseemible.

Paratype supplements and variation

NHMW 2012/0138/0006 is a dissoeiated median LAP; four times wider than high; spurs on proximal
edge very small, hardly diseemible. Four spine artieulations, ventralmost slightly smaller than remaining
three; gap separating spine artieulations and distal edge of LAP more than twiee wider than spine
artieulations. Ventral edge of LAP nearly straight, with very large eoneave tentaele noteh.

Inner side of LAP well in agreement with that of holotype.

NHMW 2012/0138/0007 is a dissoeiated distal LAP; five times wider than high; spurs on proximal edge
very small, hardly diseemible. Three poorly preserved spine artieulations; row of spine artieulations
strongly protmding dorsalwards; gap between spine artieulations and distal edge of LAP wider than

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 15. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars m external (a) and internal (b) views.
1-3. Geromura teckliformis gen. et sp. nov. from the late Valanginian (Early Cretaeeous) of the Temberg
Nappe, Austria. 1. NHMW 2012/0138/0005 (holotype), proximal LAP. 2. NHMW 2012/0138/0006
(paratype), median LAP. 3. NHMW 2012/0138/0007 (paratype), distal LAP. 4-6. Krohcoma mira gen. et
sp. nov. from the late Sinemurian to early Pliensbaehian (Early Jurassie) of the Glasenbaeh Gorge, Austria.
4. NHMW 2012/0137/0013 (holotype), proximal LAP. 5. NHMW 2012/0137/0014 (paratype), median
LAP. 6. NHMW 2012/0137/0015 (paratype), distal LAP. 7-8. Krohcoma sp. nov. innom from the late
Bathonian (Middle Jurassie) of Jumara, India. 7. GZG.INV.78574, proximal LAP. 8. GZG.INV.78575,
median to distal LAP. 9-12. Krohcoma ampla gen. et sp. nov. from the early Kimmeridgian of the Pointe
du Chay (9-10), Franee, and the late Kimmeridgian of Traneoso, Portugal (11-12). 9. GZG.INV.78577
(holotype), proximal LAP. 10. GZG.INV.78578 (paratype), median LAP. 11. GZG.INV.78579 (paratype),
median LAP. 12. GZG.INV.78580 (paratype), distal LAP. One eommon seale bar per speeies is given.

European Journal of Taxonomy 48: 1-242 (2013)

one spine artieulation. Ventral edge of LAP very gently eoneave, no tentaele noteh; hardly diseemible
tentaele opening near ventro-distal edge of ventralmost spine artieulation.

Inner side of LAP obseured by sediment.

Remarks

Differenees between the present LAPs and Geromura touertensis sp. nov. are diseussed above. The
present LAPs are so highly distinetive that there is hardly any ehanee to eonfuse them with any other
ophiuroid speeies.

Occurrence

Late Valanginian of Austria.

Genus Kroh coma gen. nov.

um:lsid:zoobank.org:aet:0A950939-8454-48EQ-853A-A431FB153F6F

Type species

Krohcoma mira sp. nov., by present designation.

Other species included

Krohcoma ampla sp. nov.

Diagnosis

Ophiaeanthid genus with relatively stout FAPs devoid of eonspieuous outer surfaee ornament; spine
artieulations very large, with thiek dorsal and ventral lobes and very large musele opening, freestanding
on strongly elevated ridge, arranged in eonspieuously dorso-proximally reeeding row; spine artieulations
not sharply separated from remaining outer surfaee; tentaele noteh large to very large.

Etymology

Genus named in honour of my friend and eolleague Andreas Kroh for his valuable support in the eladistie
phylogenetie anaylsis of the Ophiaeanthidae and in sampling the speetaeular Glasenbaeh Gorge seetion,
whieh produeed the type speeies of the genus; from coma, Fatin for “hair”, a eommonly used suffix in
ophiuroid names, gender feminine.

Remarks

Most fossil FAP types assignable to the Ophiaeanthidae ean be related to an extant lineage on the basis
of strong morphologieal s im ilarities. Among the more ehallenging fossil ophiaeanthid FAP types is
one whieh is eharaeterised by very large, ear-shaped spine artieulations arranged in a eonspieuously
dorso-proximalwards obliquely reeeding and ventrally protruding row, and displaying a large musele
opening. These relatively stout FAPs, unambiguously assignable to the Ophiaeanthidae on aeeount of the
sigmoidal fold and the absenee of a single large perforation on the inner side, furthermore display a very
large tentaele noteh. Although artieulated speeimens have yet to be diseovered, it seems highly probable
that the large tentaele notehes, indeed, refleet large tentaele pores as deflned by Thuy et al. (2012), whieh
would plaee the FAP type in question among the basal, large-pored ophiaeanthids formerly united as
the Ophiotominae.

Among the eurrently known large-pored ophiaeanthid lineages, Ophiotoma and the Lapidaster-
Ophiologimus lineage elearly differ in having a non-bulging or elevated distal portion of their FAPs.
The FAPs of Ophiolimna and Ophiopristis Verrill, 1899 display a eonspieuous vertieal striation on the
outer surfaee and fundamentally different ridge struetures on their inner side, and in Geromura gen. nov.

THUYB., Fossil record of ophiacanthid brittle stars

the LAPs are extremely elongate. There is a superficial similarity to the LAPs of Eolaxoporus gen. nov.,
which, however, fundamentally differ in having proximally widely separate dorsal and ventral lobes of
the spine articulations. Closest similarities are shared with the LAPs of Ophiomedea Koehler, 1906 and
Leadagmara Thuy et a/., 2012. Neither of these, however, display a dorso-proximal wards receding row
of spine articulations. Krohcoma gen. nov. is thus introduced here to accommodate the above-mentioned
LAPs. Its exact phylogenetic position remains elusive. On the basis of LAP morphology, however,
Krohcoma gen. nov. seems closest to Eolaxoporus gen. nov. and to the Ophiomedea-Leadagmara clade.

Krohcoma mira sp. nov.

um:lsid:zoobank.org:act:79C26A85-E693-4AF7-8A41-36FB956BE7ED

Fig. 15: 4-6

Diagnosis

Species of Krohcoma gen. nov. with relatively small EAPs, displaying very poorly defined, large spur
in the middle of the proximal edge; up to five very large, equal-sized spine articulations; row of spine
articulations protruding ventrally; tentacle notch very large, equalling half of the total ventral EAP edge
width; ridge on inner side of EAPs merged with ventral EAP edge.

Etymology

Name derived from mirus, Eatin for “astonishing”, in reference to the palaeohabitat of the species
suggesting a deep-water origin of the genus and thus challenging widely accepted concepts on the role
of the deep sea in macroevolutionary patterns.

Type material
Holotype

NHMW 2012/0137/0013.

Paratypes

NHMW 2012/0137/0014 and NHMW 2012/0137/0015.

Type locality and horizon

Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbachian, Early Jurassic.

Additional material

NHMW 2012/0137/0015 (10 dissociated EAPs).

Description

Holotype

NHMW 2012/0137/0013 is a dissociated, small, proximal EAP; nearly as high as wide; dorsal edge
slightly convex; distal edge oblique, convex; proximal edge irregularly undulose, with very poorly
defined, prominent and slightly protruding central spur composed of slightly more densely meshed
stereom; ventro-proximal tip of EAP thickened into very poorly defined, prominent spur composed of
slightly more densely meshed stereom; outer surface with moderately finely meshed stereom, devoid
of conspicuous ornament elements. Five very large, ear- to horseshoe-shaped spine articulations,
freestanding in dorso-proximally receding row on strongly bulging distal portion of EAP; dorsal and
ventral lobes of spine articulations very thick, proximally merged by relatively thin connection into
continuous lobe encompassing conspicuously large muscle opening; spine articulations nearly equal
sized and equi-distant; row of spine articulations protruding ventrally. Ventral edge of EAP straight
except for protruding ventral tip of spine articulation row; tentacle notch not visible in external view.

European Journal of Taxonomy 48: 1-242 (2013)

Inner side of LAP with relatively small, narrow, sharply defined, prominent and slightly bent ridge;
dorsal tip of ridge pointing dorso-proximalwards, not widened; ventral portion of ridge merged with
thiekened ventral edge of LAP; inner side of distal edge of LAP with poorly defined, slightly prominent
but not protruding spur eomposed of slightly more densely meshed stereom; inner side of tentaele noteh
very large, aeeounting for approximately half of the total ventral LAP edge width. No perforations
diseemible.

Paratype supplements and variation

NHMW 2012/0137/0014 is a dissoeiated median LAP; slightly wider than high; dorsal edge straight
to slightly eoneave. Four very large, nearly equal-sized spine artieulations similar to those observed
on holotype; very weak dorsalward inerease in size of gaps separating spine artieulations; row of spine
artieulations only slightly protruding ventrally. Ventral edge of LAP nearly straight.

Inner side of LAP well in agreement with that of holotype; no spur diseemible on inner side of distal
edge of LAP.

NHMW 2012/0137/0015 is a dissoeiated distal LAP; almost twiee wider than high; dorsal edge elearly
eoneave as a result of a well-developed eonstrietion; proximal edge with rather poorly defined, prominent
and very slightly protmding eentral spur eomposed of slightly more densely meshed stereom; ventral
sixth of LAP slightly protmding ventro-proximal wards. Four very large, equal-sized, ear- to horseshoe¬
shaped spine artieulations on elevated distal portion of LAP, arranged in dorso-proximally reeeding row;
very slight dorsalward inerease in size of gaps separating spine artieulations. Ventral edge with very
large, weakly eoneave tentaele noteh.

Inner side of LAP obseured by sediment.

Remarks

These LAPs ean be easily differentiated from almost every other type of LAPs on aeeount of the
distinetive dorso-proximally reeeding row of very large spine artieulations. Within the group of LAPs
that display the latter eharaeter, here assigned to Krohcoma gen. nov., the above-deseribed ones are
unique in having equal-sized spine artieulations and very large tentaele notehes aeeounting for nearly
half of the total ventral LAP edge width.

Occurrence

Late Sinemurian to early Pliensbaehian of Austria.

Krohcoma sp. nov. innom.

Fig. 15: 7-8

Material examined

GZG.1NV.78574, GZG.1NV.78575 and GZG.INV.78576 (dissoeiatedLAP) from the Pateham Formation,
late Bathonian, of Jumara, India.

Description of proximal LAP

GZG.1NV.78574 is a dissoeiated relatively small, proximal LAP; slightly higher than wide; dorsal edge
strongly eoneave as a result of a well-developed eonstrietion; distal edge obliquely eonvex; proximal
edge irregularly eoneave, devoid of spurs or thiekened parts; outer surfaee with moderately finely
meshed stereom, no eonspieuous ornament elements diseemible; six very large, ear-shaped to horseshoe¬
shaped spine artieulations in eontinuous, dorso-proximalwards eonspieuously reeeding row on strongly
elevated distal portion of LAP; dorsal and ventral lobes of spine artieulations thiek, proximally merged
by relatively thin eonneetion into eontinuous, horizontally slightly elongate volute; dorsalward inerease

THUYB., Fossil record of ophiacanthid brittle stars

in size of spine articulations and of gaps separating them; row of spine articulations protruding ventrally.
Ventral edge of LAP slightly concave, tentacle notch not visible in external view.

Inner side of LAP largely obscured by sediment; ridge not clearly discernible; inner side of distal edge
of LAP devoid of spurs; inner side of tentacle notch large, accounting for slightly less than one-third of
the total ventral LAP edge width. No perforations dicemible.

Description of median to distal LAP

GZG.INV.78575 is a dissociated, small, median to distal LAP, with slightly fragmentary dorso-
proximal tip; nearly as wide as high; proximal edge devoid of spurs or thickened parts; outer surface
with moderately finely meshed stereom. Five very large spine articulations, similar to those observed
of holotype but muscle opening not obscured by sediment, very large; spine articulations arranged in
dorso-proximally strongly receding row on elevated distal portion of LAP; row of spine articulations
very strongly protruding ventrally. Ventral edge of LAP strongly concave as a result of the strongly
protruding row of spine articulations.

Inner side of LAP with large, moderately well-defined, wide, bent, prominent ridge; dorsal tip of ridge
pointing dorso-proximalwards; ventral tip of ridge merged with ventral LAP edge; inner side of distal
edge of LAP devoid of spurs; inner side of tentacle notch very large, accounting for at least one-third of
the total ventral LAP edge width. No perforations discernible.

Remarks

These LAPs unquestionably belong to Krohcoma gen. nov. on account of the position and morphology
of the spine articulations. The combination of up to six large spine articulations with slight dorsal ward
increase in size, moderately large tentacle notches, the absence of spurs on the outer proximal and inner
distal edges, and the strongly protruding ventral tip of the row of spine articulations distinguishes these
two LAPs from the two other species here assigned to Krohcoma gen. nov. These two LAPs clearly
represent a new species, the formal description of which, however, requires better-preserved material.

Krohcoma ampla sp. nov.

um:lsid:zoobank.org:act:CE375CEA-89F3-4641-9C52-71BQF7E80517

Fig. 15: 9-12

Diagnosis

Species of Krohcoma gen. nov. with large EAPs, displaying small, poorly defined, protruding spur
in dorsal half of outer proximal edge, paralleled by more clearly defined, round spur in dorsal half of
inner distal edges; up to six very large spine articulations; very strong dorsalward increase in size of
spine articulations and of gaps separating them; ventral lobe of spine articulations connected with outer
surface; row of spine articulations not protruding ventrally; tentacle notch relatively small, accounting
for slightly more than one-quarter of the total ventral EAP edge width; ridge on inner side of EAP with
widened, triangular dorsal tip.

Etymology

Name formed from amplus, Eatin for “large”, “magnificent”, in reference to the large size of the EAPs
of the species in comparison to those of its congeners.

Type material

Holotype

GZG.INV.78577.

European Journal of Taxonomy 48: 1-242 (2013)

Paratypes

GZG.1NV.78578, same locality as holotype; GZG.1NV.78579 and GZG.1NV.78580 from the upper
Kimmeridgian Amaral Formation of Trancoso, Portugal.

Type locality and horizon

Pointe du Chay near La Rochelle, France; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late
Jurassic.

Additional material

GZG.1NV.78581 (dissociated LAP) from the Kimmeridgian of Pointe du Chay, France; GZG.1NV.78582
(12 dissociated LAPs) from the upper Kimmeridgian Amaral Formation of Trancoso, Portugal.

Description

Holotype

GZG.1NV.78577 is a very large, dissociated proximal LAP; at least twice higher than wide; dorsal edge
nearly straight; distal edge obliquely convex; proximal edge irregularly concave, with small, poorly
defined and weakly prominent, yet protruding spur; outer surface with finely meshed stereom, devoid
of conspicuous ornament elements. Six very large, ear-shaped spine articulations arranged in dorso-
proximally strongly receding row on elevated distal portion of LAP; very strong dorsalward increase in
size of spine articulations and of gaps separating them; dorsal and ventral lobes of spine articulations
thick, merged into continuous volute encompassing conspicuously large muscle opening; ventral lobe of
spine articulations connected with finely meshed outer surface; row of spine articulations not protruding
ventrally. Ventral edge of LAP irregularly convex, tentacle notch not discernible in external view.

Inner side of LAP with large, well-defined, prominent ridge; dorsal half nearly straight, oblique, with
widened triangular dorsal tip, separated from ventral half by rounded kink; ventral half short, less well-
defined than dorsal one, not connected with ventral edge of LAP; inner side of distal edge of LAP with
small, moderately well-defined, slightly prominent spur composed of slightly more densely meshed
stereom; inner side of tentacle notch large, accounting for slightly more than a quarter of the total ventral
LAP edge width. Vertical row of small perforations distally bordering kink between dorsal and ventral
portions of the ridge, with dorsalward increase in size of perforations and of gaps separating them.

Paratype supplements and variation

GZG.1NV.78578 is a dissociated median LAP; slightly higher than wide; well matching holotype; spur
on proximal edge slighty better defined and more prominent. Five very large spine articulations similar
to those observed on holotype; connection between ventral lobe of spine articulations and finely meshed
stereom of outer surface slightly more prominent.

Inner side of LAP largely obscured by sediment, only ventral portion of ridge discernible, separated
from ventral edge of LAP; inner side of distal edge of LAP with small, poorly defined, round and
weakly prominent spur composed of slightly more densely meshed stereom. Inner side of tentacle
notch moderately large, distally bordered by moderately well-defined, oblique, prominent ridge. No
perforations discernible.

GZG.1NV.78579 is a dissociated median LAP; slightly higher than wide; dorsal edge concave; outer
surface with slightly more coarsely meshed stereom than in holotype, probably as a result of poorer
preservation. Four very large spine articulations similar to those observed in holotype but with less well-
developed connection between outer surface and ventral lobe of spine articulations, again probably due
to slightly poorer preservation.

Inner side of LAP with well-defined ridge separated by round kink into dorsal portion with slightly
widened dorsal tip, and much shorter ventral portion not connected with ventral edge of LAP; inner

THUYB., Fossil record of ophiacanthid brittle stars

side of tentacle notch large, distally bordered by poorly defined, short, oblique ridge-like knob. No
perforations discernible.

GZG.INV.78580 is a dissociated distal LAP; slightly wider than high; proximal edge slightly fragmentary.
Three very large spine articulations, with very strong dorsalward increase in size; dorsal gap between
spine articulations larger than ventral one.

Inner side of LAP with very poorly defined, oblique, weakly prominent ridge composed of more finely
meshed stereom; dorsal half of inner side of distal LAP edge with small, round, well-defined, prominent spur.

Remarks

Although, at first sight, these LAPs seem to differ significantly from those assigned to Krohcoma gen.
nov., similarities in spine articulation morphology and arrangement are striking. In fact, large spine
articulations with thick dorsal and ventral lobes encompassing a conspicuously large muscle opening,
arranged in a dorso-proximalwards receding row on the elevated distal portion of the LAPs are a highly
distinctive feature which is not found in any other ophiacanthid LAP type. There are admittedly strong
differences between these LAPs and those of its congeners in terms of size of tentacle notch, connection
between outer surface and ventral lobe of spine articulations and size and shape of the ridge on the inner
side. These differences might, in fact, warrant separation at the generic level. On the basis of the striking
similarities in spine articulation morphology and arrangement, however, the present LAPs are here
considered as a new species of Krohcoma gen. nov.

Occurrence

Early Kimmeridgian of France and late Kimmeridgian of Portugal.

Genus OphiotretaYQrriW, 1899

Type species

Ophiacantha lineolata Lyman, 1883, by original designation.

Diagnosis

LAPs with nearly equal-sized spine articulations freestanding in continuous vertical row on elevated
distal portion; outer surface commonly with vertical striation composed of thin overlapping lamellae,
distalmost of which largest and undulose, sharply bordering spine articulations; commonly thin and
poorly to moderately and well-defined connecting ridge between ventral of spine articulations and
distalmost lamella; inner side of LAPs with very large conspicuous ridge composed of short, oblique
ventral portion and very long, near-vertical dorsal portion paralleling proximal edge of LAP; kink
between dorsal and ventral portions of ridge commonly with ventro-proximally pointing angle.

Remarks

The LAPs of extant species of Ophiotreta (Fig. 16:1 -4) almost invariably combine numerous near-equally
sized spine articulations on an elevated distal portion, proximally bordered by the distalmost lamella of
the outer surface striation, and a ridge on the inner side which displays a distinctively long, narrow,
near-vertical dorsal portion very close to the proximal edge separated from the shorter, oblique ventral
portion by a kink with a ventro-proximally pointing angle. While this highly distinctive combination
of characters clearly sets the FAPs of Ophiotreta apart from those of almost all other ophiacanthid
lineages, the FAPs of extant Ophiopristis Verrill, 1899 (Fig. 16: 5-6) are almost identical to those of
Ophiotreta. At first sight, this appears puzzling considering that the two genera were formerly assigned
into separate ophiacanthid subfamilies (e.g. Paterson 1985; Stohr & O’Hara 2007). Ophiotreta has been

European Journal of Taxonomy 48: 1-242 (2013)

generally eonsidered to be elosely related to Ophiacantha Muller & Trosehel, 1842, while Ophiopristis
has been interpreted as a member of the more basal, large-pored lineages (e.g. Martynov 2010).

The strong similarities in general skeletal morphology between both genera, espeeially eonsidering
the long jaws, the number, shape and arrangement of the oral papillae and the size of the tentaele
pores, however, were mentioned, although briefly, by Paterson (1985). These imply that the two genera
in question are either mueh more elosely related than previously thought, or that they independently
evolved similarly shaped jaws and tentaele pores. The above-mentioned, striking similarities in LAP
morphology favour the former interpretation, in line with the observations by Thuy & Stohr (2011)
eoneeming s im ilarities in LAP morphology and elose phylogenetie relationships.

The size of the tentaele pore needs more detailed eonsideration here sinee it was identifled as one
of the major eharaeters separating ophiaeanthid genera into the basal, large-pored lineages and the
large elade of the small-pored genera in the phylogenetie analysis of Thuy et al. (2012). In the revised
phylogenetie analysis presented here, Ophiotreta is basalmost among the large-pored genera and thus
elose to Ophiopristis. As already pointed out by Paterson (1985), tentaele pores in Ophiopristis are
rather small in eomparison with other former ophiotominids, and in Ophiotreta they are rather large for
a former ophiaeanthinid. The deflnition of the tentaele pore size as proposed by Thuy et al. (2012) might
not be suited to refleet the elose relationship between Ophiotreta and Ophiopristis adequately, whieh
obviously seem to hold an intermediate position between the basal large-pored lineages and the more
derived small-pored ones. Whether Ophiotreta and Ophiopristis represent an unusually small-pored
group within the large-pored lineages or viee versa requires a eareful reassessment of the deflnition of
the tentaele pore size with respeet to its applieation in eladistie phylogenetie analyses.

The fossil Ophiotreta- and Ophiopristis-\\kQ LAPs deseribed herein mostly display eonneeting ridges
between the distalmost lamella of the outer surfaee ornament and the ventral lobe of the spine artieulation,
a feature shared by both Ophiopristis and Ophiotreta but more eommonly observed in the latter,
espeeially when in proximal LAPs. Thus, the fossil LAPs in question are here assigned to Ophiotreta,
stressing, however, that Ophiotreta and Ophiopristis share barely distinguishable LAP morphologies,
and that at least some of the fossil LAPs most probably belong to undeseribed genera elose to the two
extant taxa and best ereeted on the basis of artieulated flnds. Ophiotreta and Ophiopristis most probably
represent a single lineage, of whieh the fossil LAPs deseribed herein, although assigned to Ophiotreta,
eonstitute the fossil reeord.

Ophiotreta stefaniae sp. nov.

um:lsid:zoobank.org: aet:91 Al 1 APT-3122-45D4-856B-A42B1C989127

Fig. 16: 7-10

Diagnosis

Speeies of Ophiotreta with large LAPs displaying a relatively small, protruding, pointed spur on the
outer proximal edge, paralleled by a large, round, slightly prominent but not protruding spur on the inner
distal edge eomposed of densely meshed stereom; up to six nearly equal-sized spine artieulations, all
with well-developed eonneeting ridge between ventral lobe and strongly undulose distalmost lamella of
outer surfaee striation; ridge on inner side eomposed of three parts, the ventralmost of whieh relatively
short, straight, oblique, pointing ventro-proximal wards; no knob on the ventral portion of the inner side.

Etymology

Speeies named in honour of my friend Steffl Lutz, in memory of the superb years spent together in
Tubingen, not far from the type loeality of the speeies.

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 16. Skeletal plates of fossil and Recent ophiacanthid brittle stars; lateral arm plates (LAPs) in
external (a) and internal (b) views. 1-3. Ophiotreta durbanensis (Mortensen, 1933), Recent. 1. Proximal
LAP. 2. Distal LAP. 3. Arm spine. 4. Ophiotreta valenciennesi (Lyman, 1879), Recent; proximal to
median LAP. 5-6. Ophiopristis procera (Koehler, 1904), Recent. 5. Proximal LAP. 6. Distal LAP.
7-10. Ophiotreta stefaniae sp. nov. from the late Oxfordian (Late Jurassic) of the Plettenberg, Germany.
7. GZG.INV.78583 (holotype), proximal LAP. 8. GZG.INV.78584 (paratype), proximal LAP. 9. GZG.
INV.78585 (paratype), median LAP. 10. GZG.INV.78586 (paratype), distal LAP. One common scale bar
per species is given, except for 3.

European Journal of Taxonomy 48: 1-242 (2013)

Type material

Holotype

GZG.1NV.78583.

Paratypes

GZG.1NV.78584, GZG.1NV.78585 and GZG.1NV.78586.

Type locality and horizon

Plettenberg near Balingen, southern Germany; elay poekets between sponge assoeiations in the lowest
bed exposed in the quarry, Bimammatum Zone, late Oxfordian, Late Jurassie.

Additional material

GZG.1NV.78587 (53 dissoeiated LAPs).

Description

Holotype

GZG.1NV.78583 is a dissoeiated, large, proximal LAP; more than twiee higher than wide; dorsal edge
slightly eoneave as a result of a well-developed eonstrietion; distal edge evenly eonvex; proximal edge
eoneave, with small, poorly defined, slightly prominent and protruding spur in the middle; ventral half
of proximal edge slightly fragmentary; outer surfaee with rather irregular vertieal striation eomposed
of broad lamellae separated by single very thin lines of stereom pores and eovering the proximal edge
of the strongly elevated distal portion of the LAP and the ventral portion of the outer surfaee; vertieal
striation replaeed by densely to finely meshed stereom in other parts of the outer surfaee. Six large, ear¬
shaped spine artieulations freestanding on strongly elevated distal portion of LAP, proximally sharply
bordered by undulose distalmost lamella; dorsal lobe of spine artieulations very large, separated from
smaller ventral lobe by very small, shallow noteh; short but well-developed and prominent eonneeting
ridge between distalmost lamella and ventral lobe in every spine artieulation; very weak dorsalward
inerease in size of spine artieulations and of gaps separating them. Ventral edge of LAP irregularly
eonvex, tentaele noteh not visible in external view.

Inner side of LAP with large, sharply defined, prominent and relatively narrow ridge separated by two
angular kinks into long, straight and near-vertieal dorsal part elose to the proximal edge of the LAP,
a mueh shorter, oblique, straight eentral part, and a similarly short slightly bent, oblique ventral part;
inner side of distal edge of LAP with large, oval, moderately well-defined, prominent spur eomposed of
densely meshed stereom; inner side of tentaele noteh moderately large, with eoarsely meshed stereom.
Vertieal row of small, irregular perforations in shallow, poorly defined furrow dorsally bordering
tentaele noteh.

Paratype supplements and variation

GZG.1NV.78584 is a dissoeiated proximal LAP; ventro-proximal portion missing; generally very well
in agreement with holotype; spur on proximal edge better preserved, strongly protruding, pointed. Six
spine artieulations similar to those observed in holotype.

Inner side of LAP with dorsal and eentral parts of ridge very well preserved, similar to those observed
in holotype exeept for ventro-proximally pointing angle in kink separating them; inner side of distal
edge of LAP with two moderately large, well-defined, prominent spurs eomposed of densely meshed
stereom.

GZG.1NV.78585 is a dissoeiated median LAP; nearly as high as wide; dorsal edge strongly eoneave as
a result of a strong eonstrietion; proximal edge with moderately large; rather poorly defined, weakly
prominent but protruding and pointed spur. Five spine artieulations similar to those observed in holotype;

THUYB., Fossil record of ophiacanthid brittle stars

weak dorsalward increase in size of spine articulations and of gaps separating them but dorsalmost spine
articulation as small as ventralmost one. Ventral edge irregularly convex with relatively small, concave
tentacle notch near ventralmost spine articulation.

Inner side of LAP with well-defined ridge separated by kink into long, straight, oblique dorsal part with
widened, poorly defined dorsal tip, and much shorter oblique ventral part with well-defined ventral tip;
inner side of distal edge of LAP with large, round, moderately well-defined and weakly prominent spur
composed of densely meshed stereom. Three irregular perforations in vertical row dorsally bordering
inn er side of tentacle notch.

GZG.INV.78586 is a dissociated distal LAP; approximately 1.5 times wider than high; dorsal edge
clearly concave as a result of a strong constriction; proximal edge with moderately large; rather poorly
defined, weakly prominent, protruding and pointed spur. Five spine articulations; ventral lobe of spine
articulations thickened into small, round knob, connected with the distalmost lamella of the outer
surface striation by a very short, moderately prominent connecting ridge; weak dorsalward increase
in size of spine articulations and of gaps separating them but dorsalmost spine articulation as small as
ventralmost one.

Inner side of LAP with sharply defined, straight, oblique ridge with widened, rounded and well-defined
dorsal tip, and slightly widened, ventrally pointing ventral tip. Single moderately large perforation
dorsally bordering inner side of tentacle notch.

Remarks

These LAPs display the highly distinctive combination of spine articulations with a well-developed
connecting ridge with the undulose distalmost lamella, and the ridge on the inner side composed of a
long, near-vertical dorsal part and a shorter oblique ventral part separated from the dorsal one by a kink
with a ventro-proximally pointing angle, exclusively found in the LAPs of Ophiotreta and Ophiopristis.
In contrast to the LAPs of most extant species of these two genera, however, these fossil ones display
a third part of the ridge in addition to the usual dorsal and ventral ones, pointing ventro-proximally.
Whether this difference in ridge morphology warrants separation at the generic level is questionable. It
seems highly probably, however, that the third, ventralmost part of the ridge in the present fossil LAP
is the equivalent of the knob observed on the ventral portion of the LAPs in other species of Ophiotreta
and Ophiopristis.

Awaiting the discovery of articulated specimens that can supply additional grounds for separation at the
generic level, the present specimens are assigned to Ophiotreta (see above for a detailed discussion on
a morphological analysis of LAPs of Ophiotreta and Ophiopristis). Confusion with other fossil LAPs
assigned to this genus can be ruled out on account of the protruding, pointed spur on the outer proximal
edge of these LAPs.

Occurrence

Late Oxfordian of Germany.

Ophiotreta sp. nov. innom. 1

“Ophiacanthid A” - Thuy & Kroh 2011: 781, pi. 1 figs 1-2.

Remarks

Are-examination of the four LAPs described and illustrated by Thuy & Kroh (2011) as an indeterminate
record of an ophiacanthid (“Ophiacanthid A”) from the Barremian of France has revealed that those
LAPs are assignable to Ophiotreta mainly on account of the highly distinctive shape of the ridge on
their inner side and the moderately well-developed connecting ridge between the spine articulations

European Journal of Taxonomy 48: 1-242 (2013)

and the outer surfaee. Greatest similarities are shared with the LAPs of Ophiacantha jaegeri sp. nov.
(see below), espeeially with respeet to the ventral part of the ridge, missing or redueed to a knob on
the ventral portion of the inner side of the LAP and widely separated from the remaining ridge in all
other fossil speeies of Ophiotreta. The LAPs deseribed by Thuy & Kroh (2011) differ from those of
Ophiacantha jaegeri sp. nov. in laeking the spur on the outer proximal and inner distal edges. They most
probably represent a new speeies, the formal deseription of whieh, however, requires additional, less
fragmentary speeimens. It is remarkable that this Barremian speeies of Ophiotreta is morphologieally
eloser to Ophiacantha jaegeri sp. nov., its Jurassie eongener and oldest eurrently known speeies of the
genus, than to O. striata (Kutseher & Jagt, 2000) eomb. nov. from the early Maastriehtian and all other,
younger reeords. This supports the observation by Thuy & Kroh (2011) that the Barremian ophiuroid
assemblage they deseribed was eloser to Jurassie equivalents than to Late Cretaeeous ones in terms of
faunal speetrum.

Ophiotreta striata (Kutseher & Jagt, 2000) eomb. nov.

Fig. 17: 1-2

Ophiacantha? striata Kutseher & Jagt, 2000: 64, pi. 25 figs 8-10.
non Ophiacantha? aff striata - Store & Zitt 2008: 128, fig. 4L-M.

Diagnosis

Speeies of Ophiotreta with large LAPs, displaying up to ten nearly equal-sized spine artieulations;
very weak eonneeting ridge between ventral lobe of spine artieulations and distalmost lamella of outer
surfaee striation in all LAPs, ineluding the median and distal ones; no spurs on outer proximal and inner
distal LAPs.

Material examined

GZG.INV.78588, GZG.1NV.78589 and 216 dissoeiated LAPs from the Manfred Kutseher Colleetion
in Sassnitz,Germany, the type material of Kutseher & Jagt (2000); 2 dissoeiated LAPs from the early
Maastriehtian of Lagerdorf-Kronsmoor, Germany.

Description

Dissoeiated moderately large LAPs, more than twiee higher than wide (proximal ones) to slightly wider
than high (distal LAPs); dorsal edge mostly straight to slightly eoneave as a result of a weak eonstrietion;
distal edge eonvex; proximal edge irregularly undulose, devoid of spurs; outer surfaee with vertieal
striation eomposed of broad, slightly overlapping lamellae restrieted to the proximal edge of the strongly
elevated distal portion of proximal LAPs, extending into middle of outer surfaee in median to distal
LAPs; lamellae beeoming finer proximally and replaeed by moderately finely meshed stereom towards
proximal edge of LAP. Ten (proximal LAPs) to five (distal LAPs) large, ear-shaped spine artieulations
on strongly elevated distal portion of LAPs; dorsal lobe of spine artieulations very large, separated from
smaller ventral lobe by small, moderately deep noteh; spine artieulations proximally sharply delimited
by thin, slightly undulose distalmost lamella; very weakly defined, slightly prominent eonneeting ridge
between ventral lobes of spine artieulations and distalmost lamella; very weak dorsalward inerease in
size of spine artieulations and of gaps separating them. Ventral edge of LAP straight to slightly eonvex;
tentaele noteh generally invisible in external view.

Inner side of LAPs with large, eonspieuous, sharply defined yet narrow ridge eomposed of very long,
straight, near-vertieal dorsal portion very elose to the proximal edge of the lap; and shorter and slightly
wider, straight, oblique ventral portion with slightly more prominent rounded ventral tip; ventral and
dorsal portions of ridge separated by sharp kink with ventro-proximally pointing angle; small, round,
sharply defined, prominent knob on ventral portion of inner side, widely separated from ridge; inner

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 17. Fossil skeletal plates of ophiaeanthid brittle stars; lateral arm plates (LAPs) in external (a)
and internal (b) views. 1-2. Ophiotreta striata (Kutseher & Jagt, 2000) eomb. nov. from the early
Maastriehtian of Rtigen, Germany. 1. GZG.INV.78588, proximal LAP. 2. GZG.INV.78589, distal LAP.
3-11. Ophiotreta dendrophyllicola sp. nov. from the middle Danian (Paleoeene) of Fakse, Denmark.
3. MGUH 30236 (holotype), proximal LAP. 4. NHMM 2012 050 (paratype), median LAP. 5. NHMM
2012 051 (paratype), distal LAP. 6. NHMM 2012 052 (paratype), vertebra in distal view. 7. NHMM
2012 053 (paratype), vertebra in proximal view. 8. NHMM 2012 054 (paratype), vertebra in dorsal view.
9. NHMM 2012 055 (paratype), oral plate in adradial (a) and abradial (b) view. 10. NHMM 2012 056
(paratype), arm spine fragment. 11. NHMM 2012 057 (paratype), arm spine fragment. 12-15. Ophiotreta
hedone sp. nov. from the middle Lutetian (Eoeene) of Grignon, Franee. 12. GZG.INV.78590 (holotype),
proximal LAP. 13. GZG.INV.78591 (paratype), median LAP. 14. GZG.INV.78592 (paratype), distal
LAP. 15. GZG.INV.78593 (paratype), median LAP. One eommon seale bar per speeies.

European Journal of Taxonomy 48: 1-242 (2013)

side of distal edge of LAP devoid of spurs; inner side of tentaele noteh moderately large. Vertieal row
of very small, seemingly irregularly spaeed perforations in very shallow, poorly defined furrow dorsally
bordering inn er side of tentaele noteh.

Remarks

The dissoeiated LAPs from the early Maastriehtian of Germany and Denmark, on the basis of whieh
Kutseher & Jagt (2000) deseribed the new speeies, Ophiacanthal striata, are unequivoeally assignable
to the Ophiotreta-Ophiopristis group mainly on aeeount of the highly distinetive shape of the ridge on the
inner side. The eonneeting ridges between the ventral lobe of the spine artieulations and the distalmost
lamella of the outer surfaee striation are weakly developed in this speeies, whieh makes assignment to
Ophiopristis equally probable. It is of prime importanee here to reeall that the LAP morphologies of
Ophiopristis and Ophiotreta are almost indistinguishable. In view of the faet that a speeies ean only be
assigned to a single genus, Ophiotreta is preferred here, for reasons outlined above in the diseussion
of the genus. This generie plaeement is likely to ehange as soon as more will be known of the general
skeletal morphology of Ophiotreta striata eomb. nov., but also following a systematie reappraisal of
extant speeies of Ophiotreta and Ophiopristis.

Among the fossil LAPs assigned to Ophiotreta, O. striata eomb. nov. is unambiguously eharaeterised
by the laek of spurs on the outer proximal edge and the high number of spine artieulations. The elosest
resemblanee is with Ophiotreta dendrophyllicola sp. nov. in whieh, however, the median and distal
LAPs display a small, protruding spur on the outer proximal edge, and better-developed eonneeting
ridges between the spine artieulations and the outer surfaee. The LAPs from the Turonian of the Czeeh

V V

Republie deseribed as Ophiacanthal aff striata by Store & Zitt (2008) are most probably assignable to
Ophiotreta. Their slightly better-developed eonneeting ridge suggests that they belong to an undeseribed
speeies elose to O. striata eomb. nov.

Occurrence

Early Maastriehtian of Germany and Denmark.

Ophiotreta dendrophyllicola sp. nov.
um:lsid:zoobank.org:aet:87010E71-C329-48FF-ADEB-F2A939732039

Fig. 17: 3-11

Diagnosis

Speeies of Ophiotreta with large FAPs displaying a poorly developed vertieal striation on the outer
surfaee; poorly defined, thiekened area in the middle of the proximal edge of the FAP; up to seven large
spine artieulations with a very well-developed eonneeting ridge with the distalmost lamella of the outer
surfaee stereom.

Etymology

The speeies name is eomposed of Dendrophyllia Blainville, 1830, the prevailing deep-water seleraetinian
genus at the type loeality of this ophiuroid speeies, and the Fatin suffix -cola, translating to “residing
on”, “inhabitant of’.

Type material

Holotype

MGUH 30236.

THUYB., Fossil record of ophiacanthid brittle stars

Paratypes

NHMM 2012 050-2012 057.

Type locality and horizon

Fakse, Denmark; pockets of unconsolidated sediment within azooxanthellate coral bioherms, Tylocidaris
bruennichi Zone, middle Danian, Paleocene.

Additional material

NHMM 2012 058 (114 dissociated LAPs), NHMM 2012 059 (22 dissociated vertebrae, 17 arm spine
fragments, 1 oral plate and 2 ventral arm plates).

Description

Holotype

MGUH 30236 is a dissociated, large, proximal LAP; slightly more than twice higher than wide; ventral
portion of LAP slightly protruding ventro-proximalwards; dorsal edge concave as a result of a well-
developed constriction; distal edge gently convex; proximal edge irregularly undulose to nearly straight,
with very poorly defined, slightly thickened, weakly prominent and protruding central area; outer surface
almost entirely covered by finely meshed stereom; very few broad vertical lamellae on proximal edge of
strongly elevated distal portion of LAP. Seven large, ear-shaped, nearly equal-sized spine articulations
freestanding on strongly elevated distal portion of LAP, proximally bordered by strongly undulose
distalmost lamella of outer surface striation; large dorsal lobe and smaller ventral separated by small,
sharp, moderately deep notch; ventral lobe slightly thickened into small knob, with moderately well-
developed, short connecting ridge with distalmost lamella; very weak dorsalward increase in size of
gaps separating spine articulations. Ventral edge of LAP with almost indiscernible, moderately large
tentacle notch.

Inner side of LAP with large, sharply defined, prominent, conspicuous ridge composed of long, straight,
near-vertical dorsal portion very close to proximal edge of LAP, and shorter, near-straight, oblique
ventral portion with rounded, sharply defined and slightly more prominent ventral tip; dorsal and ventral
parts of ridge separated by broad kink with ventro-proximally pointing angle; round, sharply defined,
prominent knob on ventral portion of inner side of LAP, widely separated from ventral tip of ridge; inner
side of tentacle scale moderately large, not sharply defined. Shallow, moderately well-defined vertical
furrow with small perforations dorsally bordering inner side of tentacle notch.

Paratype supplements and variation

NHMM 2012 050 is a dissociated median LAP; slightly wider than high; proximal edge concave with a
small, moderately well-defined, prominent and protruding spur composed of densely meshed stereom;
outer surface with poorly developed vertical striation composed of broad lamellae replaced by finely
meshed stereom in the proximal half of the outer surface. Five nearly equal-sized spine articulations
similar to those observed on the holotype. Ventral edge of LAP convex with relatively small, shallowly
concave tentacle notch.

Inner side of LAP with well-defined ridge with straight, oblique dorsal part with widened dorsal tip with
ventro-proximally pointing angle strongly reminiscent of kink between dorsal and ventral parts of ridge
in holotype; inner side of distal edge of LAP with small, moderately well-defined, weakly prominent
spur composed of densely meshed stereom; ventral part of ridge shorter, ventro-proximally pointing;
no knob on ventral portion of inner side. Poorly defined, shallow furrow with single perforation near its
ventral tip dorsally bordering inner side of tentacle notch.

NHMM 2012 051 is a dissociated distal LAP; nearly 1.5 times wider than high; proximal edge with
small, moderately well-defined, prominent and protruding, pointed spur; distal half of outer surface with

European Journal of Taxonomy 48: 1-242 (2013)

weakly developed vertieal striation. Five spine artieulations similar to those observed on holotype, on
strongly elevated distal portion of LAP, proximally sharply bordered by undulose distalmost lamella;
well-developed eonneeting ridge between ventral lobe of spine artieulations and distalmost lamella;
ventral lobe of spine artieulations slightly thiekened; dorsalmost spine artieulation smaller than remaining
four. Ventral edge of LAP eonvex; tentaele noteh obseured by syntaxial ealeite erystals.

Inner side of LAP well in agreement with that of paratype. No perforations diseemible.

Additional material

Vertebrae of rounded aspeet, with nearly equal-sized proximal museular fossae, large dorso-distal
and smaller ventro-distal museular fossae; large and strongly protruding distal artieular knobs,
zygospondyline artieulation.

Oral plate short, approximately as high as wide; deeply ineised noteh for ring nerve; adradial artieular
area with eonspieuous dorso-distalwards projeetion.

Spines flattened, hollow, with slight kink near base; eoarse longitudinal ribs with short thorns.

Remarks

These LAPs are unambiguously assignable to the Ophiotreta-Ophiopristis group on aeeount of the
highly distinetive spine artieulation morphology and the shape of the ridge on the inner side. For
reasons outlined above, Ophiotreta is preferred here. Closest similarities are shared with the LAPs of
Ophiotreta striata eomb. nov., whieh, however, differ in eompletely laeking spurs on the outer proximal
and inner distal edges, and in displaying a better-developed vertieal striation and more poorly developed
eonneeting ridges between the spine artieulations and the outer surfaee throughout.

Sinee the present LAPs were the only ones found in the original sample, all other ophiuroid skeletal
parts ean be assumed to have belonged to the same speeies. The flattened arm spines found in the sample
substantiate assignment to the Ophiotreta-Ophiopristis group, modem speeies of whieh eommonly
display similarly flattened arm spines.

Occurrence

Early Paleoeene of Denmark.

Ophiotreta hedone sp. nov.

um:lsid:zoobank.org:aet:959BB836-3EA8-4855-B7AC-3FCCADA44A8E

Fig. 17: 12-15

Diagnosis

Speeies of Ophiotreta with very small EAPs displaying well-developed vertieal striation; ventral sixth
to third of EAP protmding ventro-proximalwards; up to flve large spine artieulations with moderately
well-developed eonneeting ridge between ventral lobes and distalmost lamella of outer surfaee striation.

Etymology

Speeies named after Hedone, Greek for pleasure, as a homage to Freneh “savoir-vivre”.

Type material

Holotype

GZG.1NV.78590.

Paratypes

GZG.1NV.78591, GZG.1NV.78592 and GZG.1NV.78593.

THUYB., Fossil record of ophiacanthid brittle stars

Type locality and horizon

Grignon, France; base of level 2 of Merle (2008), Campanile giganteum beds, middle Lutetian, Middle
Eocene.

Additional material

GZG.INV.78594 (118 dissociated LAPs).

Description

Holotype

GZG.INV.78590 is a dissociated, small, proximal LAP; almost twice higher than wide; dorsal edge
slightly concave as a result of a weak constriction; distal edge weakly convex to straight; proximal
edge irregularly undulose, devoid of spurs; ventro-proximal portion of LAP missing; outer surface
with fine, well-developed vertical striation composed of fine, slightly overlapping lamellae restricted
to narrow band close to spine articulations, replaced by finely meshed stereom in all other parts of the
outer surface. Five, large, ear-shaped spine articulations freestanding on strongly elevated distal portion
of LAP and proximally bordered by undulose distalmost lamella; dorsal lobe large, separated from
much smaller ventral lobe by small, shallow notch; short, weakly developed connecting ridge between
ventral lobe of spine articulations and distalmost lamella; second dorsalmost spine articulation slightly
larger than remaining four; very weak dorsalward increase in size of gaps separating spine articulations.
Ventral edge of LAP fragmentary; tentacle notch not visible in external view.

Inner side of LAP with large, conspicuous, sharply defined ridge composed of near-vertical, straight
dorsal part very close to proximal edge of LAP, and straight, oblique and slightly wider ventral part with
ventrally pointing ventral tip; dorsal and ventral parts almost of equal length, separated by angular kink
with conspicuous ventro-proximally pointing angle; very small, weakly prominent, inconspicuous and
hardly discernible knob on ventral portion of LAP, widely separated from ridge; inner side of distal edge
of LAP devoid of spurs; inner side of tentacle notch moderately large. Vertical row of moderately large,
irregularly spaced perforations in very shallow, poorly defined furrow dorsally bordering inner side of
tentacle notch.

Paratype supplements and variation

GZG.INV.78591 is a dissociated proximal LAP; generally in close agreement with holotype but ventro-
proximal sixth better preserved, slightly protruding ventro-proximal wards; proximal edge slightly
undulose, devoid of spurs.

Inner side of LAP with almost indiscernible, weakly prominent and slightly elongate knob close to
ventro-distal edge of ventral LAP portion, in addition to ridge similar to that observed on holotype. Two
large, irregular perforations distally bordering ventral tip of ridge, no furrow discernible.

GZG.INV.78592 is a dissociated median LAP; slightly higher than wide; ventral third protruding ventro-
proximal wards; outer surface mostly covered by well-developed vertical striation composed of rather
broad lamellae, replaced by finely meshed stereom in narrow band near proximal edge of LAP. Four
spine articulations similar to those observed in holotype. Ventral edge of LAP oblique, tentacle notch
invisible in external view.

Inner side of LAP with oblique, straight ridge similar to the ventral part of the ridge observed in the
holotype, and with a widened dorsal tip; large, prominent but poorly defined, elongate knob near ventro-
distal edge of LAP. Two to three moderately large perforations loosely arranged in vertical row dorsally
bordering inner side of tentacle notch; no furrow discernible.

GZG.INV.78593 is a dissociated distal LAP; slightly wider than high; ventral third to quarter of LAP
slightly protruding ventro-proximal wards; well-developed striation on outer surface restricted to narrow

European Journal of Taxonomy 48: 1-242 (2013)

band near spine artieulations. Four spine artieulations, two median ones larger than ventral and dorsal
ones; ventral lobe of spine artieulations slightly thiekened into small knob, with short, thin, yet well-
developed eonneeting ridge with distalmost lamella.

Inner side of LAP with oblique, straight ridge similar to the ventral part of the ridge observed in the
holotype, and with a widened dorsal tip; no ventral knob diseemible; inner side of tentaele noteh
relatively small. No perforations diseemible.

Remarks

These LAPs are unambiguously assignable to the Ophiotreta-Ophiopristis group mainly on aeeount of
the highly distinetive shape of the ridge on the inner side. On the basis of the moderately well-developed
eonneeting ridge between the ventral lobe of the spine artieulations and the distalmost lamella of the
outer surfaee striation, even in proximal LAPs, Ophiotreta is preferred here. Their very small size, low
number of spine artieulations and unusually long ventral portion make these LAPs ineompatible with
any other fossil LAP type assigned to Ophiotreta.

Occurrence

Middle Lutetian of Franee.

Ophiotreta sp. nov. innom. 2
Fig. 18: 1-2

Material examined

NHMW 2012/0139/0001 andNHMW 2012/0139/0002 (4 dissoeiated LAPs) from the Langhian, middle
Mioeene, of Mannersdorf, Austria; NHMW 2012/0139/0003 (dissoeiated LAP) from the Langhian of
Stotzing, Austria.

Description

Small dissoeiated LAPs, proximal ones nearly twiee higher than wide, median ones slightly higher
than wide; dorsal edge straight to very weakly eoneave; distal edge eonvex; proximal edge slightly
eoneave, devoid of spurs; outer surfaee with very narrow band of fine, regular vertieal striation
eomposed of few fine lamellae elose to spine artieulations, replaeed by finely meshed stereom on
majority of outer surfaee. Up to six large, ear-shaped spine artieulations freestanding on elevated
ridge of distal portion of LAP, proximally bordered by slightly (proximal LAPs) to strongly (median
LAPs) undulose distalmost lamella; dorsal lobe of spine artieulation mueh larger than ventral one,
separated from the latter by small, shallow noteh; ventral noteh with short, weakly (proximal LAPs)
to moderately well-developed (median LAPs) eonneeting ridge with distalmost lamella; very weak
dorsalward inerease in size of spine artieulations and of gaps separating them. Tentaele noteh not
visible in external view.

Inner side of LAPs with large, eonspieuous, sharply defined and prominent ridge eomposed of straight,
near-vertieal dorsal part very elose to proximal edge of LAP, and straight, oblique slightly shorter and
wider ventral part with slightly widened, round ventral tip; dorsal and ventral parts of ridge separated by
angular kink with ventro-proximally pointing angle; no ventral knob diseemible; inner side of tentaele
noteh moderately large. Shallow, moderately well-defined vertieal furrow with medium-sized, irregular
perforations dorsally bordering inner side of tentaele noteh.

Remarks

The highly distinetive shape of the ridge on the inner side along with the arrangement of the spine
artieulations and the moderately well-developed eonneeting ridge between the spine artieulations and
the outer surfaee leave no doubt as to the assignment of these LAPs to Ophiotreta. Closest similarities

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 18. Fossil lateral arm plates (LAPs) of ophiacanthid brittle stars in external (a) and internal (b) views.
1-2. Ophiotreta sp. nov. innom 2 from the Langhian (middle Miocene) of Stotzing (1) and Mannersdorf
(2), Austria. 1. NHMW 2012/0139/0003, proximal LAP. 2. NHMW 2012/0139/0001, proximal LAP.
3-4. Europacantha paciphila gen. et sp. nov. from the late Anisian (Middle Triassic) of Felsoors,
Hungary. 3. MHI2090/1 (holotype), proximal to median LAP. 4. MHI2091/1 (paratype), proximal LAP.
5-7. Ophiacantha jaegeri sp. nov. from the latest Hauterivian (Early Cretaceous) of Sarstedt, Germany.
5. GZG.INV.78595 (holotype), proximal LAP. 6. GZG.INV.78596 (paratype), median LAP. 7. GZG.
INV.78597 (paratype), distal LAP. 8-9. Ophiacantha sp. nov. innom 1 from the latest Aptian to earliest
Albian (Early Cretaceous) of Blake Nose, NE Atlantic. 8. GZG.INV.78599, proximal EAP. 9. GZG.
INV.78600, distal EAP. 10. Ophiacantha sp. nov. innom 2 from the latest Aptian to earliest Albian (Early
Cretaceous) of Blake Nose, NE Atlantic; GZG.INV.78601, distal EAP. One common scale bar per species.

European Journal of Taxonomy 48: 1-242 (2013)

are shared with the LAPs of Ophiotreta hedone sp. nov. on aeeount of the small size and the low number
of spine artieulations. The present speeimens, however, differ in having a mueh shorter ventral portion
and up to six, rather than five, spine artieulations. All extant speeies of Ophiotreta have mueh larger
LAPs with numerous spine artieulations. Thus, it seems highly probable that the present LAPs represent
a new speeies. 1 refrain from formally deseribing this new speeies here, however, sinee it is eurrently
represented by a few plates only, most of whieh are fragmentary. With sueh limited material available,
it eannot be ruled out that the LAPs in question are from juvenile individuals rather than small-sized
adults.

