A Stereo -Atlas of Ostracod Shells edited by J. Athersuch, D. J. Horne, J. W. Neale and David J. Siveter Volume 15, Part 1; 30th May, 1988 P Published by the British Micropalaeontological Society, London Editors Dr J. Athersuch, Stratigraphy Branch, The British Petroleum Co, BP Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex TW16 7LN. Dr D.J. Horne, Department of Geology, City of London Polytechnic, Walburgh House, Bigland Street, London El 2NG. Prof. J.W. Neale, Department of Geology, The University, Hull HU6 7RH. Dr David J. Siveter, Department of Geology, The University, Leicester LEI 7RH. Editorial Board Dr J.-P. Colin, Esso Production Research - European, 213 Cours Victor Hugo, 33321 Begles, France. Dr P. De Deckker, Department of Geography, Monash University, Clayton, Victoria, Australia 3168. Dr D. van Harten, Universiteit van Amsterdam, Geologisch Instituut, Nieuwe Prinsengracht 130, Amsterdam, The Netherlands. Dr R.E.L. Schallreuter, Universitat Hamburg, Geologisch-Palaontologisches Institut, Bundesstrasse 55, D 2000 Hamburg 13, West Germany. Dr Zhao Yuhong, Nanjing Institute of Geology & Palaeontology, Academia Sinica, Chi-Ming-Ssu, Nanjing, People’s Republic of China. Officers of the British Micropalaeontological Society Chairman Dr A.C. Higgins, BP Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex TW16 7LN. Secretary Dr P.P.E. Weaver, Institute of Oceanographic Sciences (DL), Brook Road, Wormley, Godaiming, Surrey GU8 5UB. Treasurer Dr J.E. Whittaker, Department of Palaeontology, British Museum (Natural History), Cromwell Road, London SW7 5BD. Journal Editor Dr. M. Keen, Department of Geology, The University of Glasgow G12 8QQ. Newsletter Editor Dr D. J. Shipp, Robertson Research International, Ty’n-y-Coed, Llanrhos, Llandudno, Gwynedd LL30 ISA. Conodont Group Chairman Dr P. M. Smith, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ. Conodont Group Secretary Dr A. Swift, Geology Department, University of Nottingham NG7 2RD. Foraminifera Group Chairman Dr A. A. H. Wonders, B.P. Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex TW16 7LN. Foraminifera Group Secretary Dr D.J. Shipp, Robertson Research International, Ty’n-y-Coed, Llanrhos, Llandudno, Gwynedd LL30 ISA. Microplankton Group Chairman Dr G.L. Eaton, B.P. Research Centre, Chertsey Road, Sunbury-on- Thames, Middlesex TW16 7LN. Microplankton Group Secretary Dr A.J. Powell, B.P. Research Centre, Chertsey Road, Sunbury-on- Thames, Middlesex TW16 7LN. Ostracod Group Chairman Dr D.J. Horne, Geology Department, City of London Polytechnic, Walburgh House, Bigland Street, London El 2NG. Ostracod Group Secretary Dr N. G. Fuller, Phillips Petroleum Company United Kingdom Limited, Petroleum Products Division, Phillips Quadrant, 35 Guildford Road, Woking, Surrey GU22 7QT. Palynology Group Chairman Dr M. C. Boulter, Palynology Research Unit, N.E. London Polytechnic, Romford Road, London E15 4LZ. Palynology Group Secretary Dr J. E. A. Marshall, Department of Geology, The University, Southampton S09 5NH. ' Calcareous Nannofossil Group Chairman Mr M. Jakubowski, Robertson Research International, Ty’n-y-Coed, Llanrhos, Llandudno, Gwynedd LL30 ISA. Calcareous Nannofossil Group Secretary Dr J. Crux, B.P. Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex TW16 7LN. Instructions to Authors Contributions illustrated by scanning electron micrographs of Ostracoda in stereo-pairs are invited. Format should follow the style set by the papers in this issue. Descriptive matter apart from illustrations should be cut to a minimum; preferably each plate should be accompanied by one page of text only. Blanks to aid in mounting figures for plates may be obtained from any one of the Editors or Editorial Board. Completed papers should be sent to Dr David J. Siveter. The front cover shows a male right valve of Semicytherura striata (Sars) from intertidal algae collected at Blue Anchor, Somerset SW England. Photograph by Dr J. E. Whittaker, British Museum (Natural History), London. Printed in the UK by BPCC Northern Printers Ltd., Stanley Road, Blackpool FY1 4QN Member of BPCC pic Stereo-Atlas of Ostracod Shells 15 ( 1 ) 1-4 (1988) 595.337.14 (118.22) (44 : 162.002.48) : 551.35 (26.03) Loxoconcha praepontica praepontica ( 1 of 4) 552.51. ON LOXOCONCHA PRAEPONTICA PRAEPONTICA MAYBURY & WHATLEY subsp. nov. by Caroline A. Maybury & Robin C. Whatley (University College of Wales, Aberystwyth) Holotype: Type locality: Derivation of name: Figured specimens: Loxoconcha praepontica praepontica subsp. nov. British Museum (Nat. Hist.) no. OS 12866; $ LV. [Paratypes: British Museum (Nat. Hist.) nos. OS 12867-OS 12870]. Shell-rich sand, Le Temple du Cerisier, SW of Rennes (approx, lat. 48° 07' N, long. 1° 41' W), NW France; Redonian, Upper Pliocene. Latin, with reference to the similarity and probable ancestral relationship of the subspecies to Loxoconcha pontica Klie (Mitt. Kgl. Naturw. Inst., 10, 13, figs. 24-30, 1937). British Museum (Nat. Hist.) nos. OS 12866 (holotype, 9 LV: PI. 15, 2, fig. 1), OS 12867 (paratype, 9 RV: PI. 15, 2, fig. 2), OS 12868 (paratype, cf LV: PI. 15, 2, fig. 3; PI. 15, 4, figs. 3, 4), OS 12869 (paratype, cf RV: PI. 15, 4, fig. 1), OS 12870 (paratype, 9 RV: PI. 15, 4, fig. 2). All paratypes from the same sample as the holotype, except OS 12868 which is from fine, glauconitic, grey sand, depth 26. 7-32. 4m, Apigne (Borehole II), SW of Rennes (approx, lat. 48° 07' N, long. 1° 41' W, NW France; Redonian, Upper Pliocene. See J.-P. Margerel, Les Foraminiferes du Redonien, Systematique, Repartition stratigraphique, Paleoecologie, Nantes, 1, 8-26, 1968 for further geographical and sample details. Explanation of Plate 15, 2 Fig. 1, 9 LV, ext. lat. (holotype, OS 12866, 510;u,m long); fig. 2, 9 RV, ext. lat. (paratype, OS 12867, 510/u.m long); fig. 3, cf LV, ext. lat. (paratype, OS 12868, 560/u.m long). Scale A (100/u.m; x 114), figs. 1-3. Stereo- Atlas of Ostracod Shells 15, 3 Loxoconcha praepontica praepontica (3 of 4) Diagnosis: A small to medium subspecies of Loxoconcha with very prominent sieve-type normal pores, commonly contained within circular rims; wide anteroventral flange; weakly reticulate and finely punctate secondary ornament. The valves, especially those of the female, are tumid anteroven- trally. Remarks: The male of Loxoconcha pontica Klie (a Recent species from the central and eastern Mediterranean, Adriatic, Aegean, Black and Azov Seas) is similar in length and shape to the male of the new subspecies but is less high. The male left valve is also more inflated ventrally (see J. Athersuch, Stereo-Atlas Ostracod Shells, 7, 53-60, 1980). The female of the new subspecies differs in outline, is less elongate and is strongly inflated ventrally. The