Genus Europacantha gen. nov.

um:lsid:zoobank.org:aet:511AAEQ8-FCA9-4DA9-AFC4-6B2A2C39B2DB

Type and sole known species

Europacantha paciphila sp. nov.

Diagnosis

Ophiaeanthid with relatively small, stout, trapezoid LAPs devoid of eonspieuous outer surfaee ornament;
small, ineonspieuous, very weakly protruding spur on outer proximal edge; up to six large, ear-shaped
spine artieulations on strongly elevated distal portion of LAP, not bordered proximally by a ridge-like
strueture; relatively broad, gently proximally bent ridge on inner side with widened dorsal tip displaying
a ventrally projeeting extension; tentaele noteh small, invisible in external view.

Etymology

Name eomposed of Europa, a Phoenieian prineess whose name is eommonly translated into
“perspieaeious”, honouring the idea of a united Europe, and Acantha, a Greek nymph whose name
literally translates into “thorny”; gender feminine.

Remarks

The oldest known ophiaeanthid reeord is here deseribed in the form of rare dissoeiated LAPs from the
Anisian (early Middle Triassie) of Hungary. The LAPs in question are unambiguously assignable to the
Ophiaeanthidae on aeeount of the large, ear-shaped spine artieulations with a typieal sigmoidal fold,
eombined with several small perforations in a shallow vertieal furrow on the inner side. Astonishingly,
these Anisian LAPs display small tentaele notehes, almost eertainly refieeting originally small tentaele
pores as defined by Thuy et al. (2012), whieh plaees them in the more derived small-pored ophiaeanthids
rather than the basal large-pored ones.

Indeed, greatest similarities in LAP morphology are shared with the small-pored Ophiacantha, on
aeeount of the number, size and position of the spine artieulations, the absenee of more than a single spur
on the outer proximal edge, and the shape of the ridge on the inner side, as well as with Inexpectacantha
Thuy, 2011 on aeeount of the stout, trapezoid aspeet, the proximally non-bordered spine artieulations
and the laek of a eonspieuous outer surfaee ornament. Yet, in the LAPs of Ophiacantha, the spine
artieulations are proximally sharply bordered by a ridge or the distalmost lamella of the outer surfaee
striation, while in Inexpectacantha the ridge on the inner side of the LAPs laeks a ventrally projeeting
extension, and the spine artieulations are more oblique, displaying a eoarsely eorrugated ventral lobe.
On aeeount of these ineompatibilities, Europacantha gen. nov. is thus introdueed here to aeeommodate
the Anisian LAPs.

THUYB., Fossil record of ophiacanthid brittle stars

Europacanthapaciphila sp. nov.

um:lsid:zoobank.org:act:963Q76Q2-8F71-4187-B901-312179D4E69C

Fig. 18: 3-4

Diagnosis

As for genus.

Etymology

Name derived from pax, Latin for “peace”, mdPhilia, Greek for “love”, in reference to peace prevailing
between nations in Europe, against all nationalist odds.

Type material

Holotype

MHI 2090/1.

Paratype

MHI 2091/1.

Type locality and horizon

Felsoors, Hungary; Felsoors Formation, late Anisian, Middle Triassic.

Additional material

MHI 2092/1-6 (6 dissociated LAPs).

Description

Holotype

MHI 2090/1 is a dissociated, small, median to proximal LAP; approximately 1.5 times higher than wide;
rather stout, trapezoid aspect; dorsal edge oblique, very weakly concave as a result of a constriction;
distal edge gently convex; proximal edge irregularly concave, with small, round, non-prominent central
protrusion; outer surface with finely meshed stereom, devoid of vertical striation or other conspicuous
elements of ornament elements. Five large, equi-distant, ear-shaped spine articulations freestanding on
strongly elevated distal portion of LAP; ventral and dorsal lobes merged into continuous volute; dorsal
lobe larger than ventral one, thickened; dorsalward increase in size of spine articulations; gap between
spine articulations and distal edge of LAP narrow; spine articulations not bordered proximally by a
ridge-like structure. Ventral edge of LAP oblique, very gently convex.

Inner side of LAP with sharply defined, prominent, relatively broad, oblique, gently proximally bent
ridge; ventral half of ridge most strongly prominent; not merged with ventral portion fo LAP; dorsal half
of ridge widening dorsalwards, with short, ventrally pointing extension; inner side of distal edge of LAP
devoid of spurs; inner side of tentacle notch relatively small, shallow, moderately well defined laterally.
Very shallow, poorly defined vertical ridge dorsally bordering tentacle notch.

Paratype supplements and variation

MHI 2091/1 is a dissociated proximal LAP; almost twice higher than wide; ventro-proximal tip
fragmentary; slightly less stout than holotype; single small, slightly protruding andvery weakly prominent
spur in the middle of the proximal edge. Six spine articulations on strongly elevated distal portion of
LAP, poorly preserved but apparently similar to those observed on holotype; spine articulations not
sharply bordered proximally by a ridge-like structure.

Inner side of LAP poorly preserved and partly obscured by sediment; ridge not clearly discernible,
probably gently proximally bent as in holotype, with widened, near-triangular dorsal tip displaying

European Journal of Taxonomy 48: 1-242 (2013)

a very short ventrally pointing extension; no spurs on inner side of distal edge of LAP; inner side of
tentaele noteh poorly preserved, small. Very shallow, poorly preserved vertieal furrow with two or three
small, widely spaeed perforations, dorsally bordering tentaele noteh.

Remarks

Sinee these LAP type is the only one assigned to Europacantha gen. nov., its systematie affinities are
diseussed above.

Occurrence

Late Anisian of Hungary.

Genus Ophiacantha Muller & Trosehel, 1842

Type species

Ophiacantha spinulosa Muller & Trosehel, 1842 [junior synonym of Ophiacantha bidentata (Bruzelius,
1805)], by original designation.

Diagnosis

LAPs with dorsal and ventral lobes of spine artieulations fused into eontinuous volute; ventral part of
LAPs not protruding ventro-proximalwards; generally no more than one spur on the outer proximal and
inner distal edges; ridge on inner side eomposed of long, oblique, straight to slightly bent main part with
a pointed dorsal tip and with ventrally pointing, vertieal to slightly oblique or bent extension generally
at least as long as half of the main part; in many eases, main part and ventrally pointing extension fused
into large, irregularly triangular knob; tentaele noteh small.

Remarks

Ophiacantha is one of the most speeiose (Stohr et al. 2012), but also one of the most heterogeneous
genera among the extant ophiuroids (O’Hara & Stohr 2006). This morphologieal heterogeneity is
also refieeted in LAP morphology, as already pointed out by Thuy & Stohr (2011), with some speeies
sharing greater s im ilarities in LAP morphology to speeies of other ophiaeanthid genera than with their
eongeners. Thus, working out a eomprehensive and at the same time meaningful LAP morphologieal
diagnosis of Ophiacantha is a major ehallenge. To make matters worse, most eharaeters observed in the
LAPs of Ophiacantha also oeeur in other genera. The most stringent approaeh is to foeus on the LAP
morphology of the type speeies, Ophiacantha bidentata, on the basis of whieh the LAP morphologies
of the other speeies are assessed.

The LAPs of O. bidentata were deseribed in detail and illustrated by Thuy & Stohr (2011). They
are eharaeterised by a ridge on their inner side, whieh eonsists of a main oblique, straight to slightly
proximally bent part with a pointed dorsal tip and fused dorsally to a ventrally pointing, near-vertieal to
slightly oblique extension elose to the proximal edge of the LAP longer than half of the main part of the
ridge. In some eases, the main part of the ridge and its ventrally pointing dorsal extension are merged into
a single, large, irregularly triangular knob. In eombination with the large ear-shaped spine artieulations
on a strongly elevated distal portion of the LAP, with dorsal and ventral lobes merged into a eontinuous
volute, and proximally sharply bordered by the distalmost lamella of a well-developed vertieal striation
on part of the outer surfaee, the shape of this ridge is distinetive. This is important to note sinee slightly
modified versions of ridge shape are also found in other, not neeessarily elosely related ophiaeanthids
(e.g. OphiomitrellaYQxriW, 1899; Ophioplinthaca YeniW, 1899, ""Ophiophthalmus’" Matsumoto, 1917).
Many speeies of Ophiacantha share the above-mentioned eombination of features, whieh ean be thus
eonsidered as the Ophiacantha LAP morphology in its proper sense. Whether the speeies in question

THUYB., Fossil record of ophiacanthid brittle stars

also share similar general skeletal morphologies, and thus potentially represent a true clade with the
Ophiacanthidae, remains to be investigated.

A number of extant species of Ophiacantha conflict with the type species in terms of LAP morphology.
Particularly striking is the occurrence in a number of species of Ophiacantha of a ridge shape otherwise
exclusively found in Ophiotreta and Ophiopristis. The species in question include Ophiacantha anomala
G.O. Sars, 1872, O. rosea Lyman, 1878, O. spectabilis G.O. Sars, 1872 and O. vivipara Ljungman,
1872. Remarkably, these four species are known to have closely similar general skeletal morphologies in
common (Paterson 1985; O’Hara & Stohr 2006), thus most probably form a phylogenetically consistent
group. A detailed reassessment of the species in question is likely to result in separation at the generic
level, which would gain support from evidence of LAP morphology.

Other species currently assigned to Ophiacantha differ Ifom the type species in displaying generally
lower LAPs (smaller height/width ratios), proximally separated dorsal and ventral lobes of the spine
articulations which thus become slightly horizontally elongate rather than round, a single protruding
spur in the middle of the outer proximal and inner distal edges, and a densely meshed or even granulated
stereom covering the outer surface rather than a vertical striation. At the same time, they share the
highly distinctive shape of the ridge on the inner side with Ophiacantha bidentata. Such taxa include
Ophiacantha smith Ljungman, 1872, O. pentagona Koehler, 1897, O. prionota H.L. Clark, 1911
and O. levispina Lyman, 1878. Whether this grouping is artiflcial or, indeed, reflects general skeletal
morphological similarities is in need of further study. Remarkably, the species in question are closer to
species of Ophiolebes Lyman, 1878 in terms of LAP morphology than to their congeners.

According to the revised cladistic phytogeny presented here, Ophiacantha is sister taxon to the
Ophiolebes-Ophialcaea clade. Unfortunately, LAPs of extant species of Ophialcaea Verrill, 1899 could
not be examined using the standards set by Thuy & Stohr (2011). Ophiolebes, however, is shown here
to share largely similar LAP morphologies with Ophiacantha, in particular with the species mentioned
above. Similar to those of the latter, the LAPs of Ophiolebes display a ridge that is superflcially comparable
to the one seen in Ophiacantha bidentata. The main distinction between the LAPs of Ophiolebes and
those of O. bidentata and similar congeners are the proximally separated dorsal and ventral lobes of the
spine articulations.

To conclude, as currently understood, the genus Ophiacantha obviously unites a number of fundamentally
different LAP morphologies, some of which deflnitely reflect differences at the generic level to be
worked out in detail by future studies. It is very difficult to characterise the LAP morphology of the genus
convincingly, even if restricted to the type species and species with morphologically similar LAPs. The
ridge shape described above for Ophiacantha bidentata, along with spine articulations freestanding on
the elevated distal edge of the LAP, with dorsal and ventral lobes fused into a continuous volute, and
bordered proximally by a not exceedingly thickened distalmost lamella is a combination which probably
comes closest to a diagnosis of the LAP morphology of Ophiacantha in its proper sense. For the purpose
of the present, only fossil LAPs displaying this combination of characters are assigned to Ophiacantha.

Ophiacantha jaegeri sp. nov.

um:lsid:zoobank.org:act:A991EFFE-BA53-46CC-B06A-84E27C84A749

Fig. 18: 5-7

Diagnosis

Species of Ophiacantha with moderately large EAPs displaying a rather knobby general aspect; single
poorly deflned, protruding spur on outer proximal edge; outer surface devoid of vertical striation, with

European Journal of Taxonomy 48: 1-242 (2013)

coarsely meshed stereom displaying thiekened trabeeular interseetions; up to six large spine artieulations
proximally bordered by knobby, undulose ridge; tentaele noteh invisible in external view.

Etymology

Speeies named in honour of Manfred Jager, who kindly provided the sample yielding the type material
of the speeies.

Type material

Holotype

GZG.1NV.78595.

Paratypes

GZG.1NV.78596 and GZG.1NV.78597.

Type locality and horizon

Claypit Gott in Sarstedt, Germany; latest Hauterivian, Early Cretaeeous.

Additional material

GZG.1NV.78598 (6 dissoeiated LAPs).

Description

Holotype

GZG.INV.78595 is a dissoeiated, moderately large LAP; approximately 1.5 times higher than wide;
dorsal edge oblique, very weakly eoneave; distal edge evenly eonvex; proximal edge irregularly
undulose, with small, poorly defined, weakly prominent but eonspieuously protruding spur in its eentre;
outer surfaee with eoarsely meshed stereom with trabeeulae thiekened into eonspieuously large granules
in ventral sixth of outer surfaee and into smaller granules in remaining outer surfaee; narrow band of
finely meshed stereom along proximal edge. Six large, ear-shaped spine artieulations freestanding on
strongly elevated distal portion of LAP; ventral and dorsal lobes fused into near-round, eontinuous
volute; spine artieulations proximally bordered by knobby, wavy vertieal ridge; dorsalward inerease
in size of spine artieulations and in of gaps separating them; gap between spine artieulations and distal
edge of LAP as wide as one spine artieulation. Ventral edge of LAP slightly eonvex, tentaele noteh
invisible in external view.

Inner side with large, eonspieuous, sharply defined and prominent ridge eomposed of oblique, near¬
straight main part with pointed dorsal tip and with ventro-proximally pointing dorsal extension slightly
longer than main part and merged with the latter into near-triangular, vertieally elongate knob; ventral
portion of main ridge part with rounded kink and short ventro-proximally pointing extension; inn er side
of distal edge of LAP with small, poorly defined and hardly prominent spur eomposed of slightly more
densely meshed stereom; inner side of tentaele noteh relatively small, well defined laterally. Shallow but
moderately well-defined vertieal furrow dorsally bordering tentaele noteh with small, irregularly spaeed
perforations.

Paratype supplements and variation

GZG.1NV.78596 is a dissoeiated median LAP; nearly as high as wide; generally elosely matehing
holotype; spur on proximal edge very weakly defined, almost indiseemible, not protruding. Five spine
artieulations similar to those observed on holotype; gap between spine artieulations and distal edge of
LAP narrower than one spine artieulation. Ventral edge with very shallow, poorly developed tentaele
noteh.

100

THUYB., Fossil record of ophiacanthid brittle stars

Inner side of LAP with large, conspicuous, relatively wide, oblique ventralwards bent ridge with
widened, nearly triangular dorsal tip; no spur discernible on inner side of distal LAP edge; inner side of
tentacle notch relatively small, well defined laterally. Very shallow and weakly defined furrow dorsally
bordering tentacle notch, no perforations clearly discernible.

GZG.INV.78597 is a dissociated distal LAP; almost twice wider than high; generally well in agreement
with holotype but poorly preserved; dorsal edge strongly concave as a result of a well-developed
constriction; no spur discernible on outer proximal edge; outer surface with coarsely meshed stereom
replaced by finely meshed stereom in proximal third of outer surface; few trabecular intersections,
especially in ventral part of outer surface, thickened into small granules. Four poorly preserved spine
articulations on elevated distal portion of LAP, seemingly similar to those observed on holotype. Tentacle
notch not visible in external view.

Inner side of LAP with large, moderately well-defined, oblique ridge with narrow, rounded dorsal tip
and strongly widened ventral part; inner side of tentacle notch relatively small, moderately well defined
laterally. Single, poorly defined perforation dorsally bordering tentacle notch, no furrow discernible.

Remarks

The shape of the ridge on the inner side in combination with the continuous, round volute of the spine
articulations and the single spur on the outer proximal and inner distal edges strongly suggest that
these LAPs to belong to the genus Ophiacantha or at least to a very closely related, yet undescribed
genus. Morphological similarities are much closer to Ophiacantha than to the allegedly closely related
Ophiogaleus gen. nov., which is why the LAPs in question are here assigned to the former genus.
Among the fossil LAP types assigned to Ophiacantha, the ones described above are unique in lacking
a vertical striation and at the same time in displaying a generally knobby appearance, with trabecular
intersections thickened into small granules especially on the ventral portion of the outer surface but also
in other parts, and with the conspicuously knobby ridge proximally bordering the spine articulations.

Occurrence

Latest Hauterivian of Germany.

Ophiacantha sp. nov. innom. 1
Fig. 18: 8-9

Material examined

GZG.INV.78599 and GZG.INV.78600 from the latest Aptian to earliest Albian of Blake Nose, tropical
northeast Atlantic.

Description

GZG.INV.78599 is a fragment of a dissociated, medium-sized, proximal LAP of which only dorso-distal
portion is preserved; LAP fragile; dorsal edge slightly concave; distal edge convex; preserved portion
of proximal edge slightly undulose, devoid of spurs; outer surface with very narrow band of well-
developed, vertical striation composed of a few fine, overlapping lamellae close to spine articulations;
remaining outer surface with finely meshed stereom. Three large, ear-shaped spine articulations
preserved, freestanding on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine
articulations merged into continuous, round volute; spine articulations proximally sharply bordered by
strongly undulose distalmost lamella; gap between spine articulations and distal edge of LAP slightly
narrower than one spine articulation.

Inner side of LAP with dorsal tip of ridge, sharply defined, prominent, dorsally pointed, with ventro-
proximally pointing extension; possible large, poorly defined, non-prominent spur on preserved portion

101

European Journal of Taxonomy 48: 1-242 (2013)

of inner distal LAP edge and eomposed of slightly more densely meshed stereom; no perforations
diseemible.

GZG.INV.78600 is a dissoeiated distal LAP; very fragile, dorsal and ventral edges fragmentary; very
well in agreement with proximal LAP deseribed above; distal edge irregularly eonvex; proximal edge
poorly preserved, irregularly undulose, no spur diseemible. Four spine artieulations similar to those
observed in proximal LAP deseribed above. Ventral edge of LAP poorly preserved.

Inner side of LAP with large, eonspieuous, sharply defined and prominent, straight, oblique ridge with
strongly widened, near-triangular dorsal tip displaying ventro-proximally pointing extension; ventral
tip of ridge strongly widened; inner side of distal edge of LAP with large, poorly defined, weakly
prominent spur eomposed of more densely meshed stereom; inner side of tentaele noteh relatively small
and moderately well defined laterally. No perforations diseemible.

Remarks

Although this LAP type is represented by very limited material only, it displays suffieient morphologieal
detail to argue in favour of an assigmnent to Ophiacantha, based mainly on the shape of the ridge in the
distal LAP as well as the round, eontinuous volute of the large, freestanding spine artieulations. In the
absenee of more eomplete material, however, this generie plaeement must be treated with eaution. The
very fragile nature of the LAPs, the very large, near-eireular spine artieulations, and the narrow band of
very fine vertieal striation distally bordered by finely meshed stereom are not found in any other fossil
LAP type eurrently assigned to Ophiacantha. This LAP type most probably represents a new speeies,
the deseription of whieh, however, should be based on more eomplete material.

Ophiacantha sp. nov. innom 2
Fig. 18: 10

Material examined

GZG.INV. 78601 from the latest Aptian to earliest Albian of Blake Nose, tropieal northeast Atlantie.

Description

GZG.1NV.78601 is a dissoeiated, moderately large, distal LAP; more than twiee wider than high; fragile;
dorsal edge strongly eoneave as a result of a well-developed eonstrietion; distal edge eonvex; proximal
edge irregularly undulose, with large, very poorly defined, weakly prominent but strongly protmding
spur in dorsal half; outer surfaee entirely eovered with eoarsely meshed stereom, slightly beeoming finer
elose to proximal edge of LAP. Four large, equal-sized, equi-distant, near-eireular spine artieulations
freestanding on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine artieulations
thin, merged into eontinuous, near-eireular volute; spine artieulations proximally sharply bordered by
vertieal, straight, well-defined and prominent ridge; gap between spine artieulations and distal edge of
LAP relatively narrow, barely as wide as half a spine artieulation. Ventral edge of LAP weakly eoneave,
tentaele noteh invisible in external view.

Inner side of LAP with large, moderately well-defined, prominent, straight, near-horizontal ridge; dorsal
tip of ridge strongly widened, dorsally pointed, with ventro-proximally pointing extension; inner side
of distal edge with moderately large, poorly defined, non-prominent spur eomposed of slightly more
densely meshed stereom; inner side of tentaele noteh relatively large. No perforations diseemible.

Remarks

Only a single speeimen of this LAP type is eurrently known. Although it is from distal arm portions, it
displays eharaeters strongly pointing to the genus Ophiacantha, in partieular with regard to the shape
of the ridge on the inner side, as well as the shape and arrangement of the spine artieulations. Closest

102

THUYB., Fossil record of ophiacanthid brittle stars

similarities are shared with LAPs assigned to Ophiacantha from the Albian of England (see below).
These differ, however, in displaying a strongly undulose, rather than straight, ridge proximally bordering
the spine articulations. The present LAP most probably represents a new species of Ophiacantha but in
the absence of more material it cannot be formally described.

Ophiacantha sp. nov. innom. 3
Fig. 19: 1-2

Material examined

GZG.INV.78602, GZG.INV.78603 and GZG.INV.78604 (2 dissociated LAPs) from level 2 of Young
et al. (2010) in the middle Albian Loricatus Zone of Folkestone, Great Britain.

Description

GZG.INV.78602 is a dissociated, large, proximal to median LAP; dorsal edge fragmentary; distal edge
convex; proximal edge irregularly undulose; small, sharply defined, slightly prominent and protruding,
round spur in the dorsal half of the proximal edge, composed of more densely meshed stereom; outer
surface with moderately finely meshed stereom; few trabecular intersections, especially in ventral
quarter of outer surface, thickened into very small granules; moderately finely meshed stereom of outer
surface replaced by much more finely meshed stereom in relatively broad band paralleling proximal
edge of LAP. Four large, ear-shaped spine articulations freestanding on strongly elevated distal portion
of LAP; dorsal and ventral lobes of spine articulations merged into continuous, round volute; spine
articulations proximally bordered by irregularly knobby, undulose and weakly prominent ridge; very
weak dorsalward increase in size of spine articulations and of gaps separating them; gap between spine
articulations and distal edge of LAP nearly half as wide as one spine articulation. Ventral edge convex,
with conspicuous, moderately large, deeply concave tentacle notch.

Inner side of LAP with large, conspicuous ridge composed of a main central, near-straight, oblique
part and slightly shorter and wider, oblique, ventro-proximally pointing ventral part separated from the
main part by a rounded kink; dorsal tip of main part of ridge fragmentary, but originally widened and
with relatively short, pointed ventralward extension; dorsal half of inner side of distal LAP edge with
small, moderately well-defined, slightly prominent, dorsally fragmented spur; inner side of tentacle
notch deep, relatively short, well-defined laterally. No perforations discernible.

GZG.INV.78603 is a dissociated distal LAP; almost twice wider than high; dorsal edge strongly concave
as a result of a well-developed constriction; distal edge nearly straight to slightly convex; spur in dorsal
half of proximal edge very weakly defined, almost indiscernible. Four spine articulations similar to
those observed on proximal to median LAP described above; ventral edge of LAP slightly concave,
tentacle notch invisible in external view.

Inner side of LAP with large, proximally bent, sharply defined ridge; dorsal tip of ridge strongly widened;
ventral part of ridge distally bordered by round, prominent, well-defined knob; spur in dorsal half of
inner side of distal LAP edge very poorly defined, hardly discernible, slightly prominent; inner side of
tentacle notch relatively small, moderately well-defined laterally. No perforations discernible.

Remarks

The ridge displayed by these LAPs is rather atypical of Ophiacantha in that its ventrally pointing
extension is unusually short. Nevertheless, the shape of the ridge is basically compatible with the
LAP morphology of Ophiacantha in its proper sense, in particular in combination with the shape and
arrangement of the spine articulations and the single spur on the outer proximal and inner distal edges.
The LAPs in question are unambiguously recognisable on account of the deeply concave tentacle notch
visible even in external view, combined with the irregular, undulose ridge proximally bordering the

103

European Journal of Taxonomy 48: 1-242 (2013)

Fig. 19. Fossil skeletal plates of ophiaeanthid brittle stars; lateral arm plates (LAPs) in external (a)
and internal (b) views. 1-2. Ophiacantha sp. nov. innom 3 from the middle Albian (Early Cretaeeous)
of Folkestone, Great Britain. 1. GZG.INV. 78602, proximal LAP. 2. GZG.INV. 78603, distal LAP.
3-5. Ophiacantha reginae sp. nov. from the late Campanian (Late Cretaeeous) of Lagerdorf-Alsen,
Germany. 3. GZG.INV.78605 (holotype), proximal LAP. 4. GZG.INV.78606 (paratype), median
LAP. 5. GZG.1NV.78607 (paratype), distal LAP. 6-9. Ophiacantha steffenschneideri sp. nov. from the
Rupelian (Oligoeene) of Bad Freienwalde, Germany. 6. GZG.1NV.78609 (holotype), proximal LAP.
7. GZG.INV.78610 (paratype), median LAP. 8. GZG.INV. 78611 (paratype), distal LAP. 9. GZG.
1NV.78612 (paratype), arm spine. 10-12. Ophiogaleus sp. nov. innom 1 from the late Sinemurian to
early Pliensbaehian (Early Jurassie) of the Glasenbaeh Gorge, Austria. 10. NHMW 2012/0137/0017,
proximal LAP. 11. NHMW 2012/0137/0018, proximal to median LAP. 12. NHMW 2012/0137/0019,
proximal to median LAP. One co mm on seale bar per speeies exeept for 9.

104

THUYB., Fossil record of ophiacanthid brittle stars

spine articulations, and the short ventrally pointing extension of the ridge on the inner side. Although
these LAPs unquestionably represent a new species, the fragmentary condition and limited number of
plates currently available precludes a formal description of the species.

Ophiacantha reginae sp. nov.

um:lsid:zoobank.org:act:283B7CEB-644F-4997-A2FE-EFAED468A3BD

Fig. 19: 3-5

Diagnosis

Species of Ophiacantha with moderately large EAPs; outer surface stereom rather finely meshed, devoid
of vertical striation; no spur on outer proximal and inner distal edges; up to seven spine articulations
on strongly elevated distal portion of EAP; row of spine articulations strongly protruding dorsalwards.

Etymology

Species named in honour of Regina Fischer, who generously provided the sample yielding the type
material of the species.

Type material

Holotype

GZG.INV.78605.

Paratypes

GZG.INV.78606 and GZG.INV.78607.

Type locality and horizon

Alsen quarry, Eagerdorf, Germany; Galerites vulgaris Zone, late Campanian, Fate Cretaceous.

Additional material

GZG.INV.78608 (one dissociated EAP).

Description

Holotype

GZG.INV.78605 is a dissociated, moderately large, proximal EAP; slightly higher than wide; dorsal
edge strongly concave as a result of a well-developed constriction; distal edge weakly convex; proximal
edge concave, devoid of spurs; outer surface with moderately finely meshed stereom. Seven large, ear¬
shaped, round spine articulations on strongly elevated distal portion of EAP; very weak dorsalward
increase in size of spine articulations and of gaps separating them; dorsal and ventral lobes of spine
articulations merged into continuous, round volute; spine articulations proximally bordered by sharply
defined, straight edge of strongly elevated distal portion of EAP; gap between spine articulations and
distal edge of EAP from slightly narrower to clearly wider than one spine articulation, with dorsalward
increase in width; row of spine articulations conspicuously protruding dorsalwards. Ventral edge of EAP
convex, slightly pointed; tentacle notch invisible in external view.

Inner side of EAP with large, well-defined, prominent ridge; main part of ridge straight, oblique, dorsal
tip widened and merged with rather short ventrally projecting extension; ventral part of ridge slightly
shorter than main part, gently bent, ventro-proximally bent, not merged with ventral portion of EAP;
kink between ventral and main part of ridge rounded, slightly thickened; inner side of distal edge of EAP
devoid of spurs; inner side of tentacle notch small, poorly defined, shallow. No perforations or furrow
discernible.

105

European Journal of Taxonomy 48: 1-242 (2013)

Paratype supplements and variation

GZG.1NV.78606 is a dissociated median LAP; nearly as high as wide; dorso-proximal tip slightly
fragmentary; very well in agreement with holotype. Six spine artieulations similar to those observed
on holotype; edge of strongly elevated distal portion of LAP proximally bordering spine artieulations
slightly undulose. Ventral edge of LAP nearly straight.

Ridge on inner side of LAP similar to that of holotype but with slightly bent main part; very shallow,
poorly defined vertieal furrow dorsally bordering tentaele noteh, with single, small perforation at dorsal
end of furrow.

GZG.1NV.78607 is a dissoeiated distal LAP; nearly 1.5 times wider than high; ventro-proximal tip of
LAP fragmentary. Five spine artieulations similar to those of holotype; edge of strongly elevated distal
portion of LAP proximally bordering spine artieulations slightly undulose; row of spine artieulations
less strongly protruding dorsalwards than in holotype.

Ridge on inner side of LAP similar to that of holotype but with smaller, less well-defined ventralward
projeeting extension of dorsal tip. Irregular perforations loosely arranged in vertieal row dorsally
bordering tentaele noteh.

Remarks

The strueture and position of the spine artieulations, the shape of the ridge and the absenee of spurs on the
outer proximal and inner distal edges strongly suggest that these LAPs are assignable to Ophiacantha.
The eonspieuously dorsally protruding row of spine artieulations elearly differentiates this LAP type
from other types assigned to that genus. While, at first sight, this eharaeter might seem unusual for
Ophiacantha, it is not uneommon among Reeent speeies of the genus sueh as O. duplex Koehler, 1897
and O. serrata Lyman, 1878, whieh otherwise perfeetly mateh the LAP morphology of Ophiacantha in
its proper sense.

Occurrence

Late Campanian of Germany.

Ophiacantha steffenschneideri sp. nov.
um:lsid:zoobank.org:aet:4FB6425F-54A5-4285-88EE-8FD4911F63AB

Fig. 19: 6-9

Diagnosis

Speeies of with relatively large EAPs displaying a well-developed vertieal striation eonfined

to a very narrow band elose to the spine artieulations; up to seven relatively small spine artieulations;
well-developed spur on the outer proximal and inner distal edges.

Etymology

Speeies named in honour of Steffen Sehneider, who kindly provided the type material of the speeies.

Type material

Holotype

GZG.1NV.78609.

Paratypes

GZG.1NV.78610, GZG.1NV.78611 and GZG.1NV.78612.

106

THUYB., Fossil record of ophiacanthid brittle stars

Type locality and horizon

Bad Freienwalde, Germany; “Septarienton”, Rupelian, Oligocene.

Additional material

GZG.INV.78613 (710 dissociated LAPs); GZG.INV.78614 (11 dissociated arm spines).

Description

Holotype

GZG.INV.78609 is a dissociated, large, proximal LAP; approximately 1.5 times higher than wide; dorsal
edge strongly concave as a result of a well-developed constriction; distal edge convex; proximal edge
irregularly undulose, with small, moderately well-defined, slightly prominent and protruding, angular
spur; outer surface with very narrow band of a well-developed, regular, vertical striation composed
of very few fine lamellae proximally bordering spine articulations; lamellae replaced by moderately
finely meshed stereom on almost entire outer surface; trabecular intersections thickened into small
granules on ventral sixth of outer surface. Seven relatively small,< ear-shaped spine articulations
freestanding on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine articulation
merged into continuous, round volute; spine articulations proximally sharply bordered by distalmost
lamella, becoming increasingly undulose dorsalwards; spine articulations nearly equal-sized but gap
separating them with dorsalward increase in size; gap between spine articulations at least as wide as one
spine articulation. Ventral edge of LAP nearly straight except for protruding row of spine articulations;
tentacle notch invisible in external view.

Inner side of LAP with very large, conspicuous, sharply defined and prominent ridge; main part of ridge
nearly straight, oblique, dorsally strongly widened and merged with nearly vertical ventrally pointing
extension close to proximal edge and almost as long as main part of ridge; ventral part of ridge with
slightly thickened kink and short proximally pointing part; inner side of distal edge of LAP with small,
round, well-defined, weakly prominent spur composed of densely meshed stereom; inner side of tentacle
notch poorly defined, small, rather inconspicuous. Small perforations, round to vertically elongate, in
irregular vertical row dorsally bordering tentacle notch.

Paratype supplements and variation

GZG.INV.78610 is a dissociated median LAP; slightly wider than high; agreeing well with holotype;
spur on proximal edge much better defined and more strongly protruding. Five spine articulations similar
to those observed on holotype. Ventral edge of LAP concave; tentacle notch invisible in external view.
Inner side of LAP with conspicuous ridge similar to that observed on holotype; spur on inner side of
distal edge of LAP better defined. Two small, well-defined perforations dorsally bordering inner side of
tentacle notch.

GZG.INV.78611 is a dissociated distal LAP; almost twice wider than high; very well in agreement with
holotype; spur on proximal edge better defined and more strongly protruding. Five spine articulations
on strongly elevated distal portion of LAP, slightly more horizontally elongate than those of holotype;
dorsal and ventral lobes merged into continuous volute but with small, shallow notch proximally. Ventral
edge strongly concave; tentacle notch invisible in external view.

Inner side of LAP with large, well-defined, prominent ridge; dorsal part of ridge similar to that observed
on holotype; ventral part of ridge distally rather than proximally pointing and longer than dorsal part;
inner side of distal edge of LAP with relatively large, poorly defined, oblique spur composed of more
densely meshed stereom; inner side of tentacle notch small, oblique, moderately well defined. Three
relatively large, irregular perforations in oblique row dorsally bordering inner side of tentacle notch.

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European Journal of Taxonomy 48: 1-242 (2013)

GZG.1NV.78612 is a dissociated arm spine; cylindrical, slowly tapering; few eoarse, regular longitudinal
ribs irregularly beset with minute granules, separated by narrow rows of pores with oeeasional short
thorns pointing towards the apex of the spine; tip of spine broken.

Remarks

These LAPs fit the LAP morphology diagnosis of Ophiacantha in its proper sense so markedly well that
assignment to that genus is unquestionable. The LAPs in question elearly differ from all other fossil LAP
types assigned to Ophiacantha in eombining a fine vertieal striation, whieh is eonfined to a very narrow
band of the outer surfaee, with relatively small spine artieulations and the well-developed (at least in median
and distal LAPs) spur on the outer proximal and inner distal edges. It is thus deseribed here as a new speeies.

This LAP type bears striking similarities to the LAPs of extant Ophiacantha bidentata and its
morphologieally elosely similar eongener O. fraterna Verrill, 1885 (Martynov & Litvinova 2008). In
terms of the shape of the ridge on the inner side, the size of the spine artieulations and the presenee of
a spur on the outer proximal and inner distal edges, the Oligoeene speeies is eloser to O. fraterna. The
slightly better-developed eonstrietion and the more strongly undulose distalmost lamella proximally
bordering the spine artieulations, in eontrast, plaee the Oligoeene speeies eloser to O. bidentata. These
striking similarities in LAP morphology suggest that the Oligoeene taxon from the North Sea Basin shares
elose phylogenetie ties with the North Atlantie O. bidentata and O. fraterna. Interestingly, the latter two
are morphologieally so similar that they were long eonsidered to be eonspeeifie (Martynov & Litvinova
2008), implying a reeent divergenee date and/or very little morphologieal differentiation following
divergenee. In this light, Ophiacantha steffenschneideri sp. nov. would be a plausible eandidate for an
aneestor of O. bidentata and O. fraterna. However, sueh a elaim eannot, of eourse, be substantiated on
the basis of LAP morphology alone.

Occurrence

Oligoeene of Germany.

Genus Ophiogaleus gen. nov.

um:lsid:zoobank.org:aet:25557BA8-022E-49DC-99A2-ACA17793A5EB

Type species

Ophiacantha? constricta Hess, 1966, by present designation.

Other species included

Ophiacantha? danica Rasmussen, 1952; Ophiacantha? dorecki Hess, 1962 and Ophiogaleus stans sp. nov.

Diagnosis

Ophiaeanthid genus with numerous (generally at least seven) ear-shaped spine artieulations on strongly
elevated distal portion of EAP; dorsal and ventral lobes of spine artieulations merged into eontinuous
lobe; outer surfaee with moderately eoarsely meshed stereom; ridge on inner side eomposed of short,
narrow, oblique eentral part with generally strongly widened, triangular dorsal portion with near-
vertieal distal edge and pointed dorsal and ventro-proximal tips; generally several spurs at least on inner
distal edge of EAPs; arm spines forming fan dorsally at least in proximal arm segments; row of spine
artieulations eommonly protruding ventrally.

Etymology

Genus named in honour of my friend and eolleague Andy Seott Gale for his eontinuous and eneouraging
support, the delightfully shared delieaeies and wines, and for providing some of the most important

108

THUYB., Fossil record of ophiacanthid brittle stars

samples used in the present study; from ophis, Greek for “snake”, a commonly used prefix for ophiuroid
names, gender masculine.

Remarks

Ophiacanthid fossil occurrences based exclusively on dissociated LAPs were almost invariably assigned
tentatively to the genus Ophiacantha using open nomenclature (Thuy et al. 2012, plus references
therein) following Hess’s (1962) suggestion to use the type taxon of a family in case of uncertain generic
placement. Although assignment of the present species to the genus Ophiacantha is shown here to be
untenable (see above), some of the other species, including Ophiacantha? constricta and Ophiacantha?
danica, display LAP morphologies which are very close to that of Ophiacantha in its proper sense.
These similarities pertain mainly to the shape and position of the spine articulations and the shape of the
ridge on the inner side of the LAPs. In fact, the relatively short, oblique central part with the strongly
widened, triangular dorsal part displaying a near-vertical distal edge and pointed dorsal and ventro-
proximal tips observed in the fossil LAP types in question can be considered as a variant of the ridge
observed in Ophiacantha bidentata and similar extant congeners. In the latter, the ridge is composed of a
long main, oblique, straight to slightly bent part displaying a generally relatively long ventrally pointing
extension. In some cases, the main part and its ventrally pointing extension are fused into a large, near-
triangular knob, which then looks very similar to the ridge observed in the fossil LAP types in question,
except that in the latter there is a kink between the non-widened part of the ridge and the large triangular
dorsal part.

In spite of the striking similarities, in particular with respect to the shape of the ridge, the fossil LAPs
in question differ from the LAPs of Ophiacantha in displaying several spurs on the inner distal and,
to a lesser extent, the outer proximal edge. In combination with the above-mentioned kink between
the narrow central part of the ridge and its strongly widened, triangular part, this difference warrants
separation at the generic level. Ophiogaleus gen. nov. is thus introduced here to accommodate the fossil
LAPs in question. It must be stressed, however, that the striking similarities in LAP morphology strongly
suggest that Ophiogaleus gen. nov. and Ophiacantha are phylogenetically very close.

Ophiogaleus sp. nov. innom. 1
Fig. 19: 10-12

Material examined

NHMW 2012/0137/0017, NHMW 2012/0137/0018, NHMW 2012/0137/0019 and NHMW
2012/0137/0020 (12 dissociated LAPs) from the late Sinemurianto early Pliensbachianofthe Glasenbach
Gorge, Austria.

Description

Relatively large, dissociated proximal to median, fragmentary LAPs; originally much higher than wide;
dorsal edge not preserved; well-developed constriction; distal edge convex; proximal edge irregularly
undulose; at least one large, moderately well-defined, prominent and slightly protruding, oval spur in
the ventral half of the proximal edge, composed of more densely meshed stereom; outer surface with
moderately finely meshed stereom, replaced by more finely meshed stereom in a relatively broad band
paralleling proximal edge of LAP; trabecular intersections of outer surface stereom not thickened or
developed into granules. At least six large, ear-shaped spine articulations freestanding on strongly
elevated distal portion of LAP; dorsal and ventral lobes of spine articulations merged into continuous,
conspicuously oblique volute; spine articulations proximally sharply bordered by well-defined but
weakly prominent, near-straight ridge; very weak dorsalward increase in size of spine articulations and

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European Journal of Taxonomy 48: 1-242 (2013)

of gaps separating them; relatively narrow gap between spine artieulations and distal edge of LAP; row
of spine artieulations originally most probably slightly protruding ventral wards.

Inner side of LAPs with large, sharply defined and prominent ridge; ventral part long, relatively narrow,
strongly bent, ventral tip slightly pointed, sharply separated from ventral portion of LAP; dorsal part of
ridge fragmentary in all available LAPs, slightly widened, small, vertieally elongate, exaet outline not
unambiguously determinable; inner side of distal edge of LAP with one to two small, moderately well to
poorly defined, horizontally elongate and slightly prominent spurs; inner side of tentaele noteh relatively
large, well defined laterally. No perforations or furrow diseemible.

Remarks

The limited amount of material available and its fragmentary eondition make a sound systematie
assessment diffieult. While assignment to the Ophiaeanthidae is unquestionable on aeeount of the
spine artieulation strueture and the morphology of the inner side, affinities within this family are more
problematie. Greatest similarities are shared with the LAPs of Ophiogaleus gen. nov. on aeeount of
the number, position and shape of the spine artieulations and the number and position of spurs on
the outer proximal and inner distal edges. The shape of the ridge on the inner side, however, is rather
atypieal for Ophiogaleus gen. nov. with respeet to the narrow dorsal part of the ridge. In the light
of the similarly atypieal ridge in Ophiogaleus dorecki (Hess, 1962) eomb. nov. (see below), known
from more eomplete material, assignment to Ophiogaleus gen. nov. seems justified after all, espeeially
eonsidering the possibility that the above-deseribed speeimens and the slightly younger O. dorecki are
two stratigraphieally elosely spaeed representatives of the same lineage. Within Ophiogaleus gen. nov.,
the LAPs deseribed above are unique in displaying oblique spine artieulations. The fragmentary nature
of the reeord, however, preeludes a formal deseription of this speeies in the present study.

Ophiogaleus dorecki (Hess, 1962) eomb. nov.

Fig. 20: 1-2

p.p. Ophiacanthal dorecki Hess, 1962: 622, figs 17, 19 (fig. 18 is a different speeies, probably not even
an ophiaeanthid).

non Ophiacanthal ef dorecki - Kutseher 1996: 18, pi. 4, fig. 5 (probably an ophiomyeetid elose to
extant Ophiohelus Lyman, 1880).

Diagnosis

Speeies of Ophiogaleus gen. nov. with relatively large LAPs displaying up to eleven spine artieulations
on the strongly elevated, yet proximally not sharply bordered, distal portion; no spurs diseemible on
outer proximal edge; up to three small, well-defined, strongly prominent spurs on inner distal edge of
the LAP; ridge on the inner side with relatively narrow but vertieally extremely elongate dorsal part.

Material examined

NHMB M1214, NHMB M1215 and 35 dissoeiated LAPs from the late Pliensbaehian of Seewen,
Switzerland, the type material of Hess (1962).

Description

Large LAPs; proximal ones more than twiee higher than wide; distal ones nearly as high as wide;
dorsal edge slightly eoneave as a result of a moderately well-developed eonstrietion; distal edge eonvex;
proximal edge irregularly undulose, no spurs diseemible; outer surfaee with moderately finely meshed
stereom, replaeed by more finely meshed stereom in very narrow band paralleling proximal edge of
LAP. Eleven (proximal LAPs) to seven (distal LAPs) large, ear-shaped spine artieulations freestanding

110

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 20. Fossil lateral arm plates (LAPs) of ophiacanthid brittle stars in external (a) and internal (b)
views and articulated arm fragment. 1-2. Ophiogaleus dorecki (Hess, 1962) comb. nov. from the late
Pliensbachian (Early Jurassic) of Seewen, Switzerland. 1. NHMB Ml 1214, proximal LAP. 2. NHMB
Ml 1215, distal LAP. 3-5. Ophiogaleus stans sp. nov. from the early Bathonian (Middle Jurassic) of La
Pouza, France. 3. GZG.INV.78615 (holotype), proximal LAP. 4. GZG.rNV.78616 (paratype), median
LAP. 5. GZG.rNV.78617 (paratype), distal LAP. 6-7. Ophiogaleus sp. nov. innom 2 from the Callovian
(Middle Jurassic) of Jumara, India. 6. GZG.INV.78619, proximal LAP. 7. GZG.INV.78620, distal LAP.
8-10. Ophiogaleus constrictus (Hess, 1966) comb. nov. from the late Oxfordian (Late Jurassic) of Savigna,
France. 8. GZG.INV.78624, proximal LAP. 9. GZG.INV.78625, distal LAP. 10. GZG.INV.78626, proximal
arm fragment in ventral (a) and dorsal (b) views. One common scale bar per species except for 10.

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European Journal of Taxonomy 48: 1-242 (2013)

on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine artieulations merged into
eontinuous volute; spine artieulations not sharply bordered proximally; relatively narrow gap between
spine artieulations and distal edge of LAP; moderate (proximal LAPs) to weak (median and distal LAPs)
dorsalward inerease in size of spine artieulations and of gaps separating them; row of spine artieulations
strongly (proximal LAPs) to weakly (distal ones) protruding ventralwards. Tentaele noteh invisible in
external view.

Inner side of LAPs with large, eonspieuous, sharply defined, prominent ridge; short oblique eentral part
of ridge; dorsal part widened, strongly vertieally elongate, nearly triangular, with pointed (in proximal
LAPs extremely elongate) dorsal tip, ventro-proximal tip slightly pointed; ventral portion of eentral
part of ridge very short, ventro-proximally pointing, sharply separated from ventral part of LAP; inner
side of distal edge of LAP with two to three small, well-defined, strongly prominent spurs eomposed
of slightly more densely meshed stereom; inner side of tentaele noteh relatively small, poorly defined
laterally; moderately shallow, dorsally well-defined vertieal furrow with small, irregular perforations
dorsally bordering tentaele noteh.

Remarks

Hess (1962) deseribed the new speeies Ophiacanthal dorecki on the basis of dissoeiated lateral arm
plates from the Pliensbaehian of Switzerland. A re-examination of the type material, however, has
revealed that it aetually ineludes two different LAP types, one similar to the holotype (see Hess 1962,
fig. 17), the other resembling Hess’s (1962) fig. 18, eharaeterised by a slightly oblique row of elosely
spaeed spine artieulations widely separated from the distal edge of the LAP. The higher-level taxonomie
affinities of the latter type are unelear. Some features point to the Ophiaeanthidae but the sigmoidal fold,
one of the key diagnostie features of the family, eould not be unambiguously observed in the speeimens
at hand.

In eontrast, the LAP type, ineluding the holotype, unquestionably belongs to the Ophiaeanthidae. Within
this family, strongest affinities are shared with the LAPs of Ophiogaleus constrictus eomb. nov. and
O. danicus eomb. nov., on aeeount of the number, shape and position of the spine artieulations and the
number of spurs on the inner distal edge of the LAP. The shape of the ridge on the inner side of the
type speeimens of Hess (1962) is admittedly rather unusual for Ophiogaleus gen. nov., but nevertheless
eompatible with the LAP morphologieal diagnosis of the genus. Within this genus, the LAPs are unique
in displaying up to eleven spine artieulations, laeking a ridge sharply bordering the spine artieulations
proximally and in having a relatively narrow but vertieally extremely elongate dorsal part of the ridge
on the inner side.

The LAPs deseribed and illustrated by Kutseher (1996) as Ophiacanthal ef dorecki from the Toareian/
Aalenian of Germany fundamentally differ from the type material of Hess (1962), in partieular with
respeet to spine artieulation morphology. The LAPs in question share greatest similarities with those of
the extant ophiomyeetid Ophiohelus.

Occurrence

Late Pliensbaehian of Switzerland.

Ophiogaleus stans sp. nov.

um:lsid:zoobank.org:aet:lB346B9F-A7EQ-489B-B4DC-B87CCE351C95

Fig. 20: 3-5

Diagnosis

Speeies of Ophiogaleus gen. nov. with relatively small EAPs; dorsalmost spine artieulation enlarged;
row of spine artieulations slightly oblique; ventral part of the ridge on the inner side strongly bent.

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THUYB., Fossil record of ophiacanthid brittle stars

Etymology

Name formed after stare, Latin for “staunch”, in reference to the very few type specimens of the species
having been isolated, against all odds, from amongst more than 100000 crinoid ossicles.

Type material

Holotype

GZG.INV.78615.

Paratypes

GZG.INV.78616 and GZG.INV.78617.

Type locality and horizon

La Pouza, France; Zigzag Zone, early Bathonian, Middle Jurassic.

Additional material

GZG.INV.78618 (3 dissociated LAPs).

Description

Holotype

GZG.INV.78615 is a dissociated, relatively small, proximal LAP; twice higher than wide; dorsal edge
strongly concave as a result of a well-developed constriction; distal edge very weakly convex; proximal
edge irregularly undulose, with large, moderately well-defined, prominent and strongly protruding,
vertically elongate spur composed of more densely meshed stereom; outer surface with moderately
coarsely meshed stereom, except for narrow band of finely meshed stereom paralleling proximal edge of
LAP. Nine large, ear-shaped spine articulations freestanding in slightly oblique row on strongly elevated
distal portion of LAP; dorsal and ventral lobes of spine articulations merged into continuous, round volute;
spine articulations proximally sharply bordered by very weakly prominent, very narrow ridge becoming
slightly undulose dorsalwards; large, dorsalwards increasing gap separating spine articulations and distal
edge of LAP; spine articulations equi-distant and almost all of equal size; dorsalmost spine articulation
much larger than remaining ones; row of spine articulations strongly protruding ventral wards. Ventral
edge of LAP slightly convex; tentacle notch invisible in external view.

Inner side of LAP with large, conspicuous, sharply defined and strongly prominent ridge; ventral part
of ridge narrow, strongly bent dorso-proximalwards; dorsal part of ridge very large, strongly widened,
triangular, with pointed ventro-proximal angle and blunt dorsal tip; inner side of distal edge of LAP
with medium-sized, moderately well-defined, round, weakly prominent spur composed of more densely
meshed stereom; second smaller, less well-defined, almost indiscernible spur ventrally bordering large
spur; inner side of tentacle notch very small. Shallow yet well-defined vertical furrow dorsally bordering
centre of ventral ridge part; no perforations discernible in furrow.

Paratype supplements and variation

GZG.INV.78616 is a dissociated median LAP; ventro-proximal edge slightly fragmentary; slightly less
than twice higher than wide; closely agreeing with holotype; distal edge convex; preserved portion of
proximal edge slightly undulose, with very poorly defined, almost indiscernible, weakly prominent and
non-protruding spur. Seven spine articulations similar to those observed on holotype, arranged in very
slightly oblique row; gap separating spine articulations from distal edge narrower than in holotype, with
very slight dorsalward increase in width; dorsalmost spine articulation much larger than remaining ones,
as in holotype.

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European Journal of Taxonomy 48: 1-242 (2013)

Inner side of LAP with ridge similar to that observed in holotype but with slightly narrower dorsal part;
inner side of distal edge of LAP with three poorly defined, weakly prominent spurs, one medium-sized
eentral one bordered dorsally and ventrally by smaller ones.

GZG.1NV.78617 is a dissoeiated distal LAP; dorso-proximal eomer slightly fragmentary; slightly
higher than wide; distal edge eonvex. Seven spine artieulations similar to those of holotype freestanding
in vertieal row on strongly elevated distal portion of LAP; ridge proximally sharply bordering
spine artieulations slightly wider and more strongly prominent than in holotype; gap between spine
artieulations and distal edge of LAP narrow; all spine artieulations ineluding the dorsalmost of equal
size; row of spine artieulations only slightly protruding ventralwards. Ventral edge of LAP with small
eoneave tentaele noteh.

Inner side of LAP with poorly defined ridge; ventral part short, bent, prominent; dorsal part widened,
slightly fragmentary but originally nearly triangular, less prominent; no spurs on inner side of distal edge
of LAP; inner side of tentaele noteh moderately large. No furrow or perforations diseemible.

Remarks

The highly distinetive shape of the ridge in eombination with the number, position and arrangement of
the spine artieulations and the number of spurs on the inner distal edge unambiguously plaee these LAPs
in Ophiogaleus gen. nov. The LAPs in question differ markedly from other types assigned to this genus
on aeeount of the enlarged dorsalmost spine artieulation, the slightly oblique row of spine artieulations
in proximal LAPs, the strongly bent ventral part of the ridge on the inner side, and the laek of spurs in the
distal LAP. Therefore, in spite of the limited amount of material available and its slightly fragmentary
nature, this LAP type is here formally deseribed as a new speeies.

Occurrence

Early Bathonian of France.

Ophiogaleus sp. nov. innom. 2
Fig. 20: 6-7

Material examined

GZG.1NV.78619, GZG.INV.78620, GZG.1NV.78621 (20 dissoeiated FAPs) from sample 95, lower
Chari Formation, Callovian of Jumara, India; GZG.1NV.78622 (dissoeiated FAP) from sample 31,
lower Chari Formation, Callovian, Jumara, India; GZG.1NV.78623 (dissoeiated FAP) from sample 121,
upper Chari Formation, Callovian of Jumara, India.