ornament of Klie’s species is very similar to that of L. praepontica praepontica but is less pronounced; the sieve plates are smaller and less conspicuous. Overall the features of the present subspecies indicate a probable ancestral relationship to L. pontica. The only fossil record of L. pontica Klie is by Mostafawi (Meyniana, 33, 165, pi. 11, figs. 12—15 , 1981) from the late Pliocene of Kos, Greece. In our opinion, this is not conspecific with L. pontica of Klie in that it differs in shape (it is much less elongate and less pointed posteriorly) and in details of ornament (it possesses a delicate reticulum of polygonal units posteriorly). Mostafawi’s species, which we regard as new, more closely resembles L. praepontica sensu lato than L. pontica Klie but differs from the former in that the female and the left valve of the male lack the pronounced ventral tumidity. Distribution: L. praepontica praepontica has been recovered from the Redonian (Upper Pliocene) deposits of Apigne (Gite d" Apigne, Borehole II, Le Temple du Cerisier), L'Aubier and Le Bosq d'Aubigny (Manche), NW France (see J.-P. Margerel, op. cit. for sample details). Explanation of Plate 15, 4 Fig. 1, cf RV, ext. lat. (paratype, OS 12869, 560/u.m long); fig. 2, 9 RV, int . lat. (paratype, OS 12870, 460|U.m long); figs. 3, 4, cf LV, (paratype, OS 12868, 560/u.m long): fig. 3, ant. hinge element; fig. 4, post, hinge element. Scale A (100/^.m; x 114), figs. 1, 2; scale B (20/u.m; X 237), figs. 3, 4. Stereo- Atlas of Ostracod Shells 15, 2 Loxoconcha praepontica praepontica (2 of 4) Stereo-Atlas of Ostracod Shells 15, 4 Loxoconcha praepontica praepontica (4 of 4) Stereo-Atlas of Ostracod Shells 15 (2) 5-8 (1988) Loxoconcha praepontica magna ( 1 of 4) 595.337.14 (118.22) (44 : 162.006.50) : 551.35 (26.03) Holotype: ON LOXOCONCHA PRAEPONTICA MAGNA MAYBURY & WHATLEY subsp. nov. by Caroline A. Maybury & Robin C. Whatley (University College of Wales, Aberystwyth) Loxoconcha praepontica magna subsp. nov. British Museum (Nat. Hist.) no. OS 12871; 2 LV. [Paratypes: British Museum (Nat. Hist.) nos. OS 12872 - OS 12875]. Type locality: Mixed sample. Sample No. 1, Vicarage Pit, St. Erth, Cornwall, England (Nat. Grid Ref. SW 556352); Upper Pliocene. Derivation of name: Latin, referring to the greater size of this subspecies relative to the nominate subspecies, Loxoconcha praepontica praepontica Maybury & Whatley ( Stereo-Atlas Ostracod Shells, 15, 1-4, 1988). Explanation of Plate 15, 6 Fig. 1, § LV, ext. lat. (holotype, OS 12871, 640 /um long); fig. 2, 2 RV, ext. lat. (paratype, OS 12872, 640 ^im long); fig. 3, cf RV, ext. lat. (paratype, OS 12874, 630/xm long). Scale A (200 /xm; x 100), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 7 Loxoconcha praepontica magna (3 of 4) Figured specimens: British Museum (Nat. Hist.) nos. OS 12871 (holotype, 2 LV: PI. 15, 6, fig. 1), OS 12872 (paratype, 2 RV: PI. 15, 6, fig. 2), OS 12874 (paratype, cf RV: PI. 15, 6, fig. 3), OS 12873 (paratype, 2 LV: PI. 15, 8, fig. 1), OS 12875 (paratype, 2 RV: PL 15, 8, figs. 2-4). Specimen OS 12872 is from the same sample as the holotype and specimens OS 12873, OS 12874, and OS 12875 are from the type locality and type horizon. Sample Nos. 7, 29 and 13 respectively. See C. Maybury, Taxonomy, Palaeoecology and Biostratigraphy of Pliocene Benthonic Ostracoda from St. Erth and North West France, unpubl. PhD thesis, Univ. Wales, 1, 4-5, 1985 for sample details. Diagnosis: A medium, punctate, subovate subspecies of Loxoconcha praepontica with a faint reticulation peripherally around free margins, proximal to the flange. Puncta largest medianlv which area is also ‘wrinkled' due to the development of weak, subhorizontal muri. Sieve plates conspicuous. Internal features as for the genus. Remarks: This subspecies can be distinguished from Loxoconcha praepontica praepontica by its larger size, its lack of pronounced tumidity posteroventrally and its more regularly ordered ornament of coarser puncta and less prominent reticulum. Both subspecies possess prominent sieve plates and are punctate with weakly developed reticulae. The two subspecies are exclusive to the Upper Pliocene; L. praepontica magna is found in Cornwall and L. praepontica s.s. in NW France. The differences between L. pontica Klie and L. praepontica praepontica are outlined in Maybury & Whatley ( Stereo-Atlas Ostracod Shells, 15, 1-4, 1988). Distribution: This subspecies is confined to the Upper Pliocene deposits of St. Erth, Sample Nos. 1, 7, 13-14, 21, 23, 25-29 (see C. Maybury, op. cit. for sample details). Explanation of Plate 15, 8 Fig. 1, 2 LV, ext. lat. (paratype, OS 12873, 600 /u.m long); fig. 2-4, 2 RV (paratype, OS 12875, 640 pm long); fig. 2, int. lat.; fig. 3, ant. hinge element; fig. 4, post, hinge element. Scale A (200/a.m; x 100), figs. 1, 2; scale B (40/^rn; x 244), figs. 3, 4. Stereo- Atlas of Ostracod Shells 15, 6 Loxoconcha praepontica magna (2 of 4) Stereo-Atlas of Ostracod Shells 15, 8 Loxoconcha praepontica magna (4 of 4) Stereo-Atlas of Ostracod Shells 15 (3) 9-12 (1988) Loxoconcha pararhomboidea (1 of 4) 595.337.14 (118.22) (44 : 162.006.50 + 162.002.46) : 551.35 (26.03) + 552.52 + 552.54 ON LOXOCONCHA PARARHOMBOIDEA WHATLEY & MAYBURY sp. nov by Robin C. Whatley & Caroline A. Maybury ( University College of Wales, Aberystwyth) Loxoconcha pararhomboidea sp. nov. 1980 Loxoconcha rhomboidea Fischer; I. P. Wilkinson, Proc. Geol. Ass., 91(4), pi. 2. fig. 6 Holotype: British Museum (Nat. Hist.) no. OS 12876; 2 LV. [Paratypes: British Museum (Nat. Hist.) nos. OS 12877-OS 12881], Type locality: Mixed sample, Sample No. 1, Vicarage Pit, St. Erth, Cornwall, England (Nat. Grid Ref. SW 556352); Upper Pliocene. Derivation of name: Latin, because of its close morphological relationship to Loxoconcha rhomboidea (Fischer) (Abh. buyer, Akad. Wiss., 74, 656, 1855). Figured specimens: British Museum (Nat. Hist.) nos. OS 12876 (holotype, 2 LV: PI. 15, 10, fig. 1), OS 12877 (paratype, 2 RV: PI. 15, 10, fig. 2), OS 12878 (paratype, cf RV: PL 15, 10, fig. 3), OS 12879 (paratype, 2 RV; PL 15, 12, fig. 1), OS 12880 (paratype, 2 LV: PI. 15, 12, fig. 2), OS 12881 (paratype, 2 LV: PI. 15, 12, fig. 3). Specimens OS 12877 and OS 12878 are from the same sample as the holotype; specimen OS 12879 is from the type locality and type horizon. Sample No. 29 (blue clay) (see C. Maybury. Explanation of Plate 15, 10 Fig. 1, 9 LV, ext. lat. (holotype OS 12876, 530 yum long); fig. 2, 2 RV, ext. lat. (paratype OS 12877. 550/u.m long); fig. 3, cf RV, ext. lat. (paratype OS 12878, 600 /xm long). Scale A (100 /am; x 108), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 1 1 Loxoconcha pararhomboidea (3 of 4) Figured specimens (cont.): Taxonomy, Falaeoecology and Biostratigraphy of Pliocene Benthonic Ostracoda from St. Erth and North West France , unpubl. PhD thesis, Univ. Wales, 1, 4-5, 1985 for sample details). Specimens OS 12880 and OS 12881 are from a sample of yellow marl, the “cutting” at Palluau II (approx, lat. 46°48'N, long. 1°37'W) 50m SW of the Martineau pit, near Le Pas, NW France; Redonian, Upper Pliocene, (see J.-P. Margerel, Les Foraminiferes du Redonien, Systematique, Repartition stratigraphique, Paleoecologie, Nantes, 1, 8-26, 1968 for further details of the Palluau II sample). Diagnosis: Small to medium in size; like Loxoconcha rhomboidea but smaller, with a narrower posteroventral marginal rim and consistently larger punctae. Oral incurvature slight. Remarks: The Coralline Crag specimens described by Wilkinson (1980, op. cit.) as L. rhomboidea are conspecific with the present material. The length of the female left valve (543p.m) in Wilkinson's material approximates more closely to that of the new species (470-530 gm long) than to L. rhomboidea (585-659 pm long, see J. Athersuch and J. E. Whittaker, Stereo-Atlas Ostracod Shells, 3, 81-90, 1976). British and French Pliocene specimens differ in size. Adult French specimens are always smaller than their British counterparts; a difference likely to have arisen as a consequence of geographical separation. Compare the British specimens illustrated in PI. 15, 10, figs. 1-3 and PI. 15, 12, fig. 1 with the French examples in PI. 15, 12, figs. 2, 3. Distribution: This species has been recovered from the late Pliocene deposits of St. Erth (Sample Nos. 1-3, 7, 10-1 1 , 13-14, 16, 18, 21, 23, 25-29) and the Redonian (Upper Pliocene) deposits of Apigne (Gite d'Apigne, Borehole II, Le Temple du Cerisier), Beugnon (Sample No. 2), Le Bosq d'Aubigny, Le Pigeon Blanc, Palluau I, Palluau II and Saint-Jean-la-Poterie (Sample Nos. 1549.11-1549.12, 1549.15), NW France. Explanation of Plate 15, 12 Fig. 1, 2 RV, int. lat. (paratype OS 12879, 540 pm long); fig. 2, 2 LV, ext. lat. (paratype OS 12880, 490 pm long); fig. 3, 2 LV, int lat. (paratype OS 12881, 470/xm long). Scale A (lOO/nm; x 108), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 10 Loxoconcha pararhomboidea (2 of 4) Stereo-Atlas of Ostracod Shells 15, 12 Loxoconcha pararhomboidea (4 of 4) Stereo-Atlas of Ostracod Shells 15 (4) 13-16 (1988) 595.337. 14 (118.22) (44 : 162.001.47 + 002.48) 551.35 (26.03) : 552.51 Palmoconcha hornei ( 1 of 4) ON PALMOCONCHA HORNEI MAYBURY & WHATLEY sp. nov. by Caroline A. Maybury & Robin C. Whatley (University College of Wales, Aberystwyth) Holotype: Type locality: Derivation of name: Figured specimens: Palmoconcha hornei sp. nov. British Museum (Nat. Hist.) no. OS 12855; 9 LV. (Paratypes: British Museum (Nat. Hist.) nos. OS 12856-OS 12860]. Shell-rich sand, Le Temple du Cerisier, SW of Rennes (approx, lat. 48° 07' N, long. 1° 41 ' W), NW France; Redonian, Upper Pliocene. In honour of Dr. David Horne in recognition of his studies of the Loxoconchidae. British Museum (Nat. Hist.) nos. OS 12855 (holotype, 9 LV: PI. 15, 14, fig. 1), OS 12856 (paratype, cf LV: PI. 15, 14, fig. 2), OS 12857 (paratype, cf RV: PI. 15, 14, fig. 3), OS 12858 (paratype, cf RV: PI. 15, 16, fig. 1), OS 12859 (paratype, 9 car.: PI- 15, 16, fig. 2), OS 12860 (paratype, cf car.: PI. 15, 16, fig. 3). Specimens OS 12856-OS 12858 are from the same sample as the holotype. Specimens OS 12859-OS 12860 are from L’Orchere Pincourt (approx, lat. 47° 22' N, long. 0° 43' W), NW France: Redonian, Upper Pliocene (see J.-P. Margerel, Les Foraminiferes du Redonien, Systematique, Repartition stratigraphique, Paleoecologie , Nantes, 1, 8-26, 1968 for further sample details). Explanation of Plate 15, 14 Fig. 1, 9 LV, ext. lat. (holotype, OS 12855, 450/xm long): fig. 2, cf LV, ext. lat. (paratype. OS 12856, 470/am long); fig. 3, Cf RV. ext. lat. (paratype, OS 12857, 480/u.m long). Scale A (100/xm; X 135), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 15 Palmoconcha hornei (3 of 4) Diagnosis: A small, subelliptical species of Palmoconcha with a broadly rounded anterior; caudate posterior; dorsal margin straight in males and female right valve, slightly arcuate in female left valve; ventral margin sinuous. Ornament of concentrically ordered reticulum peripherally and puncta medianly and ventromedianly. Marginal rim and eye spot smooth. Inner lamella with broad anterior and narrow posterior vestibula. Selvage in right valve very distal. Flange well developed. Hinge and muscle scars typical of the genus. Remarks: In external carapace morphology Palmoconcha hornei and P. edentonensis (Swain, 1951) sensu Hazel, 1977 non P. edentonensis (Swain, 1951) (see J. E. Hazel, J. Res. U.S. Geol. Surv., 5 (3), 377, 384, pi. 19, fig. f, 1977), a late Pliocene to early Pleistocene, N American species, are similar in lateral outline and in possessing a concentrically ordered reticulate ornament. The two species differ in size and ornamental detail. The species which Hazel illustrates (length of female left valve approx. 600 fim) is 25% longer than females of P. hornei and possesses concentrically ordered reticulae over its entire lateral surface except for the marginal rim which has a minutely punctate ornament, whereas in P. hornei, the valves are punctate medianly and ventromedianly and the marginal rim is smooth. Distribution: This species has been recovered from the Redonian, Upper Pliocene deposits of Apigne (Gite d’Apigne Borehole II, , Le Temple du Cerisier), Bas Briace, Beugnon (sample nos. 1, 2), Falleron, L'Orchere Pincourt and Le Pigeon Blanc NW France. A single female carapace of P. hornei has also been noted by the authors in a Miocene sample from Pontlevoy, NW France (see J.-P. Margerel op. cit. for the geographical, stratigraphical and sample details of the Redonian material). Explanation of Plate 15, 16 Fig. 1, cf RV, int. lat. (paratype, OS 12858, 460^tm long); fig. 2, 9 car., ext. dors, (paratype, OS 12859, 440/am long); fig. 3, cf car., ext. dors, (paratype, OS 12860, 460/u.m long). Scale A (100/u.m; X 135), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 14 Palmoconcha hornei (2 of 4) la 2a 3a Stereo-Atlas of Ostracod Shells 15 (5) 17-20 ( 1988) Webby lla cyma ( 1 of 4) 595.336.12 (113.313) (944:163.147.34) : 551.351 + 552.54 ON WEBBYLLA CYMA SCHALLREUTER & SIVETER gen. et sp. nov. by Roger E. L. Schallreuter & David J. Siveter (University of Hamburg, West Germany & University of Leicester, England) Genus WEBBYLLA gen. nov. Type-species: Webbylla cyma sp. nov. In honour of Dr. Barry D. Webby, University of Sydney, Australia. A genus of Drepanellidae with three bulb-like nodes at the dorsal border (N1 . N3, N4), and a very weak forth node (N2) more or less completely fused with