Description

GZG.INV.78619 is a dissoeiated, moderately large, proximal FAP; ventral edge fragmentary, originally
probably 1.5 times higher than wide; dorsal edge nearly straight; distal edge eonvex; proximal edge
irregularly undulose with three moderately large, poorly defined, round to vertically slightly elongate,
prominent and weakly protruding spurs, two closely spaced ones in the middle of the proximal edge,
and one in the dorsal half of the proximal edge; outer surface with moderately coarsely meshed stereom;
trabeculae of outer surface stereom merging into very weakly developed vertical striation close to
ventral edge of FAP. At least five large, ear-shaped spine articulations; ventral and dorsal lobes merged
into continuous volute; very weak dorsal ward increase in size of spine articulations and slightly stronger
increase in size of gaps separating them; spine articulations proximally sharply bordered by slightly
undulose, well-defined, prominent, relatively broad ridge; gap between spine articulations and distal
edge of FAP narrow.

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THUYB., Fossil record of ophiacanthid brittle stars

Inner side of LAP with relatively small, well-defined, prominent, oblique ridge with widened, triangular
ventral part and widened, vertically elongate, triangular dorsal part with dorsalwards and ventro-
proximally pointing angles; inner side of distal edge of LAP with at least two relatively large, poorly
defined, round, weakly prominent spurs composed of more densely meshed stereom; inner side of
tentacle notch relatively small, deeply incised, partly obscured by sediment; laterally well defined. No
perforations or furrow discernible.

GZG.INV.78620 is a dissociated distal LAP; slightly wider than high; well in agreement with above-
described LAP; dorsal edge weakly concave as a result of a constriction; single, large, poorly defined,
round, prominent and weakly protruding spur on proximal edge. Five spine articulations similar to those
observed in other specimen. Ventral edge slightly convex, with very small, gently concave tentacle
notch.

Inner side of LAP with relatively small, inconspicuous oblique ridge displaying strongly widened,
triangular ventral part and slightly widened dorsal tip; single large, moderately well-defined, round,
very weakly prominent spur composed of densely meshed stereom on inner side of distal edge of LAP.

Remarks

In spite of the rather poor preservation, these specimens are assignable to Ophiogaleus gen. nov. on
account of the highly distinctive shape of the ridge on the inner side, the shape and position of the spine
articulations and the presence of more than one spur on the outer proximal and inner distal edges, at least
in proximal LAPs. Admittedly, the number of spine articulations is atypically low for Ophiogaleus gen.
nov., although it appears likely that this is an artefact of the fragmentary condition of the proximal LAPs.
There is a certain resemblance with the LAPs assigned herein to Ophiomitrella, especially on account of
the conspicuous ridge proximally bordering the spine articulations. However, the shape of the ridge on
the inner side of the LAPs differs fundamentally.

The low number of spine articulations and the poorly developed vertical striation near the ventral edge of
the outer surface suggest that the above-described LAPs belong to a new species. In the absence of more
complete and better-preserved material, however, the LAPs in question cannot be formally described.

Ophiogaleus constrictus (Hess, 1966) comb. nov.

Figs 20: 8-10; 21: 1

p.p. Ophiacanthal suprajurassicaYiQss, 1965: 1065, 1077, figs 12, 14, 43.

Ophiacanthal constricta Hess, 1966: 1031, 1054, figs 8, 11, 74-75, 78 [figs 76-77 show a different
species which is here reinterpreted as Ophiocamax dorotheae sp. nov. (see below)].

non Ophiacanthal oder Ophiothrixl sp. - Hess 1960: 417, figs 39-40.

non Ophiacanthal cf constricta - Hess & Holenweg 1985: 164, fig. 17 [material re-described by
Thuy & Meyer (2013) as Hanshessia trochitophila Thuy & Meyer, 2013].

non Ophiacanthal constricta - Kutscher 1987a: 61, pi. 3 figs 1-2 [material here redescribed as
Ophiomalleus beneficarum gen. et sp. nov. (see below)].

Diagnosis

Species of Ophiogaleus gen. nov. with relatively small LAPs displaying moderately coarsely meshed
stereom on outer surface; up to ten spine articulations on strongly elevated distal edge proximally
sharply bordered by undulose ridge; three poorly defined spurs on outer proximal edge paralleled by up
to four well-defined spurs on inner distal edge in proximal LAPs; single large, well-defined spur on outer
proximal and inner distal edges in median to distal LAPs; ridge on inner side of LAPs with strongly
widened dorsal part with conspicuously pointed dorsal and ventro-proximal angles.

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European Journal of Taxonomy 48: 1-242 (2013)

Material examined

GZG.1NV.78624, GZG.INV.78625, GZG.INV.78626, GZG.INV.78627, GZG.1NV.78628 (7 dissociated
LAPs) from sample SI of Gale (2011); GZG.1NV.78629 (14 dissoeiated LAPs) from sample S2a of Gale
(2011); GZG.1NV.78630 (72 dissoeiated LAPs) from sample S2b of Gale (2011), and GZG.1NV.78631
(4 artieulated arm fragments) from sample S2b of Gale (2011), all from the upper Oxfordian Bifurcatus
Zone of Savigna, Franee; 22 dissoeiated LAPs from the upper Oxfordian Bifurcatus Zone of Guldenthal,
Switzerland, the original material of Hess (1966); 4 dissoeiated LAPs from the lower Oxfordian Renggeri
Member of Chapois, Franee, the original material of Hess (1965a).

Description

Relatively small LAPs; at least twiee higher than wide (proximal LAPs) to nearly as high as wide (distal
LAPs); dorsal edge eoneave as a result of a well-developed eonstrietion; distal edge eonvex; proximal
edge eoneave in proximal LAPs, with three to four poorly defined, weakly prominent and very slightly
protruding spurs, ventral one of whieh largest and best defined; proximal edge in median and distal LAPs
irregularly undulose, with single large, moderately well-defined, prominent and strongly protruding spur
probably eorresponding to large, ventralmost spur in proximal LAPs; outer surfaee with moderately
eoarsely meshed stereom replaeed by finely meshed stereom in very narrow band paralleling proximal
edge of LAP; trabeeulae of moderately eoarsely meshed stereom proximally bordering spine artieulations
merged into very poorly developed vertieal striation in a few LAPs; trabeeular interseetions slightly
thiekened into granules in ventral portion of distal LAPs. Ten (proximal LAPs) to six (distal ones) large,
ear-shaped spine artieulations freestanding on strongly elevated ridge; dorsal and ventral lobes of spine
artieulations merged into eontinuous volute; spine artieulations proximally bordered by narrow, well-
defined, undulose ridge; dorsalmost and ventralmost spine artieulations slightly smaller than remaining,
nearly equal-sized ones; gap separating spine artieulations and distal edge very narrow in proximal
LAPs, slightly wider and dorsally widening in median to distal LAPs; row of spine artieulations strongly
protruding ventralwards in proximal LAPs, slightly protruding in median ones and not protruding in
distal ones. Ventral edge of LAPs nearly straight; tentaele opening generally invisible in external view.
Inner side ofLAP with very large, eonspieuous, sharply defined, prominent ridge; relatively short, slender,
oblique, straight eentral part of ridge, merged dorsally with very large, vertieally elongate (in proximal
to median LAPs), near-triangular dorsal part of ridge with eoneave edges and pointed dorsal and ventro-
proximal angles; eentral part of ridge merged ventrally with short, slender, ventro-proximally pointing
part not merged with ventral portion ofLAP; inner side of distal edge with three to four well-defined,
weakly prominent, oval spurs generally with dorsalward inerease in size and eomposed of more densely
meshed stereom in proximal LAPs; single spur in median to distal LAPs similar to the ventralmost spur
observed in proximal LAPs; inner side of tentaele noteh relatively small, nearly vertieal, moderately well
defined laterally. Very shallow, narrow, moderately well-defined vertieal furrow with small, irregularly
spaeed perforations dorsally bordering tentaele noteh in proximal to median LAPs; no furrow in distal
LAPS.

Artieulated arm fragments: LAPs broadly in eontaet dorsally and ventrally in proximal to distal arm
segments; dorsal arm plates relatively small, bell shaped, with slightly eonvex distal edge, pointed
proximal angle with slightly eoneave edges; spine artieulations meeting mid-radially forming eontinuous
band at least in proximal segments, arm spines thus originally forming fan; ventral arm plates nearly
T-shaped, weakly eonvex distal edge, deeply eoneave latero-proximal edges and obtuse proximal angle;
proximal and latero-proximal edges of ventral arm plates slightly prominent; round, slightly swollen
area of eoarsely meshed stereom in eentre of ventral arm plates; tentaele pores small, eovered by single,
spatulate, distally widening tentaele seale; arm spines slightly flattened, with eoarsely retieulate stereom
displaying small thorns, irregular longitudinal row of mueh larger thorns along both margins of the spines.

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Fig. 21. Fossil lateral arm plates (LAPs) of ophiacanthid brittle stars in external (a) and internal (b)
views and articulated arm fragment in ventral (a) and dorsal (b) views. 1. Ophiogaleus constrictus (Hess,
1966) comb. nov. from the late Oxfordian (Late Jurassic) of Savigna, France; GZG.fNV.78627 distal
arm fragment. 2. Ophiogaleus sp. from the early Kimmeridgian (Late Jurassic) of Geisingen, Germany;
GZG.INV.78632, proximal LAP. 3-4. Ophiogaleus danicus (Rasmussen, 1952) comb. nov. from the
early Maastrichtian (Late Cretaceous) of Riigen, Germany. 3. GZG.rNV.78635, proximal LAP. 4. GZG.
INV.78636, distal LAP. 5-6. Hanshessia sp. nov. innom. 1 from the late Sinemurian to early Pliensbachian
(Early Jurassic) of the Glasenbach Gorge, Austria. 5. NHMW 2012/0137/0021, proximal LAP. 6. NHMW
2012/0137/0022, proximal LAP. 7-9. Hanshessia sp. nov. innom. 2 from the early Bathonian (Middle
Jurassic) of La Pouza, France. 7. GZG.INV.78637, proximal LAP. 8. GZG.fNV.78638, proximal LAP.
9. GZG.fNV.78639, distal to median LAP. One common scale bar per species except for 1.

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Remarks

The concept of Ophiogaleus constrictus comb. nov. has repeatedly caused confusion in the past. This
form was originally described by Hess (1966) as Ophiacanthal constricta when he noted that the
type material from the Oxfordian of Switzerland and France previously described as Ophiacanthal
suprajurassica Hess, 1965 included more than one type of LAP. Hess (1966) based the distinction
on the higher number of spine articulations and the lack of a vertical striation on the outer surface
in O. constrictus comb. nov. These are, indeed, valid differences, yet the concept of O. constrictus
comb. nov. was still not sufficiently specific because Hess (1966) also included LAPs which are here
reinterpreted as Ophiocamax dorotheae sp. nov. (see Hess 1960, figs 39-40; Hess 1966, figs 76-77).
Following this confusion, Kutscher (1987a) described dissociated LAPs from the Callovian of Germany
as Ophiacanthal constricta, these markedly differ from the holotype of the species but do have clear
features in common with some of the LAPs erroneously included in that species by Hess (1966).

A re-examination of the type specimens, complemented by new, partially articulated, equivalent finds
from the Oxfordian of France, has enabled a consistent reinterpretation of Ophiacanthal constricta.
Thanks to Hess’s (1966) careful choice of the holotype (a single well-preserved proximal LAP, rather
than a less distinctive median LAP or a series of LAPs), the species in question is now unambiguously
identifiable. It is chosen as the type species of Ophiogaleus gen. nov., an assumedly close relative of
extant Ophiacantha (see above), since it is known from numerous well-preserved specimens, including
articulated arm fragments, and most typically displays the distinctive features of the genus.

Occurrence

Early to Late Oxfordian of France and Switzerland.

Ophiogaleus sp.

Fig. 21: 2

Material examined

GZG.INV.78632 and GZG.INV.78633 (2 dissociated LAPs) from the lower Kimmeridgian Lacunosa
Marls of Geisingen, Germany; GZG.INV.78634 (3 dissociated LAPs) from the upper Oxfordian
Bimammatum Zone of the Plettenberg, Germany.

Description

Small, fragmentary proximal to distal LAPs; edges poorly preserved, outline and presence of spurs
cannot be assessed; outer surface with moderately finely meshed stereom. Five (distal LAPs) to at least
seven (proximal LAPs) large, ear-shaped spine articulations freestanding on strongly elevated distal
portion of LAP; dorsal and ventral lobes merged into continuous volute; spine articulations proximally
sharply delimited by very narrow, weakly prominent dorsally very slightly undulose ridge; gap between
spine articulations and distal edge of LAP narrower than one spine articulation; very weak dorsalward
increase in size of spine articulations; row of spine articulations strongly protruding ventralwards.

Inner side of LAPs with large, conspicuous, sharply defined, prominent ridge composed of narrow
ventral part and strongly widened, vertically elongate, triangular dorsal part with pointed dorsal and
ventro-proximal angles; very short ventro-proximalward extension of ventralpart of ridge; inner side of
distal edge of LAP with up to three moderately large, weakly defined, non-prominent spurs composed
of slightly more densely meshed stereom; inner side of tentacle notch relatively small. No perforations
or furrow discernible.

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Remarks

This material unambiguously belongs to Ophiogaleus gen. nov. Its fragmentary nature, however,
precludes a detailed identification at the specific level. Closest similarities are shared with the LAPs of
Ophiogaleus constrictus comb. nov. and it is more than likely that the above-described material, indeed,
belongs to that species. In the absence of more complete specimens, however, this assignment remains
elusive.

Ophiogaleus danicus (Rasmussen, 1952) comb. nov.

Fig. 21:3-4

Ophiacanthal danica Rasmussen, 1952: 52, fig. 6.

Ophiacantha? danica - Jagt 1999a: 199, pi. 1 fig. 8. — Kutscher & Jagt 2000: 61, pi. 24 figs 7-9, pi. 25
figs 1-2 [non pi. 24 fig. 10, which most probably is an LAP of Ophiotreta striata (see above)]. — Jagt &
Odin 2001: 416, pi. 1 fig. 1.

p.p. Ophiacanthal danica - Jagt 2000: 10, pi. 2 fig. 10 [non pi. 2 figs 5-7, Ophiomitrella sp. nov. (see
below)]

Diagnosis

Species of Ophiogaleus gen. nov. with very large LAPs displaying coarsely meshed stereom on the
outer surface with strongly thickened trabecular intersections, especially in ventral part of the LAPs
developed into large granules; up to four variably developed spurs on outer proximal and inner distal
edges of proximal to distal LAPs; up to eleven spine articulations sharply separated proximally by thick,
well-defined, prominent ridge.

Material examined

GZG.INV.78635, GZG.INV.78636, and 328 dissociated LAPs from the early Maastrichtian of Riigen,
the original material of Kutscher & Jagt (2000); 16 dissociated LAPs from the early Maastrichtian of
Lagerdorf-Kronsmoor, Germany.

Description

Very large LAPs; more than twice wider than high (proximal LAPs) to slightly wider than high
(distal ones); dorsal edge strongly concave as a result of a well-developed constriction; distal edge
convex; proximal edge irregularly convex, with one to four moderately well-defined, prominent, rarely
protruding, oval spurs of variable size and position in proximal to distal LAPs; outer surface with
coarsely meshed stereom, trabecular intersections strongly thickened, in ventral part of LAP developed
into large, conspicuous granules; more finely meshed stereom in narrow band paralleling proximal edge
of LAP. Eleven (proximal LAPs) to five (distal ones) large, ear-shaped spine articulations freestanding
on strongly elevated distal portion of LAP; dorsal and ventral lobes of spine articulations merged into
continuous volute; spine articulations proximally sharply bordered by thick, well-defined, prominent,
slightly knobby and wavy ridge; gap between spine articulations and distal edge of LAP slightly
narrower than one spine articulation; very weak dorsalward increase in size of spine articulations and of
gaps separating them; row of spine articulations slightly protruding in proximal to median LAPs. Ventral
edge of LAP slightly concave; tentacle notch not visible in external view.

Inner side of LAPs with large, broad, conspicuous, sharply defined and prominent ridge; ventral part
of ridge relatively short, moderately wide, strongly bent; dorsal part of ridge conspicuously large,
triangular, vertically elongate, dorsal and ventro-proximal tips pointed, proximal and ventral edges
slightly concave, distal edge slightly convex; inner side of distal edge of LAP with one to four variably
well-defined, slightly prominent, non-protruding, oval spurs of variable size and position; inner side of

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European Journal of Taxonomy 48: 1-242 (2013)

tentacle notch very small, slightly oblique, poorly defined. Well- to moderately well-defined, narrow,
vertical furrow with very small perforations dorsally bordering tentacle notch in proximal and median
LAPS.

Remarks

Ophiogaleus danicus comb. nov. was originally described by Rasmussen (1952) from the late
Maastrichtian of Denmark. The brief description and single illustration was beautifully complemented
by Kutscher & Jagt (2000) on the basis of new material from the Maastrichtian of Germany and
Denmark. Those authors retained the species in the genus Ophiacantha, albeit in open nomenclature,
although they speculated about close similarities with the LAPs of extant Ophiomitra Lyman, 1869. In
that genus, however, the shape of the ridge on the inner side differs fundamentally. In contrast, striking
similarities are shared with the LAPs of Ophiogaleus constrictus comb. nov. from the Oxfordian of
France and Switzerland (see above), in particular with regard to the shape of the ridge, the number,
shape and position of the spine articulations, and the outer surface ornament. Thus, the present species
is here transferred to Ophiogaleus gen. nov., which is in line with Rasmussen’s (1952) initial tentative
assignment to Ophiacantha considering that both genera share highly similar LAP morphologies and
thus most probably are also phylogenetically close.

One of the specimens illustrated by Kutscher & Jagt (2000, pi. 24, fig. 10) does not belong to Ophiogaleus
danicus comb. nov. but most probably to Ophiotreta striata comb. nov. (see above). The specimens
illustrated by Jagt (2000, pi. 2, figs 5-7) almost all belong to a yet undescribed species of Ophiomitrella
(see below).

Occurrence

Late Campanian of Belgium and France, Maastrichtian of Germany and Denmark.

Genus Hanshessia Thuy & Meyer, 2013

Type species

Hanshessia trochitophila Thuy & Meyer, 2013, by original designation.

Diagnosis

Ophiacanthid with relatively large LAPs, proximal ones generally at least twice higher than wide; dorsal
edge of proximal LAPs round, tongue shaped; ventral part of LAPs protruding ventro-proximalwards;
numerous very large, ear-shaped spine articulations on strongly elevated distal portion of LAP; ridge on
inner side composed of strongly bent ventral part and straight, near-vertical dorsal part closely paralleling
proximal edge of LAP; tip of dorsal ridge part widely separated from dorsal edge of LAP; kink between
dorsal and ventral parts of ridge devoid of ventro-proximalwards protruding angle.

Remarks

Hanshessia is an extinct genus described on the basis of articulated specimens from the Bajocian of
Switzerland (Thuy & Meyer 2013) and thus one of the very few fossil ophiacanthid genera for which
detailed data on general skeletal morphology are available. The LAPs of the type specimens are well
preserved and well known, at least as far as external structures are concerned. The morphology of
the inner side, in contrast, could not be directly assessed on the basis of the type specimens. Upon
careful re-examination of the latter, however, a few dissociated vertebrae exposing the vertical groove
on the lateral side could be observed, allowing for conclusions on the shape of the ridge on the inner
side of the LAPs. In fact, the lateral groove on the vertebrae and the ridge on the inner side of the

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THUYB., Fossil record of ophiacanthid brittle stars

LAPs serve as articulation interface between both skeletal components thus sharing complementary
morphologies.

Judging from observations on the type specimens, the ridge on the inner side of Hanshessia trochitophila
is composed of an oblique, strongly bent ventral part and a slightly longer, straight, near-vertical part
sharply interrupted well below the dorsal edge of the LAP and separated from the ventral part by an
angular, but not ventro-proximalwards extended, kink. In combination with the numerous, very large
spine articulations, the tongue-shaped dorsal edge of the LAPs, and the ventro-proximally protruding
ventral portion of the LAPs, the above-described ridge shape is highly distinctive. Closest similarities in
LAP morphology are shared with the Ophiotreta-Ophiopristis group. In the latter, however, the ridge on
the inner side, although superficially almost identical, generally displays a straight ventral part, a kink
with a conspicuous ventro-proximally pointing angle, and a dorsal part which almost reaches the dorsal
edge of the LAP. In addition, the LAPs of species of Ophiotreta and Ophiopristis are characterised by
a strongly prominent, conspicuous distalmost lamella proximally bordering the spine articulations and
commonly displaying a connecting ridge with the ventral lobe of the latter.

Hanshessia sp. nov. innom. 1
Fig. 21: 5-6

Material examined

NHMW 2012/0137/0021, NHMW 2012/0137/0022 and NHMW 2012/0137/0023 (4 dissociated LAPs)
from the late Sinemurian to early Pliensbachian of the Glasenbach Gorge, Austria.

Description

Very large, dissociated proximal LAPs, with ventral portion missing; originally more than twice higher
than wide; dorsal edge convex, tongue shaped; distal edge convex; preserved portion of poximal edge
nearly straight to slightly concave, devoid of spurs; outer surface with fine, well-developed, slightly
undulose, vertical striation confined to a narrow band close to spine articulations and composed of fine
lamellae, replaced on most of outer surface by finely meshed stereom. At least four very large, ear¬
shaped spine articulations in shallow notches on strongly elevated distal portion of LAP; notches of spine
articulations deeply incising vertical striation; ventral and dorsal lobes of spine articulations merged into
continuous, near-circular volute; spine articulations proximally bordered by moderately well-defined,
weakly prominent, strongly undulose ridge; dorsalward increase in size of spine articulations and of
gaps separating them, but dorsalmost spine articulation smaller than second dorsalmost; gap between
spine articulations and distal edge of LAP relatively narrow.

Inner side of LAPs with conspicuous, sharply defined, prominent, very narrow dorsal part of ridge,
paralleling proximal edge of LAP, not reaching dorsal edge of LAP but abruptly interrupted well below
the latter; angular kink at ventral tip of dorsal part of ridge, devoid of ventro-proximally pointing angle;
ventral part of ridge not preserved; inner side of distal edge of LAP devoid of spurs; tentacle notch not
preserved. Well-defined, narrow, vertical furrow with scattered, very small perforations.

Remarks

Despite its fragmentary nature, the above-described material is unambiguously assignable to Hanshessia
on account of the shape of the ridge, the shape and arrangement of the spine articulations and the
shape of the dorsal LAP edge. The present specimens differ from the other types of LAPs assigned to
Hanshessia in displaying a fine vertical striation and lacking spurs on the outer proximal and inner distal
edges. Unfortunately, the incompleteness of the material available precludes a formal description.

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Hanshessia sp. nov. innom. 2
Fig. 21: 7-9

Material examined

GZG.1NV.78637, GZG.1NV.78638, GZG.1NV.78639 and GZG.1NV.78640 (2 dissociated LAPs) from
the lower Bathonian Zigzag Zone of La Pouza, Franee.

Description

GZG.1NV.78637 is a dissoeiated, moderately large, proximal LAP; dorsal edge fragmentary; LAP
originally more than twiee higher than wide; ventral portion of LAP protruding ventro-proximalwards;
distal edge eonvex; proximal edge irregularly undulose, with large, poorly defined, prominent and very
strongly protruding spur; outer surfaee with well-developed, fine, slightly undulose vertieal striation near
spine artieulations, eomposed by fine lamellae and replaeed by finely meshed stereom on the proximal
half of the outer surfaee. At least six very large, ear-shaped spine artieulations in shallow notehes on
the strongly elevated distal portion of the LAP; notehes of spine artieulations deeply ineising vertieal
striation; ventral and dorsal lobes of spine artieulations merged into eontinuous, near-eireular volute;
spine artieulations proximally bordered by very poorly defined, weakly prominent, strongly undulose
ridge; narrow gap between spine artieulations and distal edge of LAP; weak dorsalward inerease in size
of spine artieulations and gaps separating them. Ventral edge eonvex, with small, eoneave tentaele noteh.
Inner side of LAP with large, eonspieuous, sharply defined, prominent ridge eomposed of strongly bent
ventral part not merged with thiekened ventral portion of LAP, and straight, near-vertieal dorsal part
elosely paralleling proximal edge of LAP and abruptly interrupted well below dorsal edge of LAP;
dorsal and ventral parts of ridge separated by angular kink devoid of eonspieuous ventro-proximally
protruding angle; inner side of distal edge of LAP with large, very weakly defined, almost indiseemible
depression; inner side of tentaele noteh small, moderately well defined laterally. Narrow, poorly defined,
shallow vertieal furrow with minute irragularly spaeed perforations dorsally bordering tentaele noteh.

GZG.1NV.78638 is a dissoeiated, moderately large, proximal LAP fragment; ventral half missing; dorsal
edge eompletely preserved, eonvex, tongue shaped; preserved portion of proximal edge devoid of spur;
outer surfaee almost entirely with finely meshed stereom, only few weakly developed vertieal lamellae
between notehes of spine artieulations. Four very large spine artieulations preserved, similar to those
observed on above-deseribed speeimen; dorsalmost spine artieulation slightly smaller than remaining
three.

Inner side of LAP with narrow, sharply defined, prominent dorsal part of ridge abruptly interrupted well
below dorsal edge of LAP. Well-defined, moderately wide and deep vertieal furrow halfway between
dorsal part of ridge and distal edge of LAP.

GZG.1NV.78639 is a dissoeiated, small, distal LAP; ventral portion of LAP missing; LAP originally
at least 1.5 times higher than wide; dorsal edge slightly eonvex; proximal edge with large, moderately
well-defined, prominent and strongly protruding spur; outer surfaee almost entirely with finely meshed
stereom in dorsal half of preserved LAP portion, and with narrow area of well-defined, fine vertieal
striation. Three spine artieulations similar to those of above-deseribed speeimens preserved.

Inner side of LAP with large ridge similar to that of above-deseribed speeimen but with half of ventral
part missing; inner side of distal edge of LAP with moderately large, very poorly defined, almost
indiseemible depression. No perforations or furrows diseemible.

Remarks

The shape of the ridge on the inner side, the stmeture and arrangement of the spine artieulations and the
outline of the dorsal tip of the LAPs unambiguously plaee the present material in the genus Hanshessia.

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THUYB., Fossil record of ophiacanthid brittle stars

In contrast to the LAPs of the nearly coeval type species, H. trochitophila, however, these LAPs display
a well-developed vertical striation on their outer surface. The large, conspicuously protruding spur on the
proximal edge of the LAPs clearly differentiates them from the ones (unnamed) from the Pliensbachian
of Austria assigned to the same genus. The material described above represents a new species but in the
absence of more complete specimens it cannot be described formally.

Hanshessia sp.

Fig. 22: 1-2

Material examined

GZG.INV.78641, GZG.INV.78642 and GZG.INV.78643 (dissociated LAPs) from the Callovian lower
Chari Formation of Jumara (sample 95), India; GZG.INV.78644 (dissociated LAP) from the Callovian
of Bauer-Wehrland, Germany.

Description

Moderately large, dissociated proximal to median LAPs; dorsally and ventrally fragmentary; originally
at least twice higher than wide; distal edge convex; preserved portion of proximal edge nearly straight
to slightly concave, with small, round, poorly defined, prominent and slightly protruding spur; outer
surface with finely meshed stereom, no vertical striation. At least five very large, ear-shaped spine
articulations in very shallow notches of strongly elevated distal portion of LAP; dorsal and ventral lobes
of spine articulations merged into continuous, round volute; spine articulations proximally bordered by
poorly defined, weakly prominent, undulose ridge; relatively large gap separating spine articulations
and distal edge of LAP; dorsalward increase in size of spine articulations and of gaps separating them.
Inner side of LAPs largely obscured by sediment; large, sharply defined, prominent ridge composed
of bent ventral part and straight, near-vertical dorsal part abruptly interrupted at some distance from
dorsal edge of LAP; dorsal and ventral parts of ridge separated by kink devoid of conspicuous, ventro-
proximally pointing angle; inner side of distal edge of LAP with well-defined, round, slightly prominent
spur composed of densely meshed stereom.

Remarks

Although, unfortunately, the limited available material is highly fragmentary, the specimens display
sufficient morphological detail to allow them to be firmly assigned to Hanshessia on the basis of the
shape of the ridge on the inner side and the shape and arrangement of the spine articulations. Similarities
are closest with the LAPs of the type species, H. trochitophila. On the basis of the currently available
material, however, it is impossible to decide whether the present specimens are conspecific with H.
trochitophila or, instead, represent a new species.

Genus Alternacantha Thuy & Meyer, 2013

Type species

Alternacantha occulta Thuy & Meyer, 2013, by original designation.

Diagnosis

Ophiacanthid with large LAPs displaying a relatively large, ventro-proximalwards protruding ventral
portion; small tentacle notch; large, ear-shaped spine articulations with the position of the dorsalmost
spine articulation alternating between close to the remaining ones and widely separated from the latter.

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 22. Lateral arm plates (LAPs) of fossil and Reeent ophiaeanthid brittle stars in external (a) and
internal (b) views. 1-2. Hanshessia sp. from the Callovian (Middle Jurassie) of Jumara, India. 1. GZG.
INV.78641, proximal to median LAP. 2. GZG.INV.78642, proximal LAP. 3-4. Ophiocopa spatula Lyman,
1883, Reeent. 3. Proximal LAP. 4. Distal LAP. 5. Alternacanthal sp. from the late Pliensbaehian (Early
Jurassie) of Amellago, Moroeeo; GZG.INV.78645, proximal LAP. 6. Alternacantha sp. nov. innom. 1
from the middle Toareian (Early Jurassie) of Ee Clapier, Franee; GZG.INV.78647, proximal to median
EAP. 7-8. Alternacantha occulta Thuy & Meyer, 2013, from the early Bajoeian (Middle Jurassie) of
Eongwy, Franee. 7. GZG.INV.78648, proximal EAP. 8. GZG.INV.78649, distal EAP. 9-10. Alternacantha
sp. nov. innom. 2 from the Callovian (Middle Jurassie) of Jumara, India. 9. GZG.INV. 78652, proximal to
median EAP. 10. GZG.1NV.78653, median EAP. One eommon seale bar per speeies.

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THUYB., Fossil record of ophiacanthid brittle stars

Remarks

In terms of LAP morphology, Alternacantha is probably among the most distinctive and unambiguously
identifiable ophiacanthids. In fact, the alternating position of the dorsalmost spine articulation, varying
from close to the remaining spine articulations to widely separated from the latter, is a feature not
found in any other LAP type. Since Alternacantha is known from well-preserved, articulated specimens
(Thuy & Meyer 2013), its phylogenetic position is well understood. Together with its extinct sister taxon
Dermocoma, it holds a basal position within the large-pored ophiacanthids displaying well-developed
disc plates rather than translucent scales obscured by skin.

Indeed, the close phylogenetic relationship with Dermocoma is refiected by LAP morphology. Both
genera share ear-shaped spine articulations sunken in shallow notches of the gently elevated distal
edge, a strongly ventro-proximally protruding ventral portion of the LAPs, strongly protruding spurs
on the outer proximal edge, and a relatively simple ridge on the inner side devoid of sharp kinks or an
exceedingly widened dorsal part. While proximal LAPs of the two genera can be readily differentiated,
median and, in particular, distal LAPs can be so closely similar that distinction is very difficult, if possible
at all. Thus, it is crucial for records based exclusively on dissociated LAPs to focus on well-preserved
proximal LAPs in these genera. It should be stressed that it is strongly advisable in general to choose adult
proximal LAPs as holotypes of new ophiuroid species known solely from dissociated LAPs, as clearly
stressed by Thuy & Stohr (2011). Unfortunately, the holotype of Ophiacanthal suprajurassica Hess,
1965 is a median LAP from strata which have yielded both Dermocoma and Alternacantha. In view of
the near-identical morphologies of median and distal LAPs in these two genera, the holotype in question
cannot be unambiguously assigned. Ophiacanthal suprajurassica should therefore be considered as
a nomen dubium, even though non-type specimens assigned to Ophiacanthal suprajurassica by Hess
(1965a, 1966) can be assigned beyond doubt.

The closest extant relative of Alternacantha is Ophiocopa Lyman, 1883, which is sister to the clade
formed by Alternacantha and Dermocoma. Again, the close phylogenetic ties are refiected by LAP
morphology. In fact, the LAPs of extant Ophiocopa spatula Lyman, 1883 (Fig. 22: 3-4) closely resemble
those of the two fossil genera, in particular on account of the ventro-proximalwards protruding ventral
portion of the LAP, the shape, number and position of the spine articulations, the outer surface ornament
and the conspicuous, strongly protruding spur on the outer proximal edge. Differences pertain mainly
to the shape of the ridge on the inner side of the LAPs, which in Ophiocopa is composed of a slightly
bent, oblique dorsal part with a triangular tip, widely separated from a short knob-like part on the ventral
portion of the inner side.

All currently known species of Alternacantha share strongly similar, near-identical LAP morphologies,
making a distinction on the basis of dissociated LAPs a major challenge. Similarly indistinguishable LAP
morphologies have been reported from closely related extant taxa (Thuy & Stohr 2011). Fortunately,
most species of Alternacantha are known from articulated arm fragments, in addition to the dissociated
LAPs, providing additional features for species-level distinction.

Alternacantha? sp.

Fig. 22: 5

Material examined

GZG.INV.78645, GZG.INV.78646 (2 dissociated LAPs) from the late Pliensbachian of Amellago,
Morocco.

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European Journal of Taxonomy 48: 1-242 (2013)

Description

Dorsal tips of moderately large, dissoeiated proximal LAPs; originally more than twiee higher than
wide; dorsal tip rounded, tongue shaped; distal edge eonvex; preserved part of proximal edge gently
eoneave, devoid of spurs; outer surfaee with finely meshed stereom. Two large, widely separated, ear¬
shaped spine artieulations in shallow notehes of the moderately elevated distal portion of the LAP, not
sharply bordered proximally by a ridge; remains of a third spine artieulation suggests mueh smaller gap
between the fragmentary third and the middle spine artieulations than between the dorsalmost and the
middle ones.

Inner side of LAP with dorsal tip of a narrow, sharply defined, prominent and originally oblique ridge.
No perforations or furrow diseemible.

Remarks

Assignment of the present reeord has posed problems due to its highly fragmentary eondition. The
unusually wide gap between the two dorsalmost spine artieulations, the size and position of the latter,
and the shape of the ridge on the inner side are strongly suggestive of Alternacantha, in partieular A.
occulta, beeause of the rounded, tongue-shaped dorsal tip of the LAPs. Superfieial similarities are also
shared with the LAPs of Hanshessia. Assignment to the latter genus is less likely, however, on aeeount
of the oblique, rather than near-vertieal, dorsal part of the ridge on the inner side and the large gap
between the two dorsalmost spine artieulations. The present speeimens are thus deseribed here as a
questionable reeord of Alternacantha, indeterminate at the speeifie level.

Alternacantha sp. nov. innom. 1
Fig. 22: 6

Material examined

GZG.INV.78647 (dissoeiated LAP) from the middle Toareian of Le Clapier, Franee.

Description

The sole known speeimen is a dissoeiated, moderately large, median LAP; ventro-proximal portion
missing; LAP originally slightly wider than high; dorsal edge eoneave as a result of a well-developed
eonstrietion; distal edge eonvex; proximal edge largely missing; ventro-distal tip of LAP protruding,
tongue shaped; outer surfaee with eoarsely meshed stereom displaying thiekened trabeeulae merged
into irregular vertieal striation elose to spine artieulations. Three large, ear-shaped spine artieulations
freestanding in very shallow notehes of the slightly elevated distal portion of the LAP; ventral and dorsal
lobes eomposed of densely meshed stereom and merged into eontinuous, near-eireular volute; spine
artieulations not sharply bordered proximally by a well-defined ridge; strong dorsalward inerease in size
of spine artieulations; dorsalmost spine artieulations widely separated from ventral two.

Inner side of LAP with dorsal tip of ridge preserved, narrow, sharply defined, prominent, oblique and not
reaehing dorsal edge of LAP; inner side of distal edge of LAP with two moderately large, well-defined,
prominent, oval spurs eomposed of densely meshed stereom. No perforations or furrow diseemible.

Remarks

In spite of its fragmentary eondition, this LAP is unambiguously assignable to Alternacantha on aeeount
of the highly distinetive gap separating the dorsalmost spine artieulation from the remaining ones. All
other eharaeters preserved are in agreement with this assignment. It is very unfortunate that the present
speeimen is the only one of this type available at the time. In faet, the outer surfaee ornament, the
unusually low height/width ratio of the LAP (or, alternatively, the oeeurrenee of an alternating position
of the dorsalmost spine artieulation even in elongated distal LAPs) and the spine artieulations eomposed

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of densely rather than finely meshed stereom is a unique combination of characters. The specimen in
question clearly belongs to a new species, but its formal description requires more complete material.

Alternacantha occulta Thuy & Meyer, 2013

Fig. 22: 7-8

Synonymy

Reference is made to Thuy & Meyer (2013) for a complete synonymy of the species.

Diagnosis

[complementary to that provided by Thuy & Meyer (2013)]

Species of Alternacantha with large LAPs displaying a pointed to tongue-shaped, relatively narrow
dorsal edge; outer surface with a well-developed vertical striation; up to four moderately well-developed
spurs on the outer proximal and inner distal edges; up to five spine articulations; distal edge of ventral
arm plates evenly convex; distal edge of dorsal arm plates parabolic.

Material studied

GZG.INV.78648, GZG.INV.78649 and GZG.INV.78650 (48 dissociated LAPs) from the early Bajocian
ofLongwy, France; GZG.INV.78651 (23 dissociated LAPs) from the early Bajocian of Cirey-les-Nolay,
France.

Description

Large, dissociated LAPs; more than twice wider than high (proximal LAPs) to 1.5 times wider than
high (distal LAPs); dorsal edge convex, pointed to round and tongue like in proximal LAPs, concave as
a result of a well-developed constriction in median to distal LAPs; distal edge convex; ventral quarter
to fifth of LAP strongly protruding ventro-proximalwards; ventro-distal tip of LAP slightly protruding
ventralwards, tongue shaped; proximal edge concave with up to four, medium-sized to large, moderately
well-developed, prominent, horizontally elongate, pointedly to bluntly protruding spurs of variable
position; outer surface with well-developed, fine, regular vertical striation composed of narrow, slightly
overlapping lamellae; striation replaced by finely meshed stereom in distal half of outer surface in all
LAPs and additionally in dorsal fifth of proximal LAPs. Five (proximal LAPs) to three (distal LAPs)
large to very large, ear-shaped spine articulations in moderately shallow notches of elevated distal
portion of LAP; dorsal and ventral lobes of spine articulations merged into continuous lobe, with small,
very shallow notch at proximal point of contact; spine articulations sharply bordered by edge of notches
rather than a well-defined ridge of distalmost lamella; notches deeply incising outer surface striation;
strong dorsalward increase in size of spine articulations and of gaps separating them in all LAPs; position
of dorsalmost spine articulation varying in position between close to the remaining spine articulations
to widely separated from the latter by a gap equalling up to twice the height of the dorsalmost spine
articulation in proximal to median LAPs. Ventral edge of LAP with relatively small but deeply incised,
concave tentacle notch in all LAPs.

Inner side with large, relatively narrow (proximal and median LAPs) to moderately broad (distal LAPs),
sharply defined, prominent ridge devoid of kink or thickened part; ventral tip of ridge pointing ventro-
proximally, not merged with ventral portion of LAP; dorsal half of ridge straight and oblique, not
reaching dorsal edge of LAP; inner side of distal edge of LAP with up to four variably well-defined,
oval to lenticular, slightly prominent spurs composed of more densely meshed stereom; inner side of
tentacle notch relatively small, with coarsely meshed and slightly horizontally stretched stereom. Small,
irregular perforations densely grouped in short vertical row dorsally bordering the tentacle notch in
proximal to median LAPs; single small perforation dorsally bordering tentacle notch in distal ones.

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European Journal of Taxonomy 48: 1-242 (2013)

Remark

The original description of Alternacantha occulta on the basis of several articulated specimens (Thuy &
Meyer 2013) is here complemented by a detailed description of the LAP morphology of the species,
including the inner side of the LAPs which is not exposed on the articulated type specimens. As noted
above, species of Alternacantha share nearly indistinguishable LAP morphologies, which makes a
distinction of A. occulta from species known exclusively from arm fragments and dissociated LAPs
a major challenge. In terms of the shape of the ventral and dorsal arm plates, A. occulta is closest to
A. dilionessa sp. nov. (see below). In the former, however, the proximal LAPs are smaller, the dorsal
edge is pointed to tongue shaped, rather than broad and oblique, and the outer proximal and inner distal
edges display up to four, rather than six, spurs. In A. schwermannorum sp. nov., the ventral arm plates
have a truncated rather than evenly convex distal edge, and the LAPs are dorsally broad rather than
tongue like and display very thin, horizontally elongate rather than oval spurs on the inner distal edge.
Alternacantha arges sp. nov. is a much larger species with LAPs devoid of vertical striation, truncated
rather than evenly convex distal edges of the ventral plates and distinctively Gauss-curve-shaped rather
than parabolic distal edges of the dorsal arm plates.

Alternacantha sp. nov. innom. 2
Fig. 22: 9-10

Material examined

GZG.INV.78652 and GZG.INV.78653 from sample 95, lower Chari Formation, Callovian of Jumara,
India.

Description

GZG.INV.78652 is a dissociated, large, median LAP; slightly longer than wide; dorsal edge concave as
a result of a well-developed constriction; distal edge nearly straight; proximal edge gently convex, with
two very poorly defined, almost indiscernible, weakly prominent, non-protruding spurs; outer surface
with weakly developed, irregular vertical striation close to spine articulations composed of slender,
widely separate, vertically merged trabeculae of outer surface stereom; moderately finely to finely
meshed stereom on proximal three-quarters of outer surface. Three large, ear-shaped spine articulations
in shallow notches of strongly elevated distal portion of LAP; dorsalward increase in size of spine
articulations and of gaps separating them; gap between spine articulations and distal edge of LAP almost
as wide as one spine articulation. Ventral edge of LAP nearly straight, deeply incised but small tentacle
notch.

Inner side of LAP with small, sharply defined, very slender, oblique ridge with slightly widened ventral
tip merged with ventral portion of LAP; inner side of distal edge of LAP with two small, horizontally
elongate, moderately well-defined spurs composed of slightly more densely meshed stereom; inner side
of tentacle notch deeply incised, laterally sharply defined. No perforations or furrow discernible.

GZG.1NV.78653 is a dissociated proximal to median LAP; ventro-proximal portion missing; dorsal
spur on proximal edge similarly poorly defined and weakly prominent as in the LAP described above
but protruding; vertical striation less regular and restricted to a smaller area of outer surface. Three
spine articulations, better preserved than in the previous specimen; dorsal and ventral lobes composed
of finely meshed stereom and merged into continuous volute; spine articulations not sharply bordered
proximally; dorsal gap between spine articulations more than twice larger than ventral one.

Inner side partly obscured by sediment but visible part well in agreement with the previous specimen.

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Remarks

These specimens are unambiguously assignable to Alternacantha on account of the unusually large
gap which separates the dorsalmost spine articulation from the remaining ones. Superficial similarities
are shared with the median and distal LAPs of Ophiomalleus gen. nov., which, however, are much
more robust, display freestanding spine articulations and a broader ridge on the inner side. Within
Alternacantha, greatest similarities are shared with the single, fragmentary LAP from the Toarcian of
France described above, with respect to the outer surface ornament and the height/width ratio of the
LAPs displaying the alternating position of the dorsalmost spine articulation. In the Toarcian specimen,
however, the lobes of the spine articulation are composed of densely rather than finely meshed stereom.
The Callovian material described above most probably represents a new species, the formal description
of which, however, requires more complete material.

Alternacantha schwermannorum sp. nov.
um:lsid:zoobank.org:act:08DCE3FA-60AD-4415-80D3-127E2FDQ2F76

Fig. 23

p.p. Ophiacanthal suprajurassica-YiQSS 1966: 1030, 1054, figs 10, 70, 72 (material incorrectly referred
to Ophiacanthal suprajurassicaYlQss, 1965).

Diagnosis

Species of Alternacantha with large EAPs displaying well-developed, regular vertical striation on outer
surface; up to five poorly to moderately well-defined spurs on outer proximal edge; up to six well-
defined, horizontally strongly elongate, ridge-like spurs on inner side of distal edge of EAP; up to five
spine articulations; distal edge of ventral arm plates truncated.

Etymology

Species named in honour of my friends Eeonie and Achim Schwermann.

Type material

Holotype

GZG.INV.78654.

Paratypes

GZG.INV.78655, GZG.INV.78656, GZG.INV.78657 and GZG.INV.78658.

Type locality and horizon

Savigna, France; sample S2a of Gale (2011), Bimammatum Zone, late Oxfordian, Eate Jurassic.

Additional material

GZG.INV.78659 (102 dissociated EAPs) from sample S2a of Gale (2011); GZG.INV.78660 (47
dissociated EAPs) from sample SI of Gale (2011); GZG.INV.78661 (166 dissociated EAPs) from
sample S2b of Gale (2011).

Description

Holotype

GZG.INV.78654 is a dissociated, large, proximal EAP; dorsal edge slightly fragmentary distally,
originally slightly convex, broad; distal edge irregularly undulose; ventral seventh of EAP protruding
ventro-proximalwards, slightly fragmentary; proximal edge nearly straight, with five small, poorly
defined, prominent and protruding spurs, three of which are grouped centrally and the fourth one in

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Fig. 23. Fossil lateral arm plates in external (a) and internal (b) views and artieulated arm fragments of
Alternacantha schwermannorum sp. nov. from the late Oxfordian (Late Jurassie) of Savigna, Franee.
1. GZG.1NV.78654 (holotype), proximal LAP. 2. GZG.1NV.78655 (paratype), median LAP. 3. GZG.
1NV.78656 (paratype), distal LAP. 4. GZG.1NV.78657 (paratype), proximal arm fragment in ventral (a)
and dorsal (b) views and with detail in dorso-lateral (e) view. 5. GZG.INV.78658 (paratype), distal arm
fragment in dorsal (a) and ventral (b) view. One eommon seale bar for 1-3.

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middle of dorsal half of proximal edge; outer surface with very well-developed, fine, regular to very
slightly undulose, vertical striation composed of fine and very slightly overlapping lamellae, restricted
to distal third of outer surface near spine articulations, replaced by very finely meshed stereom on
remaining outer surface. Five large, ear-shaped spine articulations in shallow notches of elevated
distal edge; ventral and dorsal lobes of spine articulations merged into continuous volute; wide gap
between spine articulations and distal edge of LAP, nearly as wide as one spine articulation; spine
articulations proximally sharply delimited by edge of notches rather than single distalmost lamella or
well-defined, prominent ridge; dorsalward increase in size of spine articulations and in gaps separating
them; dorsalmost spine articulations separated from remaining four by larger gap. Ventral edge of LAP
with small, concave tentacle notch.

Inner side of LAP with large, conspicuous, sharply defined, very narrow ridge; ventral part of ridge
slightly bent, pointing ventro-proximalwards; central part of ridge straight, oblique and dorsal part
straight and very slightly oblique, not reaching dorsal edge of LAP; all parts connected by very
gently rounded kinks; no thickened parts or sharp kinks; inner side of distal edge of LAP with six
large, conspicuous, well-defined, slightly prominent, horizontally strongly elongate, ridge-like spurs,
becoming smaller and less well-defined dorsalwards; inner side of tentacle notch small, well defined
laterally. Very shallow, moderately well-defined, slightly irregular, vertical furrow with single small
perforation dorsally bordering tentacle notch.

Paratype supplements and variation

GZG.INV.78655 is a dissociated median LAP; well in agreement with holotype; dorsal edge straight,
broad; distal edge convex; proximal edge concave, with single, large, moderately well-defined, prominent
and slightly protruding spur. Five spine articulations similar to those observed on holotype; dorsalmost
spine articulation smallest, widely separated from remaining four.

Inner side of LAP with ridge similar to that of holotype; inner side of distal edge of LAP with one large
ventral, well-defined, prominent, horizontally strongly elongate, lenticular spur, and second dorsal, much
smaller, less well-defined spurs. Very shallow and weakly defined, irregular vertical furrow dorsally
bordering tentacle notch.

GZG.INV.78656 is a dissociated distal LAP; dorsal edge concave as a result of a well-defined
constriction; distal edge convex; proximal edge irregularly wavy, with single moderately well-defined,
prominent, lenticular, slightly protruding spur. Three spine articulations similar to those observed in
holotype; ventral spine articulation smaller than remaining two; dorsal gap slightly larger than ventral
one. Ventral edge of LAP with very small, almost indiscernible tentacle notch.

Inner side of LAP with sharply defined, prominent ridge displaying oblique, near-straight, narrow dorsal
part and shorter, strongly widened ventral part with ventro-proximalwards pointing tip; inner side of
tentacle notch small, sharply defined laterally. No perforations or furrow discernible.

GZG.INV.78657 is an articulated arm fragment preserving five median to proximal segments; LAPs well
in agreement with holotype; position of dorsalmost spine articulation alternating between close to the
remaining ones, close to the dorsal edge of the LAP, and intermediate between the latter two positions;
a few arm spine fragments preserved, broken near base, exposing lumen filled with coarsely meshed
stereom; arm spines cylindrical, with finely meshed and slightly longitudinally elongate stereom; dorsal
arm plates missing; LAPs not in contact dorsally; ventral arm plates large, nearly as long as wide, widest
distally, not separating LAPs; distal edge of ventral arm plates convex but with slightly truncated, straight
tip; lateral edges moderately strongly concave; proximal angle acute; no tentacle scales discernible.

GZG.INV.78658 is an articulated arm fragment preserving four distal segments; several arm spine
fragments preserved; most complete arm spine very large, nearly as long as two arm segments,
cylindrical, straight, slowly tapering, with finely meshed, slightly longitudinally elongate stereom beset

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European Journal of Taxonomy 48: 1-242 (2013)

with numerous minute thorns pointing towards the spine tip; dorsal arm plates leaf shaped, longer than
wide, with very aeute proximal angle, slightly eonvex lateral edges and eonvex distal edge; outer surfaee
of dorsal arm plates with very fine, regular transverse striation; ventral arm plates similar to those
observed on other paratype arm fragment, slightly longer than wide; tentaele pores very small, single
small, leaf-like tentaele seale preserved.

Remarks

This material is unequivoeally assignable to the genus Alternacantha on aeeount of the alternating
position of the dorsalmost spine artieulation. It differs from its eongeners in eombining five arm spines,
a well-developed vertieal striation on the outer surfaee, a slightly truneated distal edge of the ventral arm
plates, a parabolie distal edge of the dorsal arm plates, and, most importantly, large, well-defined, thin,
horizontally strongly elongate spurs on the inner side of the distal edge of the LAPs. The arm fragments
deseribed and illustrated by de Loriol (1872) as a new speeies, Ophiurella royeri de Loriol, 1872, from
near-eoeval strata of Haute-Mame, Franee, eould well be eonspeeifie with the present material. Sinee,
however, Ophiurella royeri is based on arm fragments whieh do not expose the inner side of the LAPs
and in partieular the highly diagnostie shape of the spurs on the inner distal edge, it eannot be ruled out
that they are rather eonspeeifie with the speeimens deseribed below as Alternacantha dilionessa sp. nov.
Ophiurella royeri should therefore be eonsidered as a nomen dubium.

Occurrence

Late Oxfordian of Franee.

Alternacantha arges sp. nov.

um:lsid:zoobank.org:aet:BlD9DEC0-8F10-4D8D-AABQ-15949F6DB8CA

Fig. 24: 1-2

Ophiothrixl rpym-Hess 1960: 396, figs 7-8 [speeimen ineorreetly assigned to Ophiothrixl royeri (de
Loriol, 1872)].

Diagnosis

Speeies of Alternacantha with extremely large LAPs devoid of vertieal striation on the outer surfaee; up
to three large, well-defined spurs on the outer proximal edge; up to four spine artieulations; distal edge
of ventral arm plates truneated; distal edge of dorsal arm plates Gauss-eurve-shaped.

Etymology

Speeies named after Arges, one of the three giant eyelopes in Greek mythology, in referenee to the
extremely large size of the speeies in eombination with the large dorsalmost spine artieulation resembling
the single eye of the eyelopes.

Holotype

NHMBM610.

Type locality and horizon

Raedersdorf, Franee; Humeralis Member, late Oxfordian, Late Jurassie.