Nl. N1 and N4 are connected ventrally by a crescent-shaped pseudovelum which ends in a blunt protuberance posteroventrally of N4. Anteriorly the pseudovelum continues in front of Nl and terminates near the dorsal border. N2, N3 and the pseudovelum almost completely encircle a more or less distinct muscle spot ( = S2) which has a small, oblique sulcal-like continuation to the dorsal border between Nl/2 and N3. Shell smooth or reticulate. The nearest relative of Webbylla is Dominina Burrett & Laurie, 1983 (in Burrett et al., Mem. Ass. Australas. Palaeontols. , 1, 191, 1983) from the middle Ordovician of Tasmania. Dominina exhibits similar lobal features and also has a connection between Nl and N4 (op. cit., fig. 15). but its pseudovelum lacks a posteroventral protuberance and is not present in front of Nl as in the more advanced, upper Ordovician Webbylla. Derivation of name: Diagnosis: Remarks: Explanation of Plate 15, 18 Fig. 1, car.. It. lat. (holotype, SUP 52900, 2.14 mm long); fig. 2, RV, ext. lat. (SUP 52901, 2.34 mm long); fig. 3, car., dors. (SUP 52902, 2.17 mm long). Scale A (250/xm; x 35), figs. 1, 2; scale B (250/u.m; x 25), fig. 3. Stereo-Atlas of Ostracod Shells 15, 19 Webbylla cyma (3 of 4) Webbylla cyma sp. nov. ? 1967 cf. Kloedenia sp.; G. H. Packham, Aust. J. Sci., 30, 3, 106. ? 1969 cf. Kloedenia fornicalis; G. H. Packham et al., J. Geol. Soc. Aust., 16, 1, 98. Holotype: Type locality: Derivation of name: Figured specimens : Diagnosis: Remarks Distribution: Acknowledgement: University of Sydney, Australia; Palaeontology (SUP) no. 52900; carapace. [Paratypes; SUP 52901 - 52906], Billabong Creek, Gunningbland - Parkes, western central New South Wales, Australia, 33° 11.5' S, 147° 59' E; Billabong Creek Limestone, lower Eastonian, upper Ordovician. Latin, cyma, young shoot, sprout; alluding to the ends of the pseudovelum. University of Sydney, SUP nos. 52900 (holotype, car.; PI. 15, 18, fig. 1), 52901 (RV: PI. 15, 18, fig. 2), 25902 (car.: PI. 15, 18, fig. 3), 25903 (LV: PI. 15, 20, fig. 1), 25904 (RV: PI. 15, 20, fig. 2), 52905 (car.: PI. 15, 20, fig. 3). All of the figured specimens are from the type locality. Species of Webbylla in which the anterior part of the pseudovelum extends anterodorsally to meet the dorsal border. Node N4 more prominent than N3; N2 confluent with Nl and is virtually obsolete. Marginal surface of value is relatively narrow. Shell surface smooth. Valve length up to 2-34 mm. In an undescribed subspecies of W. cyma from the slightly older Gerybong Limestone Member of the Daylesford Limestone, Bowan Park, New South Wales, nodes N3 and N4 are nearly equally strongly developed and the pseudovelum ends a little below the dorsal border. W. cyma differs from the older W. reticulata Schallreuter & Siveter, 1988 (Stereo-Atlas Ostracod Shells, 15, 21) in being smaller and in having unequally developed N3 and N4, a narrower marginal surface and a pseudovelum which reaches the dorsal border. The present material is silicified. In nearly all specimens (more than 50 carapaces and 100 single valves) the muscle spot is broken (or not silicified?). The reason is unknown; often this part of the shell in palaeocopes is stronger than adjacent parts. Known, so far, only from the type locality. We thank Dr. Barry Webby for sending us the material to study. Explanation of Plate 15, 20 Fig. 1, LV, ext. lat. (SUP 52903, 2.18 mm long); fig. 2, RV, int. lat. (SUP 52904, 2.20 mm long); fig. 3, car., vent. (SUP 52905, 2.06 mm long). Scale A (250yu.m; X 35), figs. 1, 2; scale B (250 /a.m; x 25), fig. 3. Stereo-Atlas of Ostracod Shells 15, 18 Webbylla cyma (2 of 4) Webby lla cyma (4 of 4) Stereo- Atlas of Ostracod Shells 15, 20 Stereo-Atlas of Ostracod Shells 15(6) 21-24 ( 1988) Webbylla reticulata ( 1 of 4) 595.336.12 (113.313) (944 : 163.148.34) : 551.351 + 552.54 ON WEBBYLLA RETICULATA SCHALLREUTER & SIVETER sp. nov. by Roger E. L. Schallreuter & David J. Siveter (University of Hamburg, West Germany & University of Leicester, England) Webbylla reticulata sp. nov. Holotype: Type locality: Derivation of name: University of Sydney, Australia; Palaeontology (SUP) no. 52907; LV. [Paratypes: SUP 52908-52912], About 1 km NE of Quondong Loc. BS5), Bowan Park, western New' South Wales, Australia, 33°20'S, 148°56'E (see Semeniuk, V. , J. Proc. R. Soc. N.S.W.. 103. 16-17, 1970); Bourimble Limestone Member, Daylesford Limestone (upper Gisbornian or lower Eastonian), upper Ordovician. With reference to the partly reticulate shell. Figured specimens: University of Sydney, SUP nos. 52907 (holotype, LV : PI. 15, 22, fig. 1), 52908 (incomplete LV : PI. 15, 22, figs. 2-4), 52909 (RV: PI. 15, 24, fig' 1), 52910 (LV: PI. 15, 24, fig. 2), 52911 (car.: PI. 15, 24, fig. 3). All of the figured specimens are from the type locality and all are silicified. Explanation of Plate 15, 22 Fig. 1, LV, ext. lat. (holotype, SUP 52907, 1.76mm long). Figs. 2-4, ant. and posterovent. incomplete LV (SUP 52908. 1.64mm long): fig. 2, ext. lat. ; fig. 3, ext. lat. detail of muscle spot and impression of presumed accessory ant. muscle scar; fig. 4, ext. lat., slightly tilted, detail of ventral marginal surface. Scale A (250/xm; x45), fig. 1; scale B (250p.m; x48), fig. 2; scale C (100/i.m; x65), figs. 3, 4. Stereo-Atlas of Ostracod Shells 15, 23 Webbylla reticulata (3 of 4) Diagnosis: Remarks: Distribution: Acknowledgement : Species of Webbylla in which nodes N3 and N4 are about equally strongly developed and the anterior part of the pseudovelum ends some distance below the valve dorsal border. Valve marginal surface is relatively broad. Reticulation on the pseudovelum and also often on the nodes. Valve length up to 1.77mm. W. reticulata is smaller than the type-species, W. cyma Schallreuter & Siveter, 1988 ( Stereo-Atlas Ostracod Shells, 15, 17) from the younger Billabong Creek Limestone of the Parkes Platform of western New South Wales. It is further distinguished by having nearly equally strongly developed N3 and N4, an anterodorsallv shorter pseudovelum, a broader marginal surface and a partly reticulate shell. An undescribed subspecies of W. cyma from the Gerybong Limestone Member of the Daylesford Limestone, w'hich is younger than W. reticulata and older than W. cyma cyma (cf. Webby, B. D. & Morris, D. G., J. Proc. R. Soc. N.S.W. 109, 126, 1976) has an intermediate morphological position between W. reticulata and W. cyma cyma. W. reticulata exhibits a small, pit-like impression in front of the non-reticulate muscle spot (PI. 15, 22. figs. 2, 3). Such a feature was observed in Platybolbina tunica by Schallreuter & Krfita ( Stereo-Atlas Ostracod Shells 11, 125, PL 11, 126, figs. 1, 3, 1984). It was considered to be the impression of an accessory muscle scar (op. cit., 11, 126). So far known only from the type locality. The drepanellid Pilla piformis Schallreuter & Siveter, 1988 ( Stereo-Atlas Ostracod Shells, 15, 25) also occurs there. We thank Dr Barry Webby, University of Sydney, for sending us the material to study. Explanation of Plate 15, 24 Fig. 1, RV, ext. lat. (SUP 52909, 1.66mm long); fig. 2, LV, int. lat. (SUP 52910, 1.61mm long); fig. 3, car., vent. (SUP 52911, 1.34mm long). Scale A (250/u.m; x50), figs. 1, 2; scale B (250^im; X40), fig. 3. Webby lla reticulata (2 of 4) Stereo- Atlas of Ostracod Shells 15, 22 mm. 5 CVv:; f . a - ••***>«» • A« * * • ***!* • *<» ? t fhm% &&•$& -•"* •/ '« »* **wV’ W - / V-- e l! «£?fp* ^ Stereo-Atlas of Ostracod Shells 15 (7) 25-28 (1988) Pilla piformis (1 of 4) 595.336.12 (113.313) (944 : 163.148.34) : 551.351 + 552.54 ON PILLA PIFORMIS SCHALLREUTER & SIVETER gen. et sp. nov. by Roger E. L. Schallreuter & David J. Siveter (University of Hamburg , West Germany & University of Leicester, England) Genus PILLA gen. nov. Type-species: Pilla piformis sp. nov. From the Greek Pi; resemblance of the pattern formed by the main nodes and pseudovelum, when turned through 180°, to the sixteenth letter of the Greek alphabet. A genus of Drepanellidae with two distinct bulb-like nodes (Nl, N4) at the dorsal border and a very weak N2 fused with Nl. Nl and N4 connected ventrally by a broad, crescent-shaped lobe-like pseudovelum which posteroventrally of N4 forms a rounded but somewhat pointed protuberance and which anteriorly extends in front of Nl to reach the dorsal border. N3 is lacking. Pilla is distinguished from the Australian genera, Dominina Burrett & Laurie (in Burrett et al., Mem. Ass. Australas. Palaeontols 1, 191, 1983) and Webbylla Schallreuter & Siveter (Stereo-Atlas Ostracod Shells 15, 17, 1988) mainly by the lack of N3. It differs further from Dominina by the Explanation of Plate 15, 26 Fig. 1, vent, incomplete RV, ext. lat. (holotype, SUP 52913, 1.59 mm long). Figs. 2 3, marginal incomplete RV (SUP 52914, 1.45 mm long): fig. 2, ext. lat.; fig. 3, ext. dors. Fig. 4, RV, ext. vent. (SUP 52915, 1.52 mm long). Scale A (250/a.m; x 50); figs. 1, 2; scale B (250/u.m; x 30), figs. 3, 4. Derivation of name: Diagnosis: Remarks: Stereo-Atlas of Ostracod Shells 15, 27 Pilla piformis (3 of 4) Remarks (cont.): Holotype: Type locality: Derivation of name: Figured specimens: Diagnosis: Remarks: Distribution: Acknowledgement: posteroventral protuberance and in having the pseudovelum present anteriorly. Dominina, Webbylla and Pilla are a closely related group of genera within the Drepanellidae. This group exhibits closer affinities to the typical North American representatives of the family such as Drepanella Ulrich, 1890 and Scofieldia Ulrich & Bassler, 1908 than to the European members such as Duplexibollia Schallreuter, 1987. Pilla piformis sp. nov. University of Sydney, Australia; Palaeontology (SUP) no. 52913; RV. [Paratypes: SUP 52914-52917], About 1 km NE of Quondong (Loc. BS5), Bowan Park, western New South Wales, Australia, 33° 20' S, 148° 56' E (see Semeniuk, V., J. Proc. R. Soc. N.S.W., 103, 16-17, 1970); Bourimbla Limestone Member, Daylesford Limestone (upper Gisbornian or lower Estonian), upper Ordovician. As for the genus. University of Sydney, SUP nos. 52913 (RV: PI. 15, 26, fig. 1), 52914 (RV: PI. 15, 26, figs. 2, 3), 52915 (RV: PI. 15, 26, fig. 4; PI. 15, 28, figs. 2-4), 52916 (RV: PI. 15, 28, fig. 1). All specimens are from the type locality and all are silicified. As for genus. Pilla is currently monotypic. The surface reticulation characteristic of this species has, unfortunately, been effaced from parts of some specimens (e.g. PI. 15, 26, fig. 2; PI. 15, 28, fig. 1) during preparation. So far known only from the type locality. The drepanellid Webbylla reticulata Schallreuter & Siveter, 1988 (Stereo-Atlas Ostracod Shells, 15, 21) also occurs there. We thank Dr. Barry Webby, University of Sydney, for sending us the material to study. Explanation of Plate 15, 28 Fig. 1, anterodors. incomplete RV, ext. lat. (SUP 52916, 1.71 mm long). Figs. 2-4, posterodors. incomplete RV (SUP 52915): fig. 2, ext. lat.; fig. 3, ext. lat. obi., detail of reticulation; fig. 4, ext. details of vent, marginal surface. Scale A (250 gm; X 45), fig. 1; scale B (250 /j.m; x 50), fig. 2; scale C (50 /urn; x 150), fig. 3; scale D (25 gm; x 300), fig. 4. Pill a piformis (2 of 4) Stereo-Atlas of Ostracod Shells 15, 26 Stereo-Atlas of Ostracod Shells 15, 28 Pilla piformis (4 of 4) Stereo-Atlas of Ostracod Shells 15 (8) 29-32 ( 1988) Tricornina (Bohemina) paragracilis (1 of 4) 595.337.14 (113.4) (430.1:161.007.51) : 551.35 ON TRICORNINA ( BOHEMINA ) PARAGRACILIS (BLUMENSTENGEL) by Gerhard Becker (University of Frankfurt, West Germany) Tricornina ( Bohemina ) paragracilis (Blumenstengel, 1965) 1965 Bohemina paragracilis sp. nov. H. Blumenstengel, Freiberger ForschHft., C 183, 18, pi. 2, figs. 1-6, pi. 14, figs. 1-3, tabs. 1. 6. 1982 Tricornina ( Bohemina ) paragracilis , Blumenstengel; G. Becker, Palaeontographica, A, 178, 146-147, pi. 9, figs. 11-18, tab. 1 (q.v. for full synonymy). 1988 Tricornina (Bohemina) paragracilis, Blumenstengel; G. Becker, Geologisches Jahrbuch Hessen, 116, pi. 1, figs. 1-3, 4a-b. 5a-b, 6-8a, pi. 2, figs. 4c, 5c, 8b-9. Holotype: Geological Institute, “Bergakademie" of Freiberg, German Democratic Republic, specimen unnumbered; an adult LV. Type locality: Bohlen, Kahlleite Quarry, German Democratic Republic; shales with limestone nodules, do 11(3, Cheiloceras stage. Upper Devonian. Cephalopod facies, ostracod faunas of Thuringian and entomozoan ecotypes. Explanation of Plate 15, 30 Fig. 1, 9 RV. ext. lat. (SMF Xe 13950, 825 pm long); fig. 2, juv. LV, ext. lat. (SMF Xe 13948, 700 gm long); fig. 3, cf RV, ext. lat. (SMF Xe 13951, 780/um long). Scale A (300/u.m; x 90), figs. 1, 3; scale B (300/um; x 65), fig. 2. Stereo-Atlas of Ostracod Shells 15, 31 Tricornina ( Bohemina) paragracilis (3 of 4) Figured specimens: Diagnosis: Remarks: Distribution: “Forschungs-Institut Senckenberg" (SMF), Federal Republic of Germany, nos. SMF Xe 13948 (juv. LV: PI. 15, 30, fig. 2; PI. 15, 32, fig. 2), SMF Xe 13950, (9 RV: PI. 15, 30. fig. 1; PI. 15, 30, fig. 1), SMF Xe 13951 (cf RV: PI. 15, 30, fig. 3; PI. 15, 32, fig. 3). Collected by W. Ziegler. All of the figured specimens are from a locality at the path-bifurcation, about 1 km NW of Allendorf village, 9 km NE Plettenberg (lat. 51° 13'N, long. 7° 53'E), Sauerland, Federal Republic of Germany; Wocklumeria stage. Upper Devonian; basinal sediments. Tricornina (Bohemina) species with strong lateral spine, subcentrally situated, without noticeably broadened base. Lateral surface smooth to more or less closely