Description of holotype

M 610 is an extremely large, artieulated arm fragment preserving nine proximal segments; LAPs more
than twiee higher than wide; dorsal edge pointed to tongue shaped; distal edge irregularly undulose;
proximal edge eoneave, with up to three very large, well-defined, strongly prominent, horizontally

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THUYB., Fossil record of ophiacanthid brittle stars

Fig. 24. Fossil lateral arm plates in external (a) and internal (b) views and articulated arm fragment of
ophiacanthid brittle stars. 1-2. Alternacantha arges sp. nov. from the late Oxfordian (Late Jurassic) of
Raedersdorf, France; M 610 in dorsal (la) and ventral (lb) views and with details of dorsal (2a) and
ventral (2b) arm plating. 3-6. Alternacantha dilionessa sp. nov. from the early Kimmeridgian of the
Pointe du Chay, France. 3. GZG.INV.78662 (holotype), proximal LAP. 4. GZG.INV.78663 (paratype),
proximal LAP. 5. GZG.INV.78664 (paratype), median LAP. 6. GZG.INV.78665 (paratype), distal LAP.
One common scale bar for 1, for 2 and for 3-6, respectively.

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European Journal of Taxonomy 48: 1-242 (2013)

elongate, protruding spurs; ventral portion of LAP small, protruding ventro-proximalwards; outer
surfaee of LAPs with finely meshed stereom, devoid of vertieal striation. Three to four very large, ear¬
shaped spine artieulations in notehes of strongly elevated distal edge; dorsal and ventral lobes of spine
artieulations merged into eontinuous volute; strong dorsalward inerease in size of spine artieulations
and of gaps separating them; position of dorsalmost spine artieulation alternating between elose to the
remaining ones and near the dorsal edge of the LAP, separated from the remaining spine artieulations by
an extremely wide gap; spine artieulations proximally sharply bordered by edge of notehes; gap between
spine artieulations and distal edge of LAP relatively large.

Inner side of LAPs not exposed.

Ventral arm plates large, wider than long, distal half widest; distal edge of ventral arm plates eonvex but
with a sharply truneated, straight tip; lateral and latero-proximal edges of ventral arm plates eoneave;
proximal angle of ventral arm plates right to slightly aeute; ventral arm plates overlapping but LAP most
probably in eontaet underneath ventral arm plates; tentaele pores small, no tentaele seales preserved;
dorsal arm plates large, nearly as wide as long, with straight distalwards diverging lateral edges and
eonspieuously Gauss-eurve-shaped distal edge with tongue-shaped tip; dorsal arm plates broadly
overlapping, separating LAPs on all preserved segments.

Remarks

Hess (1960) already provided a detailed deseription and exeellent figures of the present speeimen,
whieh he eonsidered to be eonspeeifie with de LorioLs (1872) Ophiurella royeri whieh was tentatively
transferred to the extant genus Ophiothrix Muller & Trosehel, 1840. It obviously belongs to Alternacantha
on aeeount of the alternating position of the dorsalmost spine artieulation. A detailed re-examination
of Hess’s (1960) speeimen, however, has now revealed a highly distinetive arm morphology whieh
differentiates it unambiguously from all other speeies assignable to Alternacantha, ineluding the type
material of O. ? royeri. In faet, apart from its extremely large size, the speeimen laeks a vertieal striation
on the outer surfaee, and displays only up to four spine artieulations and a eonspieuously Gauss-eurve-
shaped distal edge of the dorsal arm plates. Even if it eould be argued that the laek of a vertieal striation
on the outer surfaee is related to the larger size and thus greater heigth/width ratio of the LAPs of the
speeimen, the number of spine artieulations and shape of the distal edge of the dorsal arm plate are size-
independent features. This partieular speeimen is thus deseribed here as a new speeies.

Alternacantha dilionessa sp. nov.

um:lsid:zoobank.org:aet:FD230CAD-9ClE-4C38-B4Q7-lEAB92ElQF7Q

Figs 24: 3-6; 25: 1-3

Diagnosis

Speeies of Alternacantha with very large EAPs displaying a moderately well-defined vertieal striation
on the outer surfaee; up to six large, well-defined spurs on the outer proximal edge, paralleled by large,
relatively short, oval spurs on the inner distal edge; distal edge of ventral arm plates evenly eonvex;
distal edge of dorsal arm plates parabolie.

Etymology

Name eomposed of diligere, Eatin for “to eherish”, and “lioness”, translating into lea in Eatin, as an
affeetionate deelaration of esteem to my beloved wife Eea, without whose support the present study
would not have been possible.

Type material

Holotype

GZG.INV.78662.

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THUYB., Fossil record of ophiacanthid brittle stars

Paratypes

GZG.INV.78663, GZG.INV.78664, GZG.INV.78665, GZG.INV.78666, GZG.INV.78667 and GZG.
INV.78668.

Type locality and horizon

Pointe du Chay near La Rochelle, France; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late
Jurassic.

Additional material

GZG.INV.78669 (512 dissociated LAPs) and GZG.INV.78670 (distal articulated arm fragment).

Description

Holotype

GZG.INV.78662 is a dissociated, very large, proximal LAP; approximately twice wider than high;
dorsal edge oblique, nearly straight, with pointed dorso-proximal tip; distal edge slightly convex;
proximal edge nearly straight, with six small to moderately large, well-defined, prominent, horizontally
elongate, proximally pointed and slightly protruding spurs; second and third ventralmost spurs largest;
ventral fifth of LAP strongly protruding ventro-proximalwards; ventro-distal edge of LAP round,
weakly protruding ventralwards; outer surface with moderately well-developed, rather coarse, slightly
undulose, vertical striation restricted to narrow band near spine articulations and composed of slightly
overlapping lamellae of variable width; greater part of outer surface with finely meshed stereom. Five
very large, ear-shaped spine articulations in shallow notches of elevated distal edge; ventral and dorsal
lobes of spine articulations merged into continuous volute; spine articulations proximally sharply
bordered by edge of notches rather than well-defined ridge or single distalmost lamella; notches incising
outer surface; gap between spine articulations and distal edge of LAP slightly narrower than one spine
articulation; dorsalward increase in size of spine articulations and of gaps separating them; dorsalmost
spine articulation separated from the remaining four by very large gap with slightly more coarsely
meshed stereom. Ventral edge of LAP with relatively small but deeply concave tentacle notch.

Inner side of LAP with very large, conspicuous, sharply defined, prominent, very narrow ridge; ventral
part of ridge bent, pointing ventro-proximal wards; central part of ridge straight, oblique, and dorsal
part straight and very slightly oblique, not reaching dorsal edge of LAP; all parts connected by rounded
kinks; no thickened parts; inner side of distal edge of LAP with three large, moderately well-defined,
prominent, relatively short and high oval spurs in the centre and two smaller, poorly defined spurs
ventrally and dorsally bordering the three larger ones; inner side of tentacle notch relatively small, well
defined laterally. Shallow, poorly defined furrow dorsally bordering tentacle notch, dorsally obscured
by shell fragment.

Paratype supplements and variation

GZG.INV.78663 is a dissociated, very large, proximal LAP; approximately twice wider than high;
agreeing closely with holotype; proximal edge with one large, central, well-defined, prominent and
protruding spur and two smaller, dorsal and ventral, non-protruding spurs; striation on outer surface
limited to a very narrow band near the three ventralmost spine articulations. Four spine articulations
similar to those observed on holotype; dorsalmost one even more widely separated from remaining
spine articulations.

Inner side similar to that of holotype.

GZG.INV.78664 is a dissociated median LAP; slightly higher than wide; proximal edge with two
large, well-defined, prominent, and strongly protruding spurs. Four spine articulations similar to those
observed on holotype.

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 25. Fossil skeletal plates and artieulated arm fragments of ophiaeanthid brittle stars; lateral arm
plates (LAPs) in external (a) and internal (b) views. 1-3. Alternacantha dilionessa sp. nov. from the
early Kimmeridgian of the Pointe du Chay, Franee. 1. GZG.1NV.78666 (paratype), arm spine. 2. GZG.
INV.78667 (paratype), median arm fragment in ventral view. 3. GZG.INV.78668 (paratype), proximal arm
fragment in lateral (a) and dorsal (b) views. 4-5. Dermocoma subtilirugosa (Kristan-Tollmann & Gramann,
1992) eomb. nov. from the Rhaetian (Late Triassie) of Fiseherwiese, Austria. 4. GZG.1NV.78671, proximal
LAP. 5. GZG.INV.78672, median LAP. 6. Dermocoma sp. nov. inn om. 1 from the Rhaetian (Late Triassie)
of Fiseherwiese, Austria; GZG.1NV.78674, median LAP. One eommon seale bar per speeies exeept for 1.

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THUYB., Fossil record of ophiacanthid brittle stars

Inner side of LAP with ridge similar to that observed on holotype; inner side of distal edge of LAP with
two large, moderately well-defined, weakly prominent spurs. Shallow, moderately well-defined, slightly
oblique furrow with two very small spine articulations dorsally bordering tentacle notch.

GZG.INV.78665 is a dissociated distal LAP; slightly wider than high; dorsal edge concave as a result
of a weakly developed constriction; proximal edge with single, moderately well-defined, prominent and
slightly protruding spur; vertical striation well developed on distal two-fifths of the outer surface. Three
spine articulations similar to those observed on holotype; dorsal gap between spine articulations slightly
wider than ventral one. Ventral edge of LAP with small, weakly concave tentacle notch.

Inner side of LAP with sharply defined, prominent ridge composed of strongly widened ventral part
and ventro-proximally pointing orsal part; inner side of distal edge with single well-defined, slightly
prominent spur; inner side of tentacle notch small, sharply defined laterally, pointing ventralwards. No
perforations or furrows discernible.

GZG.INV.78666 is a dissociated, large arm spine; cylindrical; slowly tapering; straight; with finely
meshed, slightly longitudinally elongate stereom beset with scattered, minute granules; tip broken,
exposing lumen filled with loosely meshed stereom.

GZG.INV.78667 is an articulated arm fragment counting five proximal segments; LAPs well in agreement
with holotype; ventral arm plates very large, approximately bell shaped, slightly wider than high, widest
distally, with strongly and evenly convex distal edge, concave lateral and latero-distal edges and pointed
proximal angle; ventral arm plates overlapping, covering ventral portions of LAPs, the latter meeting
underneath ventral arm plates; tentacle pores small, no tentacles scales preserved; dorsal arm plates
large, nearly as wide as long, with nearly straight, short proximal edge; straight, distalwards diverging
lateral edges and convex, parabolic distal edge; short, well-defined and prominent longitudinal ridge in
proximal third of dorsal arm plate outer surface; dorsal arm plates overlapping, separating LAPs.

GZG.INV.78668 is an articulated arm fragment counting six proximal to median segments; well in
agreement with other arm fragment paratype; tentacle pores with two small, leaf-like scales.

Remarks

D’Orbigny (1850) already mentioned an articulated arm fragment from the Kimmeridgian of Chay
peninsula, France, listing it as ''Ophiurella bispinosa d’Orbigny, 1850”, and it is more than likely that
he was referring to the same species as the one described here. However, since Ophiurella bispinosa
has never been described, it must be considered as nomen nudum. The present specimens share greatest
similarities with Altemacantha occulta which, however, differs in having smaller proximal LAPs with a
pointed to tongue-shaped distal edge, as well as fewer and less well-defined spurs on the outer proximal
and inner distal edges. In A. schwermannorum sp. nov. (see above), the distal edge of the ventral arm
plates is slightly truncated rather than evenly convex, and the spurs on the inner side of the distal edge
of the LAPs are very thin, horizontally elongate and pointed rather than high and oval.

Occurrence

Early Kimmeridgian of France.

GQmxs DermocomaYtQss, 1964

Type species

Dermocoma wrighti Hess, 1964, by original designation.

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Diagnosis

Ophiacanthid with LAPs commonly displaying a fine vertical striation on their outer surface; well-
developed spurs on the inner distal and, in some cases to a lesser extent, outer proximal edge; ventral
portion of LAP strongly protruding ventro-proximalwards; up to six moderately large, ear-shaped spine
articulations with continuous volute in notches of elevated distal portion of LAP; ridge on inner side of
LAPs simple, continuous, generally slender, devoid of sharp kinks or conspicuously thickened parts;
tentacle notch small to moderately large.

Remarks

Dermocoma was introduced by Hess (1964) on the basis of articulated specimens from the Middle
Jurassic of Great Britain which were all assigned to the type, and at that time only known, species D.
wrighti Hess, 1964. While the higher taxonomic position of Dermocoma was initially left open (Hess
1964), it was later used as type taxon for the introduction of the extinct family Dermocomidae Hess,
1972 (Hess 1972a). Thuy & Meyer (2013), however, showed it to be unambiguously assignable to the
Ophiacanthidae.

Since the original description of Dermocoma wrighti provided only few data on LAP morphology, a re¬
examination of the type specimens was called for in order to work out a comprehensive LAP morphology
including as many characters as possible. Dermocoma and its sister genus Alternacantha share basically
similar LAP morphologies, as already noted above. While the median and distal LAPs of both genera
may be almost indistinguishable, the proximal LAPs allow for an unambiguous distinction. In fact, in
the proximal LAPs of Dermocoma the position of the dorsalmost spine articulation never alternates,
the distal portion of the LAPs is less strongly elevated and the notches of the spine articulations are
generally deeper. As in Alternacantha, however, distinction of species within Dermocoma on the basis
of dissociated LAPs can be a major challenge with differences occasionally found in the finest details
only.

The LAPs of Dermocoma can be easily distinguished from those of other ophiacanthids on account
of the position of the spine articulations, the ventro-proximally protruding ventral part, and the simple
ridge on the inner side devoid of sharp kinks and conspicuously widened parts. The LAPs assignable to
Dermacantha gen. nov. (see below) share the greatest similarities with those of Dermocoma, differing
only in having generally smaller spine articulations, a discontinuous volute of the spine articulations
and a generally smaller height/width ratio. However, the similarities are so striking that Dermocoma and
Dermacantha. gen. nov. are most probably closely related.

Many of the previously known Jurassic ophiacanthid records based exclusively on dissociated LAPs
have turned out to be assignable to Dermocoma. Together with the new records described in the present
study, Dermocoma is among the most speciose and most widely distributed ophiacanthids in Mesozoic
shallow-water deposits. Scattered records from a deep-shelf to upper slope setting, however, suggests
that the genus was also present in deeper settings. The closest extant relative Ophiocopa spatula, sister to
the Dermocoma-Alternacantha clade (see above), inhabits upper to middle bathyal depths (279-965 m)
of the Pacific (O’Hara & Stohr 2006).

Dermocoma subtilirugosa (Kristan-Tollmann & Gramann, 1992) comb. nov.

Fig. 25: 4-5

Ophiacanthal subtilirugosa Kristan-Tollmann & Gramann, 1992: 468, pi. 3 figs 1-6.

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THUYB., Fossil record of ophiacanthid brittle stars

Diagnosis

Species of Dermocoma with moderately large LAPs displaying a very fine vertical striation on almost
entire outer surface; two very poorly defined spurs on the outer proximal and inner distal edges; up to
four small spine articulations in tight notches of non-elevated distal edge.

Material examined

GZG.INV.78671, GZG.INV.78672 and GZG.INV.78673 (3 dissociated LAPs) from the Rhaetian of
Fischerwiese, Austria..

Description

Moderately large LAPs; rounded, crescentic (proximal LAPs) to rectangular (distal LAPs) outline;
slightly higher than wide (proximal LAPs) to more than twice wider than high (distalmost LAPs); dorsal
edge straight to slightly convex, distal edge gently convex; ventral quarter to fifth large and protruding
ventro-proximalwards in proximal to median LAPs; proximal edge evenly concave, with up to two
small, very poorly defined, weakly prominent and not protruding, almost indiscernible spurs; outer
surface almost entirely covered by very fine vertical striation, composed of thin lamellae, distalwards
slightly overlapping, proximalwards decreasing in size and fading into finely meshed stereom close to
proximal edge of LAP; striation mostly regularly vertical, with occasional irregularities (slightly oblique
and/or branching lamellae) in ventral half of outer surface. Three (distal LAPs) to four (proximal LAPs)
small, ear-shaped, nearly equal-sized spine articulations in tight notches of distal edge, interrupting
vertical striation; gaps separating spine articulations increasing in size dorsalwards; dorsal and ventral
lobes of spine articulations forming continuous volute; very narrow gap between spine articulations
and distal edge of LAP. Ventral edge of proximal LAPs with large but weakly concave tentacle notch;
tentacle perforation ventro-distally bordering ventralmost spine articulation in distal LAPs.

Inner side of proximal and median LAPs with narrow, well-defined, prominent ridge separated by
rounded kink into dorsal and ventral portions; dorsal portion oblique, bent dorso-proximalwards, with
widened slightly less prominent and less well-defined dorsal tip; ventral portion much shorter than
dorsal one, pointing ventro-proximalwards, sharply separated from thickened ventral edge of LAP;
ridge in distal LAPs short, oblique, well-defined, prominent, without kink, bone-shaped to triangular.
Very faint vertical row of small, irregular perforations close to distal edge of LAPs, separating inner side
into coarsely meshed main portion, and narrow, finely meshed distal portion. Tentacle notch in proximal
and median LAPs large, distally bordered by narrow, oblique ridge.

Remarks

LAPs similar to the ones described here were first recorded from the Rhaetian of rocks dredged from
the northern Exmouth Plateau and described as Ophiacanthal subtilirugosa by Kristan-Tollmann &
Gramann (1992). The new material from the Rhaetian of Austria now enables a reassessment of this
species in accordance with the most recently set standards in ophiuroid micropalaeontology (Thuy &
Stohr 2011). The shape, size and position of the spine articulations, the outer surface ornament and the
shape of the ridge on the inner side strongly suggest assignment to Dermocoma. Among the LAP types
assigned to this genus, the present one differs in combining small spine articulations with a fine vertical
striation which covers almost the entire outer surface and two almost indiscernible spurs on the outer
proximal and inner edges.

Occurrence

Rhaetian of Austria and the Wombat Plateau off northern Australia.

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European Journal of Taxonomy 48: 1-242 (2013)

Dermocoma sp. nov. inn om. 1
Fig. 25: 6

Material examined

GZG.INV.78674 from the Rhaetian of Fischerwiese, Austria.

Description

Single, dissoeiated, moderately large, median LAP known; nearly as high as wide; dorsal edge slightly
eoneave as a result of a eonstrietion; distal edge eonvex; ventral sixth of LAP protruding ventro-
proximalwards; proximal edge irregularly undulose, with two medium-sized, very poorly defined,
weakly prominent but protruding spurs, one in the middle of the dorsal half, the other in the middle
of the ventral half; outer surfaee with rather eoarse, poorly developed vertieal striation eomposed of
broad, slightly overlapping lamellae elose to spine artieulations, replaeed by finely meshed stereom on
proximal half of outer surfaee. Four large, ear-shaped spine artieulations in moderately deep notehes of
elevated distal edge of LAP; ventral and dorsal lobes merged into eontinuous volute; ventral lobe not
eonneeted with outer surfaee; spine artieulations proximally sharply bordered by edge of notehes; spine
artieulations nearly of equal size exeept for slightly smaller ventralmost one; very weak dorsalward
inerease in size of gaps separating spine artieulations. Ventral edge of LAP with moderately large,
eoneave tentaele noteh.

Inner side of LAP with moderately large, well-defined, rather broad, prominent, oblique, bent
ridge; dorsal and ventral tips of ridge slightly widened, rounded, dorsal one pointing dorsalwards,
ventral one pointing ventro-proximalwards and not merged with thiekened ventral portion of LAP;
inner side of distal edge with single large, poorly defined, oval, weakly prominent spur eomposed
of more densely meshed stereom; inner side of tentaele noteh rather small, deeply ineised, sharply
defined laterally. Very shallow, poorly defined vertieal furrow dorsally bordering tentaele noteh; no
perforations diseemible.

Remarks

The single speeimen available differs markedly from eo-oeeurring LAPs of Dermocoma subtilirugosa
eomb. nov. with respeet to the mueh larger spine artieulations on an elevated distal portion, the protruding
spurs and the poorly developed vertieal striation restrieted to a narrow band near the spine artieulations.
Assignment to Dermocoma seems warranted on aeeount of the position of the spine artieulations in
notehes of the eomparatively weakly elevated distal portion of the LAP, the ventro-proximalwards
protruding ventral portion of the LAP and the shape of the ridge on the inner side. Within this genus,
similarities are greatest with the LAPs of Dermocoma potti sp. nov. on aeeount of the spine artieulations
whieh are not eonneeted with the outer surfaee stereom, the rather poorly developed outer surfaee
striation and the two poorly defined spurs on the outer proximal and inner distal edges. In view of the
faet that many speeies of Dermocoma share almost indistinguishable LAP morphologies, this single
reeord of an allegedly median LAP eannot be identified in more detail. It is likely that it represents a
new speeies but in the absenee of material it ean at present only be listed as a new reeord of Dermocoma
whieh differs markedly from eo-oeeurring D. subtilirugosa eomb. nov.

Dermocoma faberi sp. nov.

um:lsid:zoobank.org:aet:563DC91F-6457-4DDE-AQEE-A4C9D2A0477Q

Fig. 26: 1-3

Ophiacanthal toarcensis - T\my 2005: 40, pi. 5 figs 1-6 (material ineorreetly assigned to Ophiacanthal
toarcensisYlQ?,^, 1962).

140

THUYB., Fossil record of ophiacanthid brittle stars

Diagnosis

Species of Dermocoma with large LAPs displaying a fine, vertical striation on almost entire outer surface;
up to four spurs on outer proximal and inner distal edges; up to six relatively small spine articulations.

Etymology

Species named in honour of Alain Faber, who provided valuable support, especially at the very beginning
of my palaeontological studies.

Type material

Holotype

MnhnL HE408.

Paratypes

MnhnL HE409 and MnhnL HE410.

Type locality and horizon

Vance, Belgium; sample Vanl of Thuy (2005), Planorbis Zone, early Hettangian, Early Jurassic.

Additional material

MnhnE HE411 (385 dissociated EAPs), MnhnE HE256 and HE 257 (7 dissociated EAPs), original
material from sample Vanl of Thuy (2005); MnhnE HE412 (239 dissociated EAPs), original material
from sample Van2 of Thuy (2005); MnhnE HE413 (457 dissociated EAPs) from level c of Delsate et al.
(2002), Liasicus Zone, Hettangian of Fontenoille, Belgium; original material of Thuy (2005) from the
Hettangian of Bourglinster, Bereldange and Bridel in Euxembourg.

Description

Holotype

MnhnE HE408 is a dissociated, large, proximal EAP; approximately 1.5 times higher than wide, with
oblique, slightly concave dorsal edge as a result of a very weak constriction; distal edge weakly convex;
ventral quarter of EAP protruding ventro-proximalwards; proximal edge of EAP gently concave, with
four horizontally elongate, prominent and strongly protruding, poorly defined but conspicuous spurs;
second dorsalmost spur in the centre of the proximal edge, more than twice larger than remaining three
spurs of near-equal size; outer surface with fine vertical striation consisting of thin, slightly distalwards
overlapping lamellae; striation covering almost entire outer surface, with slight irregularities in ventral
half of outer surface, otherwise very regularly vertical; lamellae decreasing in size and fading into finely
meshed stereom towards proximal edge of EAP. Six relatively small, ear-shaped spine articulations in
notches of distal edge interrupting vertical striation; no connecting ridge between spine articulation and
striation; spine articulations of nearly equal size, with very weak dorsalward increase in size; dorsal and
ventral lobes forming continuous, round lobe; very strong dorsalward increase in size of gaps separating
spine articulations; relatively wide gap between spine articulations and distal edge of EAP. Ventral edge
of EAP with moderately large, gently concave tentacle notch.

Inner side of EAP with narrow, sharply defined, prominent ridge separated by gentle kink into ventral
and dorsal portions; dorsal portion oblique with dorsal tip widened, less sharply defined and bent
dorsalwards; ventral portion bent proximalwards, slightly less prominent and more weakly defined than
dorsal portion but not merged with thickened ventral edge of EAP; inner side of distal edge thin and with
relatively wide vertical band of finely meshed stereom sharply separated from coarsely meshed stereom
of remaining inner side; four relatively small, horizontally elongate, poorly defined, prominent, albeit
not protruding, spurs in finely meshed band of distal edge; second dorsalmost spur slightly larger than
remaining three. Tentacle notch relatively large, proximally bordered by thickened ventral edge of EAP,

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 26. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars m external (a) and internal (b) views.
1-3. Dermocomafaberi sp. nov. from the Hettangian (Early Jurassie) of Vanee, Belgium. 1. MnhnL HE408
(holotype), proximal LAP. 2. MnhnL HE409 (paratype), median LAP. 3. MnhnL HE410 (paratype), distal
LAP. 4-6. Dermocomapotti sp. nov. from the late Pliensbaehian (Early Jurassie) of Feuguerolles, Franee.
4. GZG.1NV.78675 (holotype), proximal LAP. 5. GZG.1NV.78676 (paratype), median LAP. 6. GZG.
1NV.78677 (paratype), distal LAP. 7-8. Dermocoma toarcensis (Hess, 1962) eomb. nov. from the late
Toareian (Early Jurassie) of Seewen, Switzerland. 7. NHMB Ml 1216, proximal LAP. 8. NHMB Ml 1217,
distal LAP. 9-11. Dermocoma longwyensis sp. nov. from the early Bajoeian (Middle Jurassie) of Longwy,
Franee. 9. GZG.INV.78679 (holotype), proximal LAP. 10. GZG.INV.78680 (paratype), median LAP.
11. GZG.1NV.78681 (paratype), distal LAP. One eommon seale bar per speeies.

142

THUYB., Fossil record of ophiacanthid brittle stars

and distally by short nearly vertical ridge close to ventro-distal tip of LAP. Hardly discernible, irregular,
vertical row of perforations at boundary between finely meshed stereom of distal edge and coarsely
meshed stereom of remaining inner surface.

Paratype supplements and variation

MnhnL HE409 is a dissociated median LAP, slightly higher than wide; dorsal edge oblique, nearly
straight to slightly convex; proximal edge slightly broken, with only single poorly defined, slightly
prominent and protruding, horizontally elongate spur approximately in centre of proximal edge. Four
ear-shaped, nearly equal-sized spine articulations; dorsalward increase in size of gaps separating spine
articulations.

Inner side of LAP with ridge similar to that in holotype; inner side of distal edge with two weakly
defined, slightly prominent, horizontally elongate ridges, ventral one of which slightly better defined and
protruding as a result of the distal edge of the LAP being broken.

MnhnL HE410 is a dissociated distal LAP; twice wider than high, of nearly perfectly rectangular outline;
dorsal and ventral edges straight; distal edge slightly convex, proximal straight, bordered by with oblique
dorso-proximal and ventro-proximal tips of LAP; no spurs discernible on proximal edge. Three spine
articulations sunken into notches of distal edge. Ventralmost spine articulation ventro-distally bordered
by tentacle perforation.

Inner side of LAP with sharply defined, short, oblique ridge, slightly pointed dorso-proximally and
ventro-distally; distal edge of LAP with two very weakly defined, slightly protruding spurs near dorso-
and ventro-distal tips of LAP. Large tentacle perforation in the centre of the distal half of the LAP.

Remarks

These specimens were originally recorded by Thuy (2005) as Ophiacanthal toarcensis Hess, 1962, who
acknowledged that they were not entirely compatible with the diagnosis of the species. The discrepancies
in LAP morphology, originally interpreted as within-species variability (Thuy 2005), are here identified
as differences of systematic importance warranting separation at the specific level, in line with the
observations by Thuy & Stohr (2011) on variability patterns in LAP morpologies of extant ophiuroid
species.

The size, shape and position of the spine articulations, the outer surface ornament and the shape of the
ridge on the inner side strongly suggest that these LAPs are assignable to Dermocoma. Within this genus,
greatest similarities are, indeed, shared with Dermocoma toarcensis comb, nov., originally described as
Ophiacanthal toarcensis, on account of the higher number of spine articulations and spurs on the outer
proximal and inner distal edges. However, the present LAPs differ in displaying up to four, rather than
three, spurs, as well as smaller spine articulations on a less strongly elevated distal portion of the LAP.

Occurrence

Hettangian of Belgium and Luxembourg.

Dermocoma potti sp. nov.

um:lsid:zoobank.org:act:3AD371F8-AFDl-4629-A4FF-448AlQFQ4ABl

Fig. 26: 4-6

Diagnosis

Species of Dermocoma with large LAPs displaying a well-developed vertical striation; two moderately
well-defined spurs on outer proximal and inner distal edge, dorsal one of which slightly larger and better
defined; up to four relatively large spine articulations; ridge on inner side with strongly widened and
dorsalwards pointing dorsal tip.

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European Journal of Taxonomy 48: 1-242 (2013)

Etymology

Species named in honour of my friend and colleague Christian Pott, who will always find a moment to
share and spread happiness.

Type material

Holotype

GZG.1NV.78675.

Paratypes

GZG.1NV.78676 and GZG.INV.78677.

Type locality and horizon

Feuguerolles, France; calcarenitic sediments infilling topography on surface of unconformity, late
Pliensbachian, Early Jurassic.

Additional material

GZG.1NV.78678 (63 dissociated LAPs).

Description

Holotype

GZG.1NV.78675 is a dissociated, large, proximal to median LAP; slightly higher than wide; dorsal edge
oblique, nearly straight; distal edge gently convex; ventral fifth ofLAP protruding ventro-proximalwards;
proximal edge of LAP gently concave, with large, moderately well-defined, prominent and pointedly
protruding, horizontally elongate spur in the centre of the proximal edge; second smaller, less prominent
and not protruding, weakly defined spur halfway between central spur and ventro-proximal tip ofLAP;
outer surface with very fine vertical striation composed of thin lamellae, very slightly overlapping
distalwards, proximalwards slightly decreasing in size and fading into finely meshed stereom close to
proximal edge ofLAP. Four relatively large, ear-shaped spine articulations in tight notches of distal
edge, interrupting vertical striation; spine articulations nearly equal-sized and equi-distant; dorsal and
ventral lobes forming continuous volute; no connecting ridge between spine articulations and vertical
striation; moderately wide gap between spine articulations and distal edge ofLAP. Ventral edge ofLAP
with large, deeply concave tentacle notch.

Inner side of LAP with narrow, well-defined, prominent ridge, with very narrow, oblique central part,
strongly widened dorsalwards pointing dorsal tip and short, narrow, ventro-proximalwards pointing
ventral tip sharply separated from thickened ventral edge ofLAP; inner side of distal edge ofLAP with
central, large, well-defined, horizontally elongate, prominent but not protruding spur composed of more
densely meshed stereom; second, smaller and less well-defined spur close to ventro-distal edge ofLAP.
Inner side of tentacle notch distally bordered by short, oblique ridge. No perforations discernible on
inn er side ofLAP.

Paratype supplements and variation

GZG.1NV.78676 is a dissociated, median LAP; nearly as high as wide; dorsal edge straight; distal edge
convex; ventral sixth ofLAP slightly protruding; proximal edge ofLAP weakly concave, with two very
poorly defined, slightly prominent but not protruding spurs; vertical striation on outer surface limited
to narrow band close to spine articulations, proximalwards fading into finely meshed stereom. Three
spine articulations, ventralmost of which slightly smaller than remaining two; dorsal gap between spine
articulations slightly larger than ventral one. Ventral edge ofLAP with hardly discernible tentacle notch.
Ridge on inner side ofLAP well in agreement with that of holotype, ventral portion of ridge less well
defined; two barely discernible spurs on inner side of distal edge. Inner side of tentacle notch large.

144

THUYB., Fossil record of ophiacanthid brittle stars

GZG.INV.78677 is dissociated, distal LAP; almost twice wider than high; of rectangular outline, with
straight dorsal edge and slightly convex distal edge; proximal edge weakly concave, with two almost
indiscernible, weakly prominent spurs; outer surface entirely covered by finely meshed stereom, no
vertical striation. Two spine articulations in tight notches of distal edge; very narrow gap between spine
articulations and distal edge of LAP. Ventral edge of LAP weakly convex, with small, weakly concave
tentacle notch.

Inner side with short, oblique, well-defined ridge with pointed dorso-proximal and ventro-distal tips;
two almost indiscernible, very weakly prominent spurs on inner side of distal edge of LAP. Tentacle
notch narrow, deeply encompassed by thickened ventral edge.

Remarks

These LAPs are unambiguously assignable to Dermocoma on account of the size, shape and position
of the spine articulations, the strongly protruding ventral portion of the LAPs and the shape of the ridge
on the inner side. Within this genus, the presence of up to four spine articulations and two horizontally
elongate spurs on the outer proximal edge makes it incompatible with any other currently known LAP
type assigned to this genus. It is thus described here as a new species.

Occurrence

Late Pliensbachian of France.

Dermocoma toarcensis (Hess, 1962) comb. nov.

Fig. 26: 7-8

Ophiacanthal toarcensis YIqss, 1962: 649, figs 122-125.

“Seewen Typ IIA” - Hess 1962: 635, fig. 28.

Ophiacanthal toarcensis 1996: 17, pi. 3 figs 1-5. —Kutscher&Villier2003: 183, pi. 3 figs 5-7.

non Ophiacanthal toarcensis - Thuy 2005: 40, pi. 5 figs 1-6, pi. 6 figs 5-6.
non Ophiacanthal cf toarcensis - Kutscher & Hary 1991: 45, pi. 1 fig. 4.

Diagnosis

Species of Dermocoma with moderately large LAPs displaying a well-developed vertical striation
on outer surface; up to three spurs on outer proximal and inner distal edges; up to six large spine
articulations; ventral lobe merged with distalwards pointing tip of outer surface separating notches of
spine articulations; ridge on inner side of LAPs slender, dorsal part not thickened.

Material examined

NHMB Ml 1216, NHMB Ml 1217 and 161 dissociated LAPs from the late Toarcian of Seewen,
Switzerland, the type material of Hess (1962) termed “Seewen Typ IIA”; 17 dissociated LAPs from the
late Pliensbachian of Seewen, Switzerland, the original material of Hess (1962) described as Seewen;
the original material of Kutscher (1996) and Kutscher & Villier (2003).

Description

Moderately large, dissociated LAPs, proximal ones nearly twice higher than wide, distal ones almost
twice wider than high; dorsal edge straight to slightly concave as a result of a weak constriction;
distal edge convex; proximal edge irregularly undulose, with up to three poorly to moderately well-
defined, horizontally elongate, prominent and protruding spurs, dorsal one of which slightly smaller
than remaining two; ventral quarter to fifth of LAP strongly protruding ventro-proximalwards; outer

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European Journal of Taxonomy 48: 1-242 (2013)

surface with fine, regular, vertieal striation eomposed of slightly overlapping lamellae and replaeed in
proximal half of outer surfaee by finely meshed stereom. Six (proximal LAPs) to three (distal LAPs)
large, ear-shaped spine artieulations in notehes of elevated distal edge; dorsal and ventral lobes of spine
artieulations merged into eontinuous volute; ventral lobe merged with distal wards pointing tips of outer
surfaee separating notehes; spine artieulations proximally sharply delimited by edge of notehes rather
than single distalmost lamella or well-defined ridge; notehes ineising vertieal striation of outer surfaee;
spine artieulations nearly equal sized, with slighty dorsalward inerease in size of gaps separating them;
gap between spine artieulations and distal edge of LAP narrow. Ventral edge of LAP with small but
elearly eoneave tentaele noteh in proximal to median LAPs, straight and devoid of tentaele noteh in
distal LAPs.

Inner side of LAPs with large, eonspieuous, sharply defined, prominent and relatively narrow ridge;
ventral part of ridge pointing ventro-proximalwards, sharply separated from thiekened ventral portion of
LAP, oblique eentral part and near-vertieal, slender dorsal part, with all parts eonneeted by very gentle,
rounded kinks; ridge in distal LAPs short, with thiekened ventral tip and dorso-proximally pointing,
slender dorsal tip; inner side of distal edge of LAP with up to three large, moderately well- to well-
defined, oval, prominent spurs eomposed of more densely meshed stereom; inner side of tentaele noteh
relatively small, with eoarsely meshed, horizontally slightly elongate stereom, sharply defined laterally.
Small, irregular perforations in poorly defined vertieal row dorsally bordering tentaele noteh in proximal
to median LAPs.

Remarks

A re-examination of the LAPs originally deseribed by Hess (1962) as Ophiacanthal toarcensis from
the Toareian of Switzerland has now revealed that the speeies should be transferred to Dermocoma on
aeeount of the size, shape and position of the spine artieulations, the strongly protruding ventral portion
of the LAP and the shape of the ridge on the inner side. Within this genus, D. toarcensis is unique in
eombining six spine artieulations and up to three spurs on the outer proximal and inner distal edges.

Subsequent reeords of this speeies from eoeval or slightly younger strata by Kutseher (1996) and
Kutseher & Villier (2003) have proved to be eonspeeifie. The Hettangian and Sinemurian reeords by
Thuy (2005) and Kutseher & Hary (1991), respeetively, belong to different speeies. The former is here
reinterpreted as a new speeies of Dermocoma, and the latter is a still unknown speeies whieh is most
probably assignable to Dermocoma - it ean only be formally deseribed after re-examination of the
original material and/or diseovery of new finds. At the present state, this Sinemurian reeord is best listed
as Dermocoma sp.

The LAPs from the Pliensbaehian of Seewen, Switzerland, deseribed and illustrated as “Seewen Typ llA”
by Hess (1962) almost eertainly belong to Dermocoma toarcensis eomb. nov. Kutseher & Hary (1991)
synonymised the LAPs termed “Seewen Typ llA” with those of “Seewen Typ lA”, here re-interpreted
as Ophiotoma vadosa sp. nov. (see above), and assigned them to their new speeies Ophioctenl seeweni
Kutseher & Hary, 1991, whieh was based on dissoeiated LAPs from the Sinemurian of Luxembourg.
The latter are, however, neither eonspeeifie with “Seewen Typ llA” nor with “Seewen Typ lA” (original
speeimens of “Seewen Typ IB and IIB” were not examined). Ophioctenl seeweni is here transferred to
Dermacantha gen. nov. (see below).

Occurrence

Late Pliensbaehian to Late Toareian of Switzerland, Toareian of Franee and Toareian/Aalenian of
Germany.

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THUYB., Fossil record of ophiacanthid brittle stars

Dermocoma longwyensis sp. nov.

um:lsid:zoobank.org:act:2EC1952C-3BD6-47Q8-9BDQ-6FCB36214D97

Fig. 26: 9-11

Diagnosis

Species of Dermocoma with relatively small FAPs displaying a well-developed, slightly undulose
vertical striation; no discernible spurs on outer proximal edge in proximal FAPs; up to two, large, very
poorly defined spurs on proximal edge in median to distal FAPs; single moderately well-defined spur on
inner distal edge of proximal FAPs, two in median and distal FAPs; up to six large spine articulations;
ventral lobe connected with distalwards projecting tip of outer surface stereom separating notches; ridge
on inner side long, slender, devoid of thickened dorsal part.

Etymology

Named after Fongwy, the type locality.

Type material

Holotype

GZG.INV.78679.

Paratypes

GZG.INV.78680 and GZG.INV.78681.

Type locality and horizon

Piedmont near Fongwy, France; Laeviuscula Zone, early Bajocian, Middle Jurassic.

Additional material

GZG.INV.78682 (91 dissociated FAPs) from the early Bajocian of Fongwy; GZG.1NV.78683 (29
dissociated FAPs) from the Humphriesianum Zone, early Bajocian of Cirey-les-Nolay, France.

Description

Holotype

GZG.INV.78679 is a dissociated, small, proximal FAP; slightly more than 1.5 times higher than wide;
dorsal edge slightly convex; distal edge convex; proximal edge concave, devoid of well-developed,
discernible spurs; ventral fifth of FAP strongy protruding ventro-proximalwards; outer surface with
moderately fine, slightly undulose vertical striation composed of slightly overlapping, irregular lamellae
and replaced by finely meshed stereom on proximal half of outer surface. Six large, ear-shaped spine
articulations in notches of elevated distal portion of FAP; slighty dorsalward increase in size of spine
articulations; gaps separating spine articulations clearly increasing in size larger towards dorsal edge of
FAP; ventral and dorsal lobes of spine articulations merged into continuous volute; ventral lobe connected
with distalwards projecting tips of outer surface stereom separating notches; spine articulations sharply
bordered proximally by edge of notches rather than single distalmost lamella or ridge; notches incising
vertical striation; narrow gap separating spine articulations and distal edge of FAP. Ventral edge of FAP
with moderately large, concave tentacle notch.

Inner side of FAP with long, well-defined, prominent, rather slender ridge; ventral part of ridge gently
bent, pointing ventro-proximal wards, merged ventrally with slightly thickened ventral portion of FAP;
central part of ridge straight, oblique; dorsal part largely obscured by sediment, straight and almost
vertical, not widened; three parts of ridge connected with very gentle, round kinks; inner side of distal
edge of FAP with single small, moderately well-defined, very weakly prominent, round spur composed
of densely meshed stereom; inner side of tentacle notch moderately large, well defined laterally; shallow.

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moderately well-defined vertieal furrow with few small, seattered perforations dorsally bordering
tentaele noteh.

Paratype supplements and variation

GZG.1NV.78680 is a dissoeiated median LAP; slightly less than 1.5 times higher than wide; very well in
agreement with holotype; single large, slightly prominent, non-protruding, very poorly defined, almost
indiseemible spur in ventral half of proximal edge. Five spine artieulations similar to those observed on
holotype.

Ridge on inner side of LAP better preserved; dorsal part straight, almost vertieal, very elose to proximal
edge of LAP. Few small, seattered perforations loosely arranged in vertieal row dorsally bordering
tentaele noteh.

GZG.INV.78681 is a dissoeiated distal LAP; slightly wider than high; proximal edge with two large,
weakly prominent, non-protruding, very poorly defined, almost indiseemible spurs; vertieal striation
on outer surfaee more regular than in holotype. Four spine artieulations similar to those observed on
holotype; eonneetion between ventral lobe of spine artieulations and distal wards projeeting tip of outer
surfaee stereom separating notehes very thin, weak. Ventral edge of LAP with small, weakly eoneave
tentaele noteh.

Ridge on inner side of LAP with oblique, slender dorsal part pointing dorso-proximal wards; ventral part
of ridge widened, nearly triangular, separated from thiekened ventral portion of LAP. Single, moderately
large, irregular perforation dorsally bordering tentaele noteh.

Remarks

These LAPs display all distinetive features to warrant assignment to the genus Dermocoma. The presenee
of up to six spine artieulations is a feature shared with the LAPs of Dermocoma toarcensis eomb. nov.
and D. numbergerorum sp. nov. While the former differ in having up to three, rather than two, spurs on
the outer proximal and inner distal edges, the latter display two mueh better-defined, widely separated
spurs, a generally larger size and eonspieuously large, wide ventral portions.

Occurrence

Early Bajoeian of France.

Dermocoma wrighti Hess, 1964
Fig. 27: 1-2

Dermocoma wrighti Hess, 1964: 78, figs 42-45, pi. 6, pi. 10 fig. 2.

p.p. “Liesberg Typ 1” - Hess 1963: 1151, figs 19-21.

p.p. Dermocoma wrighti - Hess & Holenweg 1985: 146, fig. 2.

Dermocoma wr/g/zfi - Kutseher 1987a: 62, pi. 2 fig. 2, pi. 4 fig. 1.

non Dermocoma wrighti -Y{qss 1972a: 36, figs 39-41, pi. 13 fig. 1.

Diagnosis

Speeies of Dermocoma with moderately large LAPs displaying two poorly to moderately well-defined
spurs on the outer proximal edge, dorsal one of which larger, developed as swollen part of proximal edge
rather than well-defined spur; outer surface with well-defined, moderately fine vertical striation; up to
five large spine articulations in notches of distal portion of LAP, and with distalward increase in size;
ridge on the inner side with long, near-straight, oblique dorsal portion devoid of thickened parts.

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Material examined

NHMB Ml 1218, NHMB Ml 1219 and 13 dissociated LAPs from the Koenigi Zone, early Callovian
of Liesberg, Switzerland, the original material of Hess (1963); GZG.INV.78684 (133 dissociated
LAPs) from the Humphriesianum Zone, early Bajocian of Cirey-les-Nolay, France; GZG.INV.78685
(8 dissociated LAPs) from the Humphriesianum Zone, early Bajocian of Delkhofen, Germany; GZG.
INV. 78686 (3 dissociated LAPs) from the Callovian of Bauer-Wehrland, Germany, the original material
of Kutscher (1987a).

Description

Moderately large, dissociated LAPs; proximal ones slightly higher than wide, distal ones slightly wider
than high; dorsal edge straight to weakly concave as a result of a poorly developed constriction; distal
edge convex; proximal edge concave, with two poorly to moderately well-defined spurs, dorsal one
large, prominent, strongly protruding, developed as swollen part of proximal edge rather than sharply
defined spur; ventral spur much smaller, less strongly protruding; ventral fifth of LAPs strongly
ventro-proximalwards protruding; outer surface with well-developed, moderately fine vertical striation
composed of slightly irregular, weakly overlapping lamellae, and replaced by finely meshed stereom on
proximal half of outer surface. Five large, ear-shaped spine articulations in notches of elevated distal
portion of LAP; ventral and dorsal lobes of spine articulations merged into continuous volute; ventral
lobe connected with distalwards projecting tips of outer surface separating notches; spine articulations
proximally sharply separated by edge of notches rather than single distalmost lamella or ridge; dorsalward
increase in size of spine articulations and of gaps separating them; moderately wide gap between spine
articulations and distal edge of LAP. Ventral edge of LAP with small, concave tentacle notch in all LAPs.
Inner side of LAPs with large, conspicuous, sharply defined, prominent, slender ridge; ventral part of
ridge ventro-proximalwards bent, not merged with thickened ventral portion of LAP; dorsal part of
ridge much longer than ventral one, almost straight, slightly oblique devoid of thickened part; ridge in
distal LAPs moderately short, strongly oblique, with dorso-proximally pointing dorsal tip, and widened
ventral tip; inner side of distal edge of LAP with two moderately well-defined spurs, dorsal one of
which slightly larger than ventral one; inner side of tentacle notch relatively small, well defined laterally.
Shallow, poorly defined vertical furrow with irregular, scattered minute perforations dorsally bordering
tentacle notch in proximal to median LAPs.

Remarks

The original description of Dermocoma wrighti, the type species of the genus, by Hess (1964) provided
only limited data on LAP morphology. A careful re-examination of the type specimens has now enabled
a detailed, comprehensive LAP morphological diagnosis to be worked out as a basis of comparison
with other records based exclusively on dissociated LAPs. In this way it has been possible to confirm
Kutscher’s (1987a) observation that the dissociated LAPs from the Callovian of Switzerland described
earlier by Hess (1963) as “Liesberg Typ I” were assignable to Dermocoma wrighti. The LAPs of this
species are characterised by the combination of up to five spine articulations and two moderately well-
defined spurs on the outer proximal and inner distal edges, the dorsal one which being larger and better
defined. This combination is also found in the LAPs originally described as Ophiacanthal biformis
Hess, 1975, here shown to be assignable to Dermocoma (see below). In that species, however, the spine
articulations are nearly of equal size, whereas in D. wrighti they display a dorsalward increase in size.
In addition, the ridge of D. wrighti is devoid of thickened parts.

Occurrence

Early Bajocian of France and Germany; early Callovian of Switzerland and Callovian of Germany.

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 27. Fossil lateral arm plates in external (a) and internal (b) views and artieulated arm fragment
of ophiaeanthid brittle stars. 1-2. Dermocoma wrighti Hess, 1964 from the early Callovian (Middle
Jurassie) of Liesberg, Switzerland. 1. NHMB Ml 1218, proximal LAP. 2. NHMB Ml 1219, distal LAP.
3-4. Dermocoma sp. 1 from the Callovian (Middle Jurassie) of Jumara, India. 3. GZG.INV.78687,
proximal LAP. 4. GZG.1NV.78688, distal LAP. 5-8. Dermocoma biformis (Hess, 1975) eomb. nov. from
the late Oxfordian (Late Jurassie) of Guldental, Switzerland (5-6) and Savigna, Franee (7-8). 5. NHMB
Ml 1220, proximal LAP. 6. NHMB Ml 1221, distal LAP. 7. GZG.1NV.78690, proximal LAP. 8. GZG.
INV.78692, proximal arm fragment in ventral (a) and dorsal (b) views. One eommon seale bar for 1-2,
3-4, 5-6, 7 and 8 respeetively.

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Dermocoma sp. 1
Fig. 27: 3-4

Material examined

GZG.INV.78687 and GZG.INV.78688 from sample 95, lower Chari Formation, Callovian of Jumara,
India; GZG.rNV.78689 (dissociated LAP) from sample 24, Patcham Formation, late Bathonian of
Jumara, India.

Description

GZG.INV.78687 is a dissociated, moderately large, proximal LAP; slightly higher than wide; dorsal
edge fragmentary; distal edge convex; proximal edge irregularly concave, poorly preserved, no
spurs discernible; ventral fifth of LAP strongly protruding ventro-proximalwards; outer surface with
moderately coarse, regular vertical striation composed of very weakly overlapping lamellae replaced by
finely meshed stereom on ventral portion of LAP and proximal third of outer surface. Four moderately
large, equal-sized, ear-shaped spine articulations in shallow notches of slightly elevated distal edge
of LAP; spine articulations proximally bordered by edge of notches; dorsal and ventral lobes of spine
articulations merged into continuous volute; notches of spine articulations incising outer surface striation;
very weak dorsalward increase in size of gaps separating spine articulations; probably very weak, thin
connection between ventral lobe of spine articulations and distalwards projecting tip of outer surface
stereom separating notches. Ventral edge of LAP with small, concave tentacle notch.

Inner side of LAP with relatively small, very slender, well-defined, slightly prominent ridge composed
of ventro-proximalwards bent ventral part and nearly straight, oblique, dorso-proximalwards pointing,
non-thickened dorsal part; no spurs discernible on inner side of distal edge of LAP; inner side of tentacle
notch moderately small. No perforations or furrow discernible.

GZG.INV.78688 is a dissociated distal LAP; slightly less than 1.5 times wider than high; dorsal edge very
weakly concave; proximal edge concave, with two small, poorly defined, prominent, weakly protruding,
horizontally elongate spurs; vertical striation on almost entire outer surface. Three poorly preserved
spine articulations similar to those observed in the specimen described above; weak dorsalward increase
in size of spine articulations and of gaps separating them. Ventral edge of LAP gently convex; tentacle
notch invisible in external view.

Inner side of LAP largely obscured by sediment; inner side of distal edge with two small, poorly defined,
weakly prominent, horizontally elongate spurs; inner side of tentacle notch moderately small.

Remarks

In spite of its poor preservation, this material displays a distinctive combination of characters that
warrants assignment to Dermocoma. The limited amount of material precludes a meaningful assessment
at the species level. Nevertheless, it is worth recording this material since it is the first known record of
Dermocoma from the Southern Hemisphere.

Occurrence

Late Bathonian to Callovian of India.

Dermocoma biformis (Hess, 1975) comb. nov.

Fig. 27: 5-8

Ophiacanthal biformis Hess, 1975a: 594, figs 10-12, pi. 1 fig. 6 [non pi. 1 fig. 5, which is not an
ophiacanthid].

Ophiacanthal biformis -Y{qss 1975b: 608, figs 8-9.

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European Journal of Taxonomy 48: 1-242 (2013)

Diagnosis

Species of Dermocoma with very large LAPs displaying two well-defined spurs on outer proximal and
inner distal edges; dorsal spur very large, prominent and strongly protruding, ventral spur smaller and
less strongly protruding; fine, well-developed vertical striation on distal half of outer surface; up to five
moderately large, equal-sized spine articulations in tight notches of distal portion of LAP; ridge on inner
side large, relatively slender, with long, near-straight, almost vertical dorsal part slightly thickened at
its centre.

Material examined

NHMB Ml 1220, NHMB Ml 1221 and 120 dissociated LAPs from the Gtinsberg Member, late Oxfordian
of Guldental, Switzerland; GZG.1NV.78690 and GZG.1NV.78691 (137 dissociated LAPs) from sample
S2a of Gale (2011) from the late Oxfordian of Savigna, France; GZG.INV.78692, GZG.1NV.78693 (51
dissociated LAPs) from sample S2b of Gale (2011) from the late Oxfordian of Savigna, France; GZG.
INV. 78694 (36 dissociated LAPs) sample SI of Gale (2011) from the late Oxfordian of Savigna, France;
14 dissociated LAPs from the Humeralis Member, late Oxfordian of Raedersdorf, France, original
material of Hess (1975b); 33 dissociated LAPs from the Bifurcatus Zone, late Oxfordian of Guldental,
Switzerland, the original material of Hess (1966); 11 dissociated LAPs from the Renggeri Member,
early Oxfordian of Chapois, France, the original material of Hess (1965a).

Description

Very large, dissociated LAPs; proximal ones 1.5 times higher than wide, distal ones almost twice wider
than high; dorsal edge slightly convex (proximal LAPs) to slightly concave (distal ones) as a result of a
weak constriction; distal edge convex; proximal edge concave, with two spurs; dorsal spur very large,
well-defined, oval, prominent and strongly protruding at least in proximal to median LAPs; ventral
spur much smaller, less well-defined, weakly prominent and protruding; ventral fifth of LAPs strongly
protruding ventro-proximalwards; outer surface with well-developed fine, vertical striation composed
of slightly wavy, fine, weakly overlapping lamellae close to spine articulations, and replaced by very
finely meshed stereom on proximal half of outer surface. Five (proximal LAPs) to three (distal ones)
moderately large, ear-shaped spine articulations in relatively tight notches of the slightly elevated distal
portion of the LAPs; ventral and dorsal lobes of spine articulations merged into continuous volute; ventral
lobe with very weak and thin connection with distalwards projecting tips of outer surface separating
notches; spine articulations proximally sharply separated by edge of notches; spine articulations nearly
equal sized; dorsalward increase in size of gaps separating spine articulations; narrow gap between spine
articulations and distal edge of LAP. Ventral edge of LAP with small, concave tentacle notch in all but
the distalmost LAPs.

Inner side of LAPs with large, conspicuous, sharply defined, prominent, moderately slender ridge;
ventral part of ridge ventro-proximalwards bent, confiuent with thickened ventral portion of LAP; dorsal
part of ridge longer than ventral one, almost straight, slightly oblique with weakly thickened central part;
ridge in distal LAPs short, oblique, with dorso-proximalwards pointing dorsal tip, widened ventral tip,
and distally bordered by small round knob; inner side of distal edge with two moderately well-defined,
oval spurs composed of densely meshed stereom; dorsal spur much larger than ventral one in proximal
to median LAPs; inner side of tentacle notch small, deeply incised and sharply bordered laterally. Very
shallow, poorly defined vertical furrow with few, minute perforations dorsally bordering tentacle notch
and distally bordered by moderately well-defined, narrow and weakly prominent ridge; no perforations
or furrow discernible in distal LAPs.

Articulated arm fragments preserving median to proximal segments; ventral arm plates large, slightly
longer than wide, polygonal, with straight to weakly concave distal edge, straight distalwards converging
latero-distal edges; concave lateral and latero-proximal edges and a right to slightly acute proximal
angle; LAPs in contact ventrally but not separating ventral arm plates; tentacle pores small, covered

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by at least one small, leaf-like tentacle scale; dorsal arm plates large, slightly longer than wide, widest
distally separating LAPs, nearly trapezoid in outline, with convex distal edge, distalwards diverging,
straight lateral edges and slightly convex proximal edge; dorsal arm plates with very fine transverse
striation.

Remarks

Hess (1975a) originally described a set of dissociated LAPs from the Oxfordian of Switzerland as
Ophiacanthal biformis, the species name being chosen to refiect the fact that median and distal LAPs
display a vertical striation which the proximal ones completely lack. However, as suggested by the
observations of Thuy & Stohr (2011), the type of ornament on the outer surface of the LAPs within
one species is very unlikely to change fundamentally according to the position along the arm. Indeed, a
careful re-examination of the type material has revealed that it included more than one type of LAPs and
that a number of proximal LAPs, including the holotype, display the same vertical striation, although
limited to a narrow band near the spine articulations, as observed on the median and distal LAPs. The
original description and diagnosis of Ophiacanthal biformis are based on at least two different types of
LAPs, which is a prime example of why, for new species based on dissociated LAPs, the holotype and
the paratypes should always be described individually (Thuy & Stohr 2011).

The LAP type corresponding to the holotype of Ophiacanthal biformis can unambiguously be assigned
to the genus Dermocoma on account of the shape, size and position of the spine articulations, the strongly
protruding ventral portion of the LAPs and the shape of the ridge on the inner side. Closest similarities
are shared with the LAPs of D. wrighti which, however, differ in displaying a dorsalward increase in size
of the spine articulations, a slender ridge devoid of thickened parts, and a slightly less sharply defined
dorsal spur on the outer proximal edge.

New finds assignable to Dermocoma biformis comb. nov. from the Oxfordian of France include articulated
arm fragments which complement the morphological data based on dissociated LAPs. The additional
data on arm morphology are in agreement with the assignment to Dermocoma and furthermore suggest
that the dorsal arm plate illustrated by Thuy (2005) and originally assigned to Ophiacanthal toarcensis
(see above), indeed, belongs to Dermocoma, most probably to D. faberi sp. nov.

Occurrence

Early Oxfordian of France; late Oxfordian of Switzerland and France.

Dermocoma numbergerorum sp. nov.
um:lsid:zoobank.org:act:EADlDA00-C38B-49E3-B753-867F4C4DFA62

Fig. 28: 1-4

Diagnosis

Species of Dermocoma with large EAPs displaying a well-developed, fine vertical striation on distal
half of outer surface; ventral portion of proximal EAPs very large and wide; two large, nearly equal¬
sized, strongly protruding, moderately well-defined and widely separate spurs on proximal outer edge
of proximal EAPs: up to six large, nearly equal-sized spine articulations; dorsalward increase in gaps
separating spine articulations; ridge on the inner side with long, slender, near-straight and oblique dorsal
part with triangular, elongate, pointed dorsal tip.

Etymology

Species named in honour of Sabine and Klaus Numberger, the best in-laws of the Phanerozoic.

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European Journal of Taxonomy 48: 1-242 (2013)

Type material

Holotype

GZG.1NV.78695.

Paratypes

GZG.1NV.78696, GZG.1NV.78697 and GZG.INV.78698.

Type locality and horizon

Foug, France; marly pockets between coral bioherms, Transversarium Zone, middle Oxfordian, Late
Jurassic.

Additional material

GZG.1NV.78699 (201 dissociated LAPs).

Description

Holotype

GZG.INV.78695 is a dissociated, large, proximal LAP; 1.5 times higher than wide; dorsal edge nearly
straight; distal edge slightly convex; ventral quarter of LAP very large, wide, strongly protruding ventro-
proximalwards; proximal edge irregularly undulose, with two large, almost equal-sized, moderately
well-defined, prominent and conspicuously protruding, widely separate spurs; outer surface with very
fine, regular vertical striation composed of slender, slightly overlapping lamellae, and replaced by very
finely meshed stereom on the proximal two-thirds of the outer surface. Five large, nearly equal-sized,
ear-shaped spine articulations in tight notches of elevated distal portion of LAP; ventral lobe merged
with dorsal one into continuous volute, and connected with distalwards projecting tip of outer surface
separating notch; spine articulations proximally sharply separated by edge of notch; dorsalward increase
in size of gaps separating spine articulations; notches deeply incising vertical striation; moderately wide
gap between spine articulations and distal edge of LAP. Ventral edge of LAP with moderately large,
concave tentacle notch.

Inner side of LAP with large, sharply defined, prominent, slender ridge; ventral part of ridge gently bent
ventro-proximalwards, not merged with weakly thickened ventral portion of LAP; dorsal part of ridge
much longer than ventral one, nearly straight, oblique, with elongate, very slender triangular, pointed,
approximately knife-shaped dorsal tip; inner side of distal edge with two moderately well-defined, widely
separate, weakly prominent, oval spurs composed of more densely meshed stereom; ventral spur slightly
smaller than dorsal one; inner side of tentacle notch moderately large, well defined laterally. Shallow,
moderately well-defined vertical furrow dorsally bordering tentacle notch; no perforations discernible.

Paratypes

GZG.1NV.78696 is a dissociated proximal LAP; very well in agreement with holotype; proximal edge
and ventral portion slightly fragmentary; spurs on proximal edge as in holotype. Six spine articulations
similar to those observed on holotype but less well preserved.

Inner side of LAP matching that of holotype. Vertical furrow with few small, scattered perforations.

GZG.1NV.78697 is a dissociated median LAP; slightly higher than wide; proximal edge with two
moderately well-developed, strongly prominent and protruding spurs; not as widely separated as in
holotype, and dorsal spur slightly larger than ventral one; vertical striation on distal half rather than third
of outer surface. Five spine articulations similar to those observed on holotype; dorsalward increase in
size of gaps separating spine articulations stronger than in holotype; gap between spine articulations and
distal edge of LAP narrower.

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THUYB., Fossil record of ophiacanthid brittle stars

Fig. 28. Fossil lateral arm plates (LAPs) of ophiacanthid brittle stars in external (a) and internal (b)
views. 1-4. Dermocoma numbergerorum sp. nov. from the middle Oxfordian (Late Jurassic) of Foug,
France. 1. GZG.rNV.78695 (holotype), proximal LAP. 2. GZG.rNV.78696 (paratype), proximal LAP.
3. GZG.INV.78697 (paratype), median LAP. 4. GZG.INV.78698 (paratype), distal LAP. 5-8. Dermocoma
simonschneideri sp. nov. from the early Kimmeridgian (Late Jurassic) of the Pointe du Chay, France (5) and
the late Kimmeridgian (Late Jurassic) of Trancoso, Portugal (6-8). 5. GZG.INV.78700 (holotype), proximal
LAP. 6. GZG.fNV. 78701 (paratype), proximal LAP. 7. GZG.fNV.78702 (paratype), median LAP. 8. GZG.
INV. 78703 (paratype), distal LAP. 9. Dermocoma sp. nov. innom. 2 from the early Kimmeridgian (Late
Jurassic) ofGeisingen, Germany; GZG.INV.78705, median to distal LAP. Dermocoma nov. innom.

3 from the late Valanginian (Early Cretaceous) of the Lemberg Nappe, Austria. 10. NHMW 2012/0138/0009,
proximal LAP. 11. NHMW 2012/0138/0010, distal LAP. One common scale bar per species.

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European Journal of Taxonomy 48: 1-242 (2013)

Inner side of LAP with ridge similar to that of holotype; spurs on inner side of distal LAP edge almost
indiseemible. Two to three irregular, variably sized perforations dorsally bordering tentaele noteh; no
furrow diseemible.

GZG.INV.78698 is a dissoeiated distal LAP; slightly wider than high; dorsal edge slightly eoneave as a
result of a weak eonstrietion; ventral portion of LAP weakly protruding ventro-proximal wards; spurs as
in holotype; distal two-thirds of outer surfaee with vertieal striation. Four spine artieulations similar to
those observed on holotype. Tentaele noteh not visible in external view.

Inner side of LAP with sharply defined, slender, bent ridge; dorsal part of ridge dorso-proximally pointing,
not thiekened, with rounded tip; ventral part of ridge ventro-proximally pointing, with very weakly
thiekened ventral tip; inner side of tentaele noteh relatively small, with eoarsely meshed, horizontally
elongate stereom, and sharply defined laterally. Very shallow, poorly defined vertieal furrow dorsally
bordering tentaele noteh.

Remarks

Assignment of these LAPs to Dermocoma is eorroborated by the strongly ventro-proximally protruding
ventral portion of the LAPs, the shape and position of the spine artieulations and the shape of the
ridge on the inner side. Within this genus, the present LAPs are unique in eombining up to six spine
artieulations, two well-defined, widely separate spurs on the outer proximal and inner distal edges,
and a eonspieuously large and wide ventral portion. They are thus deseribed here as a new speeies of
Dermocoma.

Dermocoma simonschneideri sp. nov.
um:lsid:zoobank.org:aet:D3449C2A-A9Fl-42Fl-87B0-CB8EQ210232A

Fig. 28: 5-8

Diagnosis

Speeies of Dermocoma with large LAPs displaying a very well-developed vertieal striation on at least
half of the outer surfaee; large, oval and eonspieuously oblique spur on proximal edge; four spine
artieulations sunken in deep notehes of a poorly elevated distal LAP portion; ridge on inner side very
slender, with ventral tip merged with ventral portion of LAP, and dorsal tip slightly widened and merged
with proximal edge of LAP.

Etymology

Speeies named in honour of Simon Sehneider, who kindly provided the samples yielding the type
material of the speeies.

Type material

Holotype

GZG.1NV.78700.

Paratypes

GZG.1NV.78701, GZG.1NV.78702 and GZG.1NV.78703 from the late Kimmeridgian (Late Jurassie) of
Traneoso, Portugal.

Type locality and horizon

Pointe du Chay near La Roehelle, Franee; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late
Jurassie.

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Additional material

GZG.INV.78704 (14 dissociated LAPs) from the Am aral Formation, late Kimmeridgian of Trancoso,
Portugal.

Description

Holotype

GZG.INV.78700 is a dissociated, large, proximal to median LAP; slightly higher than wide; dorsal and
distal edges convex; proximal edge irregularly concave, with large, moderately well-defined, slightly
prominent, non-protruding, oval and conspicuously oblique spur; ventral quarter of LAP strongly
protruding ventro-proximalwards; distal half of outer surface with very well-developed, fine, regular
vertical striation composed of overlapping lamellae, replaced by finely meshed stereom on proximal
half of outer surface. Four relatively large, ear-shaped, nearly equal-sized spine articulations in deep
notches of slightly elevated distal portion of LAP; ventral lobe merged with dorsal one into continuous
volute but only weakly connected with distally projecting tip of outer surface between notches; spine
articulations proximally sharply separated by edge of notches; weak dorsalward increase in size of gaps
separating spine articulations; gap between spine articulations and distal edge of LAP very narrow.
Ventral edge of LAP with small, weakly concave tentacle notch.

Inner side of LAP with moderately large, very slender, gently bent ridge; ventral tip pointing ventral wards,
merged with ventral portion of LAP; dorsal tip pointing dorso-proximally, slightly widened and merged
with proximal edge of LAP; inner side of distal edge of LAP with small, well-defined, prominent, oval
and oblique spur composed of densely meshed stereom; inner side of tentacle notch relatively large,
with coarsely meshed, horizontally elongate stereom; well defined laterally. Short, shallow, rather broad,
irregular and slightly oblique furrow with highly variable perforations dorsally bordering tentacle notch.

Paratypes

GZG.INV.78701 is a dissociated proximal LAP; approximately 1.5 times higher than wide; very well in
agreement with holotype; outer surface less well defined, vertical striation not discernible. Four spine
articulations similar to those of holotype.

Inner side of LAP with ridge similar to that of holotype but slightly longer; spur on inner side of distal
edge poorly defined. Short, slightly oblique furrow as in holotype but distally bordered by broad, poorly
defined and weakly prominent ridge.

GZG.INV.78702 is a dissociated median LAP; slightly wider than high; very well in agreement with
holotype; vertical striation slightly finer and on distal two-thirds rather distal half of outer surface. Four
spine articulations slightly smaller than those observed on holotype, otherwise similar.

Ridge on inner side of LAP with more strongly widened dorsal tip; spur on inner side of distal LAP edge
very poorly defined, almost indiscernible. No perforations or furrow discernible.

GZG.INV.78703 is a dissociated distal LAP; more than 1.5 times wider than high; dorsal edge slightly
concave as a result of a very weak constriction; proximal edge with two moderately well-defined spurs,
dorsal one of which largest; vertical striation on three-quarters of outer surface. Four spine articulations
smaller than those of holotype and poorly preserved, otherwise similar. Tentacle notch invisible in
external view.

Inner side of LAP with small, sharply defined ridge, with pointed, proximalwards bent dorsal tip, and
widened ventral tip, not merged with ventral portion of LAP; inner side of distal edge of LAP with two
poorly defined, large, oval, weakly prominent spurs; inner side of tentacle notch small, oblique, laterally
well defined. Single, relatively large perforation dorsally bordering tentacle notch.

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European Journal of Taxonomy 48: 1-242 (2013)

Remarks

In spite of the limited amount of material available, these LAPs are unambiguously assignable to the
genus Dermocoma on aeeount of the highly eharaeteristie eombination of the strongly protruding
ventral portion of the LAP, the nearly equal-sized spine artieulations in regularly spaeed notehes of the
weakly elevated distal portion of the LAP, and the simple ridge on the inner side devoid of sharp kinks
or eonspieuously widened parts. The single large, eonspieuously oblique spur on the outer proximal and
inner distal edges of the proximal and median LAPs is a highly distinetive feature not found in any other
speeies assigned to Dermocoma.

Occurrence

Early Kimmeridgian of France and late Kimmeridgian of Portugal.

Dermocoma sp. nov. innom. 2
Fig. 28: 9

Material examined

GZG.1NV.78705 from the Lacunosa Marls, early Kimmeridgian of Geisingen, Germany.

Description

GZG.1NV.78705 is a small, dissociated median to distal FAP; slightly wider than high; dorsal edge
weakly concave; distal edge convex, slightly oblique; proximal portion of FAP small, very weakly
protruding ventro-proximalwards; proximal edge concave, with two very poorly defined, small, weakly
prominent albeit protruding, horizontally elongate spurs; outer surface with poorly developed, irregular,
vertical striation composed of slightly overlapping lamellae close to spine articulations, replaced by finely
meshed stereom in proximal three-quarters of outer surface. Four large, ear-shaped spine articulations
in shallow notches of very weakly elevated distal portion of FAP; strong dorsalward increase in size of
spine articulations and of gaps separating them; dorsal and ventral lobes of spine articulations merged
into continuous volute; row of spine articulations dorso-proximalwards receding; gap between spine
articulations and distal edge of FAP narrow, widest near ventralmost spine articulation. Ventral edge of
FAP nearly straight, with small, very shallow, almost indiscernible tentacle notch.

Inner side of FAP with relatively small, well-defined, prominent, oblique ridge with slender dorso-
proximalwards pointing dorsal part and strongly widened, short, ventro-proximal wards pointing ventral
part; inner side of distal edge of FAP with two moderately large, poorly defined, weakly prominent
spurs; inner side of tentacle notch small, moderately well-defined laterally. No perforations or furrow
discernible.

Remarks

In spite of the very limited amount of material available, this FAP type is clearly assignable to Dermocoma
on account of the spine articulation structure, the two spurs on the outer proximal and inner distal edges,
and the shape of the ridge on the inner side of the FAP. Both FAPs available are from median to even
distal arm portions, which hampers a sound systematic assessment. It seems clear, however, that this
FAP type is incompatible with any known species of Dermocoma on account of the oblique distal edge
and similarly oblique row of spine articulations which display a strong dorsalward increase in size. In
the absence of more material, in particular from proximal arm portions, the present FAP type is here
treated as a new, still unnamed, species of Dermocoma.

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Dermocoma sp. nov. inn om. 3
Fig. 28: 10-11

Material examined

NHMW 2012/0138/0009, NHMW 2012/0138/0010 and NHMW 2012/0138/0011 (25 dissociated
LAPs) from the Verrucosum Zone, late Valanginian of the KB 1 -A section of Lukeneder (2004), Temberg
Nappe, Austria.

Description

Dissociated, small, fragile, fragmentary proximal to median LAPs and a single complete distal LAP;
proximal ones originally as high as wide or slightly higher; median ones slightly wider than high; distal
LAP more than twice wider than high; dorsal edge concave in median to distal LAPs as a result of a
weak constriction; distal edge convex; proximal edge of distal LAP with two small, poorly defined,
slightly prominent and protruding spurs; no spurs discernible in fragmentary proximal edge of median
to distal LAPs; ventral portion of median to proximal LAP fragmentary, originally most probably
protruding; outer surface with very fine, irregular, slightly wavy vertical striation composed of very
slender, slightly overlapping lamellae, and replaced by finely meshed stereom on proximal three-quarters
of outer surface. Three rather small, ear-shaped spine articulations in notches of weakly elevated distal
portion of LAP; possibly more spine articulations in proximal LAP; weak dorsalward increase in size of
spine articulations in proximal LAP; ventral lobe of spine articulations not connected with outer surface
stereom and merged with dorsal lobe into continuous volute; spine articulations proximally bordered by
edge of notches; gap between spine articulations and distal edge of LAP narrow. Small, weakly concave
tentacle notch in median LAPs; ventral edge of distal LAP evenly concave, tentacle opening emerging
at ventro-distal edge of ventralmost spine articulation.

Inner side of proximal to median LAPs with sharply defined, prominent, very slender, slightly bent,
oblique ridge dorsal tip of which pointing dorso-proximalwards and ventral tip pointing ventro-
proximalwards; two widely separate, sharply defined, prominent knobs on inner side of distal LAP,
proximal one nearly triangular, distal one minute, almost indiscernible; inner side of distal edge of LAP
with up to two poorly to moderately well-defined, small, oval, slightly prominent spurs; inner side of
tentacle notch not preserved in proximal LAP, moderately large, well-defined laterally and with coarsely
meshed, horizontally elongate stereom in median LAP; distal LAP with large tentacle perforation in the
middle of the distal third. Two small, irregular perforations loosely arranged in vertical row on inner side
of proximal LAP fragment.

Remarks

This material is very limited and largely fragmentary; yet, the shape and position of the spine articulations,
the spurs on the outer proximal and inner distal edges and the shape of the ridge on the inner side strongly
suggest assignment to Dermocoma. The fragmentary nature precludes assignment at the species level.
Nevertheless, the material is very important since it was recovered from deep shelf to upper slope
sediments and thus represents the deepest occurrence of Dermocoma recorded to date.

Dermocoma sp. nov. innom. 4
Fig. 29: 1

Material examined

NHM EE 14844 from the Tardefurcata Zone, early Albian of heighten Buzzard, Great Britain.

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European Journal of Taxonomy 48: 1-242 (2013)

Description

Dissociated, single, very large, proximal LAP; approximately twiee higher than wide; dorsal and
distal edges eonvex; ventral fifth of LAP strongly protruding ventro-proximalwards; proximal edge of
LAP eoneave, with large eentral, swollen, protruding part not diseemible as spur; outer surfaee with
well-developed, regular vertieal striation eomposed of fine, overlapping lamellae deereasing in size
proximal wards; striation replaeed by finely meshed stereom on proximal third of outer surfaee. Six
moderately large, ear-shaped spine artieulations in notehes of weakly elevated distal portion of LAP;
spine artieulations equal-sized exeept for slightly smaller ventralmost one; weak dorsalward inerease in
size of gaps separating spine artieulations; spine artieulations proximally sharply bordered by edge of
notehes; ventral lobe of spine artieulations with weak eonneetion with distalwards projeeting tip of outer
surfaee stereom separating notehes, and merged with dorsal lobe into eontinuous volute; gap between
spine artieulations and distal edge of LAP very narrow. Ventral edge of LAP with small, eoneave tentaele
noteh.

Inner side of LAP with moderately well-defined, prominent, very slender ridge with ventralwards
pointing ventral part not merged with thiekened ventral portion of LAP; dorsal part of ridge slightly
bent, oblique, pointing dorso-proximal wards; ridge devoid of thiekened parts and sharp kinks; inner side
of distal edge with single, large, moderately well-defined, prominent, round spur; inner side of tentaele
noteh small, well defined laterally. Very shallow, poorly defined vertieal furrow with small, seattered
perforations dorsally bordering tentaele noteh and distally bordered by narrow, moderately well-defined,
weakly prominent ridge.

Remarks

The single LAP deseribed here displays the distinetive eombination of relatively small spine artieulations
in notehes of the weakly elevated distal edge, with the strongly protruding ventral portion of the LAP
and the simple, slender ridge on the inner side devoid of sharp kinks and thiekened parts, whieh
unambiguously plaees it in the genus Dermocoma. Within this genus, a number of speeies have up to six
spine artieulations but all of them display at least two spurs on the outer proximal and distal edge rather
than a single, large, swollen, protruding area on the outer proximal edge and a moderately well-defined,
round spur on the inner distal edge. This LAP elearly belongs to a new speeies, the formal deseription of
whieh, however, should not be based on only a single speeimen.

Genus Dermacantha gen. nov.

um:lsid:zoobank.org:aet:D73D5436-6AQA-43Cl-8298-C5C4BE5D5CA3

Type species

Dermacantha leonorae sp. nov., by present designation.

Other species included

Dermacantha pattyana sp. nov., Ophioctenl seeweni Kutseher & Hary, 1991 and Dermacantha carli
sp. nov.

Diagnosis

Ophiaeanthid with small to moderately large LAPs; small height/width ratio, even in proximal LAPs;
relatively few (up to five) small spine artieulations in notehes of slightly elevated distal portion of LAP;
ventral and dorsal lobes of spine artieulations proximally separated by small knob; ventral portion of
LAP generally strongly protruding ventro-proximalwards; up to two poorly to well-defined spurs on
outer proximal and inner distal edges; inner side of LAPs with simple, slender ridge devoid of sharp
kinks or strongly thiekened parts; tentaele noteh small.

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■i

.\'m

Fig. 29. Fossil lateral arm plates (LAPs) of ophiacanthid brittle stars in external (a) and internal (b)
views. 1. Dermocoma sp. nov. innom. 4 from the early Albian (Early Cretaceous) of Leighton Buzzard,
Great Britain; NHM EE 14844, proximal LAP. 2-5. Dermacantha pattyana gen. et sp. nov. from the
Hettangian (Early Jurassic) of Fontenoille, Belgium. 2. MnhnL HE414 (holotype), proximal LAP.
3. MnhnL HE415 (paratype), proximal LAP. 4. MnhnL HE416 (paratype), median LAP. 5. MnhnL
HE417 (paratype), distal LAP. 6-8. Dermacantha seeweni (Kutscher & Hary, 1991) comb. nov. from the
late Sinemurian (Early Jurassic) of Bishop’s Cleeve, Great Britain. 6. GZG.INV.78706, proximal LAP.
7. GZG.INV. 78707, median LAP. 8. GZG.INV.78708, distal LAP. 9-11. Dermacantha leonorae gen. et
sp. nov. from the early Pliensbachian (Early Jurassic) of Blockley, Great Britain. 9. GZG.INV.78710
(holotype), proximal LAP. 10. GZG.INV.78711 (paratype), median LAP. 11. GZG.INV.78712 (paratype),
distal LAP. One common scale bar per species.

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European Journal of Taxonomy 48: 1-242 (2013)

Etymology

Name composed of derma, Greek for “skin”, and Acantha, a nymph in Greek mythology whose name
literally translates as “thorny”, in reference to the striking similarities in LAP morphology shared with
Dermocoma.

Remarks

The ophiacanthid fossil record includes a number of dissociated LAP types which, at first sight, seem
compatible with the LAP morphological diagnosis of Dermocoma, in particular with respect to the
strongly protruding ventral portion of the LAPs, the position of the spine articulations, the presence of
spurs on the outer proximal and inner distal edges and the shape of the ridge on the inner side. The spine
articulation morphology, however, differs markedly. In fact, while the LAPs of Dermocoma display spine
articulations with a continuous volute, those of the LAP type in question have the ventral and dorsal lobes
proximally separated by one or several small knobs. This significant difference is generally combined
with a smaller height/width ratio, even in proximal LAPs, and with smaller spine articulations than in
Dermocoma. Since these differences co-occur consistently, Dermacantha gen. nov. is introduced here to
accommodate the Dermocoma-liks LAP types with small spine articulations displaying a discontinuous
volute. The striking similarities in LAP morphology, however, strongly suggest that Dermocoma and
Dermacantha gen. nov. share close phylogenetic ties, as suggested by the name of the new genus.

Superficial similarities are shared with the LAPs of Lapidaster gen. nov. with respect to the weakly
elevated distal portion of the LAPs and the spurs on the outer proximal and inner distal edges. In
Lapidaster gen. nov., however, the spine articulations are never sunken into notches of the distal LAP
portion, and the tentacle notch generally is much larger.

Dermacanthapattyana sp. nov.

um:lsid:zoobank.org:act:4F9EF5AE-AF42-4815-B870-EF9964CEAEC8

Fig. 29: 2-5

Diagnosis

Species of Dermacantha gen. nov. with small EAPs displaying a very finely meshed stereom on the
outer surface; trabeculae of outer surface stereom merging into very poorly developed, irregular vertical
striation close to spine articulations; two very weakly defined spurs on the outer proximal and inner
distal edges; up to four relatively small spine articulations; ridge on inner side relatively short and wide.

Etymology

Species named in honour of my friend and near-sister Patty Muller.

Type material

Holotype

MnhnE HE414.

Paratypes

MnhnE HE415, MnhnE HE416 and MnhnE HE417.

Type locality and horizon

Fontenoille, Belgium; level c of Delsate et al. (2002), Liasicus Zone, Hettangian, Early Jurassic.

Additional material

MnhnE HE418 (294 dissociated EAPs).

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THUYB., Fossil record of ophiacanthid brittle stars

Description

Holotype

MnhnLHE414 is a dissociated, small, proximal to median LAP; nearly as high as wide; dorsal edge straight;
distal edge convex; proximal edge irregularly concave, with two large, poorly defined, horizontally
elongate and weakly prominent spurs, ventral one slightly larger and more strongly protruding; ventral
sixth of LAP slightly protruding ventro-proximalwards; outer surface with very finely meshed stereom;
trabeculae of outer surface stereom merging into very faint, poorly developed, irregular vertical striation
close to spine articulations. Four relatively small, ear-shaped spine articulations sunken individually into
moderately deep notches of the non-elevated distal LAP edge; ventral and dorsal lobes thin, separated by
small knob proximally; spine articulations equal-sized and equi-distant; gap between spine articulations
and distal edge of LAP moderately wide, slightly narrower than the width of one spine articulation,
decreasing in width ventralwards. Ventral edge of LAP with small, concave tentacle notch.

Inner side of LAP with well-defined, prominent, relatively broad, short ridge; dorsal tip of ridge slightly
widened, tongue shaped, pointing dorso-proximalwards; ventral part of ridge merged with thickened
ventral LAP portion; inner side of distal edge with two medium-sized, poorly defined, oval, weakly
prominent spurs; inner side of ventro-distal tip of LAP thickened; inner side of tentacle notch moderately
large, sharply defined laterally. No perforations or furrow discernible.

Paratype supplements and variation

MnhnL HE415 is a dissociated proximal LAP; ventral portion missing; LAP originally higher than
wide; generally well in agreement with holotype; dorsal edge oblique, slightly convex; two spurs on
proximal edge very weakly defined; ventro-distal tip of LAP strongly protruding ventro-distalwards,
tongue shaped; trabeculae of very finely meshed stereom on outer surface not merging into vertical
striation. Four spine articulations similar to those observed on holotype.

Ridge on inner side of LAP slightly narrower and longer than that of holotype, almost vertical dorsally.

MnhnL HE416 is a dissociated median LAP; slightly higher than wide; spurs on outer proximal edge
very poorly defined; ventro-distal tip of LAP very slightly protruding ventro-distalwards, rounded;
trabeculae of outer surface stereom more commonly merging into vertical striation than in holotype;
vertical striation better developed and more widespread rather than restricted to a very narrow band near
the spine articulations. Four spine articulations similar to those observed in holotype; gap between spine
articulations and distal edge of LAP narrower than in holotype; ventralmost spine articulation smaller
than remaining three.

Inner side of LAP similar to that of holotype.

MnhnL HE417 is a dissociated distal LAP; approximately 1.5 times wider than high; poorly preserved;
dorsal edge very slightly concave; spurs on proximal edge very poorly defined, almost indiscernible;
only very few trabeculae of finely meshed outer surface stereom merged into poorly developed vertical
striation. Two poorly preserved spine articulations apparently similar to those observed on holotype.
Ventral edge of LAP nearly straight, with small, weakly concave tentacle notch.

Inner side with small, well-defined, nearly triangular, oblique ridge, with dorso-proximally pointing
dorsal tip; ventral part widest, not merged with ventral portion of LAP; spurs on inner side of distal edge
of LAP almost indiscernible.

Remarks

These LAPs are unambiguously assignable to Dermacantha gen. nov. on account of the general
Dermocoma-like morphology with smaller spine articulations displaying a discontinuous volute.
Greatest similarities are shared with the LAPs of Dermacantha seeweni comb, nov., which, however.

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European Journal of Taxonomy 48: 1-242 (2013)

display a better-developed vertieal striation on the outer surfaee, only one poorly defined spur, and up to
five spine artieulations with a eonspieuously distalwards projeeting ventral lobe.

Occurrence

Hettangian of Belgium.

Dermacantha seeweni (Kutseher & Hary, 1991) eomb. nov.

Fig. 29: 6-8

Ophioctenl seeweni Kutseher & Hary, 1991: 46, pi. 1 fig. 3a-d.

non Ophioctenl seeweni - Kutseher 1996: 15, pi. 2 figs 1-5. — Kutseher & Villier 2003: 189, pi. 5 figs
8-9, pi. 6 figs 1-2.

Diagnosis

Speeies of Dermacantha gen. nov. with small LAPs displaying a well-developed, very fine vertieal
striation on distal half of outer surfaee, eomposed of merged trabeeulae of finely meshed stereom;
single, very poorly defined spur on outer proximal and inner distal edges of proximal LAPs; up to five
small spine artieulations in notehes of non-elevated distal portion of LAP; ventral and dorsal lobes of
spine artieulations separated by two to three small knobs; ventral lobe larger than dorsal one, projeeting
ventro-proximalwards.

Type locality and horizon

Bishop’s Cleeve near Cheltenham, Great Britain; lowest part of the elaypit, Obtusum Zone, late
Sinemurian, Early Jurassie.

Material examined

GZG.1NV.78706, GZG.INV.78707, GZG.1NV.78708 and GZG.1NV.78709 (9 dissoeiated LAPs) from
the late Sinemurian of Bishop’s Cleeve, Great Britain; the type material of Kutseher & Hary (1991).

Description

Small, LAPs; proximal ones slightly higher than wide, distal ones slightly wider than high; dorsal edge
slightly eonvex; distal edge eonvex; proximal edge irregularly undulose, with single poorly defined,
almost indiseemible, weakly prominent, horizontally elongate, non-protruding spur near ventral edge in
proximal to median LAPs, two very poorly defined, almost indiseemible, horizontally elongate, weakly
prominent spurs in distal LAPs; ventral fifth of LAP protmding ventro-proximalwards; ventro-distal
tip of LAP protmding ventralwards, rounded; outer surfaee with finely meshed stereom, trabeeulae of
whieh merged into fine, irregular vertieal striation in distal half of outer surfaee; very narrow band of
finely, faintly horizontally striped stereom along proximal edge of LAP. Five (proximal LAPs) to four
(median to distal LAPs) moderately large, ear-shaped spine artieulations in notehes of non-elevated
distal portion of LAP; ventral and dorsal lobes of spine artieulations separated by two to three small
knobs; ventral lobe larger than dorsal one, ventro-distalwards projeeting; spine artieulations not sharply
bordered proximally, direetly eneompassed by finely meshed outer surfaee stereom; gap between spine
artieulations and distal edge of LAP moderately large, approximately as wide as half the width of a spine
artieulation; very weak dorsalward inerease in size of spine artieulations; dorsalmost gap between spine
artieulations slightly larger than remaining ones. Ventral edge of LAP with moderately large, eoneave
tentaele noteh.

Inner side of LAP with large, sharply defined, prominent, long, oblique, nearly straight, relatively narrow
ridge; dorsal tip of ridge slightly widened, pointing dorso-proximalwards; ventral part of ridge bent.

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THUYB., Fossil record of ophiacanthid brittle stars

pointing ventro-proximal wards, separated from thickened ventral edge; inner side of distal edge of LAP
with very weakly defined, almost indiscernible spur; inner side of tentacle notch relatively large, well
defined laterally, with coarsely meshed, very slightly horizontally elongate stereom. No perforations or
furrow discernible.

Remarks

The relatively small spine articulations with the discontinuous volute combined with a general
Dermocoma-likQ morphology unquestionably place these LAPs in Dermacantha gen. nov. Within
this, these LAPs are unique in displaying conspicuously distally projecting ventral lobes of the spine
articulations, and are thus described here as a new species.

Occurrence

Early Sinemurian of Luxembourg and late Sinemurian of Great Britain.

Dermacantha leonorae sp. nov.

um:lsid:zoobank.org:act:95EF2CA2-C31C-415F-A639-417842BQEEC6

Fig. 29: 9-11

Diagnosis

Species of Dermacantha gen. nov. with small EAPs; proximal to median ones devoid of vertical striation
on outer surface; five small spine articulations; single moderately well-defined spur near outer ventro-
proximal and inner ventro-distal tips of EAP; ridge on inner side very narrow but with strongly widened
dorsal tip.

Etymology

Species named in hoinour of my friend and colleague Eeonora Martin-Medrano, for her extraordinary
hospitality and as an encouragement to her to pursue research in ophiuroid palaeontology.

Type material

Holotype

GZG.INV.78710.

Paratypes

GZG.INV.78711 and GZG.INV.78712.

Type locality and horizon

Blockley, near Cheltenham, Great Britain; shell lenses in clay matrix, Davoei Zone, early Pliensbachian,
Early Jurassic.

Additional material

GZG.INV.78713 (7 dissociated EAPs).

Description

Holotype

GZG.INV.78710 is a dissociated, small, proximal EAP; slightly higher than wide; dorsal edge gently
convex; distal edge convex; proximal edge concave, with single, moderately well-defined, prominent,
horizontally elongate spur close to ventro-proximal tip of EAP; ventral sixth of EAP protruding ventro-
proximal wards; outer surface with very finely meshed stereom; no vertical striation; narrow band of
very finely horizontally striated stereom along proximal edge. Five small, ear-shaped spine articulations

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European Journal of Taxonomy 48: 1-242 (2013)

in notches of non-elevated distal edge; dorsal and ventral lobes separated by small, thin knob; spine
artieulations proximally direetly eneompassed by outer surfaee stereom; spine artieulations nearly
of equal size; dorsalward inerease in size of gaps separating spine artieulations; gap between spine
artieulations and distal edge of LAP very narrow. Ventral edge of LAP with moderately large, very
gently eoneave tentaele noteh.

Inner side of LAP with moderately large, eonspieuous, sharply defined, prominent, very narrow ridge;
dorsal tip strongly enlarged, nearly triangular; ventral part of ridge pointing ventro-proximalwards, not
merged with slightly thiekened ventral portion of LAP, separated from dorsal part of ridge by gentle,
rounded kink; well-defined, oval, slightly prominent knob on ventro-distal tip of LAP; inner side of
tentaele noteh relatively large, with eoarsely meshed, horizontally elongate stereom, well defined
laterally. Very short and narrow, rather deep and well-defined furrow dorsally bordering tentaele noteh.

Paratype supplements and variation

GZG.1NV.78711 is a dissoeiated median LAP; slightly wider than high; very well in agreement with
holotype; dorsal edge very slightly eoneave; spur near ventro-proximal tip of LAP sharply defined,
lentieular, strongly prominent, eomposed of more densely meshed stereom. Five spine artieulations
similar to those observed on holotype; dorsalward inerease in size of gaps separating spine artieulations
slightly weaker; ventral and dorsal lobes of spine artieulations separated by one to three very small
knobs.

Inner side of LAP well in agreement with that of holotype; dorsal tip of ridge slightly less strongly
widened. No furrow diseemible.

GZG.1NV.78712 is a dissoeiated distal LAP; slightly wider than high; ventro-distal tip of LAP strongly
protruding ventralwards, rounded; trabeeulae of outer surfaee stereom merging into short, poorly
developed, irregular vertieal striation elose to spine artieulations. Four spine artieulations similar to
those observed on holotype; dorsalmost spine artieulation smallest; gap between spine artieulations and
distal edge of LAP moderately large, widening ventralwards. Ventral edge of LAP with large, deeply
eoneave tentaele noteh.

Inner side of LAP in agreement with that of holotype; dorsal tip of ridge slightly less strongly widened;
spur on inner side of ventro-distal tip of LAP oblique. No furrow diseemible.

Remarks

These LAPs are unambiguously assignable to Dermacantha gen. nov. on aeeount of their spine
artieulation stmeture eombined with the general Dermocoma-like morphology. They represent the sole
LAP type within this genus whieh eompletely laeks a vertieal striation on the outer surfaee. Closest
similarities are shared with the LAPs of Dermacantha pattyana sp. nov., in partieular those with redueed
vertieal striation on the outer surfaee. In the latter speeies, however, the ridge on the inner side is shorter
and broader.

Occurrence

Early Pliensbaehian of Great Britain.

Dermacantha sp. nov. innom.

Fig. 30: 1-3

Material examined

GZG.1NV.78714, GZG.1NV.78715, GZG.1NV.78716 and GZG.1NV.78717 (12 dissoeiated LAPs) from
the Bajoeian-Bathonian boundary of Touert near Chaudon, Franee.

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THUYB., Fossil record of ophiacanthid brittle stars

Description

GZG.INV.78714 is a dissociated, moderately large, proximal LAP; nearly as high as wide; dorsal edge
slightly concave as a result of a weak constriction; distal edge almost straight; ventral sixth ofLAP ventro-
proximalwards protruding; proximal edge slightly undulose, with large, swollen, slightly protruding
central part dorsally and ventrally bordered by small, well-defined, horizontally elongate, prominent
spurs; outer surface with very fine, regular, vertical striation composed of fine, very weakly overlapping
lamellae replaced by finely meshed stereom on proximal third of outer surface. Four relatively small,
ear-shaped spine articulations in shallow notches of slightly elevated distal portion of LAP; ventral
and dorsal lobes proximally separated by small knob; very weak connection between ventral lobe of
spine articulations and distalwards projecting tips of outer surface stereom separating notches; spine
articulations of nearly equal size, except for slightly smaller ventralmost one; very weak distalward
increase in size of spine articulations; gap between spine articulations and distal edge ofLAP narrow.
Ventral edge ofLAP with small, weakly concave tentacle notch.

Inner side ofLAP with relatively small, sharply defined, prominent, slender ridge; ventral half of ridge
bent, pointing ventro-proximalwards, not merged with thickened ventral portion of LAP; dorsal half
of ridge straight, oblique, with very weakly thickened dorsal tip; inner side of distal edge ofLAP with
two small, well-defined, prominent, oval, horizontally elongate spurs; inner side of tentacle notch small,
laterally well defined. No perforations or furrow discernible.

GZG.INV.78715 is a dissociated median LAP; 1.5 times wider than high; well in agreement with
holotype; vertical striation restricted to a smaller area of the outer surface. Four equal-sized spine
articulations similar to those observed on holotype; gap separating spine articulations and distal edge of
LAP as wide as one spine articulation.

Inner side similar to previous LAP described.

GZG.INV.78716 is a dissociated distal LAP; almost twice wider than high; vertical striation on outer
surface slightly less well developed than in holotype. Three equal-sized spine articulations similar to
those of holotype; distal edge ofLAP slightly fragmentary, width of gap between spine articulations and
distal edge ofLAP not determinable.

Inner side ofLAP with small, sharply defined, prominent, oblique, straight ridge; ventral tip of ridge
widened.

Remarks

These LAPs, unambiguously assignable to Dermacantha gen. nov. on account of the general Dermocoma-
like morphology combined with a discontinuous volute of the relatively small spine articulations, bear a
striking similarity to the LAPs described below as Dermacantha carli sp. nov., to such an extent that both
LAP types are almost indistinguishable. Minor differences pertain to the slightly thicker ventral portion
and the slightly wider ridge in proximal LAPs of the present form. In addition, the vertical striation
in the proximal LAPs of D. carli sp. nov. is composed of slightly larger, more strongly overlapping
lamellae. Yet, these differences are so small that a formal description of the present specimens as a
new species appears unjustified. To make matters worse, the amount of currently available material is
too limited to appreciate fiilly the variability of the characters on which species separation would be
based on. It seems unlikely that the present material is conspecific with D. carli sp. nov., in particular
taking into account the long stratigraphic gap (Bajocian-Kimmerdigian) and the fundamentally different
depositional settings (mud bottom slope versus deep shelf sponge reef) of both occurrences. In the
absence of more diagnostic material, the present specimens are here treated as a probably new, still
undescribed species of Dermacantha gen. nov.

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 30. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b)
views. 1-3. Dermacantha sp. nov. innom. from the Bajoeian-Bathonian boundary of Touert, Franee.
1. GZG.1NV.78714, proximal LAP. 2. GZG.1NV.78715, median LAP. 3. GZG.1NV.78716, distal LAP.
4-6. Dermacantha carli gen. et sp. nov. from the late Oxfordian (Late Jurassie) of the Plettenberg, Germany.
4. GZG.1NV.78718 (holotype), proximal LAP. 5. GZG.1NV.78719 (paratype), median LAP. 6. GZG.
INV. 78720 (paratype), distal LAP. 7-9. Ishidacantha hirokoae gen. et sp. nov. from the middle Toareian
(Early Jurassie) of Le Clapier, Franee. 7. GZG.1NV.78723 (holotype), proximal LAP. 8. GZG.1NV.78724
(paratype), median LAP. 9. GZG.1NV.78725 (paratype), distal LAP. One eommon seale bar per speeies.

168

THUYB., Fossil record of ophiacanthid brittle stars

Dermacantha carli sp. nov.

um:lsid:zoobank.org:act:3FDC618A-F737-47FC-B0BA-9AE3CD84B586

Fig. 30: 4-6

Diagnosis

Species of Dermacantha gen. nov. with moderately large LAPs generally displaying a vert small height/
width ratio, with even proximal LAPs slightly wider than high; two small, nearly equal-sized, well-
defined, proximally pointed, prominent spurs on outer proximal edge; distal quarter of outer surface
with regular, well-defined vertical striation; four relatively small spine articulations with dorsal and
ventral lobes separated by small knob; three dorsal spine articulations in distal LAPs with conspicuous
lip-shaped distal knob; ridge on inner side small very slender, with very weakly widened, strongly
oblique dorsal part.

Etymology

Species named in honour of Carl, my friend, companion, family member, for his cheerful support and
all the ideas that emerged during the many outdoor walks with him.

Type material

Holotype

GZG.INV.78718.

Paratypes

GZG.INV.78719 and GZG.INV.78720.

Type locality and horizon

Plettenberg near Balingen, Germany; clay pockets between sponge associations in the lowest bed
exposed in the quarry, Bimammatum Zone, late Oxfordian, Late Jurassic.

Additional material

GZG.INV.78721 (300 dissociated LAPs) from the late Oxfordian of the Plettenberg, Germany; GZG.
INV. 78722 (64 dissociated LAPs) from the Lacunosa Marls, early Kimmeridgian of Geisingen, Germany.

Description

Holotype

GZG.INV.78718 is a dissociated, moderately large, proximal LAP; slightly wider than high; dorsal
edge slightly concave as a result of a weakly developed constriction; distal edge convex; proximal
edge concave, with two small, well-defined, prominent, slightly protruding, proximally pointed spurs
composed of densely meshed stereom; dorsal spur slightly larger than ventral one; ventral quarter of LAP
strongly protruding ventro-proximalwards; ventro-distal tip of LAP protruding ventralwards, rounded;
outer surface with narrow band of regular, vertical striation composed of rather broad, overlapping
lamellae close to spine articulations, replaced by finely meshed stereom on proximal three-quarters of
outer surface. Four relatively small, ear-shaped spine articulations in shallow notches of slightly elevated
distal portion of LAP; ventral lobe of spine articulation separated from dorsal one proximally by small
knob, and connected with distalwards projecting tip of outer surface stereom separating notches; spine
articulations proximally separated by edge of notches; dorsalward increase in size of gaps separating
spine articulations; ventralmost spine articulation slightly smaller than remaining, nearly equal-sized
ones; notches very shallowly incising vertical striation; gap between spine articulations and distal edge
of LAP almost as wide as one spine articulation. Ventral edge of LAP with moderately large, deeply
concave tentacle notch.

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European Journal of Taxonomy 48: 1-242 (2013)

Inner side of LAP with relatively small, sharply defined, prominent and very slender ridge; ventral part
of ridge strongly bent ventro-proximalwards, not merged with non-thiekened ventral portion of LAP;
dorsal part of ridge straight, strongly oblique, slightly widened dorsally; inner side of distal edge of LAP
with two relatively small, well-defined, rounded, prominent spurs eomposed of densely meshed stereom;
inner side of tentaele noteh relatively small, deeply ineised; sharply defined laterally. No perforations or
furrows diseemible.

Paratype supplements and variation

GZG.1NV.78719 is a dissoeiated median LAP; nearly twiee wider than high; ventral sixth slightly
protruding ventro-proximal wards; ventro-distal tip of LAP very weakly protruding; spurs on proximal
edge and outer surfaee ornament as in holotype. Three spine artieulations similar to those observed on
holotype. Ventral edge of LAP with small, weakly eoneave tentaele noteh.

Inner side of LAP partly obseured by sediment; dorsal part of ridge exposed, as slender, straight, oblique
as fine ridge observed on holotype; spurs on inner side of distal edge slightly better preserved than those
of holotype.

GZG.1NV.78720 is a dissoeiated distal LAP; more than three times wider than high; rod like; dorsal and
ventral edges eoneave as a result of a eonstrietion; proximal edge with two large, poorly defined, weakly
prominent but very strongly protruding spurs. Four spine artieulations, ventralmost similar to those
observed on holotype, remaining three slightly larger and with eonspieuous, lip-shaped, distal knob
eomposed of densely meshed stereom. Tentaele opening invisible in external view, emerging on distal
side of ventralmost spine artieulation.

Inner side of LAP with two small, sharply defind, prominent knobs, proximal one horizontally slightly
elongate, triangular, and distal one mueh smaller, round; inner side of distal edge of LAP with two
poorly defined, prominent spurs. Large tentaele opening in the middle of the distal third of the LAP.

Remarks

These speeimens display diagnostie eharaeters that warrant inelusion in Dermacantha gen. nov., in
spite of the unusually well-developed vertieal striation on the outer surfaee and the well-defined spurs
on the outer proximal and inner distal edges. On aeeount of the latter, the LAPs in question ean be
unambiguously differentiated from any other eurrently known speeies of the genus. Greatest similarities
are shared with an unnamed type of LAPs here assigned to Dermacantha gen. nov. from the Bajoeian-
Bathonian of Franee. As diseussed in detail above, the Middle Jurassie LAPs are almost indistinguishable
from the present ones, with possible differenees pertaining to minor and potentially variable details in
LAP morphology. Sinee the above-deseribed Late Jurassie LAPs are represented by numerous well-
preserved speeimens, they are formally deseribed as new speeies of Dermacantha gen. nov. The Middle
Jurassie reeord, in eontrast, is deseribed as probably new, but remains speeifieally unnamed.

The presenee of lip-shaped distal knobs in the three dorsal spine artieulations of the distal LAP deseribed
above is intriguing. Similar knobs are known from the distal LAPs of Early Jurassie Inexpectacantha
acrobatica Thuy, 2011 and of extant Ophiolycus purpureus (Dtiben & Koren, 1846) and Ophiura
(Ophiuroglypha) robusta (Ayres, 1854) (Thuy 2011; Thuy & Stohr 2011). Remarkably, in all eases the
lip-shaped knobs are assoeiated with speeialised, hook-shaped spines, whieh suggests that distal arm
segments of Dermacantha carli sp. nov. bore sueh spines as well.

Occurrence

Late Oxfordian to early Kimmeridgian of Germany.

170

THUYB., Fossil record of ophiacanthid brittle stars

Genus Ishidacantha gen. nov.

um:lsid:zoobank.org:act:0AA3C0DE-CB77-4AA9-847F-782B5B76F6CC

Type species

Ophiopholisl trispinosa Hess, 1965, by present designation.

Other species included

Ishidacantha hirokoae sp. nov. and Ishidacantha fuersichi sp. nov.

Diagnosis

Ophiacanthid with large to moderately large FAPs displaying a very small height/width ratio, with
even proximal FAPs almost twice wider than high; ventral portion of FAPs very large, wide, strongly
protruding ventro-proximal wards; fine vertical striation on at least part of the outer surface; two variably
well-defined, horizontally elongate and generally protruding spurs on the outer proximal and inner distal
edges; three to four relatively large, ear-shaped spine articulations on elevated distal edge of FAP; inner
side of FAP with two separate ridges, even in proximal FAPs; proximal ridge generally much longer
than distal one; deeply incised but relatively small tentacle notches commonly developed as within-plate
perforations in distal FAPs.

Etymology

Genus named in honour of my friend Yoshiaki Ishida, for his outstanding contributions to ophiuroid
palaeontology and, most importantly, for his friendship and indefatigable support, and from Acantha, a
nymph in Greek mythology whose name literally translates to “thorny”; gender feminine.

Remarks

The ophiacanthid fossil record inlcudes an unusual type of dissociated FAPs charactersied by a very
small height/width ratio, coarsely meshed or vertically striated stereom on the outer surface, a strongly
protruding, very large and wide ventral portion, three to four relatively large spine articulations, two
separate ridges on the inner side, and relatively small but deeply incised tentacle notches. FAPS of this
type were described by Hess (1965a) from the Oxfordian of France as Ophiopholisl trispinosa Hess,
1965. Very similar FAPs from the Toarcian/Aalenian of Germany and the Toarcian of France were
described by Kutscher (1996) and Kutscher &Villier (2003), respectively, and in both cases assigned
to Sinosura brodiei (Wright, 1866), an extinct genus with probable ophioleucinid affinities (Thuy et al.
2011). Surprisingly, neither the close morphological similarities between these occurrences nor their
ophiacanthid affinities have been commented on previously.