spinose. Sexual dimorphism: ornamental extradomicial. Adult tecnomorphs with single adventral ridge or row of denticles; juveniles with additional ornamented adventral field. Heteromorphs with two smooth or dentate adventral ridges. Blumenstengel (1965, op. cit) describes the specimens from E Thuringia as having 1-2, partly dentate adventral ridges. The Rhenish material herein indicates that this “variability" may be due to sexual dimorphism. In tecnomorphic valves from the Sauerland area, adventral denticles are developed, becoming smaller towards the dorsal parts of the valve. The subventral field (of the juveniles only?) shows delicately dentate ripplings (cf. also the greater magnifications in Becker 1988, pi. 1, figs. 6d and 8a). T. paragracilis is believed to be a nectobenthic species. E Thuringian and Rechtsrheinisches Schiefergebirge, Germany; SE Cantabrian Mountains, N Spain; ? W Serbia. Upper Devonian (do I-VI). Basinal facies. Explanation of Plate 15, 32 Fig. 1, 9 RV, vent. obi. (SMF Xe 13950); fig. 2, juv. LV, vent. obi. (SMF Xe 13948); fig. 3, cf RV, vent. obi. (SMF Xe 13951). Scale A (300/xm; x 90), figs. 1, 3; scale B (300^m; x 65), fig. 2 Tricornia paragracilis (2 of 4) Stereo- Atlas of Ostracod Shells 15, 30 Stereo-Atlas of Ostracod Shells 15, 32 Tricornia paragracilis (4 of 4) Stereo-Atlas of Ostracod Shells 15 (9) 33-36 ( 1988) Bradleya normani (1 of 4) 595.337.14 (119.9) (265.1:164.074.51) : 551.352 (26.03:24.08.527) ON BRADLEYA NORMANI (BRADY) by David W. Foster & Roger L. Kaesler (University of Kansas, Lawrence, Kansas, USA) Bradleya normani (Brady, 1865) 1865 Cythere normani sp. nov. G. S. Brady, Trans, zool. Soc. Loud., 5, 379-380, pi. 61, figs. 5a-d. 1880 Cythere normani Brady; G. S. Brady, Rep. scient. Results Voy. Challenger, Zoology, 1, 101-102 (pars), pi. 17, figs. 3a-d only ( non pi. 26, figs. 4a, b). 1972 Bradleya normani (Brady); R. H. Benson, Smithsonian Contributions to Paleobiology, no. 12, 38-39. fig. 13C, pi. 2, fig. 7, pi. 7, fig. 8. Lectotype: Type locality: Figured specimens: Diagnosis: Designated herein. Hancock Museum, Newcastle-upon-Tyne, England, no. 1.32.32; 9 right valve, 780/am long. [Paralectotype: middle specimen of three on slide no. 2.06.32]. Abrolhos Bank off Brazil (approx, lat. 17° 30'S, long. 39° 00'W), depth unknown: Recent, marine. Hancock Museum, Newcastle-upon-Tyne, England, no. 1.32.32 (lectotype, 9 RV: Text-fig. Id). Museum of Invertebrate Paleontology, University of Kansas, USA, nos. 1,122,943 (9 LV, morph 1: PI. 15, 34, fig. 1; PI. 15, 36, fig. 3; Text-fig. la), 1,122,948 (9 LV. morph 2: PI. 15, 34, fig. 2; Text-fig. lb), 1,122,945 (9 LV, morph 3: PI. 15, 34, fig. 3; Text-fig. lc), 1,122,933 (cf RV: PI. 15, 36, fig. 1), 1,122,939 (9 RV: PI. 15, 36, fig. 2), 1,122,934 (9 LV: PI. 15, 36, fig. 4). All except lectotype are from Recent sediment, lat. 52° 50' - 51'S, long. 73° 55'W, depth 526.7 m. Strait of Magellan, off southern Chile (SE Pacific) from dredge samples collected in 1969 by the junior author aboard N.S.F. RV Hero , cruise 69-5. Carapace large, with coarse primary reticulation; some simplification of reticular pattern by reduction of muri and partial fusion of fossae. Muri characteristically foveolate. Subcentral Explanation of Plate 15, 34 Fig. 1, 9 LV, morph 1, ext. lat. (1,122,943, 927/zm long); fig. 2, 9 LV, morph 2, ext. lat. (1,122,948, 905 /urn long); fig. 3, 9 LV, morph 3, ext. lat. (1,122,945, 909/um long). Scale A (500/um; x 58), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 35 Bradleya normani (3 of 4) Diagnosis (cont.): tubercle strongly developed. Ocular ridge weak, posterior median ridge replaced by sublinear box-like arrangement of fossae. Ventrolateral carina with terminal spine, more strongly developed than dorsal carina. Marginal spines concentrated on anteroventral and posteroventral margins. Blind. Appendages unknown. Remarks: This species is morphologically quite variable. We have identified three morphs, each with a different posteroventral reticular pattern, which are characterized by the specimens illustrated in PI. 15, 34, figs. 1-3 and detailed in Text-fig. 1. Fossae of morph 1 are subrounded and separated by thick to moderately thick muri. Muri of morph 2 are greatly reduced between three pairs of fossae resulting in partial fusion of the fossae. Morph 3 is characterized by weak muri between two pairs of fossae and a fully fused, much smaller fossa capping the two. The lectotype belongs to morph 2; fossae of the paralectotype are infilled with a matrix that obscures the reduced murae. Males are rare, comprising less than five percent of our collections. Text-fig 1. Camera-lucida drawing of posteroventral reticular pattern of three morphs and the lectotype of Bradleya normani. Distribution: Atlantic Ocean, eastern Pacific Ocean, southern oceans; typically found in upper bathyal depths but shallower at high latitudes. Acknowledgements: We are grateful to R. H. Benson, K. G. McKenzie, J. E. Whittaker, D. J. Horne, and P. S. Davis for their help with various aspects of the research. Our work was partially supported by National Science Foundation grants G A- 12472 and GV-25157 and by The University of Kansas General Research Fund, grant 3656-20-0038. Explanation of Plate 15, 36 Fig. 1, cf RV, morph 1, ext. lat. (1,122,933, 873/um long); fig. 2, 9 RV, int. lat. (1,122,939, 909 /am long); fig. 3, 9 LV, ext. lat., detail of posteroventral reticular pattern, morph 1 (1,122,943); fig. 4, 9 LV, int. lat., detail of muscle-scar pattern (1,122,934). Scale A (500/am; X 58), figs. 1, 2; scale B (100/am; x 290), fig. 3; scale C (100/am; x 225), fig. 4. Bradley a normani (2 of 4) Stereo-Atlas of Ostracod Shells 15, 34 Stereo-Atlas of Ostracod Shells 15, 36 Bradleya normani (4 of 4) Stereo-Atlas of Ostracod Shells 15 (10) 37-40 (1988) Reticulocosta ornatoreticulata (1 of 4) 595.337.14 (118.13) (669:161.004.06) : 552.52 ON RETICULOCOSTA ORNATORETICULATA (REYMENT) by Richard Reyment (Department of Historical Geology & Palaeontology, University of Uppsala, Sweden) Genus RETICULOCOSTA Grundel, 1974 Type-species (by original designation): Veenia (Veenia) ornatoreticulata Reyment, 1963. Diagnosis: Lateral outline of carapace rectanguloid, with rounded anterior margin and bluntly pointed posterior. Left valves have a weak hinge-ear. Lateral surface irregularly reticulate; there is an anterior ridge, anterior of which are coarse reticulations, and a corresponding posterior ridge. There are three lateral ribs, the ventral of which is flat; the ventral and median ribs are arched and unite anteriorly. The indistinct adductor muscle tubercle is located on the median rib. Eye-tubercles prominent, with broad internal sockets (the location of which is visible on the valve-surface as a truncated riblet); the eye-tubercle is joined to the anterior ridge. Dorsal surface of each valve with two rows of coarse reticulations; ventral surface of each with two rows of ovoid reticulations. The anterior and posterior denticulations are stronger in the ventral halves of the margins. Left hinge comprises an anterior socket, pointed postjacent tooth, a smooth median bar, and a partly breached posterior socket. There is an overlapping extension of the left valve immediately in front of the anterior hinge-element. Right hinge with an anterior tooth, a postjacent re-entrant socket, a smooth median furrow, and a stepped and angled posterior tooth. Line of concrescence and inner margin not exactly coincident. Marginal pore-canals numerous and Explanation of Plate 15, 38 Fig. 1, 9 car., rt- lat. (PMAf 127, 675/um long); fig. 2, cf car., dors. (PMAf 130, 810/am long); fig. 3, 9 car.. It. lat. (PMAf 126, 655 /am long); fig. 4, 9? car., vent. (PMAf 131, 730/xm long). Scale A (100/am; x 90), figs 1, 3; scale B (100/am; x 75), fig 2; scale C (100/am; x 100), fig. 4. Stereo-Atlas of Ostracod Shells 15, 39 Reticulocosta ornatoreticulata (3 of 4) Diagnosis (cont.): simple. Central muscle field with four scars in a vertical row and an anterior v-shaped scar. Sexual dimorphism strong: males longer and lower than females. Late juvenile instars regularly reticulated and indistinctly ribbed. Remarks: Reticulocosta resembles Repandocosta Hazel, 1967 in many respects, such as shape and mode of reticulation, but differs in details of the curved ribbing and in having a less prominent adductor muscle tubercle and smooth hinge elements. Mosaeleberis Deroo, 1966, is also quite similar but lacks an anterior ridge. Distribution: Early Paleocene of Nigeria and the Maastrichtian of Ghana. Possibly also occurs in the Santonian of South Africa. Reticulocosta ornatoreticulata (Reyment, 1963) Veenia ( Veenia ) ornatoreticulata sp. nov., R. A. Reyment, Stockh. Contr. Geol., 10, 188, pi. 2, fig. 6, pi. 6, figs, la-c, pi. 16, fig. 7, Text-fig. 49. Reticulocosta ornatoreticulata (Reyment); J. Grundel, Freiberger ForschHft., C 298, 88, fig. 5. Mosaeleberis ornatoreticulata (Reyment); R. A. Reyment, Bull. geol. Instn Univ. Uppsala, NS 9,63, pi. 8, fig. 12, pi. 9, fig. 8. Holotype: Geological Department, University of Stockholm, no. G10 1132; a carapace. Subsurface of western Nigeria, Araromi borehole (approx, lat. 06° 35' N, long. 04° 55' E) at a depth of 1454 ft; in the Araromi Shale, early Paleocene. Palaeontological Museum, University of Uppsala, Sweden, nos. PMAfl26 (9 car.: PI. 15, 38, fig. 3) , PMAfl27 (9 car.: PI. 15, 38, fig. 1), PMAH28 (cf RV: PI. 15, 40, figs. 1, 3, 4), PMAA29 (9 LV: PI. 15, 40, figs. 2, 5, 6), PMAfl30 (cf car.: PI. 15, 38, fig. 2), PMAfl31 (9 car.: PI. 15, 38, fig. 4) . All from the type locality and horizon. A variably reticulate form showing variation in the strength of the adductor muscle tubercle. The proportion of males to females in this species does not have the normal Mendelian sex-ratio, there being 24.5 - 37.4% of males in the samples available for study. Distribution: Maastrichtian to early Paleocene of West Africa. 1963 1974 1981 Type locality: Figured specimens: Diagnosis: Remarks: Explanation of Plate 15, 40 Fig. 1, 3, 4, cf RV (PMAfl28, 835 /am long): fig. 1, int. lat.; figs. 3, 4, details of anterior and posterior hinge elements. Figs. 2, 5, 6, 9 LV (PMAfl29, 680 /am long): fig. 2, int. lat.; figs. 5, 6, details of posterior and anterior hinge elements. Scale A (lOO/am; x 75), fig. 1; scale B (100/am; X 90), fig. 2; scale C (100/am; x 150), figs. 3-6. Stereo-Atlas of Ostracod Shells 15, 38 Reticulocosta ornatoreticulata (2 of 4) Reticulocosta ornatoreticulata (4 of 4) Stereo-Atlas of Ostracod Shells 15, 40 Stereo-Atlas of Ostracod Shells 15(11) 41-44 ( 1988) Quadracythere keeni (1 of 4) 595.337.14 (118.15) (420:162.002.50) : 551.35/551.313.2 ON QUADRACYTHERE KEENI SLIPPER sp. nov. by Ian J. Slipper (City of London Polytechnic, England) Quadracythere keeni sp. nov. 1977 Quadracythere diversinodosa (Lienenklaus); M. C. Keen, in: F. M. Swain (ed.), Stratigraphic Micropaleontology of Atlantic Basin and Borderlands, Develop. Palaeont. Stratigr., Amsterdam, 6. 488, pi. 2, fig. 6. 1978 Quadracythere nodosa Haskins; M. C. Keen, in: R. H. Bate & E. Robinson (eds), A. Stratigraphical Index of British Ostracoda, Geol. J. Spec. Issue, 8, 420, pi. 11, fig. 17; non pi. 11, figs. 14, 16. British Museum (Nat. Hist.) no. OS 13044; $ carapace. [Paratypes: British Museum (Nat. Hist.) nos. OS 13045 - 13047], Northern end of Whitecliff Bay, Isle of Wight, Hampshire, England (lat. 50° 40' N, long. 1° 05' W); Oyster bed, base of the Bembridge Marls Member, Bouldnor Formation, Solent Group, Oligocene. After Dr. M. C. Keen, in recognition of his studies of Tertiary ostracods. British Museum (Nat. Hist.) nos. OS 13045 (paratype, cf car.: PI. 15, 42, figs. 1, 2), OS 13044 (holotype, $ car.: PI. 15, 42, figs. 3, 4), OS 13047 (paratype, 9 RV: PI. 15, 44, figs. 1-3), OS 13046 (paratype, 9 car.: PI- 15, 44, fig. 4). All collected by the author from the type horizon and locality. Species of Quadracythere with ornament of irregular fossae and tuberculate muri surrounding the main anterocentral tubercle where the carapace attains greatest inflation. Ventral margin strongly sinuous in left valve, weakly so in right valve. Very prominent, curved ventrolateral carina partly overhanging ventral margin, curving strongly upwards posteriorly. Dorsolateral muri coalesce posterodorsally in an angular projection. Posterior hinge tooth in right valve robust with obscure jobation. Explanation of Plate 15, 42 Figs. 1, 2, cf car. (paratype, OS 13045, 580 pm long); fig. 1, It. lat.; fig. 2, car. dors., figs. 3, 4. 