A careful, SEM-supported re-examination of this material has now confirmed the ophiacanthid affinites
and enabled a reinterpretation of the material in question, along with news finds from the Toarcian of
France and the Callovian of India, as a new morphologically consistent ophiacanthid FAP type. The only
other ophiacanthid FAP type to display comparably small height/width ratios and two separated ridges
on the inner side even in proximal FAPs is found in Geromura gen. nov. (see above). The two FAP types,
however, differ fundamentally with respect to the size of the tentacle notch. In fact, while the FAPs of
Geromura gen. nov. display a genuinely large tentacle notch, those of the new type in question have a
deeply incised, but ultimately relatively small notch. The size of the ventral portion of the present FAPs,
the oblique ventro-proximal tip and the relatively small semi-circular outline of the actual tentacle notch
strongly suggest that the articulated arms were covered by large ventral plates separated by the FAPs
and encompassing small tentacle pores as defined by Thuy et al. (2012). The present FAP type thus
belongs to a small-pored ophiacanthid, here described as Ishidacantha gen. nov., whereas Geromura
gen. nov. clearly is a large-pored genus. This implies that the striking morphological similarities, in

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European Journal of Taxonomy 48: 1-242 (2013)

fact, reflect convergent evolution, presumably as a result of paedomorphosis leading to elongated arm
segments, a typieally juvenile eharaeter (Stohr 2005). At least some of the shared eharaeters, sueh as the
presenee of two separate ridges on the inner side, might be the result of biomeehanieal eonstraints due
to the small height/width ratios.

Ishidacantha hirokoae sp. nov.

um:lsid:zoobank.org:aet:CD39B010-D3BF-4BFA-9913-863830744D67

Fig. 30: 7-9

p.p. Sinosura brodiei- Kutscher 1996: 10, pi. 2 flgs 9-13. —Kutseher & Villier 2003: 185, pi. 4 flgs 3-6
[material ineorreetly assigned to Sinosura brodiei (Wright, 1866)].

Diagnosis

Speeies of Ishidacantha gen. nov. with large LAPs displaying a well-developed, regular vertieal striation
on distal half of outer surfaee and eomposed of overlapping lamellae; two poorly developed spurs on
outer proximal edge paralleled by two small, slightly better-deflned spurs on inner distal edge; three
moderately large, nearly equal-sized spine artieulations proximally sharply delimited by distalmost
lamellae; ventral and dorsal lobes of spine artieulations separated by two or three small, notehes; inner
side of proximal LAPs with dorso-proximalwards bent, eontinuous proximal ridge and round distal
knob; tentaele noteh relatively small.

Etymology

Speeies named in honour of Hiroko Ishida, for her outstanding hospitality.

Type material

Holotype

GZG.1NV.78723.

Paratype

GZG.1NV.78724 and GZG.INV.78725.

Type locality and horizon

Le Clapier, Franee; debris flow bed rieh in skeletal detritus, middle Toareian, Early Jurassie.

Additional material

GZG.1NV.78726 (18 dissoeiated LAPs) from sample 1 of the middle Toareian of Le Clapier; GZG.
INV.78727 (11 dissoeiated LAPs) from sample 2 of the middle Toareian of Le Clapier; the original
material of Kutseher (1996) and Kutseher & Villier (2003).

Description

Holotype

GZG.INV.78723 is a dissoeiated, large, proximal LAP; approximately twiee wider than high; dorsal
edge strongly eoneave as a result of a well-developed eonstrietion; distal edge eonvex with a small,
non-prominent protrusion; ventral half of LAP strongly protruding ventro-proximalwards, very large
and wide; ventro-distal tip of LAP protruding, tongue shaped; ventro-proximal tip of LAP oblique;
proximal edge of LAP with two very poorly deflned, weakly prominent, very slender, non-protruding
and horizontally elongate spurs; outer surfaee with well-developed, regular vertieal striation eomposed
of overlapping lamellae; strong proximalward deerease in size of lamellae; vertieal striation replaeed
by flnely meshed stereom on proximal half of outer surfaee. Three relatively small, nearly equal-sized

172

THUYB., Fossil record of ophiacanthid brittle stars

and equi-distant, ear-shaped spine articulations freestanding on elevated distal portion of LAP; dorsal
and ventral lobes of spine articulations separated by two or three very small notches; spine articulations
proximally sharply delimited by two distalmost lamellae; gap between spine articulations and distal
edge of LAP almost as wide as one spine articulation. Ventral edge of LAP nearly straight, except for
extremely deeply incised, relatively small, more than semi-circular tentacle notch.

Inner side of LAP slightly obscured by sediment, with two closely spaced, but separate ridges; proximal
one sharply defined, relatively broad, prominent and dorso-proximalwards bent ridge devoid of thickened
parts or sharp kinks; distal ridge very short, knob like, sharply defined and moderately widely separated
from proximal ridge; inner side of distal edge of LAP with small, moderately well-defined, weakly
prominent, very slender, horizontally elongate. No perforations or furrow discernible.

Paratype supplements and variation

GZG.INV.78724 is a dissociated median LAP; slightly more than twice wider than high; very well in
agreement wth holotype; vertical striation on outer surface slightly less well developed and regular as
in holotype. Three spine articulations similar to those observed on holotype. Tentacle notch slightly not
as deep as in holotype.

Inner side of LAP with two ridges similar to those of holotype but more widely separate, and proximal
one shorter and with slightly widened ventral tip; two spurs on inner side of distal edge of LAP shorter
than in holotype. No perforations or furrow discernible.

GZG.INV.78725 is a dissociated distal LAP; approximately 2.5 times wider than high; well in agreement
with holotype; vertical striation on outer surface better developed than in holotype, replaced by finely
meshed stereom only on proximal quarter of outer surface. Three spine articulations similar to those
observed on holotype. Ventral edge of LAP slightly concave; tentacle opening developed as perforation
emerging on ventral edge of ventralmost spine articulation.

Inner side of LAP obscured by sediment.

Remarks

These specimens appear to be identical to at least part of the LAPs described and illustrated by Kutscher
(1996) and Kutscher & Villier (2003) from the Toarcian/Aalenian of Germany and the Toarcian of
France, respectively, and assigned in both cases to the ophioleucinid Sinosura brodiei (Wright, 1866).
Are-examination of the type material of the latter (see Hess 1964), however, has revealed fundamental
differences in LAP morphology, in particular with respect to spine articulation morphology. The LAPs in
question show clear ophiacanthid affinities and, as discussed above, are here considered to belong to the
same LAP type as the material described as Ophiopholisl trispinosa Hess, 1965 from the Oxfordian of
France, for which Ishidacantha gen. nov. is here introduced. Within this genus, these LAPs are unique in
combining three equal-sized spine articulations with a well-developed vertical striation on outer surface
and two poorly defined spurs on the outer proximal edge. They are thus described here as a new species.

Kutscher (1996) and Kutscher & Villier (2003) mentioned up to six spine articulations in their
descriptions of the above-mentioned LAPs. The specimens illustrated, however, invariably show three
spine articulations just like the Toarcian material of France described here. Thus, it seems probable that
Kutscher (1996) and Kutscher & Villier (2003) included more than one LAP type in their descriptions.

Occurrence

Middle Toarcian of France, Toarcian/Aalenian of Germany.

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European Journal of Taxonomy 48: 1-242 (2013)

Ishidacantha fuersichi sp. nov.

um:lsid:zoobank.org:act:261Q5676-35QE-423A-A101-8AEAC88B0FF8

Fig. 31: 1-4

Diagnosis

Species of Ishidacantha gen. nov. with moderately large FAPs displaying a well-developed, slightly
irregular vertical striation on distal third of outer surface and composed of overlapping lamellae;
two well-defined, slender, horizontally strongly elongate spurs on the outer proximal and inner distal
edges; spurs on the inner distal edge protruding; up to four moderately large, nearly equal-sized spine
articulations proximally tightly delimited by distalmost lamellae; ventral and dorsal lobes of spine
articulations separated by one to three small, notches; inner side of proximal FAPs with very large
dorso-proximalwards bent, continuous proximal ridge and shorter, vertical, distal ridge; tentacle notch
relatively small.

Etymology

Species named in honour of Franz T. Ftirsich for his contributions on the palaeontology of the type
locality and for generously providing the samples yielding the type material of the species.

Type material

Holotype

GZG.1NV.78728.

Paratypes

GZG.1NV.78729, GZG.1NV.78730 and GZG.1NV.78731.

Type locality and horizon

Jumara, Kachchh, India; sample 119, upper Chari Formation, Callovian, Middle Jurassic.

Additional material

GZG.1NV.78732 (29 dissociated FAPs) from sample 117; GZG.1NV.78733 (27 dissociated FAPs)
from sample 119; GZG.1NV.78734 (88 dissociated FAPs) from sample 121, all from the upper Chari
Formation, Callovian.

Description

Holotype

GZG.INV.78728 is a dissociated, moderately large, proximal FAP; fragile; almost twice wider than
high; dorsal edge slightly fragmentary, originally nearly straight; distal edge undulose, with two small,
pointed, non-prominent protrusions; ventral third of FAP protruding ventro-distal wards; ventro-distal
tip of FAP protruding ventralwards, rounded, slightly tongue shaped; ventro-proximal tip of FAP
slightly fragmentary, originally oblique; proximal edge with two well-defined, moderately large, equal¬
sized, horizontally strongly elongate, slender, weakly prominent and slightly protruding spurs; outer
surface with well-developed, slightly irregular vertical striation composed of overlapping lamellae
displaying strong proximalward decrease in size; vertical striation replaced on proximal two-thirds of
outer surface by finely meshed stereom; irregular band of very finely meshed stereom along proximal
edge of FAP. Four relatively small, nearly equal-sized and equi-distant, ear-shaped spine articulations
on slightly elevated distal portion of FAP; dorsal and ventral lobes separated by one to three very small
notches; spine articulations proximally tightly delimited by two distalmost lamellae; gap between spine
articulations and distal edge of FAP almost as wide as one spine articulation. Ventral edge of FAP nearly
straight except for relatively small but very deeply incised, semi-circular tentacle notch.

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THUYB., Fossil record of ophiacanthid brittle stars

Fig. 31. Lateral arm plates (LAPs) of fossil and Recent ophiacanthid brittle stars in external (a) and internal
(b) views. 1-4. Ishidacantha fuersichi gen. et sp. nov. from the Callovian (Middle Jurassic) of Jumara,
India. 1. GZG.INV.78728 (holotype), proximal LAP. 2. GZG.INV.78729 (paratype), proximal LAP.
3. GZG.INV.78730 (paratype), medianLAP. 4. GZG.INV.78731 (paratype), distal LAP. S-6. Ishidacantha
trispinosa (Hess, 1965) comb. nov. from the early Oxfordian (Late Jurassic) of Longecombe, France.
5. NHMB Ml 1222, proximal LAP. 6. NHMB Ml 1223, distal LAP. 7-9. Ophiomitrella conferta (Koehler,
1922), Recent. 7. Proximal LAP. 8. median LAP. 9. distal LAP. 10-12. Ophiomitrellal sp. 1 from the
Callovian of Bauer-Wehrland, Germany. 10. GZG.INV.78735, proximal LAP. 11. GZG.INV.78736,
median LAP. 12. GZG.INV.78737, distal LAP. One common scale bar per species.

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European Journal of Taxonomy 48: 1-242 (2013)

Inner side of LAP with two sharply defined, prominent, elosely spaeed but separate ridges; proximal
ridge large, eonspieuous, slender, slightly dorso-proximalwards bent with weakly widened dorsal and
ventral tips; distal ridge shorter than half the length of the proximal one; nearly vertieal; inner side of
distal edge of LAP with two sharply defined, horizontally elongate, prominent and slightly protruding
spurs. No perforations or furrow diseemible.

Paratype supplements and variation

GZG.INV.78729 is a dissoeiated, fragmentary proximal LAP; preserved portions very well in agreement
with holotype. Four spine artieulations similar to those observed on holotype.

Inner side with very large, oblique, slightly bent, dorsally thiekened proximal ridge with small, round
knob distally bordering ventral tip of the latter; ridge and knob direetly adjaeent but not merged.

GZG.1NV.78730 is a dissoeiated median LAP; twiee wider than high; well in agreement with holotype;
ventral quarter slightly less strongly protruding ventro-proximalwards. Three spine artieulations similar
to those observed on holotype.

Inner side of LAP with two ridges similar to those of holotype but slightly shorter.

GZG.1NV.78731 is a dissoeiated distal LAP; nearly 2.5 times wider than high; dorsal edge straight;
ridge on proximal edge slightly smaller and less well defined than in holotype; ventral portion of LAP
not protruding. Three spine artieulations similar to those observed on holotype. Ventral edge of LAP
eoneave; tentaele opening developed as perforation emerging at ventro-proximal edge of ventralmost
spine artieulation.

Inner side of LAP with two sharply defined, prominent, elosely spaeed but separate knobs; proximal
knob nearly triangular; distal knob mueh smaller, round; very large tentaele perforation in the middle of
the distal third of the LAP.

Remarks

The unusually small height/width ratio, the large, strongly protruding ventral portion, the two protruding
spurs on the outer proximal and inner distal edges and the two separate ridges on the inner side
unambiguously plaee these LAPs in Ishidacantha gen. nov. The presenee of up to four relatively small
spine artieulations is not found in any other LAP type assigned to this genus. The development of the
ridges on the inner side in the present LAPs suggests that the distanee between the ridges eorrelates with
the position of the LAPs in the arm and thus with their height/width ratio.

Occurrence

Callovian of India.

Ishidacantha trispinosa (Hess, 1965) eomb. nov.

Fig. 31: 5-6

p.p. Ophiopholisl trispinosa Hess, 1965a: 1075, figs 36-37 [non figs 16, 38-41, referable to Lapidaster
etteri gen. et sp. nov.]

Diagnosis

Speeies of Ishidacantha gen. nov. with large LAPs displaying eoarsely meshed stereom on the outer
surfaee with a very narrow band of poorly developed vertieal striation near spine artieulations; two
moderately well-defined, horizontally elongate spurs on outer proximal and inner distal edges in
proximal to median LAPs, dorsal one of whieh protruding; three large spine artieulations in all LAPs,
with eontinuous volute and strong dorsalward inerease in size; inner side of proximal LAPs with two
round, slightly oblique knobs in vertieal row eonneeted by poorly defined, irregular, slender, weakly

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THUYB., Fossil record of ophiacanthid brittle stars

prominent vertical ridge in proximal half, and short, near-vertical ridge in distal half; tentacle notch
large.

Material examined

NHMB Ml 1222, NHMB Ml 1223; 5 dissociated LAPs from the Renggeri Member, early Oxfordian of
Longecombe, France, the type material of Hess (1965a).

Description

Large dissociated LAPs; proximal ones almost twice wider than high, distal ones slightly more than twice
wider than high; dorsal edge strongly concave as a result of a well-developed constriction; distal edge
convex with a conspicuous, pointed protrusion in dorsal half of distal edge, best developed in proximal
LAPs; proximal edge irregularly undulose, in proximal to median LAPs with two moderately well-
developed, prominent, protruding, horizontally elongate, ridge-like spurs, dorsal one of which larger
than ventral one; spurs almost indiscernible in distal LAPs; ventro-distal tip of LAPs strongly protruding
ventralwards, tongue shaped; ventro-proximal tip of LAP strongly oblique; ventral half to third of LAP
strongly protruding ventro-proximalwards, large, wide; outer surface of LAPs with coarsely meshed
stereom, replaced by finely meshed stereom in narrow band along proximal edge of LAP; trabeculae
of coarsely meshed stereom merged into poorly developed vertical striation in very narrow band near
spine articulations in proximal LAPs. Three large, ear-shaped spine articulations freestanding on
strongly elevated distal portion in all LAPs; ventral and dorsal lobes of spine articulations merged into
continuous volute; spine articulations not sharply bordered proximally; very strong dorsalward increase
in size of spine articulations; weaker dorsalward increase in size of gaps separating spine articulations;
gap between spine articulations and distal edge of LAP almost as wide as one spine articulation. Ventral
edge of LAPs nearly straight, except for large, conspicuous, very deeply incised almost semi-circular
tentacle notch.

Inner side of LAPs with two sharply defined, prominent ridge-like structures, proximal one separated
into two, round, oblique knobs arranged in vertical row and connected by very poorly defined, narrow,
weakly prominent irregular ridge; distal ridge-like structure consisting of single vertical, slightly oblique
ridge in proximal to median LAPs, and of a small, round knob in distal LAPs; inner side of distal edge
of proximal to median LAPs with two well-defined, prominent, horizontally elongate spurs composed
of more densely meshed stereom, dorsal one of which slightly larger and protruding; spurs very poorly
defined in distal LAPs; inner side of tentacle notch very large, widely encompassed by non-thickened
ventral portion of LAPs. No perforations or furrow discernible.

Remarks

Hess (1965a) described Ophiopholisl trispinosa Hess, 1965 on the basis of dissociated LAPs and
articulated arm fragments from the Oxfordian of France, which are here shown to belong to two different
species. The smaller LAPs and the articulated arm fragments are assignable to Lapidaster gen. nov.,
a probably close relative of extant large-pored Ophiologimus (see above). Most of the larger LAPs,
including the holotype, are here demonstrated to belong to the new small-pored ophiacanthid genus
Ishidacantha gen. nov. Among the LAP types assigned to this genus, the above-mentioned ones are
unique in displaying three large spine articulations with a strong dorsalward increase in size, a coarsely
meshed stereom with a very poorly developed vertical striation, and a proximal ridge on the inner side
separated into a ventral and a dorsal knob. Thus, they are described here as a new species which displays
the highly distinctive characters of the new genus best and is therefore selected as the type species of
Ishidacantha gen. nov.

Occurrence

Early Oxfordian of France.

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European Journal of Taxonomy 48: 1-242 (2013)

Genus Ophiomitrella NquiW, 1899

Type species

Ophiacantha laevipellis Lyman, 1883, by monotypy.

Diagnosis

Ophiacanthid with moderately large, ear-shaped spine artieulations proximally sharply separated by a
prominent, generally strongly thiekened distalmost lamella or ridge; row of spine artieulations extended
tentaele noteh very small, ineonspieuous; ridge on inner side oblique, with ventro-proximalwards bent
ventral part; dorsal tip of ridge widened and with ventralwards projeeting extension.

Remarks

Many extant ophiaeanthid lineages, in partieular the small-pored ones, share highly similar LAP
morphologies, as already pointed out by Thuy & Stohr (2011). As a result, it ean be a major ehallenge
to work out eomprehensive LAP morphologieal diagnoses on the basis of whieh dissoeiated LAPs ean
be unambiguously assigned on genus level. Ophiomitrella eertainly is one of the more ehallenging
eases, being one of the genera whieh laek any striking, distinetive feature sueh as the lip-shaped ventral
lobe of the spine artieulations in Ophiolimna or the shape of the ridge in Ophiopristis and Ophiotreta.
Although Ophiomitrella is a relatively eommon and diverse genus (O’Hara & Stohr 2006), only four
extant speeies [O. clavigera (Ljungman, 1865), O. conferta (Koehler, 1922), O. granulosa (Lyman,
1878) and O. tenuis (Koehler, 1904)] of the genus were assessed with respeet to the morphology of their
LAPs (Fig. 31: 7-9). On the basis of this admittedly limited evidenee, the LAPs of Ophiomitrella are
probably best eharaeterised by the relatively large, ear-shaped spine artieulations that are proximally
sharply bordered by a near-straight, prominent, well-defined and strongly thiekened distalmost lamella
or ridge, and the oblique ridge with a ventro-proximalwards bent ventral part and a widened dorsal tip
with a ventralwards projeeting extension.

It is true that this eombination of eharaeters is not among the most distinetive, eonsidering how similar
the LAPs of some speeies of Ophiacantha are. To make matters worse, the LAP morphology of the
type speeies Ophiomitrella laevipellis is largely unknown, whieh poses problems eonsidering that
numerous speeies of Ophiomitrella are probably not eongenerie with O. laevipellis (eompare O’Hara &
Stohr 2006). Therefore, in order not to add to the eonfusion but at the same time eonfer a maximum
of taxonomie information, the diagnosis above is here taken as a referenee to assign fossil dissoeiated
LAPs to the genus Ophiomitrella, stressing, however, that the diagnosis is not among the most robust
and only valid with eertainty for the four extant speeies of the genus that have been examined personally.

Ophiomitrella? sp. 1
Fig. 31: 10-12

Material examined

GZG.1NV.78735, GZG.INV.78736, GZG.1NV.78737 and GZG.1NV.78738 (8 dissoeiated LAPs) from
the Callovian of Bauer-Wehrland, Germany; GZG.1NV.78739 (1 dissoeiated LAP) from the Callovian
of Althtittendorf, Germany.

Description

GZG.1NV.78735 is a dissoeiated, small, median LAP; slightly higher than wide; dorsal edge straight;
distal edge eonvex; proximal edge eoneave, devoid of spurs; distal half of outer surfaee with densely
meshed stereom; trabeeulae of densely meshed stereom merged into few, thiek, irregular vertieal ridges;
proximal half with moderately eoarsely meshed stereom. Five moderately large, nearly equal-sized, equi-

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THUYB., Fossil record of ophiacanthid brittle stars

distant, ear-shaped spine articulations freestanding on elevated distal portion of LAP; spine articulations
proximally sharply bordered by near-straight, prominent, strongly thickened ridge; gap between spine
articulations and distal edge of LAP very narrow; ventral and dorsal lobes of spine articulations merged
into continuous volute but with very gentle kink proximally resulting in slightly oval spine articulations.
Ventral edge of LAP nearly straight; tentacle notch invisible in external view. Row of spine articulations
slightly protruding ventral wards.

Inner side of LAP with rather inconspicuous, well defined, prominent, oblique ridge with slightly
widened, ventro-proximalwards pointing ventral tip, widened dorsal tip with ventralward projecting
extension; inner side of distal edge of LAP with poorly defined, round area of slightly more densely
meshed stereom; inner side of tentacle notch relatively small. Irregular row of perforations dorsally
bordering tentacle notch; ventralmost perforation large, horizontally elongate, irregular.

GZG.INV.78736 is a dissociated median LAP; slightly higher than wide; well in agreement with the
LAP described above; outer surface slightly less well preserved, with finely meshed stereom probably
originally covered by coarsely meshed stereom. Five spine articulations similar to those observed on
previous LAP; proximally bordered by slightly undulose, sharply defined, thick, prominent ridge.

Ridge on inner side of LAP similar to that of previous specimens, slightly better preserved; no area of
slightly more densely meshed stereom on inner side of distal edge of LAP; inner side of tentacle notch
smaller. Perforations on inner side loosely arranged in vertical row dorsally bordring tentacle notch;
nearly of equal size.

GZG.INV.78737 is a dissociated proximal LAP fragment; originally clearly higher than wide; all edges
broken; outer surface with coarsely and densely meshed stereom. At least five spine articulations similar
to those observed on specimens described above; proximally bordered by sharply defined, prominent,
broad ridge.

Inner side poorly preserved; shape of oblique, rather broad ridge not discernible; inner side of distal edge
of LAP with moderately large, poorly defined, round area of slightly more densely meshed stereom.
Irregular vertical row of moderately large, poorly preserved perforations.

Remarks

Although the material described above is scanty, it does display a combination of characters which is
reminiscent of at least ome of the extant species of Ophiomitrella. Strong similarities are also shared
with the LAPs of Ophiacantha, especially on account of the shape of the ridge on the inner side and the
absence of well-developed spurs on the outer proximal edge. The unusually broad, sharply defined and
straight ridge proximally bordering the spine articulations, however, is more typical of Ophiomitrella.
Thus, pending a revision of the highly heterogeneous genera Ophiacantha and Ophiomitrella, the LAPs
described above are here considered as a possible, indeterminate fossil record of Ophiomitrella.

Ophiomitrella? sp. 2
Fig. 32: 1

Material examined

GZG.INV.78740 (1 dissociated LAP) from sample 89, Jhurio Formation, middle Bathonian, Middle
Jurassic of Jumara, India.

Description

GZG.INV.78740 is a dissociated, small, median to distal LAP; nearly as high as wide; dorsal edge very
weakly concave as a result of a constriction; distal edge convex; proximal edge concave, devoid of
spurs; outer surface partly obscured by sediment; probably with coarsely meshed stereom displaying
irregularly thickened trabeculae. Six nearly equal-sized, equi-distant, ear-shaped spine articulations

179

European Journal of Taxonomy 48: 1-242 (2013)

Fig. 32. Fossil skeletal plates of ophiaeanthid brittle stars; lateral arm plates (LAPs) in external (a) and
internal (b) views. 1. Ophiomitrellal sp. 2 from the Bathonian (Middle Jurassie) of Jumara, India; GZG.
INV.78740, median to distal LAP. 2. Ophiomitrella sp. nov. from the late Maastriehtian (Late Cretaeeous)
of Maastrieht, the Netherlands; NHMM JJ 5104, proximal LAP. 3-6. Ophiomalleus beneficarum gen. et
sp. nov. from the Callovian of Bauer-Wehrland (3), Althiittendorf (4-5) and Hohensaaten (6), Germany.
3. GZG.INV.78741 (holotype), proximal to median LAP. 4. GZG.INV. 78742 (paratype), proximal LAP.
5. GZG.1NV.78743 (paratype), distal LAP. 6. GZG.1NV.78744 (paratype), arm spine. 7-9. Ophiomalleus
stevenwilsoni gen. et sp. nov. from the latest Hauterivian (Early Cretaeeous) of Sarstedt, Germany.
7. GZG.1NV.78748 (holotype), proximal LAP. 8. GZG.1NV.78749 (paratype), median LAP. 9. GZG.
1NV.78750 (paratype), distal LAP. One eommon seale bar per speeies exeept for 6.

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THUYB., Fossil record of ophiacanthid brittle stars

freestanding on elevated distal portion of LAP; proximally sharply bordered by exceptionally thick,
straight, strongly prominent ridge; gap between spine articulations and distal edge of LAP very narrow.
Ventral edge of LAP weakly convex, no tentacle notch discernible.

Inner side of LAP largely obscured by sediment; inner side of distal edge devoid of spurs; inner side of
tentacle notch very small.

Remarks

The single, poorly preserved specimen described above shares greatest similarities with the median
to distal LAPs of at least some of the extant species of Ophiomitrella, in particular with respect to
the conspicuous, unusually thick ridge proximally bordering the spine articulations. This assignment,
however, is far from robust, and the absence of better-preserved material precludes both a more secure
and precise taxonomic assessment and a comparison with the above-described, slightly younger LAPs
from Germany, here tentatively assigned to Ophiomitrella.

Note

The articulated specimen from the upper Maastrichtian Gronsveld Member (Maastricht Formation) of
Maastricht, the Netherlands, assigned by Jagt (2000) to Ophiacanthal danica, most probably represents
an undescribed species of Ophiomitrella. Corresponding dissociated LAPs (Fig. 32: 2) found in adjacent
beds corroborate such an assignment. This new species of Ophiomitrella is here only mentioned as such;
it will be described fiilly in a future study.

Genus Ophiomalleus gen. nov.

um:lsid:zoobank.org:act:9E006789-898D-45DB-97FF-2FC9569AFF88

Type species

Ophiomalleus beneficarum sp. nov. by present designation.

Other species included

Ophiomalleus stevenwilsoni sp. nov.

Diagnosis

Ophiacanthid with very large, massive LAPs displaying a large, conspicuous, strongly protruding
ventral portion; main portion of LAP generally rectangular; three to five large to very large, ear-shaped
spine articulations freestanding on elevated distal portion of LAP; inner side of LAP with simple, broad
ridge devoid of angular kinks or strongly widened parts; tentacle notch small but conspicuously deeply
incised and generally more than semi-circular at least in proximal LAPs.

Etymology

Name composed of ophis, Greek for “snake”, a commonly used prefix in ophiuroid names, and malleus,
Latin for “hammer”, in reference to the massive, rectangular aspect of the LAPs; gender masculine.

Remarks

Among all ophiacanthid LAP types currently known, one stands out on account of its particularly
massive, rectangular general appearance. Further characters of the LAP type in question are three to
four large spine articulations freestanding on the elevated distal portion of the LAP, a large and strongly
protruding ventral portion, a simple ridge on the inner side devoid of angular kink and strongly widened
parts, and a small but deeply incised and at least semi-circular tentacle notch. This combination of
characters is highly distinctive and not found in any other currently known type of LAPs within the
Ophiacanthidae. Ophiomalleus gen. nov. is thus introduced here to accommodate this LAP type.

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European Journal of Taxonomy 48: 1-242 (2013)

Closest similarities are shared with the LAPs of Ishidacantha gen. nov. on aeeount of the large, strongly
protruding ventral portion, the low number of spine artieulations and the small, deeply ineised, at least
semi-eireular, tentaele notehes. In the light of the fundamentally differing ridge struetures on the inner
side of the LAPs, however, these similarities are superfieial at most. Ophiomalleus gen. nov. elearly
belongs to the small-pored ophiaeanthids but any more detailed phylogenetie relationships remain
elusive in the absenee of artieulated speeimens.

Ophiomalleus beneficarum sp. nov.

um:lsid:zoobank.org:aet:7B911036-lEQl-4EDA-AF2C-E56F0Q27B8F4

Fig. 32: 3-6

Ophiacanthal constricta - Kutseher 1987a: 61, pi. 3 figs 1-2 (material ineorreetly assigned to
Ophiacanthal constricta Hess, 1966).

Diagnosis

Speeies of Ophiomalleus gen. nov. with very large EAPs displaying a poorly developed vertieal striation
on narrow band near spine artieulations; at least six poorly defined spurs on proximal outer edge in
proximal EAPs; up to five spine artieulations with finely eorrugated proximal edge and strong dorsalward
inerease in size exeept for often very small dorsalmost one; single, moderately broad, strongly prominent,
S-shaped ridge on inner side.

Etymology

Name formed after beneficum, Eatin for “eharitable”, in referenee to the infamous malleus maleficarum,
to reeall that witeh hunts, regrettably, did not go extinet for good in the Dark Ages.

Type material

Holotype

GZG.1NV.78741.

Paratype

GZG.1NV.78742, GZG.1NV.78743 Althutendorf, Germany; and GZG.1NV.78744 Hohensaaten, Germany;
all from glaeial erratie boulders, Callovian, Middle Jurassie.

Type locality and horizon

Bauer-Wehrland, Germany; glaeial erratie boulders, Callovian, Middle Jurassie.

Additional material

GZG.1NV.78745 (18 dissoeiated EAPs) from the Callovian of Bauer-Wehrland, Germany; GZG.
1NV.78746 (5 dissoeiated EAPs) from the Callovian of Althtittendorf, Germany; GZG.1NV.78747 (11
dissoeiated EAPs) from the Callovian of Hohensaaten, Germany.

Description

Holotype

GZG.INV.78741 is a dissoeiated, very large, proximal to median EAP; approximately 1.5 times
higher than wide; main portion of EAP of rounded reetangular outline; dorsal and distal edges gently
eonvex; proximal edge nearly straight, with four relatively small, poorly defined, almost indiseemible,
horizontally elongate spurs; ventral portion of EAP very large, eonspieuously protruding ventralwards;
ventro-distal tip of EAP strongly protruding ventralwards, tongue shaped; outer surfaee of EAP with
fine, rather irregular vertieal striation eomposed of slender, non-overlapping lamellae, and restrieted to

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THUYB., Fossil record of ophiacanthid brittle stars

distal third of outer surface bordering spine articulations; moderately finely meshed stereom on ventral
portion of LAP and most of the median third of the outer surface; proximal third with very finely meshed
and between spurs weakly horizontally striated stereom. Four very large, ear-shaped spine articulations
freestanding on strongly elevated distal portion of LAP; very strong dorsalward increase in size of spine
articulations and weaker dorsalward increase in size of gaps separating them; ventral and dorsal lobes
of spine articulations merged into continuous volute; proximal edge of volute finely but irregularly
corrugated; ventralmost spine articulation on protruding ventro-distal tip of LAP; dorsalmost spine
articulation not at dorsal edge of LAP; row of spine articulations slightly oblique; gap between spine
articulations and distal edge of LAP nearly as wide as half one spine articulation. Ventral edge of LAP
nearly straight, with deeply incised, relatively small, more than semi-circular tentacle notch.

Inner side of LAP with large, moderately broad, strongly prominent, nearly S-shaped ridge, with ventral
tip pointing ventro-proximalwards and confiuent with ventral portion of LAP, and dorsal tip pointing
dorsalwards and separated from dorsal edge of LAP; inner side of distal edge of LAP with two relatively
large, well-defined, slightly prominent, horizontally elongate spurs. Three irregular perforations loosely
arranged in vertical row dorsally bordering tentacle notch.

Paratype supplements and variation

GZG.INV.78742 is a dissociated proximal LAP; ventral portion missing; LAP originally more than
1.5 times higher than wide; main portion of LAP nearly rectangular to trapezoid in outline; dorsal
edge irregularly convex; distal edge nearly straight; proximal edge gently concave, with at least six
small to moderately large, poorly defined, horizontally slightly elongate, weakly prominent, non¬
protruding spurs; outer surface with moderately finely meshed stereom; trabeculae of stereom near spine
articulations thickened and merged into very poorly developed, irregular vertical striation. Five spine
articulations similar to those of holotype; strong dorsalward increase in size of spine articulations except
for very small dorsalmost one.

Dorsal half of ridge on inner side preserved, uniformly broad, well defined, strongly prominent, composed
of straight, near-vertical dorsal portion and oblique, slightly bent central part; both parts connected by
round kink; at least three spurs similar to those observed on holotype. Three very small, closely spaced
perforations in very short vertical row dorsally bordering tentacle notch.

GZG.INV.78743 is a dissociated distal LAP; nearly as wide as high; very well in agreement with
holotype; dorsal edge concave as a result of a constriction; proximal edge with three spurs similar to
those of holotype; outer surface with moderately finely meshed stereom, no vertical striation. Three
spine articulations similar to those of holotype, slightly smaller, in shallow notches of elevated distal
edge of LAP and with better-developed fine corrugation on proximal edge of volute. Ventral edge of
LAP slightly concave, with deeply incised slightly less than semi-circular tentacle notch.

Ridge on inner side of LAP similar to that of holotype except for a shorter, near-vertical dorsal portion
of the ridge.

GZG.INV.78744 is a very large, cylindrical, slightly bulgy arm spine; tip broken, exposing hollow lumen;
spine with moderately coarse, irregularly longitudinal trabecular ridges beset with minute granules.

Remarks

The specimens at hand were initially described and figured as Ophiacanthal constricta Hess, 1965 by
Kutscher (1987a) as a result of the misleading inclusion of more than one type of LAPs in the concept
of that species. The LAP type including the holotype of 0.1 constricta, here transferred to Ophiogaleus
gen. nov. (see above), however, fundamentally differs from the LAPs described above. The latter are
here assigned to Ophiomalleus gen. nov., as discussed above. Within this genus, these LAPs are unique
in displaying up to five spine articulations, a poorly developed vertical striation in median and, to a lesser
extent, proximal LAPs, up to six poorly defined spurs on the outer proximal edge, and a moderately

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European Journal of Taxonomy 48: 1-242 (2013)

broad, S-shaped ridge on the inner side. Sinee the LAPs deseribed above display the highly distinetive
features of the new genus best it is ehosen as its type speeies.

Occurrence

Callovian of Germany.

Ophiomalleus stevenwilsoni sp. nov.
um:lsid:zoobank.org:aet:201BCFBC-5C34-4C2C-827A-3QAFQF678279

Fig. 32: 7-9

Diagnosis

Speeies of Ophiomalleus gen. nov. with large LAPs devoid of vertieal striation on the outer surfaee and
of spurs on the outer proximal and inner distal edges; up to four large, ear-shaped spine artieulations
not bordered proximally by a ridge; ridge on inner side of LAP very broad, with widened dorsal tip and
shallow, poorly defined furrow in its eentre.

Etymology

Speeies named in honour of British musieian Steven Wilson, one of the eontemporaneous masters of
originality and ereativity, whose musie often taught me how to let ideas develop and materialise.

Type material

Holotype

GZG.1NV.78748.

Paratypes

GZG.1NV.78749 and GZG.1NV.78750.

Type locality and horizon

Claypit Gott in Sarstedt, Germany; latest Hauterivian, Early Cretaeeous.

Additional material

GZG.1NV.78751 (7 dissoeiated LAPs).

Description

Holotype

GZG.1NV.78748 is a dissoeiated, large, proximal LAP; slightly higher than wide; main portion of LAP
nearly reetangular; dorsal and distal edges gently eonvex; proximal edge gently eoneave, devoid of spurs;
ventral fifth of LAP large, strongly protruding ventro-proximalwards; outer surfaee with moderately
finely meshed stereom, replaeed by narrow and slightly sunken band of very finely meshed stereom
along proximal edge. Four very large, ear-shaped spine artieulations freestanding on elevated distal
edge of LAP; spine artieulations not bordered proximally by ridge; dorsal and ventral lobes merged into
eontinuous volute; very strong dorsalward inerease in size of spine artieulations; gap between spine
artieulations and distal edge of LAP relatively narrow. Ventral edge of LAP with deeply ineised but
small tentaele noteh.

Inner side of LAP with large, well-defined, prominent, broad ridge; ventral tip ventro-proximalwards
bent, not merged with ventral portion of LAP; dorsal tip widened, round, dorso-proximal wards pointing;
shallow, poorly defined furrow in the middle of the ridge, following its eourse; inner side of distal edge
of LAP devoid of spurs; inner side of tentaele noteh small, semi eireular. Two minute perforations
loosely arranged in vertieal row dorsally bordering tentaele noteh.

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THUYB., Fossil record of ophiacanthid brittle stars

Paratype supplements and variation

GZG.INV.78749 is a dissociated median LAP; slightly wider than high; very well in agreement with
holotype; ventral sixth of LAP strongly protruding ventro-proximalwards. Four spine articulations
similar to those observed on holotype.

Inner side of LAP similar to that of holotype. Shallow, poorly defined, slightly oblique furrow dorsally
bordering tentacle notch.

GZG.INV.78750 is a dissociated distal LAP; slightly wider than high; dorsal edge concave as a result
of a constriction. Three spine articulations similar to those observed on holotype. Tentacle less deeply
incised, small.

Ridge on inner side of LAP similar to that of holotype, slightly shorter and broader; furrow in the middle
of the ridge slightly better defined. No perforations discernible.

Remarks

These LAPs are unequivocally assignable to Ophiomalleus gen. nov. on account of the massive, near-
rectangular aspect of the main portion, the strongly protruding ventral portion, the shape and arrangement
of the spine articulations and the shape of the ridge on the inner side. Within this genus, the LAPs
described above are unique in entirely lacking vertical striation on the outer surface and spurs on the
outer proximal and inner distal edges.

Genus Inexpectacantha Thuy, 2011

Type species

Inexpectacantha acrobatica Thuy, 2011, by original designation.

Diagnosis

Ophiacanthid with small to moderately large LAPs of thick, massive and generally bulging aspect; outer
surface devoid of conspicuous ornament; no spurs on outer proximal and inner distal edges; small, ear¬
shaped spine articulations freestanding or in shallow depressions of bulging distal portion of LAP; spine
articulations commonly tilted; ventral lobe rugged to irregularly corrugate, commonly confiuent with
outer surface stereom; spine articulations not sharply bordered proximally and with dorsalward increase
in size; short, broad, dorso-proximalwards bent, tongue-shaped ridge devoid of kinks or widened parts;
tentacle notch very small, poorly defined.

Remarks

Inexpectacantha acrobatica is probably one of the best-known fossil ophiuroids. In fact, the original
description was based on outstandingly well-preserved material from the Pliensbachian of France,
comprising both articulated skeletons and dissociated skeletal parts, including LAPs, allowing for a
morphological analysis of exceptional detail (Thuy 2011). As a result, fossil dissociated LAPs compatible
with the LAP morphological diagnosis of Inexpectacantha are unambiguously identifiable and thus
provide evidence for bracketing the divergence time of the genus.

The LAPs of Inexpectacantha are among the most characteristic of all ophiacanthid LAP types. In fact,
the a massive, thick, round and bulging general aspect, the lack of conspicuous outer surface ornament
and spurs on the outer proximal and inner distal edges, small spine articulations with dorsalward increase
in size and not bordered proximally by a ridge, a large, broad, tongue-shaped ridge devoid of kinks,
extensions or strongly widened parts on the inner side, and very small, poorly defined tentacle notches are
a combination of characters not found in any other ophiacanthid genus. Superficial similarities are shared
with the LAPs of Ophiochondrus Lyman, 1869, in which, however, the spine articulations are generally

185

European Journal of Taxonomy 48: 1-242 (2013)

not oblique and not confluent with the outer surface stereom. In addition, the LAPs of Ophiochondrus
are less massive, and the ridge on the inner side displays a ventro-proximalwards projecting extension.

Greatest similarities are shared with the LAPs of Ophioleviathan gen. nov.(see below), particularly
with respect to the massive and thick general aspect, and the shape of the spine articulations and of the
ridge on the inner side. The LAPs of Ophioleviathan gen. nov., however, are signiflcantly larger than
those of Inexpectacantha and display larger, near-vertical spine articulations in deeper notches and
composed of distal and proximal rather than dorsal and ventral lobes, with a strongly thickened distal
lobe. Nevertheless, as discussed below, the LAP morphologies of both genera as so similar that they
most likely represent sister taxa.

Interestingly, the currently known species of Inexpectacantha fall into two groups on the basis of LAP
morphology: I. ritae sp. nov. and/, lunaris (Hess, 1962), plus I. weisi sp. nov. and/, acrobatica. The
two last named are characterised by generally smaller LAPs with smaller height/width ratios, spine
articulations freestanding rather than in notches, a more coarsely meshed stereom on the outer surface,
and lip-shaped distal knobs in the spine articulations of the distal LAPs. Most of these characters are
typically indicative of a paedomorphic condition (Stohr 2005, 2011). Indeed, the articulated specimens
of Inexpectacantha acrobatica display a strikingly paedomorphic general morphology (Thuy 2011).

Inexpectacantha ritae sp. nov.

um:lsid:zoobank.org:act:7CCF96E7-E90E-4FD8-B307-lDEC45F8F82F

Fig. 33: 1-3

Sigsbeial lunaris - Thuy 2005: 41, pi. 4 flgs 6-10 [material incorrectly assigned to Sigsbeial lunaris
(Hess, 1962)].

Diagnosis

Species of Inexpectacantha with moderately large EAPs; outer surface with flnely meshed stereom,
devoid of constriction, furrow or depressed area along proximal edge; up to six moderately large spine
articulations in shallow notches of bulging distal portion, slightly oblique in proximal EAPs, more
strongly oblique in median and distal ones; ridge on inner side EAP relatively slender, strongly bent
dorso-proximalwards.

Etymology

Species named in honour of Rita Hellers, who gave me life and all the prerequisites to All it with
happiness, love and fulfllment.

Type material

Holotype

MnhnE HE419.

Paratypes

MnhnE HE420 and MnhnE HE421.

Type locality and horizon

Bourglinster, Euxembourg; sample Bou of Thuy (2005), Planorbis Zone, Hettangian, Early Jurassic.

Additional material

MnhnE HE422 (55 dissociated EAPs) from sample Bou of Thuy (2005) from the Hettangian of
Bourglinster, Euxembourg; MnhnE HE423 (16 dissociated EAPs) from sample Vanl of Thuy (2005)

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THUYB., Fossil record of ophiacanthid brittle stars

from the Hettangian of Vance, Belgium; MnhnL HE254 (5 dissociated LAPs), MnhnL HE424 (20
dissociated LAPs) from sample Van2 of Thuy (2005) from the Hettangian of Vance, Belgium.

Description

Holotype

MnhnL HE419 is a dissociated, moderately large, proximal LAP; almost twice higher than wide; of
massive and stout aspect; dorsal edge weakly convex, oblique; distal edge convex; proximal edge
concave, devoid of spurs; no constriction or furrow along proximal edge; outer surface with moderately
finely meshed stereom becoming slightly more finely meshed close to proximal edge of LAP Six
moderately large, ear-shaped, oval, horizontally slightly elongate, weakly oblique spine articulations in
shallow notches of bulging distal portion of LAP; notches of three ventral spine articulations merged;
spine articulations not sharply bordered proximally, edge of notches gentle; ventral lobe of spine
articulations thin, rugged, confiuent with stereom of notch and merged proximally with larger, thicker
and more prominent dorsal lobe into continuous volute; strong dorsalward increase in size of gaps
separating spine articulations; dorsalward increase in size of spine articulations very weak; gap between
spine articulations and distal edge of LAP narrow. Ventral edge of LAP oblique, slightly convex; tentacle
notch invisible in external view.

Inner side ofLAP with large, moderately well-defined, prominent, relatively slender, dorso-proximalwards
bent, tongue-shaped ridge devoid of kinks or strongly widened parts; ventral tip of ridge not merged
with ventral portion ofLAP; no spurs on inner side of distal edge ofLAP; inner side of tentacle notch
very small, poorly defined, shallow. No perforation or furrow discernible.

Paratype supplements and variation

MnhnL HE420 is a dissociated median LAP; slightly higher than wide; very well in agreement with
holotype, of slightly more rounded aspect. Five spine articulations similar to those observed on holotype
but more strongly oblique; weaker dorsalward increase in size of gaps separating spine articulations;
two ventralmost spine articulations in very shallow notches, remaining ones freestanding.

Inner side similar to that of holotype.

MnhnL HE421 is a dissociated distal LAP; slightly higher than wide. Four spine articulations similar to
those of holotype but more strongly oblique, almost vertical; weaker dorsalward increase in size of gaps
separating spine articulations; two ventralmost spine articulations in very shallow notches, remaining
two freestanding.

Inner side similar to that of holotype.

Remarks

These LAPs from the Hettangian of Luxembourg were originally recorded by Thuy (2005), along
with conspecific LAPs from the Hettangian of Belgium, and erroneously assigned to Sigsbeial lunaris
(Hess, 1962). While it is clear from the highly distinctive combination of characters that these LAPs are
assignable to Inexpectacantha, the type specimens of Sigsbeial lunaris differ from the LAPs described
above in the more strongly oblique spine articulations even in proximal LAPs, the presence of a slightly
depressed band along part of the proximal edge, and the much wider and less strongly bent ridge on the
inner side. Evidently, these LAPs are incompatible with any currently known LAP type assignable to
Inexpectacantha and are thus described here as a new species.

Occurrence

Hettangian of Luxembourg and Belgium.

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 33. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal
(b) views. 1-3. Inexpectacantha ritae sp. nov. from the Hettangian (Early Jurassie) of Bourglinster,
Luxembourg. 1. MnhnL HE419 (holotype), proximal LAP. 2. MnhnL HE420 (paratype), median LAP.
3. MnhnL HE421 (paratype), distal LAP. 4-6. Inexpectacantha weisi sp. nov. from the Hettangian (Early
Jurassie) of Fontenoille, Belgium. 4. MnhnL HE425 (holotype), proximal LAP. 5. MnhnL HE426
(paratype), median LAP. 6. MnhnL HE427 (paratype), distal LAP. 7-8. Inexpectacantha lunaris (Hess,
1962) eomb. nov. from the late Sinemurian (Early Jurassie) of Bishop’s Cleeve, Great Britain. 7. GZG.
1NV.78752, proximal LAP. 8. GZG.1NV.78753, proximal to median LAP. 9-10. Inexpectacantha
acrobatica Thuy, 2011 from the early Pliensbaehian (Early Jurassie) of Bloekley, Great Britain (9) and
the early Toareian (Early Jurassie) of Aix-sur-Cloie, Belgium (10). 9. GZG.1NV.78755, proximal LAP.
10. GZG.1NV.78757, juvenile proximal LAP. One eommon seale bar per speeies.

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THUYB., Fossil record of ophiacanthid brittle stars

Inexpectacantha weisi sp. nov.

um:lsid:zoobank.org:act:96A19195-86C6-4EA8-B6F2-AEDA14589A66

Fig. 33: 4-6

Hemieuryalel n. sp. -Kutscher & Hary 1991: 54, pi. 2 fig. 4a-d.

Diagnosis

Species of Inexpectacantha with small LAPs displaying a coarsely meshed stereom on the outer surface;
no constriction and no furrow along proximal edge; spine articulations freestanding, not in depressions,
oblique; single spine articulation with lip-shaped distal knob.

Etymology

Species named in honour of my friend and colleague Robert Weis for his continuous encouragement and
for digging up the type locality of the species.

Type material

Holotype

MnhnL HE425.

Paratypes

MnhnL HE426 and MnhnL HE427.

Type locality and horizon

Fontenoille, Belgium; level c of Delsate et al. (2002), Liasicus Zone, Hettangian, Early Jurassic.

Additional material

MnhnL HE428 (81 dissociated LAPs) from the Hettangian of Fontenoille, Belgium; MnhnL HE429 (28
dissociated LAPs) from the Bucklandi Zone, early Sinemurian of Remerschen, Luxembourg.

Description

Holotype

MnhnL HE425 is a dissociated, small, proximal LAP; slightly higher than wide; of thick, massive and
rounded aspect; dorsal edge oblique but straight; distal edge convex; proximal edge nearly straight,
devoid of spurs; outer surface with moderately coarsely meshed stereom, except for poorly defined,
weakly sunken area of finely meshed stereom near ventro-proximal tip of LAP; no vertical striation or
other conspicuous ornament elements. Five small, ear-shaped, oblique spine articulations freestanding
on bulging distal portion of LAP, not sharply separated proximally from outer surface stereom and
not sunken; ventral lobe rugged, thin, merged proximally with much thicker, smoother and more
prominent dorsal lobe into continuous volute; weak dorsalward increase in size of spine articulations
but not in size of gaps separating them; gap between spine articulations and distal edge almost as
wide as one spine articulation. Ventral edge of LAP oblique, weakly convex; tentacle notch invisible
in external view.

Inner side of LAP with very large, broad, conspicuous, well-defined, prominent, strongly dorso-
proximalwards bent, tongue-shaped ridge; dorsal part of ridge wider than ventral one; ventral tip of
ridge not merged with ventral portion of LAP; no spur on inner side of distal edge of LAP; inner side of
tentacle notch very small, shallow and poorly defined. Very poorly defined, shallow, almost indiscernible
vertical furrow dorsally bordering tentacle notch; no perforations discernible.

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European Journal of Taxonomy 48: 1-242 (2013)

Paratype supplements and variation

MnhnL HE426 is a dissociated median LAP; slightly wider than high; very well in agreement with
holotype; outer surfaee better preserved, with eoarsely meshed stereom devoid of vertieal striation
or granules; narrow and of more finely meshed stereom along proximal edge inereasing in width
ventralwards. Four equi-distant spine artieulations similar to those observed on holotype but better
preserved; strong dorsalward inerease in size of spine artieulations; gap between spine artieulations and
distal edge of LAP narrower.

Inn er side of LAP well in agreement with that of holotype.

MnhnL HE427 is a dissoeiated distal LAP; approximately 1.5 times wider than high; dorsal edge straight,
weakly oblique; proximal edge irregularly eoneave. Four spine artieulations similar to those observed on
holotype exeept for ventralmost one with small, lip-shaped, strongly protruding distal knob; dorsalward
inerease in size of spine artieulations and of gaps separating them; gap between spine artieulations and
distal edge of LAP narrower than in holotype. Ventral edge of LAP slightly eonvex.

Ridge on inner side of LAP smaller, narrower and less elearly tongue shaped than in holotype, with
pointed dorsal tip and distally bordered by small, poorly defined knob.

Remarks

These LAPs are unambiguously assignable to Inexpectacantha on aeeount of the stout, thiek, rounded
general aspeet, the laek of outer surfaee ornament and spurs, the shape, size and position of the spine
artieulations and the shape of the ridge on the inner side. Within this genus, greatest similarities are
shared with the LAPs of Inexpectacantha acrobatica, espeeially with respeet to the freestanding spine
artieulations. The LAPs deseribed above, however, laek a eonstrietion or a furrow along the proximal
edge, and display a more eoarsely meshed stereom on the outer surfaee and fewer spine artieulations. They
are thus here deseribed as a new speeies. The strongly prominent, lip-shaped knob on the ventralmost
spine artieulation in the distal LAP noted above most probably bore a hook-shaped spine similar to those
known from the type material of I. acrobatica (see Thuy 2011).

Kutseher & Hary (1991) deseribed and illustrated dissoeiated LAPs from the Sinemurian of Luxembourg
as ''Hemieuryalel n. sp.”, reeognising the speeies as new but refraining from formally naming it on
aeeount of the limited amount of material available. The speeimens in question appear to be eonspeeifie
with the LAPs deseribed here, although only some of the original speeimens of Kutseher & Hary
(1991) eould be examined by myself The material from the Pliensbaehian of Great Britain deseribed
as Hemieuryalel lunaris Hess, 1962 by Hess (1964) was eonsidered by Kutseher & Hary (1991) to be
eonspeeifie with their unnamed LAPs. As shown below, however, Hess’s (1964) original assignment
was eorreet.

Occurrence

Hettangian of Belgium, early Sinemurian of Luxembourg.

Inexpectacantha lunaris (Hess, 1962) eomb. nov.

Fig. 33: 7-8

Hemieuryalel lunaris Hess, 1962: 627, figs 29-33, 45-47.

Hemieuryalel lunaris - Hqss 1964: 762, figs 4-10.

non Sigsbeial lunaris - Kutseher 1996: 12, pi. 3 figs 6-8, pi. 4 figs 12-14. — Kutseher & Villier 2003:
189, pi. 6 figs 7-8, pi. 7 figs 1-2. — Thuy 2005: 41, pi. 4 figs 6-10. — Hess 2006: 66, pi. 29 figs 8-9.

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THUYB., Fossil record of ophiacanthid brittle stars

Diagnosis

Species of Inexpectacantha with moderately large LAPs devoid of constriction but displaying a slightly
depressed band of variable width along most of the proximal edge; outer surface with finely meshed
stereom; up to six small, near-vertical spine articulations in shallow notches of bulging distal portion of
LAP; ridge on inner side of LAP very broad and only slightly bent dorso-proximalwards.

Material examined

GZG.INV.78752, GZG.INV.78753 and GZG.INV.78754 (dissociated LAPs) from the Obtusum Zone,
late Sinemurian of Bishop’s Cleeve, Great Britain; 17 dissociated LAPs from the late Pliensbachian of
Seewen, Switzerland, the type material of Hess (1962); the original material of Hess (1964).

Description

Moderately large, dissociated LAPs of thick, massive and rounded aspect; proximal LAPs nearly twice
higher than wide, distal ones slightly higher than wide; dorsal edge straight to slightly convex, oblique;
no constriction; distal edge convex; proximal edge straight to slightly concave, devoid of spurs; slightly
depressed band of varible width, from one-fifth to one-third of the total LAP width, along most of the
proximal edge, widest in the middle, not reaching dorso- and ventro-proximal tips of LAP; depressed
band not sharply separated from remaining outer surface distally and without conspicuous change in
stereom mesh size. Six (proximal LAPs) to four (distal LAPs) small, ear-shaped, strongly oblique to
near-vertical spine articulations in shallow notches of bulging distal edge; dorsalward increase in size
of spine articulations and of gaps separating them; ventral lobe of spine articulations rugged, confiuent
with stereom of notch, merged proximally with almost equal-sized dorsal lobe into continuous volute;
gap between spine articulations and distal edge of LAP nearly as wide as one spine articulation or
slightly wider; spine articulations not sharply bordered proximally, not even by edge of notches. Ventral
edge of LAPs oblique, straight; tentacle notch invisible in external view.

Inner side of LAP with very large, sharply defined, prominent, conspicuously broad, tongue-shaped
ridge; ventral tip of ridge not merged with ventral portion of LAP; dorsal part of ridge wider than ventral
one, weakly bent dorso-proximalwards; shallow, poorly defined furrow along distal edge of ridge; no
spurs on inner side of distal edge of LAP; inner side of tentacle notch very small, weakly defined, almost
indiscernible in many LAPs. Shallow, poorly defined, vertical furrow dorsally bordering tentacle notch.
Articulated arm fragments from the Pliensbachian of Great Britain, assignable to this species, were
described in detail and illustrated by Hess (1964).

Remarks

Hess (1962) originally described dissociated LAPs from the Pliensbachian of Switzerland as
Hemieuryalel lunaris, comparing them with Recent hemieuryalids such as Hemieuryale von Martens,
1867 and Sigsbeia Lyman, 1878. He later (Hess 1964) assigned dissociated LAPs and articulated arm
fragments from the Pliensbachian of Great Britain to Hemieuryalel lunaris, stressing that the minor
morphological differences between the Swiss type material and the British specimens could be ascribed
to the better preservation of the latter.

Following these two reports, however, confusion has arisen over the concept of Hemieuryalel lunaris.
First, Kutscher & Hary (1991) described dissociated LAPs from the Sinemurian of Luxembourg which
they considered to be conspecific with Hess’s (1964) Brirish specimens but no with the type material
from Switzerland. Then, Kutscher (1996) reported on dissociated LAPs from the Toarcian/Aalenian of
Germany which he assigned to Hess’s (1962) species, tentatively transferring it to the extant hemieuryalid
genus Sigsbeia. Finally, Thuy (2005) recorded dissociated LAPs from the Hettangian of Belgium and
Luxembourg which were assigned to Sigsbeial lunaris. By that time, the concept of Sigsbeial lunaris
had been infiated beyond meaningful limits as far as LAP morphology is concerned, including every

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European Journal of Taxonomy 48: 1-242 (2013)

type of thick, massive, rounded LAPs with small, more or less oblique spine articulations and a broad
ridge on the inn er side.

A re-examination of the original material of those three papers has allowed to disentangle the different
LAP types previously assigned to S.l lunaris. Hess’s (1962) type material from Switzerland and the
British specimens (Hess 1964) are, indeed, conspecific and differ mainly in their state of preservation.
They display the highly distinctive combination of characters typical of the o^hidiC?in\hi&Inexpectacantha
and are thus here transferred to that genus. The LAPs of Kutscher & Hary (1991) are here shown
to be assignable to Inexpectacantha weisi sp. nov. Those of Kutscher (1996) and Kutscher &Villier
(2003), in contrast, fundamentally differ from Inexpectacantha lunaris comb, nov., in particular with
respect to the spine articulation morphology. They most probably even belong to a different family.
Their exact systematic position requires more detailed investigations involving comparison with Recent
non-ophiacanthid genera, which is beyond the scope of the present study.

Inexpectacantha lunaris comb, nov., as defined here, is unambiguously distinguishable from its congeners
in displaying small, near-vertical spine articulations in shallow notches, a slightly depressed area along
most of the proximal edge, and a very broad, weakly bent ridge on the inner side. Closest similarities
are shared with the LAPs of Inexpectacantha ritae sp. nov., especially on account of the larger size, the
larger general height/width ratio and the position of the spine articulations. Similarities with the LAPs of
Ophioleviathan gen. nov. are more superficial and mainly pertain to the near-vertical spine articulations,
the broad ridge on the inner side and the very narrow, slightly depressed band along the proximal edge.
The LAPs of Ophioleviathan gen. nov., however, are considerably larger and display almost overturned
spine articulations in deeper notches and with much thicker, more strongly prominent dorsal lobes.

Occurrence

Late Sinemurian to early Pliensbachian of Great Britain, late Pliensbachian of Switzerland.

Inexpectacantha acrobatica Thuy, 2011
Fig. 33: 9-10

Inexpectacantha acrobatica Thuy, 2011: 217, pis 1-3, pi. 4 figs 1-6.

Inexpectacantha acrobatica - Thuy et al. 2011: 179, fig. 3f

Diagnosis

Species of Inexpectacantha with small LAPs; relatively small height/width ratio; outer surface with
moderately coarsely meshed stereom and slight constriction resulting in concave dorsal edge and
shallow, poorly defined furrow parallel to proximal edge; up to six moderately large, ear-shaped, oblique
spine articulations freestanding on strongly bulging distal portion of LAP; ridge on inner side of LAP
moderately broad and strongly bent dorso-proximalwards; two ventralmost spine articulations of distal
LAPs with conspicuous, strongly prominent, lip-shaped distal ridges originally supporting hook-shaped
arm spines.

Material examined

GZG.1NV.78755 and GZG.1NV.78756 (dissociated LAP) from the early Pliensbachian of Blockley,
Great Britain; GZG.1NV.78757 and GZG.1NV.78758 (70 dissociated LAPs) from the early Toarcian of
Aix-sur-Cloie, Belgium; the type material of Thuy (2011).

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THUYB., Fossil record of ophiacanthid brittle stars

Remarks

The LAPs of Inexpectacantha acrobatica were described in detail and illustrated by Thuy (2011).
The LAP morphological diagnosis presented above allows for an unambiguous distinction from other
species of Inexpectacantha, including those known exclusively from dissociated LAPs. Two additional
occurrences of the species are listed here, one of which extends the stratigraphic range into the early
Toarcian.

Occurrence

Early Pliensbachian of France and Great Britain, early Toarcian of Belgium.

Genus Ophioleviathan gen. nov.

um:lsid:zoobank.org: act: 3 AT 8EBQ1-EA44-4C91 -9614-CCFBE921662C

Type and sole known species

Ophioleviathan watsoni sp. nov.

Diagnosis

Ophiacanthid with extremely large, thick and massive EAPs; outer surface devoid of conspicuous
ornament elements; no spurs on outer proximal and inner distal edges; poorly defined, slightly depressed
narrow band along the middle part of the proximal ridge in proximal EAPs; up to seven large, ear-shaped
spine articulations in deep notches of strongly bulging distal portion of EAP; spine articulations vertical
to slightly overturned, with rather slender, rugged distal lobe merged with much larger, thicker and more
strongly prominent distal lobe into continuous volute; inner side with extremely large, wide, slightly
dorso-proximalwards bent, tongue-shaped ridge devoid of kinks and widest dorsally; tentacle notch very
small and poorly defined.

Etymology

Name composed of ophis, Greek for “snake”, a commonly used prefix in ophiuroid names, and
“Eeviathan”, a biblical sea monster literally translating into “coiled, twisted”, referring to the genus as
an unusually large ophiuroid with arms capable of considerable coiling that lived in the greater depths
of the ancient Tethys Ocean; gender masculine.

Remarks

Eower Jurassic Tethyan deep-sea sediments from Austria have yielded one of the most extraordinary
types of dissociated EAPs, characterised by an unusually large size, a very thick and massive aspect, and
an exceptionally large ridge on the inner side. The presence of a sigmoidal fold in the spine articulations
unambiguously places the EAPs in question in the family Ophiacanthidae, in spite of their highly
unusual morphology. Within this family, greatest similarities are shared with the EAPs of the extinct
ophiacanthid Inexpectacantha, especially on account of the massive and thick aspect, the lack of outer
surface ornament and of spurs on the outer proximal and inner distal edges, the shape of the spine
articulations and of the ridge on the inner side, and the very small, poorly defined tentacle notches. As
a matter of fact, very similar EAPs from near-coeval, deeper-water sedimentary rocks of Switzerland,
considered here to be conspecific with the EAP type in question, were described by Hess (2006) and
assigned by him to Inexpectacantha lunaris comb. nov.

In spite of the striking similarities, the above-mentioned EAPs differ from those of Inexpectacantha in
several aspects: they are considerably larger, thicker and display a larger height/width ratio, the spine
articulations are vertical to slightly overturned and in deeper notches, the distal (dorsal) lobe of the spine
articulations is much larger, thicker and more prominent than the proximal (ventral) lobe, the ridge on

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European Journal of Taxonomy 48: 1-242 (2013)

the inner side of the LAPs is mueh larger and wider, and the dorsal and ventral tips of the inner side
protrude towards the arm midline. These dififerenees are here eonsidered to warrant separation at the
generie level. Ophioleviathan gen. nov. is thus introdueed here to aeeommodate the above-mentioned
LAP type.

Ophioleviathan gen. nov. and Inexpectacantha are most probably sister taxa, as suggested by the highly
distinetive spine artieulation morphology and shape of the ridge on the inner side shared by both genera
and not found in any other ophiaeanthid. In terms of LAP morphology, Ophioleviathan gen. nov. is
eloser to the less paedomorphie group within Inexpectacantha, formed by I. ritae sp. nov. and I. lunaris
eomb. nov. (see above), espeeially on aeeount of the larger size, the larger height/width ratio and the
position of the spine artieulations in notehes. The LAPs of Ophioleviathan gen. nov., however, have an
even less paedomorphie appearanee than those of the above-mentioned group within Inexpectacantha.

Ophioleviathan watsoni sp. nov.

um:lsid:zoobank.org:aet:657FB229-47E4-48Fl-8913-9A83DD42ABQ5

Fig. 34: 1-4

Sigsbeial lunaris - Hess 2006: 66, pi. 29 figs 8-9 [material ineorreetly assigned to Sigsbeia? lunaris
(Hess, 1962)].

Diagnosis

As for genus.

Etymology

Speeies named in honour of Paul Watson, founder of the Sea Shepherd Conservation Soeiety, in admiring
reeognition of his relentless co mm itment to the proteetion of marine wildlife.

Type material
Holotype

NHMW 2012/0137/0024.

Paratypes

NHMW 2012/0137/0025, NHMW 2012/0137/0026 and NHMW 2012/0137/0027.

Type locality and horizon

Glasenbaeh Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbaehian, Early Jurassie.

Additional material

NHMW 2012/0137/0028 (21 dissoeiated EAPs) from the late Sinemurian to early Pliensbaehian of
the Glasenbaeh Gorge, Austria; original material of Hess (2006) from the late Pliensbaehian of Arzo,
Switzerland.

Description

Holotype

NHMW 2012/0137/0024 is a very large, dissoeiated proximal EAP; nearly 2.5 times higher than wide;
of massive and extremely thiek aspeet; dorsal edge eonvex, oblique; distal edge evenly eonvex; proximal
edge irregularly eoneave, devoid of spurs; very narrow, slightly depressed area along the eentral part of
the proximal ridge; outer surfaee with finely meshed stereom, devoid of eonspieuous ornament elements.
Seven large, ear-shaped spine artieulations in deep notehes of strongly bulging distal portion of EAP;

194

THUYB., Fossil record of ophiacanthid brittle stars

-iiJm

Fig. 34. Lateral arm plates (LAPs) of fossil and Recent ophiacanthid brittle stars in external (a) and internal
(b) views. 1-4. Ophioleviathan watsoni gen. et sp. nov. from the late Sinemurian to early Pliensbachian
(Early Jurassic) of the Glasenbach Gorge, Austria. 1. NHMW 2012/0137/0024 (holotype), proximal LAP.
2. NHMW 2012/0137/0025 (paratype), proximal LAP. 3. NHMW 2012/0137/0026 (paratype), median
LAP. 4. NHMW 2012/0137/0027 (paratype), distal LAP. 5-7. Manfredura curvata (Kutscher & Jagt,
2000) comb. nov. from the early Maastrichtian (Late Cretaceous) ofRligen, Germany. 5. GZG.INV.78759,
proximal LAP. 6. GZG.1NV.78760, median LAP. 7. GZG.1NV.78761, distal LAP. 8-9. Ophiomitra valida
Lyman, 1869, Recent. 8. Proximal LAP. 9. Median LAP. One co mm on scale bar per species.

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European Journal of Taxonomy 48: 1-242 (2013)

spine articulations vertical or even slightly overturned, composed of distal and proximal rather than
dorsal and ventral lobes; proximal lobe relatively slender, rugged and confluent with stereom of notch;
dorsally merged with much larger and thicker, much more strongly prominent distal lobe into continuous,
vertically elongate volute; middle spine articulations largest, with dorsalward and ventralward decrease
in size; spine articulations nearly equi distant and proximally sharply bordered by edge of notches; gap
between spine articulations and distal edge of LAP almost as wide as one spine articulation. Ventral edge
of LAP oblique, very weakly convex.

Inner side of LAP with extremely large, broad, well-deflned, prominent, slightly dorso-proximalwards
bent, tongue-shaped ridge devoid of kinks; ventral tip of ridge not merged with ventral tip of LAP;
dorsal part of ridge wider than ventral part; no spurs on inner side of distal edge of LAP; inner side of
tentacle notch extremely small, very poorly deflned, almost indiscernible; dorsal and ventral tips of LAP
protruding towards midline of arm. Shallow, poorly deflned, vertical furrow dorsally bordering tentacle
notch; no perforations discernible.

Paratype supplements and variation

NHMW 2012/0137/0025 is a dissociated proximal LAP; approximately twice higher than wide; very
well in agreement with holotype. Six spine articulations similar to those observed on holotype.

Ridge on inner side of LAP slightly better preserved than in holotype, very large, extremely wide, with
much more slender ventral part not merged with ventral portion of LAP; inner side of tentacle notch
very small, poorly deflned. Shallow, moderately well-deflned vertical furrow dorsally bordering tentacle
notch, with two to three minute, irregularly spaced perforations.

NHMW 2012/0137/0026 is a dissociated median LAP; slightly higher than wide; dorsal edge oblique,
straight; slightly depressed band along central part of proximal edge very weakly developed, almost
indiscernible. Five spine articulations similar to those observed on holotype, less sharply deflned
proximally. Ventral edge of LAP straight, oblique.

Ridge on inner side of LAP similar to that of holotype but shorter, broader; inner side of tentacle notch
as small and poorly deflned as in holotype, oblique; dorsal and ventral tips of LAP protruding towards
midline of arm. No perforations or furrow discernible.

NHMW 2012/0137/0027 is a dissociated distal LAP; nearly as high as wide, ofrounded aspect; depressed
area along the middle part of the proximal edge absent. Five large, spine articulations similar to those
observed on holotype; distal lobe even larger, thicker, more prominent than in holotype; gap between
spine articulations and distal edge of LAP narrower.

Ridge on inner side of LAP similar to that of holotype but slightly smaller, narrower and shorter. No
perforations or furrow discernible.

Remarks

This LAP type is the only one currently assignable to Ophioleviathan gen. nov. Its systematic placement
and affinities with other LAP types are discussed above.

Occurrence

Late Sinemurian to early Pliensbachian of Austria, late Pliensbachian of Switzerland.

Genus Manfredura gen. nov.

um:lsid:zoobank.org:act:48A7EB27-E847-4C00-A732-8D8EAC80227B

Type and sole known species

Ophiomyxal curvata Kutscher & Jagt, 2000.

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THUYB., Fossil record of ophiacanthid brittle stars

Diagnosis

Ophiuroid with large, conspicuously thick and strongly curved LAPs; proximal LAPs several times
higher than wide; numerous non-oblique, ear-shaped spine articulations freestanding on strongly
elevated distal portion of LAPs; inner side of LAP with very small, slender ridge; LAPs of neighbouring
arm segments originally in contact as evidenced by strongly depressed, narrow band along most of the
proximal edge.

Etymology

Genus named in honour of Manfred Kutscher, for his generous support and indefatigable, long-standing
research on the echinoderms of the Riigen Chalk, which yielded the type material of the only known
species of the genus; from oura, Greek for “tail”, a commonly used suffix in ophiuroid names; gender
feminine.

Remarks

Kutscher & Jagt (2000) described ahighly distinctive type of dissociated LAPs from the early Maastrichtian
of Germany and Denmark as Ophiomyxal curvata. A reassessment of the type material has revealed that
these LAPs display large ear-shaped spine articulations with a well-developed sigmoidal fold. Along
with the general morphology, the spine articulation structure precludes assignment to the Ophiomyxidae
Ljungman, 1867 but rather places this LAP type in the Ophiacanthidae. Within this family, however,
affinities are more problematic. Similarly curved, thick and massive LAPs devoid of outer surface
ornament are found only in Ophioleviathan gen. nov. and, to a lesser extent, Inexpectacantha. The LAPs
of these two, however, display fundamentally different spine articulations, and the ridge on the inner
side of the LAPs is much larger. Superficial similarities are shared with the LAPs of extant Ophientrema
Verrill, 1899, in particular on account of the extremely large height/width ratio, the strong curvature
and the lack of outer surface ornament. However, while these two genera are characterised by a large
uncalcified gap between the LAPs of neighbouring arm segments, the LAPs known as Ophiomyxal
curvata display a strongly depressed, narrow band along most of the proximal edge, suggesting that the
LAPs were in contact or even slightly overlapped. In addition, the LAPs of Ophiomyxal curvata display
a much shorter, tongue-shaped ridge.

These LAPs cannot be reconciled convincingly with the LAP morphological diagnosis of any currently
known ophiacanthid. It thus seems best to introduce Manfredura gen. nov. to accommodate them. The
similarities in general LAP morphology, the small, poorly defined tentacle notch and the considerably
smaller but similarly shaped ridge on the inner side, suggests that Manfredura gen. nov. is closest to
Ophioleviathan gen. nov. and Inexpectacantha. It seems unlikely, however, that it belongs to the same
lineage, considering the fundamental differences in spine articulation morphology. At the present state
of knowledge, the phylogenetic position of Manfredura gen. nov. within the small-pored ophiacanthids
remains elusive.

Manfredura curvata (Kutscher & Jagt, 2000) comb. nov.

Fig. 34: 5-7

Ophiomyxal curvata Kutscher & Jagt, 2000: 53, pi. 31 figs 4-7.

v v

non Ophiomyxal cf curvata - Store & Zitt 2008: 125, fig. 4G-K.

Diagnosis

As for genus.

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European Journal of Taxonomy 48: 1-242 (2013)

Material examined

GZG.1NV.78759, GZG.1NV.78760, GZG.1NV.78761 and 416 dissociated LAPs in the Manfred
Kutseher Colleetion, Sassnitz, Germany, the type material of Kutseher & Jagt (2000); GZG.1NV.78762
(3 dissoeiated LAPs) from the early Maastriehtian of Lagerdorf-Kronsmoor, Germany.

Description

Large dissoeiated LAPs, of massive, thiek and strongly eurved aspeet; proximal LAPs almost three
times higher than wide, distal ones slightly higher than wide; dorsal edge straight, oblique (proximal
LAPs) to strongly eoneave as a result of a eonstrietion (distal LAPs); distal edge eonvex; proximal edge
irregularly eoneave, with a weakly protruding, non-prominent eentral part; proximal to median LAPs
with strongly depressed, distally well-defined band as wide as one-quarter of the total LAP width along
the proximal edge exeept for its ventralmost part; mueh less well-defined, depressed band along eentral
part of proximal edge in distal LAPs; outer surfaee with finely meshed stereom, devoid of eonspieuous
ornament elements. Ten (proximal LAPs) to seven (distal LAPs) large, ear-shaped spine artieulations
freestanding on strongly elevated distal portion of LAP; dorsal lobe of spine artieulations larger and
thieker than ventral one, merged with the latter into eontinuous volute; weak dorsalward inerase in
size of spine artieulations and of gaps separating them; gap between spine artieulations and distal edge
of LAP relatively narrow; spine artieulations not sharply bordered proximally by ridge-like strueture.
Ventral edge of LAP irregularly eoneave; tentaele noteh invisible in external view.

Inner side of LAP with very small, sharply defined, prominent, slender, dorso-proximalwards bent,
tongue-shaped ridge devoid of kinks and strongly widened parts; small, well-defined, prominent,
vertieally elongate knobs elose to the dorso-proximal and ventro-proximal tips of the proximal and
median LAPs; ridge on inner side of distal LAPs larger, no knobs; no spurs on inner side of distal edge
of LAPs; inner side of tentaele noteh very small, shallow and poorly defined, almost indiseemible. Few,
minute, ineonspieuous perforations in vertieal row distally bordering ventral tip of ridge.

Remarks

The LAPs of Manfredura curvata eomb. nov. are highly diagnostie and eannot be eonfused with any other
type of LAP, exeept for the material from the Turonian of the Czeeh Republie deseribed and illustrated

V s/

by Store & Zitt (2008), who tentatively assigned this to Ophiomyxal curvata. The speeimens in question
indeed display a striking similarity to the LAPs of M. curvata eomb. nov. with respeet to general shape,
height/width ratio, shape and position of the spine artieulations and size of the tentaele noteh. While it
seems likely that the LAPs in question are assignable to Manfredura gen. nov., they elearly belong to a
different, still undeseribed speeies. In faet, the Turonian LAPs display spine artieulations with a mueh
stronger dorsalward inerease in size, a less well-developed depressed band along the proximal edge,
a mueh more slender ridge on the inner side, and no knobs on the inner side of the dorso- and ventro-
proximal tips of the LAP.

Occurrence

Early Maastriehtian of Germany.

Genus Ophiocamax Lymmi, 1878

Type species

Ophiocamax vitrea Lyman, 1878, by monotypy.

Diagnosis

Ophiaeanthid with large to very large LAPs eommonly devoid of any eonspieuous outer surfaee
ornament; single variably well-defined, protruding spur on outer proximal and inner distal edges; large

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THUYB., Fossil record of ophiacanthid brittle stars

to very large ear-shaped spine articulations freestanding on strongly elevated distal third or even half
of the proximal and median LAPs, with especially the dorsal spine articulations commonly widely
separated from distal edge of LAP; elevated portion of LAP commonly beset with scattered thorns or
granules; dorsalmost spine articulation at some distance from dorsal edge of LAP, commonly pointing
dorsalwards; dorsalmost and second dorsal spine articulations often much smaller than remaining ones;
dorsal lobe of spine articulations with conspicuous central notch; ridge on inner side with strongly
widened, generally short, triangular dorsal tip and evenly ventro-proximally bent ventral part; tentacle
notch very small, deeply incised, well defined and generally at least semi circular.

Remarks

Ophiocamax is one of the most distinctive and homogeneous genera in the Ophiacanthidae, consistently
displaying a number of characters not found in any other ophiacanthid. The same holds true for the
LAPs of Ophiocamax (Fig. 35: 1-6), at least for the species examined herein with respect to their LAP
morphologies, namely O. austera Verrill, 1899, O. fasciculata Lyman, 1883, O. hystrix Lyman, 1878
and the type species, O. vitrea. In fact, the LAPs of Ophiocamax display several highly distinctive
features, including spine articulations freestanding in the middle of the strongly elevated distal third or
even half of the LAPs and thus commonly widely separated from the distal edge of the LAP, dorsalwards
pointing dorsalmost spine articulations well below the dorsal edge of the LAP, dorsalmost and second
dorsal spine articulations which are often much smaller than the remaining ones, and a very small, well-
defined and at least semi-circular tentacle notch. In addition, the dorsal lobe of the spine articulations of
Ophiocamax displays a conspicuous central notch, which results in spine articulations that are seemingly
composed of proximal and distal rather than dorsal and ventral lobes.

The LAPs of extant Ophiomitra Lyman, 1869 (Fig. 34: 8-9), sister to Ophiocamax, share some important
characters with the LAPs of the latter, in particular the spine articulations freestanding on the strongly
elevated distal third or half of the LAP, the lack of a conspicuous outer surface ornament, and the
strongly widened dorsal tip of the ridge on the inner side. In contrast to the LAP of Ophiocamax,
however, those of Ophiomitra display nearly equal-sized spine articulations the dorsalmost of which
commonly being very close to the dorsal edge of the LAP. In addition, the dorsal lobe of the spine
articulation in Ophiomitra lacks the central notch.

Thanks to the numerous highly distinctive characters, the LAPs of Ophiocamax are expected to be
easily recognised in the form of dissociated fossil LAPs. Yet, only very few occurrences of dissociated
LAPs and articulated arm fragments assignable to Ophiocamax are currently known from shallow-
water settings, and all are from the Oxfordian. Another record from deep-sea deposits is noticeably
fundamentally similar to the LAPs of extant Ophiocamax but differs in a few minor respects and is thus
assigned to a new, most probably very closely related, genus, Reitneracantha gen. nov. (see below).

Ophiocamax dorotheae sp. nov.

um:lsid:zoobank.org:act:412FC94A-B8E6-48B2-915D-E719B0ADlQCC

Fig. 35: 7-11

Ophiacanthal suprajurassicaHQSS, 1965a: 1065, 1077.

Ophiacanthal sp. or Ophiothrixl sp. - Hess 1960: 419, fig. 39.

Ophiacanthal suprajurassica - Hess 1966: 1030, 1054, figs 76-77 (material incorrectly assigned to
Ophiacanthal suprajurassica Hess, 1965).

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European Journal of Taxonomy 48: 1-242 (2013)

Diagnosis

Species of Ophiocamax with large LAPs displaying large, well-defined, strongly protruding spur on
the outer proximal edge paralleled by a large, non-prominent, rounded area of densely meshed stereom
on the inner distal edge; up to five spine articulations, two dorsalmost of which always largest; ridge
on inner side of LAP relatively short, with strongly widened dorsal tip; dorsal arm plates irregularly
pentagonal to blazon-shaped, with small granules or thorns scattered on outer surface.

Etymology

Species named in honour of Dorothea Hause-Reitner for her friendship and generous assistance in
scanning electron microscopy.

Type material

Holotype

GZG.1NV.78763.

Paratypes

GZG.1NV.78764, GZG.1NV.78765, GZG.1NV.78766 and GZG.1NV.78767.

Type locality and horizon

Savigna, France; sample S2b of Gale (2011), Bimammatum Zone, late Oxfordian, Late Jurassic.

Additional material

GZG.1NV.78768 (29 dissociated LAPs) from sample S2b of Gale (2011), GZG.1NV.78769 (6 dissociated
LAPs) from sample SI of Gale (2011), GZG.1NV.78770 (8 dissociated LAPs) from sample S2a of Gale
(2011), all from the Bifurcatus Zone, late Oxfordian of Savigna, France; dissociated LAP from the
Bifurcatus Zone, late Oxfordian of Guldental, Switzerland, the original material of Hess (1966); 26
dissociated LAPs from the Renggeri Member, early Oxfordian of Chapois, France, the original material
of Hess (1965a); 2 dissociated LAPs from the Renggeri Member of Longecombe, France, the original
material of Hess (1965a).

Description

Holotype

GZG.1NV.78763 is a dissociated, large, proximal LAP; nearly as high as wide; dorsal edge strongly
concave as a result of a well-developed constriction; distal edge strongly convex; proximal edge
irregularly undulose, with a large, sharply defined, prominent and strongly protruding, oval, horizontally
elongate spur composed of densely meshed stereom; weakly defined, shallow depression in ventral half
of proximal edge, composed of more finely meshed stereom; outer surface with finely meshed stereom,
fining towards proximal edge. Five large ear-shaped spine articulations freestanding on strongly elevated
distal half of LAP; strong dorsalward increase in size of spine articulations and of gaps separating them;
ventral and dorsal lobes merged into continuous volute; dorsal lobe with conspicuous central notch; gap
between spine articulations and distal edge of LAP as wide as one spine articulation, strongly increasing
in width dorsalwards, parallel to dorsalward increase in size of spine articulations; dorsalmost spine
articulation below dorsal edge of LAP, pointing dorsalwards; spine articulations proximally sharply
bordered by undulose edge of elevated distal half of LAP. Ventral edge of LAP nearly straight, with very
small, weakly concave, almost indiscernible tentacle notch.

Inner side of LAP with very large, broad, sharply defined, prominent ridge with evenly bent, ventro-
proximally pointing ventral part, and strongly widened, near-triangular dorsal part; inner side of distal
edge of LAP with large, well-defined, rounded, non-prominent spur composed of densely meshed

200

THUYB., Fossil record of ophiacanthid brittle stars

Fig. 35. Skeletal plates and arm fragments of fossil and Recent ophiacanthid brittle stars; lateral arm plates
(LAPs) in external (a) and internal (b) views. 1-3. Ophiocamax vitrea Lyman, 1878, Recent. 1. Proximal
LAP. 2. Median LAP. 3. Dorsal arm plate. 4-5. Ophiocamax hystrix Lyman, 1878, Recent. 4. Proximal
LAP. 5. Median LAP. 6. Ophiocamax austera Verrill, 1899, Recent; proximal LAP. 7-11. Ophiocamax
dorotheae sp. nov. from the late Oxfordian (Late Jurassic) of Savigna, France. 7. GZG.rNV.78763
(holotype), proximal LAP. 8. GZG.rNV.78764 (paratype), median LAP. 9. GZG.INV.78765 (paratype),
distal LAP. 10. GZG.INV.78766 (paratype), proximal arm fragment in ventral view. 11. GZG.INV.78767
(paratype), median arm fragment in dorsal view. One common scale bar per species except for 10 and 11.

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European Journal of Taxonomy 48: 1-242 (2013)

stereom; inner side of tentaele noteh very small, semi-eireular, well defined laterally. No perforations or
furrow diseemible.

Paratype supplements and variation

GZG.1NV.78764 is a dissoeiated median LAP; slightly wider than high; very well in agreement with
holotype; dorsal edge less strongly eoneave; spur on proximal edge slightly smaller than in holotype.
Five spine artieulations similar to those of holotype; gap between spine artieulations and distal edge
of LAP slightly narrower. Ventral edge of LAP weakly eoneave, with very small, almost indiseemible
tentaele noteh.

Inner side of LAP with very large, well-defined, short ridge with strongly widened ventral and dorsal
edges; inner side of tentaele noteh very small, sharply defined, semi eireular.

GZG.1NV.78765 is a dissoeiated distal LAP; almost twiee wider than high; very well in agreement
with holotype; depression in ventral half of outer surfaee smaller and even less well defined than in
holotype, almost indiseemible. Four spine artieulations similar to those of holotype; dorsalmost spine
artieulation not pointing dorsalwards; gap between spine artieulations and distal edge of LAP mueh
narrower. Ventral edge of LAP gently eoneave; tentaele noteh invisible in external view.

Inner side of LAP with large, poorly defined, broad, weakly prominent ridge displaying strongly widened
ventral part and dorso-proximalwards pointing dorsal tip; spur on inner side of distal edge slightly less
well defined; inner side of tentaele noteh very small, more than semi eireular.

GZG.1NV.78766 is an artieulated arm fragment preserving two median segments; LAPs well in
agreement with dissoeiated ones deseribed above; dorsal arm plates large, widely separated by LAPs,
slightly longer than wide, widest distally, irregularly pentagonal to blazon shaped, with gently eonvex
distal edge, slightly proximalwards eonverging lateral edges and nearly right proximal angle; outer
surfaee of dorsal arm plates with small, seattered granules or thorns; ventral arm plates widely separated
by LAPs; slighty wider than long, widest distally, with gently eonvex to slightly angular distal edge,
short, straight lateral edges, small half-eireular tentaele notehes and obtuse proximal angle; few very
short arm fragments preserved, originally eylindrieal, with moderately eoarsely meshed outer surfaee
stereom, no further details preserved.

GZG.1NV.78767 is an artieulated arm fragment preserving three median to distal segments; one seeond
ventralmost arm spine nearly eompletely preserved, straight, eylindrieal, almost as long as one arm
segment, with moderately eoarsely meshed and slightly longitudinally elongate stereom.

Remarks

The highly distinetive shape and position of the spine artieulations, eombined with the laek of a
eonspieuous outer surfaee ornament, the distinetively shaped ridge on the inner side and the very small,
well-defined, semi-eireular tentaele noteh unambiguously plaee these LAPs in the genus Ophiocamax or
at least in a very elosely related form (more elosely related than to Ophiomitra, on aeeount of the mueh
eloser similarities in LAP morphology). The low number of spine artieulations and the very weakly
ventralwards protruding row of spine artieulations preeludes assignment to the elosely related Late
Jurassie Ophiosternle crinitum (Quenstedt, 1876). The present LAPs are by far the oldest reeord that is
assignable to Ophiocamax, predating the Mioeene reeords from Japan (Ishida 2001) and the Grenadines
(Jagt et al. in press).

The present LAPs differ in that the two dorsalmost spine artieulations invariably are the largest, rather
than mueh smaller than the remaining ones as in the LAPs of most extant speeies of Ophiocamax.
Greatest similarities are shared with the LAPs of extant O. vitrea, espeeially on aeeount of the shape and
position of the spine artieulations, the presenee of a well-developed spur on the outer proximal and inner

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distal edge, and the development of the tentacle notch. In addition, the shape and outer surface ornament
of the dorsal arm plates is markedly similar in O. vitrea and these fossil specimens. The shape of the
ridge on the inner side, in contrast, is more reminiscent of that observed in the LAPs of O. austera. In
the light of these minor, yet significant, morphological differences and the huge stratigraphic gap, the
fossil LAPs are here described as a new species.

Occurrence

Early to late Oxfordian of France, late Oxfordian of Switzerland.

Genus Reitneracantha gen. nov.

um:lsid:zoobank.org:act:3BFFDD52-C9E7-45QB-9QQl-EQ9134B80477

Type, and only known, species

Reitneracantha dissidens sp. nov.

Diagnosis

Ophiacanthid with moderately large FAPs devoid of conspicuous outer surface ornament or spurs on
the outer proximal edge; up to five large to very large, ear-shaped spine articulations freestanding on
the strongly elevated distal third or half of the FAP; proximal edge of the spine articulation irregularly
corrugated; dorsal lobe of the spine articulations vertically elongate, much larger than ventral one;
dorsalmost spine articulation invariably largest, conspicuously dorsalwards pointing, in proximal FAPs
well below dorsal edge of FAP; ridge on inner side relatively short with widened dorsal tip; tentacle
notch small, well defined laterally, semi circular.

Etymology

Genus named in honour of my friend and colleague Joachim Reitner, for his generous support and the
delightfully shared delicacies and wines; from Acantha, a nymph in Greek mythology whose name
literally translates to “thorny”; gender feminine.

Remarks

A very unusual type of dissociated FAPs was recovered from Early Jurassic deep-sea sediments of
Austria. The presence of large, ear-shaped spine articulations with a sigmoidal fold, combined with
the absence of a single large perforation on the inner side, clearly place these in the Ophacanthidae.
Within this family, such FAPs are close to those of extant Ophiocamax. The most important similarities
include the position of the spine articulations on the strongly elevated distal third or half of the FAP,
the central notch in the dorsal lobe of the spine articulations, the strong dorsalward increase in size of
the spine articulations, the conspicuously dorsalwards pointing dorsalmost spine articulation well below
the dorsal edge of the FAP, the lack of a conspicuous outer surface ornament, the widened dorsal tip of
the ridge on the inner side of the FAPs, and the very small, well-defined, semi-circular tentacle notch.

The shape of the spine articulations in these fossil FAPs, however, differs in displaying an irregularly
corrugated proximal edge of the volute. In addition, the dorsal lobe of the spine articulations in the
fossil FAPs is dorsally elongate and much larger than the ventral one. On account of these minor, yet
significant, differences, the present FAPs are here assigned to a new genus, Reitneracantha gen. nov.
However, similarities in FAP morphology are so close that Reitneracantha gen. nov. and Ophiocamax
most probably share close phylogenetic ties. From an FAP morphological perspective, the phylogenetic
relationships between Reitneracantha gen. nov. and Ophiocamax are probably even closer than between
the latter and its extant sister taxon Ophiomitra. Thus, Reitneracantha gen. nov. and Ophiocamax are
here considered to be members of the same lineage.

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European Journal of Taxonomy 48: 1-242 (2013)

Reitneracantha dissidens sp. nov.

um:lsid:zoobank.org:act:ElA8998E-3QEE-4921-B054-371C65DB6C9D

Fig. 36: 1-3

Diagnosis

As for genus.

Etymology

From dissidere, Eatin for “intractable, dissenting with an established policy”, in reference to the fact that
this species challenges established concepts of the role of the deep-sea in macroevolutionary patterns.

Type material
Holotype

NHMW 2012/0137/0029.

Paratypes

NHMW 2012/0137/0030 and NHMW 2012/0137/0031.

Type locality and horizon

Glasenbach Gorge, Austria; Hauptknollenbrekzie, late Sinemurian to early Pliensbachian, Early Jurassic.

Additional material

NHMW 2012/0137/0032 (3 dissociated EAPs).

Description

Holotype

NHMW 2012/0137/0029 is a dissociated, moderately large, proximal EAP; dorsal edge nearly straight,
oblique; distal edge convex; proximal edge nearly straight, except for small, very poorly defined, almost
indiscernible, weakly prominent and protruding spur; outer surface with finely meshed stereom, devoid
of conspicuous ornament. Five large, ear-shaped spine articulations freestanding on strongly elevated
distal half of EAP; dorsal edge of spine articulations vertically elongated, with conspicuous central notch,
much larger than ventral lobe, merged with the latter into continuous volute; very strong dorsalward
increase in size of spine articulations and of gaps separating them; dorsalmost spine articulation
largest, well below dorsal edge of EAP, comspicuously dorsalwards pointing; proximal edge of spine
articulations irregularly corrugated; spine articulations sharply bordered proximally by edge of elevated
portion, except for dorsalmost one; gap between spine articulations and distal edge of EAP as wide as
one spine articulation. Ventral edge of EAP nearly straight; tentacle notch invisible in external view.
Inner side of EAP with small, sharply defined, prominent, gently bent ridge displaying a ventro-
proximally bent ventral part not merged with ventral portion of EAP, and a widened, angular dorsal tip;
inner side of distal edge of EAP devoid of spurs; inner side of tentacle notch small, well defined laterally,
semi circular. No perforations or furrow discernible.

Paratype supplements and variation

NHMW 2012/0137/0030 is a dissociated median EAP; as high as wide; of rectangular to trapezoid
aspect; dorsal edge concave as a result of a constriction; distal edge nearly straight, oblique; proximal
edge devoid of spurs. Four spine articulations similar to those observed on holotype; dorsalmost spine
articulation much larger than remaining ones and widely separated from the latter, dorsalwards pointing,
near dorsal edge of EAP. Ventral edge of EAP straight, no tentacle notch visible.

Ridge on inner side of EAP similar to that of holotype but with less strongly widened dorsal tip.

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THUYB., Fossil record of ophiacanthid brittle stars

Fig. 36. Lateral arm plates (LAPs) of fossil and Recent ophiacanthid brittle stars in external (a) and internal
(b) views. 1-3. Reitneracantha dissidens gen. et sp. nov. from the late Sinemurian to early Pliensbachian
(Early Jurassic) of the Glasenbach Gorge, Austria. 1. NHMW 2012/0137/0029 (holotype), proximal
LAP. 2. NHMW 2012/0137/0030 (paratype), median LAP. 3. NHMW 2012/0137/0031 (paratype), distal
LAP. 4-5. Ophiohamus nanus O’Hara & Stohr, 2006, Recent. 4. Proximal to median LAP. 5. Proximal to
median LAP. 6-8. Sabinacantha archetypa gen. et sp. nov. from the late Oxfordian (Late Jurassic) of the
Plettenberg, Germany. 6. GZG.INV.78771 (holotype), proximal LAP. 7. GZG.INV.78772 (paratype),
median LAP. 8. GZG.INV.78773 (paratype), distal LAP. One common scale bar per species.

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European Journal of Taxonomy 48: 1-242 (2013)

NHMW 2012/0137/0031 is a dissociated distal LAP; slightly wider than high; dorsal edge strongly
eoneave as a result of a well-developed eonstrietion; proximal edge gently eoneave, devoid of spurs.
Four spine artieulations similar to those of holotype, freestanding on slightly elevated distal third of
LAP; dorsalmost spine artieulation mueh larger than remaining ones and widely separated from the
latter, pointing dorsalwards, at some distanee from the dorsal edge of the LAP Ventral edge of the LAP
eoneave, no tentaele noteh visible in external view.

Ridge on inner side of LAP similar to that of holotype but with weakly widened dorsal tip; inner side of
distal edge of LAP devoid of spurs; inner side of tentaele noteh moderately small, well defined laterally,
semi eireular.

Remarks

The taxonomie affinities of these LAPs have been diseussed above.

Genus Sabinacantha gen. nov.

um:lsid:zoobank.org:aet:DBFBC938-27CE-42Al-932C-F397C289B2E7

Type and sole known species

Sabinacantha archetypa sp. nov.

Diagnosis

Ophiaeanthid with moderately large EAPs of thiek, massive and rounded aspeet; single poorly to
moderately well-defined, protruding spur on outer proximal edge paralleled by large, round, weakly
prominent area of more densely meshed stereom on inner side of distal EAP edge; outer surfaee with
eoarse, irregular striation; three small, ear-shaped, oval, horizontally elongate spine artieulations tightly
grouped on weakly elevated ventral third to half of distal edge of EAP; dorsalward deerease in size of
spine artieulations; inner side of EAPs with well-defined, uniformly prominent, short, broad ridge with
widened, round dorsal tip; inner side of tentaele noteh small.

Etymology

Genus named in honour of my friend and eolleague Sabine Stohr, who has guided me when 1 took my
very first steps in ophiuroid researeh; from Acantha, a nymph in Greek mythology whose name literally
translates to “thorny”; gender feminine.

Remarks

Among the most unusual EAP types of extant ophiaeanthids is that of Ophiohamus nanus O’Hara &
Stohr, 2006 (Fig. 36: 4-5). In this small-sized speeies, the EAPs appear atypieally massive and rounded
for an ophiaeanthid. The most striking feature, however, are the four small, oval spine artieulations with
separated dorsal and ventral lobes, and grouped in the ventral half of weakly elevated distal edge. This
eombination of eharaeters is highly distinetive and not found in any other eurrently known ophiaeanthid
EAP type, exeept for a remarkable extinet one from the Kimmeridgian of Germany, reeorded herein.

These fossil EAPs are mueh larger and thieker that those of Ophiohamus nanus but nevertheless display
the highly eharaeteristie rounded aspeet and the small, oval spine artieulations with the diseontinuous
volute, tightly grouped in ventral half of weakly elevated distal edge. Other elose similarities are seen
in the shape of the ridge on the inner side, although in the fossil EAPs it is better defined and uniformly
prominent. Other minor differenees pertain to the presenee of a single, well-developed spur on the outer
proximal and inner distal edges in the fossil EAPs, and the outer surfaee ornament whieh, in the fossil
EAPs, eonsists of a eoarse, highly irregular vertieal striation, generally best defined elose to the spine
artieulations.

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THUYB., Fossil record of ophiacanthid brittle stars

These close similarities in LAP morphology strongly suggest that the fossil LAP type in question and
Ophiohamus nanus share strong phylogenetic ties, most probably forming a single lineage. The fossil
LAPs probably are not congeneric with the latter, on account of the minor, yet significant, differences
including the size of the LAPs, the number of the spine articulations, the development of the ridge on
the inner side, and the outer surface ornament. Anew genus, Sabinacantha gen. nov., is thus introduced
here to accommodate these Ophiohamus-\ikQ fossil LAPs.

There is, indeed, a close resemblance with the LAPs of extant Ophiochondrus convolutus Lyman, 1869,
which is closely related to Ophiohamus nanus in the revised phylogenetic analysis presented herein,
especially on account of the massive, rounded aspect of the LAPs, the weakly elevated distal edge of the
LAPs, the small, oval, horizontally elongate spine articulations with separated dorsal and ventral lobes,
the dorsalward decrease in size of the spine articulations, and even the shape of the ridge on the inner
side. These astonishing similarities are perfectly in line with the observation by Thuy & Stohr (2011)
that the closest similarities in LAPs are to be found in more closely related ophiuroid taxa.

Sabinacantha archetypa sp. nov.

um:lsid:zoobank.org:act:6CDF4231-69E4-419E-8596-AA9BDE71DC3C

Fig. 36: 6-8

Diagnosis

As for genus.

Etymology

Name formed after archetypum, Eatin for “archetype” or “idol”, referring to the precursor state of the
species in the Sabinacantha-Ophiohamus lineage.

Type material

Holotype

GZG.INV.7877L

Paratype

GZG.INV.78772 and GZG.INV.78773.

Type locality and horizon

Plettenberg near Balingen, Germany; clay pockets between sponge associations in the lowest bed
exposed in the quarry, Bimammatum Zone, late Oxfordian, Eate Jurassic.

Additional material

GZG.INV.78774 (3 dissociated EAPs).

Description

Holotype

GZG.INV.78771 is a dissociated, moderately large, proximal EAP; thick, massive, rounded aspect;
slightly higher than wide; dorsal edge and dorsal half of distal edge evenly convex, not separated by kink;
ventral half of distal edge slightly concave; proximal edge convex, with small, moderately well-defined,
rounded, prominent and very weakly protruding spur; ventro-proximal tip of EAP protruding; outer
surface with coarse, irregular vertical striation composed of thick, non-overlapping lamellae replaced
by moderately finely meshed stereom in proximal quarter of outer surface, with ventro-proximalward
fining of stereom. Three small, ear-shaped, equi-distant, oval, horizontally slightly elongate spine

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European Journal of Taxonomy 48: 1-242 (2013)

articulations freestanding on very weakly elevated ventral third of otherwise striated distal edge of LAP;
weak dorsalward deerease in size of spine artieulations; dorsal and ventral lobes of spine artieulations
separated by small noteh proximally; spine artieulations sharply bordered proximally by lamella of outer
surfaee striation. Ventral edge of LAP eonvex, no tentaele noteh diseemible.

Inner side of LAP with large, short, very broad, well-defined, uniformly prominent ridge; ventral
part of ridge narrowest, pointing ventralwards, not merged with ventral portion of LAP; dorsal part
of ridge strongly widened, rounded, pointing dorso-proximalwards; inner side of distal edge of LAP
with moderately large, round, well-defined, very weakly prominent spur eomposed of densely meshed
stereom; inner side of tentaele noteh small, well defined laterally, slightly oblique. No perforations or
furrow diseemible.

Paratype supplements and variation

GZG.1NV.78772 is a dissoeiated median LAP; nearly as high as wide; well in agreement with holotype;
part of proximal edge with spur strongly protmding; spur itself poorly defined, almost indiseemible;
vertieal striation on outer surfaee less well developed and less regular than in holotype, replaeed by
eoarsely meshed stereom on most of the outer surfaee exeept near the spine artieulations and in the
ventro-proximal area of finely meshed stereom. Three spine artieulations similar to those observed on
holotype but on weakly elevated ventral half (rather than third) of distal LAP edge.

Inner side similar to that of holotype. Group of very small, irregular perforations dorsally bordering
tentaele noteh.

GZG.1NV.78773 is a dissoeiated distal LAP; slightly wider than long; spur on proximal edge of LAP
moderately well defined, strongly protmding, eomposed of densely meshed stereom; ventro-proximal
tip of LAP strongly oblique; outer surfaee ornament as in holotype. Three spine artieulations similar to
those observed on holotype but on ventral half rather than third of distal edge of LAP.

Inner side of LAP similar to that of holotype; ridge slightly shorter; spur on inner side of distal edge
slightly larger, less well defined.

Remarks

These LAPs are the only ones assigned to Sabinacantha gen. nov. For a diseussion of their taxonomie
affinities, referenee is made to the seetion “Remarks” of the genus.

Occurrence

Late Oxfordian of Germany.

Genus Ophiochondrus Lymm, 1869

Type species

Ophiochondrus convolutus Lyman, 1869, by monotypy.

Diagnosis

Ophiaeanthid with small LAPs of massive, thiek and rounded aspeet; outer surfaee eommonly with
thiekened trabeeulae in some eases merged into a poorly developed vertieal striation; generally a
single, variably well-defined, protmding spur in the middle of the proximal edge, ventrally bordered
by a slightly depressed area of finely meshed stereom; small, oval, horizontally slightly elongate spine
artieulations freestanding and evenly distributed on very weakly elevated distal portion of the LAP;
dorsal and ventral lobes of spine artieulations separated proximally; spine artieulations of equal size
or with weak dorsalward deerease in size; ridge on inner side of LAPs moderately well defined, short.

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with ventro-proximalwards projecting extension of dorsal tip; tentacle notch very small, poorly defined,
almost inconspicuous.

Remarks

Ophiochondrus has traditionally been considered to be a member of the Hemieuryalidae Verrill, 1899
(e.g., Matsumoto 1917; Fell 1960; Smith et al. 1995), although the ophiacanthid affinities of the genus
have repeatedly been hinted at (Mortensen 1927, 1936; O’Hara & Stohr 2006). Eventually, Martynov
(2010) transferred Ophiochondrus to the Ophiacanthidae, along with the other former hemieuryalid
Ophiomoeris Koehler, 1904, on the basis of spine articulation morphology. This transfer is corroborated
by the phylogenetic anaylsis of Thuy et al (2012) and the revised phytogeny presented herein.

Indeed, in terms of LAP morphology (Fig. 37: 1-3), Ophiochondrus is closely similar to the ophiacanthid
genera Ophiolamina Stohr & Segonzac, 2006, Ophiohamus O’Hara & Stohr, 2006 and, to a lesser extent,
Ophiolebes. The LAPs of Ophiochondrus can be easily differentiated from those of Ophiohamus and
Ophiolamina on the basis of the shape and position of the spine articulations. Unfortunately, knowledge
of the LAP morphology of Ophiomoeris is incomplete, in particular with respect to the structures on
the inner side, which hampers the elaboration of a comprehensive diagnosis of LAP morphology for
Ophiochondrus. However, since the LAPs of the type species of Ophiochondrus are well known, an
attempt is made here to work out a diagnosis of LAP morphology for the genus. This is all the more
important because the ophiacanthid fossil record includes a type of dissociated LAPs which has a lot in
common with the LAPs of extant Ophiochondrus.

Ophiochondruspunctatus (Kutscher & Jagt, 2000) comb. nov.

Fig. 37: 4-5

Ophiacanthal punctata Kutscher & Jagt, 2000: 62-63, pi. 25 figs 3-5.

Diagnosis

Species of Ophiochondrus with small LAPs displaying a coarsely meshed stereom on the outer surface
with trabecular intersections strongly thickened into slightly vertically elongate granules or knobs;
small, very poorly defined, weakly prominent and protruding spur on the outer proximal edge, paralleled
on the inner distal edge by a moderately well-defined, rounded area of densely meshed stereom; up to
eight small, slightly oval, spine articulations, proximally bordered by thick, slightly knobby ridge; gap
between spine articulations and distal edge of LAP with trabecular intersections thickened into small
granules; ridge on inner side relatively small, short.

Material examined

GZG.INV.78775, GZG.INV.78776 and 260 dissociated LAPs in the Manfred Kutscher Collection in
Sassnitz, Germany, the type material of Kutscher & Jagt (2000).

Description

Small, dissociated LAPs, proximal ones slightly higher than wide, distal ones approximately 1.5 times
wider than high; proximal to median LAPs of massive, thick, rounded aspect; dorsal edge straight
(proximal LAPs) to concave (median and distal LAPs) as a result of a well-developed constriction; distal
edge convex; proximal edge nearly straight, with small, very poorly defined, weakly prominent and very
slightly protruding spur ventrally bordered by small, poorly defined, non-depressed area of slightly more
finely meshed stereom; outer surface with coarsely meshed stereom slightly fining towards proximal
edge; trabecular intersections of coarsely meshed stereom thickened into large, very weakly vertically
elongate granules or knobs. Eight (proximal LAPs) to six (distal LAPs) small, ear-shaped, slightly oval

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European Journal of Taxonomy 48: 1-242 (2013)

•V* jk « *.'•♦{’fis?*^''

^»r'

|S?"^3

Fig. 37. Lateral arm plates (LAPs) of fossil and Reeent ophiaeanthid brittle stars in external (a) and
internal (b) views. 1-2. Ophiochondrus convolutus Lyman, 1869, Reeent. 1. Proximal LAP. 2. Median
LAP. 3. Ophiochondrus stelliger Lyman, 1879, Reeent; proximal LAP. 4-5. Ophiochondrus punctatus
(Kutseher & Jagt, 2000) eomb. nov. from the early Maastriehtian (Early Cretaeeous) of Rtigen,
Germany. 4. GZG.1NV.78775, proximal LAP. 5. GZG.1NV.78776, distal LAP. 6-7. Ophiochondrus?
semirotundus (Kutseher & Jagt, 2000) eomb. nov. from the early Maastriehtian of Rtigen, Germany.
6. GZG.INV.78800, proximal LAP. 7. GZG.INV.78801, median LAP. 8-9. Ophiaeanthidae gen. et sp.
nov. innom. from the late Oxfordian (Late Jurassie) of the Plettenberg, Germany. 8. GZG.INV.78802,
proximal LAP. 9. GZG.1NV.78803, median or distal LAP. 10-11. Ophiojagtus argoviensis (Hess, 1966)
eomb. nov. from the late Oxfordian (Late Jurassie) of Savigna, Franee. 10. NHMB Ml 124, proximal
LAP. 11. NHMB Ml 1225, proximal to median LAP. One co mm on seale bar per speeies.

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THUYB., Fossil record of ophiacanthid brittle stars

spine articulations freestanding on weakly to fairly elevated distal portion of LAP; spine articulations
proximally bordered by thick, well-defined, knobby ridge composed of vertically merged thickened
trabeculae of coarsely meshed outer surface stereom; ventral and dorsal lobes of spine articulations
separated proximally by very small notch; spine articulations nearly of equal size or with very weak
dorsalward decrease in size; gap between spine articulations and distal edge of LAP at most as wide as
one spine articulation, with dorsalward increase in width, with trabecular intersections of moderately
finely meshed stereom thickened into small granules. Ventral edge of LAP weakly concave; tentacle
notch invisible in external view.

Inner side of LAPs with relatively small, short, well-defined, prominent ridge with ventro-proximalwards
bent ventral part not merged with ventral portion of LAP; dorsal tip of ridge slightly widened, with short
ventro-proximalwards projecting extension; small, round knob distally bordering ridge in distal LAPs;
inner side of distal edge of proximal to median LAPs with relatively small, moderately well-defined,
round, very weakly protruding area of more densely meshed stereom; inner side of tentacle notch very
small, shallow, moderately well defined laterally. No perforations or furrow discernible.

Remarks

Kutscher & Jagt (2000) described this LAP type from the early Maastrichtian of Germany and Denmark
in detail and tentatively assigned it to Ophiacantha using open nomenclature. They stressed, however,
that this assignment was highly doubtful when the fossil LAPs were compared with those of extant
species of Ophiacantha. Thanks to a systematic SEM-supported assessment of LAP morphologies
in Recent ophiacanthids performed in the course of the present study, it is now possible to constrain
the generic placement of these LAPs even further. Strongest similarities are shared with the LAPs of
Ophiochondrus, mainly on account of the massive, thick, rounded general aspect of the LAPs, the shape,
size and position of the spine articulations, the outer surface ornament, and the shape of the ridge on the
inner side. It is the first fossil record of Ophiochondrus or at least of a very closely related, extinct genus.

The LAPs of Ophiochondrus punctatus comb. nov. cannot be confused with any other fossil type of LAP.
Those of co-occurring Ophiochondrus? semirotundus (Kutscher & Jagt, 2000) comb. nov. have fewer
spine articulations not bordered proximally by a ridge, and large contact surfaces with the opposite LAP
on the inner side. LAPs assigned to Inexpectacantha display strongly tilted spine articulations with a
ventral lobe commonly merged with the outer surface stereom, and a ridge on the inner side lacking the
ventro-proximalwards projecting extension.

Occurrence

Early Maastrichtian of Germany and Denmark.

Ophiochondrus? semirotundus (Kutscher & Jagt, 2000) comb. nov.

Fig. 37: 6-7

Ophiothelal semirotunda Kutscher & Jagt, 2000: 74-75, pi. 29 figs 11-13.

Diagnosis

Species tentatively assigned to Ophiochondrus with small, massive, rounded and thick EAPs displaying
a coarsely granular outer surface; proximal edge slightly thickened, separated from the remaining outer
surface by a shallow, moderately well-defined furrow; no spurs discernible on outer proximal and inner
distal edges; up to six small, oval, horizontally elongate spine articulations on bulging distal portion of
EAP; inner side of EAP with small, rather poorly defined ridge displaying weakly widened dorsal tip;
large dorsal and ventral contact surfaces with opposite EAP facing midline of arm.

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European Journal of Taxonomy 48: 1-242 (2013)

Material examined

GZG.1NV.78800, GZG.1NV.78801 and 32 dissociated LAPs in the Manfred Kutseher Colleetion in
Sassnitz, Germany, the type material of Kutseher & Jagt (2000).

Description

Small, dissoeiated LAPs, proximal ones slightly higher than wide, distal ones slightly wider than high;
of rounded, massive, thiek aspeet; dorsal edge slightly eoneave as a result of a eonstrietion; distal edge
eonvex; proximal edge nearly straight to slightly eonvex, with proximally protruding ventro-proximal
tip; proximal edge slightly thiekened, separated from remaining outer surfaee by shallow, moderately
well-defined furrow; no spurs on proximal edge; outer surfaee with moderately eoarsely granular
stereom even between spine artieulations and on thiekened part of proximal edge; granules on outer
surfaee with weak tendeney to merge into short, knobby, irregular vertieal ridges. Six (proximal LAPs)
to five (distal LAPs) small, equal-sized and nearly equi-distant, ear-shaped, oval, horizontally elongate
spine artieulations freestanding on bulging distal portion of LAP; not bordered proximally by a ridge;
dorsal and ventral lobes nearly horizontal, separated proximally; gap between spine artieulations and
distal edge of LAP as wide as half a spine artieulation; row of spine artieulations slightly oblique, dorso-
proximalwards reeeding. Ventral edge of LAPs eonvex; tentaele noteh invisible in external view.

Inner side of LAPs with small, short, poorly defined, prominent, ineonspieuous ridge, with ventro-
proximalwards bent, slightly widened ventral part not merged with ventral portion of LAP; dorsal tip
of ridge slightly widened, no extension diseemible; inner side of distal edge of LAP devoid of spurs;
inner side of tentaele noteh very small, moderately well defined laterally, shallow; dorsal, ventral and
ventro-proximal edges faeing midline of arm with large, vertieal eontaet surfaees. No perforations or
furrow diseemible.

Occurrence

Early Maastriehtian of Germany and Denmark.

Remarks

This LAP type from the Early Maastriehtian of Germany and Denmark was first deseribed by Kutseher &
Jagt (2000) as Ophiothelal semirotunda. Assignment to the ophiotriehid genus Ophiothela Verrill, 1867
is untenable eonsidering the fundamental differenees in spine artieulation morphology (Martynov 2010).
Interestingly, Kutseher & Jagt (2000) mentioned that their new speeies showed a eertain resemblanee
to small-sized ophiaeanthids, and later primarily eompared it to EAP types originally assigned to
hemieuryalids (here reinterpreted as speeies of the ophiaeanthid Inexpectacantha; see above). Indeed,
the presenee of a sigmoidal fold in the spine artieulations unambiguously plaees the EAPs in question
in the Ophiaeanthidae.

A eomparison with the EAPs of Reeent ophiaeanthids reveals that elosest similarities are shared with the
EAPs of Ophiochondrus, in partieular on aeeount of the generally round, massive and stout aspeet, the
size, shape and position of the spine artieulations, and the outer surfaee ornament. Signifieant differenees,
however, ean be found in the stmeture of the inner side. In faet, these fossil EAPs display large eontaet
surfaees with the opposite EAP, faeing the midline of the arm. Sueh eontaet surfaees are eommonly
found in speeies of the ophiolepidid genus Ophiomusium Eyman, 1869 (e.g. Kutseher & Jagt 2000), but
are atypieal of Ophiochondrus. This differenee is very likely to warrant separation at the generie level.
However, as long as the inner side of the EAPs of Ophiomoeris remains unknown, assignment to this
genus eannot be mled out. At the present state of knowledge, it thus seems best to tentatively assign
the present EAPs to Ophiochondrus, stressing, however, that there are signifieant differenees in EAP
morphology between the fossil EAPs and those of Reeent Ophiochondrus, in partieular the type speeies
of the genus.

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THUYB., Fossil record of ophiacanthid brittle stars

Ophiacanthidae gen. et sp. nov. innom.
Fig. 37: 8-9

Material examined

GZG.INV.78802, GZG.INV.78803 and GZG.INV.78804 (dissociated LAPs) from the Bimammatum
Zone, late Oxfordian, Late Jurassic of the Plettenberg, Germany.

Description

GZG.INV.78802 is a dissociated, tiny, proximal LAP; very fragile, dorso- and ventro-proximal tips
missing; originally at least twice higher than wide; distal edge convex; outer surface with finely
and moderately densely meshed stereom. At least six very large, densely spaced spine articulations
freestanding on elevated distal portion of LAP; shape of spine articulations very unusual, complex;
dorsal lobe very large, distally encompassing several openings of variable size; sigmoidal fold well
developed but very short, proximally bordering very small nerve opening; ventral lobe very slender,
proximally merged with dorsal lobe; spine articulations slightly oval, horizontally elongate; middle spine
articulations largest, with dorsalward and ventralward decrease in size; spine articulations proximally
sharply bordered by straight, well-defined but weakly prominent edge of elevated distal portion of LAP;
gap between spine articulations and distal edge of LAP generally narrow, widest near middle spine
articulations. No tentacle notch discernible in external view.

Inner side of LAP with very slender, moderately well-defined, weakly prominent, oblique and near¬
straight ridge with widened, vertically elongate dorsal tip composed of more finely meshed stereom;
ventral tip of ridge indiscernible or poorly preserved; single, well-defined, prominent, oval spur
composed of densely meshed stereom in ventral half of inner side of distal LAP edge; inner side of
tentacle notch not preserved or indiscernible. No perforations or furrow discernible.

GZG.INV.78803 is a dissociated median or distal LAP, strongly broken; outer surface with very densely
meshed stereom. At least four very closely spaced spine articulations similar to those observed on the
proximal specimen described above, displaying dorsalward increase in size; row of spine articulations
ventrally bordered by very large, oblique, lenticular, round, strongly prominent ridge-like structure
composed of dense stereom.

Inner side of LAP with very slender, moderately well-defined, prominent ridge similar to the main part
of the ridge observed on the previous specimen; ventral tip of ridge merged with large, well-defined,
strongly prominent, oblique, elongate knob composed of densely meshed stereom; spur on inner side
of distal edge of LAP much larger than in previous specimen; very large, round, lenticular, strongly
prominent structure ventrally bordering row of spine articulations almost completely exposed in internal
view.

Remarks

These specimens probably are among the most unusual ophiuroid LAPs ever recorded. The very
weird, complex spine articulations display a sigmoidal fold, which suggests that the LAPs in question
are assignable to the Ophiacanthidae. Affinities within this family, however, are purely speculative.
These LAPs appear so highly derived that it is difficult, if not impossible, to deduce any phylogenetic
relationships with other ophiacanthids on the basis of LAP morphology. It is even unfeasible to determine
with certainty if this LAP type belongs to a large-pored or a small-pored ophiacanthid. To make matters
worse, the material available is very limited and fragmentary, which hampers a proper systematic
assessment of this highly intriguing LAP type.

Striking similarities in the structure of the spine articulations are shared with the LAPs of the ophiocomid
Ophiopterispapillosa Lyman, 1875. It cannot be ruled out that these similarities refiect close phylogenetic

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European Journal of Taxonomy 48: 1-242 (2013)

ties, which would place the present LAP type in the Ophiocomidae Ljungman, 1867. However, most
of the other characters, in particular the size and fragility of the LAPs, the shape of the ridge on the
inner side, the enigmatic structure ventrally bordering the row of spine articulations and the absence
of perforations on the inner side, differ fundamentally. It thus seems more probable that the similarly
shaped spine articulations were acquired independently.

In the absence of more material, this LAP type cannot be formally described. It is clear, however, that
it represents a new genus and species most probably assignable to the Ophiacanthidae. It is hoped that
more material of this intriguing LAP type will be discovered in order to investigate its phylogenetic
position and speculate on the function of the unusual spine articulation morphology and the enigmatic
structure ventrally bordering the row of spine articulations.

Genus Ophiojagtus gen. nov.

um:lsid:zoobank.org:act:0B5FB6EE-42F6-43D5-BC67-41AE35B82EE3

Type species

Ophiojagtus acklesi sp. nov. by present designation.

Other species included

Hemieuryalel argoviensis Hess, 1966; Ophiojagtus irimurai sp. nov. and Ophiosmilaxl alternatus
Kutscher & Jagt, 2000.

Diagnosis

Ophiacanthid with stout, thick, strongly curved EAPs generally with a large height/width ratio; outer
surface devoid of ornament elements; no spurs on outer proximal and inner distal edges; ventral portion
of EAPs long to extremely long, strongly protruding ventral wards and often with widened ventral tip;
proximal edge commonly with proximally pointing protrudion; large, ear-shaped spine articulations
composed of thick, continuous volute, freestanding on bulging distal portion of EAP and not bordered
proximally by a ridge-like structure; broad, well-defined ridge on the inner side of the EAPs, generally
with dorso-proximally pointing dorsal part; tentacle notch large but poorly defined and generally shallow.

Etymology

Genus named in honour of my friend and colleague John W.M. Jagt for his generous support in the
course of the present project and for his outstanding contributions to ophiuroid palaeontology; gender
masculine.

Remarks

The Mesozoic ophiuroid fossil record includes a highly distinctive type of dissociated EAPs characterised
by a thick and massive general aspect, very long, conspicuous ventral portion, large, ear-shaped spine
articulations freestanding on the bulging distal portion of the EAP and composed of a thick, continuous
volute, and the absence of outer surface ornament and spurs. This combination of characters is not
found in any other ophiuroid EAP type. A new genus, Ophiojagtus gen. nov., is thus introduced here to
accommodate the EAP type in question.

Previous records which can be assigned to this new genus include Hemieuryalel argoviensis Hess, 1966
from the Oxfordian of Switzerland and France (Hess 1966), Ophiosmilaxl alternatus Kutscher & Jagt,
2000 from the Campanian and Maastrichtian of Germany, Denmark and Belgium (Kutscher & Jagt

'w'

2000) and records of the latter form from the Turonian of the Czech Republic and Tunisia (Store 2004).
Astonishingly, the striking similarities between these two species have not been noted previously. As a

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THUYB., Fossil record of ophiacanthid brittle stars

consequence, they were assigned to completely different genera belonging to unrelated families (Smith
et al. 1995). On account of fundamental differences in spine articulation structure, assignment either to
the Hemieuryalidae (Hemieuryale) or the Ophiomyxidae {Ophiosmilax Matsumoto, 1915) is tenable.
Rather, the presence of large, ear-shaped spine articulations with a sigmoidal fold in combination with
a series of small perforations on the inner side rather than a single large one near the ventral part of the
ridge is suggestive of strong ophiacanthid affinities, however atypical this LAP type might appear for
an ophiacanthid.

Affinities within the Ophiacanthidae, in contrast, are much more difficult to resolve. In spite of the
relatively large, poorly defined tentacle notch in the LAPs of Ophiojagtus gen. nov., the tentacle pore
in the context of the articulated arm was presumably small, considering the extremely long ventral
portion of the LAPs. Thus, it seems probable that Ophiojagtus gen. nov. belongs to the small-pored
ophiacanthids. Closest similarities seem to be shared with the LAPs of Inexpectacantha, mainly on
account of the massive, thick general aspect, the position of the spine articulations, and the lack of outer
surface ornament and of spurs. However, it is likely that these similarities are superficial, considering
the significantly different spine articulation morphologies and ridge shapes. The LAPs of Ophiojagtus
gen. nov. appear to be so highly derived that the phylogenetic relationships of the genus cannot be
further explored on the basis of LAP morphology.

As already hinted at by Store (2004), the LAPs here assigned to Ophiojagtus gen. nov. remained
morphologically conservative over considerable time intervals. Although it seems very unlikely that a

■w"

single species spanned some 20 Ma, as suggested by Store (2004), it can be challenging, if not impossible,
to differentiate stratigraphically close LAP types of Ophiojagtus gen. nov., in particular when only
few LAPs are available. In the present study, a total of four LAP types of Ophiojagtus gen. nov. are
characterised and identified at the species level. A few additional occurrences of the genus, including
those recorded by Store (2004) and Store & Zitt (2008), could not be assigned with certainty and are thus
treated here as indeterminate records of the genus.

Ophiojagtus argoviensis (Hess, 1966) comb. nov.

Fig. 37: 10-11

Hemieuryalel argoviensis YIqss, 1966: 1040, 1052, figs 24-25, 67-69.

Diagnosis

Species of Ophiojagtus gen. nov. with relatively small LAPs displaying a broad and short ventral portion
accounting for approximately one-quarter of the total LAP height; proximal edge occasionally with
very weak, rounded protrusion; five to six spine articulations with weak dorsalward increase in size
and slightly stronger dorsalward increase in the size of the gaps separating them; ridge on the inner side
relatively slender, evenly bent, with slightly widened dorsal tip and with ventral half extending well onto
the ventral portion of the LAP.

Material examined

NHMB Ml 124, NHMB Ml 1225 and 3 dissociated LAPs from the late Oxfordian of Savigna, France,
the type material of Hess (1966); GZG.INV.78805 (1 dissociated LAP) from sample SI of Gale
(2011), GZG.INV.78806 (2 dissociated LAPs) from sample S2a of Gale (2011) and GZG.INV.78807
(4 dissociated LAPs) from sample S2b of Gale (2011), all from the Bifurcatus Zone, late Oxfordian of
Savigna, France; 2 dissociated LAPs from the Bifurcatus Zone of Guldental, Switzerland, the original
material of Hess (1966).

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European Journal of Taxonomy 48: 1-242 (2013)

Description

Relatively small dissoeiated LAPs; of thiek, massive, strongly eurved general aspeet; more than twiee
higher than wide (proximal LAPs) to approximately 1.5 times higher than wide (median to distal
LAPs); dorsal edge rounded; distal edge eonvex; proximal edge eoneave, generally with very weak,
rounded protrusion; no spurs; ventral portion of the LAPs broad, weakly widened ventrally, relatively
short, aeeounting for one-quarter of the total LAP height; outer surfaee with finely meshed stereom,
devoid of eonspieuous ornament elements. Five to six large, ear-shaped spine artieulations freestanding
on bulging distal portion of LAP and eomposed of a thiek, eontinuous volute; spine artieulations not
sharply bordered proximally; weak dorsalward inerease in size of spine artieulations and slightly larger
dorsalward inerease in size of gaps separating them; gap between spine artieulations and distal edge of
LAP narrow.

Inner side of LAPs with well-defined, prominent, relatively slender, gently bent ridge; dorsal half of
ridge pointing dorso-proximalwards, with slightly widened dorsal tip; ventral half of ridge extending
onto most of the ventral portion of the LAP but not merged with the latter; no spurs on inner side of the
distal edge of LAP; inner side of the tentaele noteh moderately large, poorly defined, very shallow. Few,
small, seattered perforations in shallow, moderately well-defined vertieal furrow dorsally bordering
tentaele noteh.

Remarks

This type of LAP was originally deseribed by Hess (1966) as Hemieuryalel lunaris on the basis of
dissoeiated LAPs and vertebrae from the Oxfordian of Switzerland and Franee. A re-examination of
the type material, in addition to new finds of dissoeiated LAPs from the Oxfordian of Franee, has now
revealed that this LAP type displays the distinetive eombination of eharaeters unambiguously warranting
assignment to Ophiojagtus gen. nov.

Occurrence

Late Oxfordian of Franee and Switzerland.

Ophiojagtus irimurai sp. nov.

um:lsid:zoobank.org:aet:F0BACE55-91F5-4744-BA63-5CQ78F04C4DE

Fig. 38: 1-4

Diagnosis

Speeies of Ophiojagtus gen. nov. with wide, but eomparatively short, ventral protrusion aeeounting for
one-fifth to less than one-third of the total EAP height; proximal edge with weakly to very well-developed
protrusion; four to seven spine artieulations; weak dorsalward inerease in size of spine artieulations and
of gaps separating them; ridge on inner side relatively slender, with weakly widened dorsal tip; ventral
part of ridge extending well onto the ventral portion of the EAP; eonspieuously angular kink between
the ventral and dorsal parts of the ridge.

Etymology

Speeies named in honour of my friend and eolleague Seiiehi Irimura, in admiring reeognition of his
eontributions to ophiuroid systematies.

Type material

Holotype

GZG.1NV.78808.

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THUYB., Fossil record of ophiacanthid brittle stars

Paratypes

GZG.INV.78809, GZG.INV.78810 and GZG.INV.78811.

Type locality and horizon

Pointe du Chay near La Rochelle, France; Achilles Subzone, Cymodoce Zone, early Kimmeridgian, Late
Jurassic.

Additional material

GZG.INV.78812 (3 dissociated LAPs) from the early Kimmeridgian of the Pointe du Chay, France;
GZG.INV.78813 (1 dissociated LAP) from the Amaral Formation, late Kimmeridgian of Trancoso,
Portugal.

Description

Holotype

GZG.INV.78808 is a dissociated, large, proximal LAP; of massive, stout and strongly curved general
aspect; almost three times higher than wide; dorsal edge rounded, convex; distal edge convex; proximal
edge weakly concave, devoid of spurs, with very weak, rounded protrusion; ventral portion of LAP
moderately broad, widened ventrally, relatively short, accounting for one-fifth of the total LAP height;
outer surface with finely meshed stereom. Seven large, nearly equal-sized, ear-shaped spine articulations
freestanding on bulging distal portion of LAP and composed of thick, continuous volute; weak dorsalward
increase in size of gaps separating spine articulations; gap between spine articulations and distal edge
of LAP narrow.

Inner side of LAP with well-defined, prominent, rather slender ridge; dorsal part of ridge slightly bent,
oblique, with weakly widened dorsal tip; ventral part of ridge slightly narrower, less well defined and
less strongly prominent than dorsal one, connected with the latter by a rounded kink and extending well
onto the ventral portion of the LAP; ventral tip more strongly prominent than remaining ventral part of
the ridge; no spurs on inner side of LAP; inner side of tentacle notch relatively small, poorly defined
and shallow. Several small perforations loosely arranged in vertical row in very shallow, poorly defined
furrow dorsally bordering tentacle notch.

Paratype supplements and variaton

GZG.INV.78809 is a dissociated median LAP; approximately 1.5 times higher than wide; proximal
edge with very large, conspicuous, rounded protrusion; ventral portion of LAP wide but relatively short,
accounting for less than one-quarter of the total LAP height, protruding ventro-proximalwards. Four
spine articulations similar to those observed on holotype; very weak dorsalward increase in size of spine
articulations; stronger dorsalward increase in size of gaps separating spine articulations.

Ridge on inner side of LAP similar to that of holotype but shorter and broader; kink between dorsal and
ventral part of ridge conspicuously angular; inner side of tentacle notch relatively large, moderately well
defined but shallow. Broad, moderately well-defined, short vertical furrow with four small, irregular
perforations distally bordering kink of ridge.

GZG.INV.78810 is a dissociated median LAP; ventral portion missing; proximal edge with large but
rather weak, inconspicuous rounded protrusion. Five spine articulations similar to those of holotype;
very weak dorsalward increase in size of spine articulations and of gaps separating them.

Inner side of LAP fragmentary, with only dorsal part of ridge preserved. Two small perforations in
shallow, narrow, poorly defined vertical furrow.

GZG.INV.78811 is a dissociated distal LAP; slightly higher than wide; dorsal edge weakly convex;
proximal edge with large but rather weak and inconspicuous rounded protrusion; ventral portion of LAP
wide and moderately long, accounting for slightly less than one-third of the total LAP height, strongly

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European Journal of Taxonomy 48: 1-242 (2013)

Fig. 38. Fossil lateral arm plates (LAPs) of ophiaeanthid brittle stars in external (a) and internal (b)
views. 1-4. Ophiojagtus irimurai gen. et sp. nov. from the early Kimmeridgian (Late Jurassie) of the
Pointe du Chay, Franee. 1. GZG.INV.78808 (holotype), proximal LAP. 2. GZG.INV.78809 (paratype),
median LAP. 3. GZG.1NV.78810 (paratype), median LAP. 4. GZG.1NV.78811 (paratype), distal LAP.
5-7. Ophiojagtus acklesi gen. et sp. nov. from the late Aptian (Early Cretaeeous) of Wizard Way, Texas.
5. GZG.1NV.78814 (holotype), proximal LAP. 6. GZG.1NV.78815 (paratype), median to distal LAP.
7. GZG.1NV.78816 (paratype), proximal LAP. 8. Ophiojagtus sp. 1 from the early Cenomanian (Late
Cretaeeous) of Waeo, Texas; proximal LAP. 9-10. Ophiojagtus alternatus (Kutseher & Jagt, 2000)
eomb. nov. from the early late Maastriehtian (Late Cretaeeous) of Haeeourt, Belgium. 9. NHMM 2012
060, proximal to median LAP. 10. NHMM 2012 061, proximal LAP. One co mm on seale bar per speeies.

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THUYB., Fossil record of ophiacanthid brittle stars

protruding ventro-proximalwards. Four spine articulations similar to those observed on holotype;
dorsalward increase in size of spine articulations.

Ridge on inner side of LAP similar to that of holotype but shorter and with conspicuously angular kink
between dorsal and ventral parts. Several small perforations closely grouped in vertical row distally
bordering kink of ridge.

Remarks

These LAPs are unambiguously assignable to Ophiojagtus gen. nov. on account of the highly distinctive
general morphology, the large, protruding ventral portion, the lack of outer surface ornament, the
structure and position of spine articulations and the shape of the ridge on the inner side. Among the LAP
types assignable to this genus, the present ones stand out in displaying up to seven spine articulations, a
relatively short ventral portion and a conspicuously angular kink between the ventral and the dorsal part
of the ridge on the inner side.

Occurrence

Early Kimmeridgian of France, late Kimmeridgian of Portugal.

Ophiojagtus acklesi sp. nov.

um:lsid:zoobank.org:act:A51326C9-FAAE-4FFF-96BA-C8442F76BAQB

Fig. 38: 5-7

Diagnosis

Ophiacanthid with stout, thick, strongly curved EAPs generally with a high height/width ratio; outer
surface devoid of ornamentation elements; no spurs on outer proximal and inner distal edges; ventral
portion of EAPs long to extremely long, strongly protruding ventralwards and often with widened
ventral tip; proximal edge commonly with proximalwards pointing protrusion; large, ear-shaped spine
articulations composed of thick, continuous volute, freestanding on bulging distal portion of EAP and
not bordered proximally by a ridge-like structure; broad, well defined ridge on the inner side of the
EAPs, generally with dorso-proximalwards pointing dorsal part; tentacle notch large but poorly defined
and generally shallow.

Etymology

Species named in honour of Texas-bom actor Jensen Ackles; my wife urged me to do so.

Type material

Holotype

GZG.INV.78814.

Paratypes

GZG.INV.78815 and GZG.INV.78816.

Type locality and horizon

Wizard Way, Texas, USA; echinoid marker bed of Smith & Rader (2009), latest Aptian, Early Cretaceous.

Additional material

GZG.INV.78817 (67 dissociated EAPs).

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European Journal of Taxonomy 48: 1-242 (2013)

Description

Holotype

GZG.1NV.78814 is a dissociated, moderately large, proximal LAP; approximately twiee higher than
wide; of stout, massive and strongly eurved aspeet; dorsal edge slightly eoneave on aeeount of the
pointed dorso-proximal tip of the LAP strongly protruding towards arm midline; distal edge eonvex;
proximal edge eoneave, with two elosely spaeed, pointed protrusions, ventral one of whieh larger; ventral
portion rather narrow and very long, aeeounting for more than one-third of the total LAP height, with
widened, eonspieuously ventro-proximalwards pointing ventral tip; outer surfaee with finely meshed
stereom, devoid of ornament elements; slightly more eoarsely meshed stereom on ventral portion of
LAP Four large, nearly equi-distant, ear-shaped spine artieulations freestanding on strongly bulging
distal portion of LAP, and eomposed of a thiek, eontinuous volute; slight dorsalward inerease in size of
spine artieulations; gap between spine artieulations and distal edge of LAP rather narrow.

Inner side of LAP with well-defined, prominent, broad but very short, oblique ridge; dorsal tip of ridge
strongly widened and ventro-proximalwards extending onto inner side of protrusions of proximal edge
of LAP; ridge restrieted to the eentre of the inner side, no part of the ridge extending onto the ventral
portion of the LAP; no spurs on the inner side of the distal edge of the LAP; inner side of the tentaele
noteh relatively large, very poorly defined, shallow, almost indiseemible. Single small perforation
between tentaele noteh and ventral tip of ridge.

Paratype supplements and variation

GZG.1NV.78815 is a dissoeiated median to distal LAP; approximately 1.5 times higher than wide; very
well in agreement with holotype; ventral portion aeeounting for almost half of the total LAP height;
single, large, well-developed, round protrusion on proximal edge. Four spine artieulations similar to
those observed on holotype.

Inner side of LAP very well in agreement with that of holotype; ridge slightly shorter.

GZG.1NV.78816 is a dissoeiated proximal LAP; ventral portion missing; single large, well-developed,
rounded protrusion on proximal edge. Five spine artieulations similar to those of holotype but with
weaker dorsalward inerease in size.

Inner side similar to that of holotype.

Remarks

The highly distinetive eombination of eharaeters displayed by these LAPs unambiguously plaees them
in the genus Ophiojagtus gen. nov. Confusion with other LAP types assigned to this genus is preeluded
by the presenee of four to five spine artieulations, in eombination with a very long ventral portion and a
very short ridge on the inner side not extending onto the ventral portion of the LAP but with a strongly
widened dorsal tip projeeting onto the inner side of the well-developed protrusion of the proximal LAP
edge. Sinee this LAP type displays the diagnostie eombination of eharaeters of Ophiojagtus gen. nov.
most elearly, it is ehosen as the type speeies of the genus.

Occurrence

Latest Aptian of Texas.

Ophiojagtus sp. indet.
Fig. 38: 8

Material examined

GZG.1NV.78818 (1 dissoeiated LAP) from the early Cenomanian, Late Cretaeeous of Waeo, Texas,
USA.

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THUYB., Fossil record of ophiacanthid brittle stars

Description

GZG.INV.78818 is a dissociated, moderately large, proximal LAP; ventral portion and dorso-proximal
edge missing; distal edge convex; proximal edge with very large, conspicuous, well-developed protrusion;
outer surface with finely meshed stereom. Five large, ear-shaped spine articulations freestanding on
strongly bulging distal portion of LAP and composed of a thick, continuous volute; dorsalward increase
in the size of the spine articulations and of the gaps separating them; gap between the spine articulations
and the distal edge of the LAP narrow.

Inner side of the LAP with moderately well-defined, weakly prominent, broad ridge with conspicuous,
strongly widened dorsal tip extending ventro-proximalwards on inner side of protrusion of proximal
LAP edge; presence of a ventral part of the ridge not determinable. Single small perforation at the
ventral tip of a shallow, poorly defined vertical furrow distally bordering the ventralmost preserved part
of the ridge.

Remarks

Although the single LAP described above is unambiguously assignable to Ophiojagtus gen. nov., its
fragmentary nature precludes any species-level identification. The presence of five spine articulations

V v

places this LAP closest to O. acklesi sp. nov. or to the LAPs described by Store & Zitt (2008) and
probably erroneously assigned to O. alternatus comb. nov. (see below). However, since the ventral
portion is missing, the shape of the ridge on the inner side cannot be assessed, which precludes any
further conclusions on the placement of the specimen at the species level.

Ophiojagtus alternatus (Kutscher & Jagt, 2000) comb. nov.

Fig. 38: 9-10

Ophiosmilaxl alternatus Kutscher & Jagt, 2000 in Jagt 2000: 7, pi. 1 figs 1-2.

Ophiosmilaxl alternatus Kutscher & Jagt, 2000: 47-48, pi. 31 figs 8-12, pi. 33 figs 9-11.

Ophiosmilaxl n. sp. - Jagt 1999a: 199, pi. 1 figs 1-2.

Ophiosmilaxl alternatus - Jagt & Riegraf 2003: table 1.

non Ophiosmilaxl alternatus - Store 2004: 397, figs 6-8. — Store & Zitt 2008: 124, fig. 4A-F.

Diagnosis

Species of Ophiojagtus gen. nov. with moderately large LAPs displaying an extremely long ventral
portion, three to four spine articulations and an evenly bent, slender ridge on the inner side extending
well onto the ventral portion.

Material examined

34 dissociated LAPs in the Manfred Kutscher Collection in Sassnitz, Germany, from the early
Maastrichtian of Riigen, Germany, the type material of Kutscher & Jagt (2000); NHMM 2012 060,
NHMM 2012 061 and NHMM JJ 3679 (13 dissociated LAPs) from the early late Maastrichtian of
Haccourt, Belgium, the original material of Jagt (2000); GZG.INV.78819 (2 dissociated LAPs) from the
late Campanian of Lagerdorf-Alsen, Germany.

Description

Moderately large, dissociated LAPs of stout, massive and strongly curved aspect; proximal ones
more than twice higher than wide, distal ones less than 1.5 times higher than wide; dorsal edge
weakly concave as a result of the pointed dorso-proximal tip of the LAP slightly protruding towards
arm midline; distal edge convex; dorsal part of proximal edge evenly convex, ventral part concave;

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European Journal of Taxonomy 48: 1-242 (2013)

ventral portion of LAP narrow, extremely long, aeeounting for more than half of the total LAP height
in proximal LAPs to slightly less than half of the total LAP height in distal ones; outer surfaee with
finely meshed stereom. Three to four large, ear-shaped spine artieulations freestanding on strongly
bulging distal portion of LAP and eomposed of thiek, eontinuous volute; dorsalward inerease in size
of spine artieulations and of gaps separating them; gap between spine artieulations and distal edge of
LAP narrow.

Inner side of LAP with well-defined, prominent, slender, evenly bent ridge with ventral part extending
well onto the ventral portion of the LAP, and widened dorsal tip with ventro-proximalwards pointing
extension; no spurs on inner side of distal edge of LAP; inner side of tentaele noteh very weakly defined,
almost indiseemible. Small, irregular perforations in very shallow, poorly defined vertieal furrow distally
bordering ridge.

Remarks

Kutseher & Jagt (2000) first deseribed this speeies on the basis of dissoeiated LAPs and vertebrae
from the early Maastriehtian of Germany and Denmark. As noted above, the original assignment to the
ophiomyxid Ophiosmilax, even if tentative, is untenable. The LAPs in question elearly belong to the
new ophiaeanthid genus Ophiojagtus gen. nov. Within this genus, they are unique in displaying three to
four spine artieulations, an extremely long ventral portion and a slender, evenly bent ridge on the inner
side extending well onto the ventral portion of the LAP.

The LAPs deseribed and illustrated as Ophiosmilaxl alternatus by Store (2004) from the Turonian of the
Czeeh Republie and Tunisia display mueh more eoarsely meshed stereom on the outer surfaee and thus
most probably belong to a different, still unnamed speeies of the present genus. The LAPs deseribed by

v s/

Store & Zitt (2008) from the Turonian of the Czeeh Republie seem to display four to five, rather than
three to four, spine artieulations, whieh would ehallenge assignment to Ophiojagtus alternatus eomb.
nov. In order to elarily the exaet systematie position of these Turonian oeeurrenees of Ophiojagtus
gen. nov., the original material needs to be re-examined, in partieular the diagnostieally important, but
insulfieiently deseribed and unillustrated inner side.

Occurrence

Late Campanian of Germany, early Maastriehtian of Germany and Belgium.

Acknowledgments

For generously providing samples, 1 wish to thank Regina Fiseher, Franz Fiirsieh, Andy S. Gale, Manfred
Jager, John W.M. Jagt, Andreas Kroh, Manfred Kutseher, Gero Moosleitner, Mike Reieh and Simon
Sehneider; for permitting aeeess to ophiuroid eolleetions at the Naturhistorisehes Museum Basel, thanks
go to Walter Etter, Hans Hess, Christian Meyer and Olivier Sehmidt; Manfred Kutseher, Mike Reieh
and Anne Mehlin Sorensen provided items of literature, for whieh 1 am grateful. 1 thank Andreas Kroh
and Sabine Stohr for their hospitality during my Synthesys visits to Vienna and Stoekholm, respeetively;
Andreas Kroh for his enormous support in eomputing the phytogenies; Toshihiko Fujita, Yoshiaki Ishida
and Dave Pawson for generous donations of Reeent speeimens for eomparison; Wolfgang Drose and
Dorothea Hause-Reitner for assistanee with seanning eleetron mieroseopy; Hans Hess for pieking the
La Pouza residues; Andy Gale, Steffen Kiel and Joaehim Reitner for inspiring and exeiting diseussions;
and the journal referees, John W.M. Jagt and an anonymous reviewer whose eomments greatly improved
an earlier version of this manuseript. The present study gained support from the European Union-funded
Synthesys programme (grants AT-TAF-1307 and SE-TAF-1297) and from German Researeh Foundation
(grant DFGRE2599/6-1).

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THUYB., Fossil record of ophiacanthid brittle stars

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Manuscript received: 1 November 2012
Manuscript accepted: 20 March 2012
Published on: 2 July 2012
Topic editor: Christian de Muizon
Desk editor: Charlotte Thionois

Printed versions of all papers are also deposited in the libraries of the institutes that are members of
the EJT consortium: Museum National d’Histoire Naturelle, Paris, France; National Botanic Garden
of Belgium, Meise, Belgium; Royal Museum for Central Africa, Tervuren, Belgium; Natural History
Museum, London, United Kingdom; Royal Belgian Institute of Natural Sciences, Brussels, Belgium;
Natural History Museum of Denmark, Copenhagen, Denmark.

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THUYB., Fossil record of ophiacanthid brittle stars

Appendix 1. Faunal list for the assemblages studied with corresponding counts of lateral arm plates or
articulated individual (art.). Note that previously published assemblages which lack ophiacanthids or for
which no significant taxonomic changes or new counts are proposed have been omitted. Records marked
with an asterisk (*) are not described in the present study.

SHALLOW-WATER ASSEMBLAGES

Locality

Taxon

LAP count

Baden

non-ophiacanthids

111

Rauchstallbrunngraben

non-ophiacanthids

208

Mannersdorf

Ophiotreta sp. nov. innom 2

non-ophiacanthids

467

Wiesfleck

non-ophiacanthids

549

Stotzing 1

Ophiotreta sp. nov. innom 2

non-ophiacanthids

103

Stotzing 3

non-ophiacanthids

Obemalb

non-ophiacanthids

214

Grignon

Ophiotreta hedone sp. nov.

122

non-ophiacanthids

604

Eben Emael

non-ophiacanthids

393

Maastricht

Ophiomitrella sp. nov. innom. 1 *

1 (art)

non-ophiacanthids

31 (art)

Rilgen

Ophiologimus rugosus comb. nov.

Ophiotreta striata comb. nov.

216

Ophiogaleus danicus comb. nov.

332

Manfredura curvata comb. nov.

416

Ophiochondrus punctatus comb. nov.

260

Ophiochondriisl semirotundus comb. nov.

Ophiojagtus alternatus comb. nov.

Ophiacanthidae gen. et sp. 1 *

non-ophiacanthids

13479

Eagerdorf-Kronsmoor

Ophiotreta striata comb. nov.

Ophiogaleus danicus comb. nov.

Manfredura curvata comb. nov.

non-ophiacanthids

1689

Haccourt (Maastr.)

Ophiojagtus alternatus comb. nov.

non-ophiacanthids

953

Aachen

non-ophiacanthids

690

Haccourt (Camp.)

Ophiologimus rugosus comb. nov.

non-ophiacanthids

256

Eagerdorf-Alsen

Ophiacantha reginae sp. nov.

Ophiojagtus alternatus comb. nov.

non-ophiacanthids

584

Ivb Klack

non-ophiacanthids

426

Piesting

non-ophiacanthids

239

Waco

Ophiojagtus sp. 1

non-ophiacanthids

432

Saginaw

non-ophiacanthids

392

Folkestone (level 6)

non-ophiacanthids

206

Folkestone (level 2)

Lapidaster mathcore sp. nov.

Ophiacantha sp. nov. innom. 3

non-ophiacanthids

Eeighton Buzzard

Dermocoma sp. nov. innom. 4

non-ophiacanthids

198

Wizard Way

Ophiojagtus acklesi sp. nov.

non-ophiacanthids

380

Cuchia

Ophiojagtus sp. 2*

non-ophiacanthids

171

237

European Journal of Taxonomy 48: 1-242 (2013)

Sarstedt

Ophiacantha jaegeri sp. nov.

Ophiomalleus stevenwUsoni sp. nov.

non-ophiacanthids

335

Trancoso

Ophiolimna lisae sp. nov.

Krohcoma ampla sp. nov.

Dermocoma simonschneideri sp. nov.

Ophiojagtiis irimurai sp. nov.

non-ophiacanthids

246

Geisingen

Lapidaster mastodon sp. nov.

Lapidaster sp. nov. innom. 2

Ophiogaleus sp.

Dermocoma sp. nov. innom. 2

Dermacantha carli sp. nov.

non-ophiacanthids

824

Pointe du Chay

Ophiotoma charlottae sp. nov.

Ophiolimna lisae sp. nov.

Krohcoma ampla sp. nov.

Alternacantha dilionessa sp. nov.

532

Dermocoma simonschneideri sp. nov.

Ophiojagtus irimurai sp. nov.

non-ophiacanthids

330

Plettenberg

Lapidaster mastodon sp. nov.

197

Ophiotreta stefaniae sp. nov.

Ophiogaleus sp.

Dermacantha carli sp. nov.

303

Sabinacantha archetypa sp. nov.

Ophiacanthidae gen. et sp. nov innom.

non-ophiacanthids

846

Guldental (Hess 1975a)

Dermocoma biformis comb. nov.

122

non-ophiacanthids

562

Raedersdoif

Dermocoma biformis comb. nov.

non-ophiacanthids

1962

Savigna (SI)

Ophiogaleus constrictus comb. nov.

Alternacantha schwermannorum sp. nov.

Dermocoma biformis comb. nov.

Ophiocamax dorotheae sp. nov.

Ophiojagtus argoviensis comb. nov.

non-ophiacanthids

124

Savigna (S2a)

Ophiogaleus constrictus comb. nov.

Alternacantha schwermannorum sp. nov.

105

Dermocoma biformis comb. nov.

138

Ophiocamax dorotheae sp. nov.

Ophiojagtus argoviensis comb. nov.

non-ophiacanthids

781

Savigna (S2b)

Ophiogaleus constrictus comb. nov.

Alternacantha schwermannorum sp. nov.

182

Dermocoma biformis comb. nov.

Ophiocamax dorotheae sp. nov.

Ophiojagtus argoviensis comb. nov.

non-ophiacanthids

782

Guldental (Hess 1966)

Ophiogaleus constrictus comb. nov.

Dermocoma biformis comb. nov.

Ophiocamax dorotheae sp. nov.

Ophiojagtus argoviensis comb. nov.

Foug

Dermocoma numbergerorum sp. nov.

205

non-ophiacanthids

163

Chapois

Lapidaster etteri sp. nov.

238

THUYB., Fossil record of ophiacanthid brittle stars

Ophiogaleus constrictus comb. nov.

Dermocoma biformis comb. nov.

Ophiocamax dorotheae sp. nov.

non-ophiacanthids

316

Longecombe

Lapidaster etteri sp. nov.

307

Ishidacantha trispinosa comb. nov.

Ophiocamax dorotheae sp. nov.

non-ophiacanthids

221

Jumara (117)

Lapidaster varuna sp. nov.

Ishidacantha fuersichi sp. nov.

non-ophiacanthids

Jumara (119)

Lapidaster varuna sp. nov.

Ishidacantha fuersichi sp. nov.

non-ophiacanthids

Jumara (121)

Lapidaster varuna sp. nov.

Ophiogaleus sp. nov. innom. 2

Ishidacantha fuersichi sp. nov.

non-ophiacanthids

Jumara (95)

Ophiogaleus sp. nov. innom. 2

Hanshessia sp.

Alternacantha sp. nov. innom. 2

Dermocoma sp. 1

Jumara (31)

Ophiolimna malagasica sp. nov.

Ophiogaleus sp. nov. 2

Ophiacanthidae gen. et sp. 2*

non-ophiacanthids

Althilttendorf

Ophiomitrellal sp. nov. 1

Ophiomalleus beneficarum sp. nov.

non-ophiacanthids

311

Bauer-Wehrland

Hanshessia sp. nov. innom. 2

Dermocoma wrighti Hess, 1964

Ophiomitrellal sp. 1

Ophiomalleus beneficarum sp. nov.

non-ophiacanthids

1331

Hohensaaten

Ophiomalleus beneficarum sp. nov.

non-ophiacanthids

435

Liesberg

Dermocoma wrighti Hess, 1964

non-ophiacanthids

2492

Jumara (24)

Ophiolimna malagasica sp. nov.

Krohcoma sp. nov. innom.

Dermocoma sp. 1

non-ophiacanthids

111

Jumara (15)

Ophiolimna malagasica sp. nov

non-ophiacanthids

Jumara (89)

Ophiolimna malagasica sp. nov.

Ophiomitrellal sp. 2

Ophiacanthidae gen. et sp. 3*

Ophiacanthidae gen. et sp. 2*

non-ophiacanthids

196

La Pouza

Lapidaster sp.*

Ophiogaleus stans sp. nov.

Hanshessia sp. nov. innom. 2

Dermocoma sp. 3*

non-ophiacanthids

Delkhofen

Dermocoma wrighti Hess, 1964

non-ophiacanthids

242

Cirey-les-Nolay

Alternacantha occulta Thuy & Meyer, 2013

239

European Journal of Taxonomy 48: 1-242 (2013)

Dermocoma longwyensis sp. nov.

Dermocoma wrighti Hess, 1964

133

non-ophiacanthids

Longwy

Alternacantha occulta Thuy & Meyer, 2013

Dermocoma longwyensis sp. nov.

non-ophiacanthids

266

See wen (Toarc.)

Lapidaster sp. nov. innom. 1

Dermocoma toarcensis comb. nov.

163

non-ophiacanthids

258

Le Clapier 1

Lapidaster fasciatus comb. nov.

Alternacantha sp. nov. innom. 1

Ishidacantha hirokoae sp. nov.

non-ophiacanthids

420

Le Clapier 2

Lapidaster fasciatus comb. nov.

Ishidacantha hirokoae sp. nov.

non-ophiacanthids

126

Aix-sur-Cloie

Dermocoma sp. 2*

Inexpectacantha acrobatica Thuy, 2011

non-ophiacanthids

132

Seewen (Pliensb.)

Ophiotoma vadosa sp. nov.

175

Ophiogaleus dorecki comb. nov.

Dermocoma toarcensis comb. nov.

Inexpectacantha lunar is comb. nov.

non-ophiacanthids

1069

Amellago

Alternacantha^ sp.

Ophiacanthidae gen. et sp. 4*

non-ophiacanthids

119

Feuguerolles

Dermocoma potti sp. nov.

non-ophiacanthids

124

Blockley

Lapidaster hystricarboris comb. nov.

Ophiotoma vadosa comb. nov.

Dermacantha leonorae comb. nov.

Inexpectacantha acrobatica Thuy, 2011

non-ophiacanthids

561

Sedan

Inexpectacantha acrobatica Thuy, 2011

210

non-ophiacanthids

683

Sedan

Inexpectacantha acrobatica Thuy, 2011

78 (art)

non-ophiacanthids

210 (art)

Bishop’s Cleeve

Dermacantha seeweni comb. nov.

Inexpectacantha lunar is comb. nov.

non-ophiacanthids

167

Remerschen

Dermocoma sp. nov. innom. 6*

Inexpectacantha weisi sp. nov.

non-ophiacanthids

242

Fontenoille

Dermocoma faberi sp. nov.

457

Dermacantha patty ana sp. nov.

298

Inexpectacantha weisi sp. nov.

non-ophiacanthids

1616

Vance (Vanl)

Dermocoma faberi sp. nov.

392

Inexpectacantha ritae sp. nov.

non-ophiacanthids

732

Vance (Van2)

Dermocoma faberi sp. nov.

239

Inexpectacantha ritae sp. nov.

non-ophiacanthids

519

Fischerwiese

Dermocoma subtilirugosa comb. nov.

Dermocoma sp. nov. innom. 1

non-ophiacanthids

232

240

THUYB., Fossil record of ophiacanthid brittle stars

Jushui (C30)

Eolaxoporus hagdorni sp. nov.

non-ophiacanthids

1689

Jushui (C36)

Eolaxoporus hagdorni sp. nov.

non-ophiacanthids

316

Jushui (C33)

Eolaxoporus hagdorni sp. nov.

non-ophiacanthids

340

Alpe di Specie

non-ophiacanthids

249

Romerlo

non-ophiacanthids

120

Milieres

Eolaxoporus sp. nov. innom.

non-ophiacanthids

284

Oberscheffach

Eolaxoporus sp.

non-ophiacanthids

245

Schillingstadt

non-ophiacanthids

278

Gorazdze

non-ophiacanthids

253

Strzelce Opolski

non-ophiacanthids

282

Felsobrs

Europacanthapaciphila sp. nov.

non-ophiacanthids

509

Recoaro

non-ophiacanthids

296

Soly

non-ophiacanthids

292

Kitakami Mountains

non-ophiacanthids

383

DEEP-SEE ASSEMBLAGES

Locality

Taxon

LAP count

Bad Freienwalde

Ophiacantha steffenschneideri sp. nov.

713

Ophiacanthidae gen. et sp. 5*

non-ophiacanthids

385

Fakse

Ophiotreta dendrophyllicola sp. nov.

177

Blake Nose

Ophiologimus martynovi sp. nov.

Ophiologimus aiodipius sp. nov.

Ophiotoma incredibilis sp. nov.

Ophiolimna kucerai sp. nov.

756

Ophiacantha sp. nov. innom. 1

Ophiacantha sp. nov. innom 2

Ophiotreta sp. nov. innom. 3*

Ophiacanthidae gen. et sp. 6*

103

non-ophiacanthids

1051

Carniol

Lapidaster coreytaylori sp. nov.

non-ophiacanthids

Temberg

Lapidaster lukenederi sp. nov.

Geromura teckliformis sp. nov.

126

Dermocoma sp. nov. innom. 3

non-ophiacanthids

Toueit

Lapidaster wolfii

Geromura touertensis sp. nov.

Dermacantha sp. nov. innom.

non-ophiacanthids

Glasenbach Gorge

Eolaxoporus imminens sp. nov.

Lapidaster caeloscopus sp. nov.

Ophiotoma sp. nov. innom.

Ophiolimna tiamatia sp. nov.

Krohcoma mira sp. nov.

Ophiogaleus sp. nov. innom. 1

Hanshessia sp. nov. innom 1

Ophioleviathan watsoni sp. nov.

Reitneracantha dissidens sp. nov.

Ophiacanthidae gen. et sp. 7*

non-ophiacanthids

263

241

European Journal of Taxonomy 48: 1-242 (2013)

Appendix 2. Matrix for phylogenetic analysis

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