9 car. (holotype, OS 13044, 600 pm long); fig. 3, It. lat.; fig. 4, car. dors. Scale A (100 /am; x 100), figs. 1-4. Holotype: Type locality: Derivation of name: Figured specimens: Diagnosis: Stereo-Atlas of Ostracod Shells 15, 43 Quadracythere keeni (3 of 4) Remarks: Distribution: This species, from the basal Oligocene, Isle of Wight, was initially referred to Q. diversinodosa (Lienenklaus, 1894) (Z. dt. geol. Ges., 46, 212-213, pi. 15, fig. la-d) by Keen (1977 op. cit.) who used it to define zone 13a (early Oligocene) in his zonation of the NW European Tertiary. In a revised zonation. Keen (1978, op. cit.) excluded zone 13a, referring his specimens instead to the Eocene species Q. nodosa Haskins, 1971 ( Revue Micropaleont., 14, 155, pi. 2, figs. 21-28). Comparison of the present material with type specimens of Q. nodosa and Q. diversinodosa (see D. J. Horne & I. J. Slipper, Stereo-Atlas Ostracod Shells, 15, 45-48, 1988) has shown that the three are distinct (see Text-fig. 1 for comparative outlines). Keen’s Oligocene form is accordingly described herein as a new species, Q. keeni; it is most easily recognised by the strongly curved ventrolateral carina, which overhangs the ventral margin. It follows that Keen’s original zone 13a may be considered valid (early Oligocene, represented by the Bembridge Marls in southern England). Early Oligocene (Keen 1978, op. cit.); possibly restricted to the Bembridge Marls Member of the Hampshire Basin, southern England. Text-fig. 1. Comparative outlines of carapaces (It. lat. and dors, views) of: a, Q. keeni; b, Q. diversinodosa; c, Q. nodosa. All drawn from type material. Explanation of Plate 15, 44 Figs. 1-3, 9 RV (paratype, OS 13047, 550 yum long): fig. 1, int. lat.; fig. 2, ant. hinge element; fig. 3, post, hinge element; fig. 4, 9 car. vent, (paratype, OS 13046, 540yum long). Scale A (lOOyum; x 100), figs. 1, 4; scale B (lOOyum; x 200), figs. 2, 3. Stereo-Atlas of Ostracod Shells 15, 44 Quadracythere keeni (4 of 4) Stereo-Atlas of Ostracod Shells 15, 42 Quadracythere keeni (2 of 4) Stereo-Atlas of Ostracod Shells 15 (12) 45-48 ( 1988) Quadracythere nodosa (1 of 4) 595.337.14 (118.14) (420 : 162.002.50) 551.35 ON QUADRACYTHERE NODOSA HASKINS by David J. Horne & Ian J. Slipper (City of London Polytechnic, England) Quadracythere nodosa Haskins, 1971 1971 Quadracythere nodosa sp. nov. C. Haskins, Revue Micropaleont. , 14, 155, pi. 2, figs. 21-28. 1978 Quadracythere nodosa Haskins; M. C. Keen, in: R. H. Bate & E. Robinson (eds.), A Stratigraphical Index of British Ostracoda, Geol. J. Spec. Issue, 8, 420, pi. 11, figs. 14, 16; non pi. 11, fig. 17. Holotype: University of Hull, no. HU.14.T.6.2288; a left valve. [Paratypes: University of Hull, nos. HU. 14.T.6. 2289-2296; one complete carapace, seven detached valves]. Type locality: Alum Bay, Isle of Wight, Hampshire, England, approx, lat. 50° 40' N, long. 01°34' W ; Barton Clay Formation, Barton Group, late Eocene. Figured specimens: University of Hull, nos. HU.14.T.6.2288 (holotype, LV: PI. 15, 46, fig. 1), HU.14.T.6.2302 (paratype, LV: PI. 15, 46, fig. 2), HU.14.T.6.2298 (paratype, RV: PI. 15, 46, fig. 3. PI. 15, 48, fig. 1), HU.14.T.6.2289 (paratype, car.: PI. 15, 48, figs. 2, 3). All from the type locality and horizon. Explanation of Plate 15, 46 Fig. 1, LV, ext. lat. (holotype, HU.14.T.6.2288, 500/u.m long); fig. 2, LV, int. lat. (paratype, HU.14.T.6.2302, 520 yum long); fig. 3, RV, int. lat. (paratype, HU.14.T.6.2298, 530/xm long). Scale A (100 yarn; xllO), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 47 Quadracythere nodosa (3 of 4) Diagnosis: Species of Quadracythere with ornament of tuberculate muri forming coarse reticulation surrounding the main anterocentral tubercle where the carapace attains greatest inflation. Ventral margin weakly convex in left valve, sinuous in right valve. Dorsal margin of left valve with slight arch between prominant anterior and posterior cardinal angles, evenly curved in right valve. Anterior marginal area with distinct fossae. Ventrolateral carina weakly curved upwards posteriorly. Raised dorsolateral muri coalesce posterodorsally in a projection. Weak posterior hinge tooth in right valve with obscure lobation. Remarks: Q. nodosa is similar to Q. diversinodosa (Lienenklaus, 1894 (Z. dt. geol. Ges., 46, 212-213, pi. 15, fig. la-d). Type material of the latter was kindly loaned to us by Dr S. Ritzkowsky (Institut und Museum fur Geologie und Palaontologie, Gottingen). The holotype (illustrated by B. Moos, Geol. Jb., 82, pi. 1, fig. 10, 1963), is poorly preserved, but comparison with topotypes shows significant differences: Q. diversinodosa has a straighter dorsal margin, less regular anterior marginal fossae, and is larger (670yum long). Q. nodosa sensu Keen (op. cit. pi. 11, fig. 17) is now assigned to Q. keeni Slipper, 1988 ( Stereo-Atlas Ostracod Shells, 15, 41-44). Distribution: Late Eocene, Hampshire Basin, southern England. Explanation of Plate 15, 48 Fig. 1, RV, ext. lat. (paratype, HU.14.T.6.2298, 530yu.m long); figs. 2, 3, car. (paratype, HU.14.T.6.2289, 500 pm long): fig. 2, car, dors.; fig. 3, car. vent. Scale A (100 yu-m; xllO), figs. 1-3. Quadracythere nodosa (4 of 4) Quadracythere nodosa (2 of 4) Stereo-Atlas of Ostracod Shells 15, 46 Stereo-Atlas of Ostracod Shells 15, 48 Stereo- Atlas of Ostracod Shells 15 (13) 49-56 (1988) Timiriasevia uptoni (1 of 8) 595.337.14 (116.222) (420 : 162.002.51) : 551.312 + 552.52). ON TIMIRIASEVIA UPTONI TIMBERLAKE sp. nov. by Simon Timberlake (Sedgwick Museum, University of Cambridge) Timiriasevia uptoni sp. nov. 1976 Timiriasevia sp. I. W. M. Rohr, Inaug. Diss. Free Univ. Berlin, 66-67 , pi. 10. British Museum (Nat. Hist.) no. OS 12992; 9 LV. [Paratypes: nos. OS 12993-OS 13000, OS 13081-OS 13084]. SE section of old clay pit near the ‘Round House’, Tarlton, Cirencester, Gloucestershire, England (Nat. Grid Ref. SO 970000); non-marine band in Forest Marble Clay. Pale grey marly clay, 25-53 cm below base of the Lower Cornbrash Limestone, Bathonian, middle Jurassic. In honour of Charles Upton who described fossil Characea and first recorded the presence of marine, estuarine and ‘fresh-water’ ostracod genera from this locality (Proc. Cotteswold Nat. Fid Club, 16 (3), 237-239, 1909). British Museum (Nat. Hist.) nos. OS 12992 (holotype, 9 LV : PI. 15, 50, fig. 1), OS 12993 (paratype, 9 RV : PI. 15, 50, fig. 2), OS 12994 (paratype, cf LV : PI. 15, 52, fig. 1), OS 12995 (paratype, cf RV : PI. 15, 52, fig. 2), OS 12996 (paratype, 9 car- : PI- 15, 54, fig. 1), OS 12997 (paratype, 9 car- : PI- 15, 54, fig. 2), OS 12998 (paratype, cf car. : PI. 15, 54, fig. 3), OS 12999 (paratype, cf car. : PI. 15, 56, fig. 7), OS 13000 (paratype, 9 LV : PI. 15, 56, fig. 1), OS 13081 (paratype, 9 RV : PI. 15, 56, fig. 2), OS 13082 (paratype, cf LV : PI. 15, 56, fig. 3), OS 13083 (paratype, cf RV : PI. 15, 56, figs. 4, 5), OS 13084 (paratype, A-2 juv. RV : PI. 15, 56, fig. 6). The paratypes are from the same sample (T6A) as the holotype or from sample T5BI; both pale grey marly clay, respectively 31-38 and 46-53 cm below the base of the Lower Cornbrash Limestone at the type locality. Explanation of Plate 15, 50 Fig. 1, 9 LV, ext. lat. (holotype, OS 12992, 615/am long); fig. 2, 9 RV, ext. lat. (paratype, OS 12993, 655/am long). Scale A (100/am; x 140), figs. 1, 2. Holotype: Type locality: Derivation of name: Figured specimens: Stereo-Atlas of Ostracod Shells 15, 51 Timiriasevia uptoni (3 of 8) Diagnosis: A moderate sized Timiriasevia species; strongly dimorphic - females larger than males, carapace ovate (male) or truncate pyriform (female) in dorsal view. Valves semicircular to elongate triangular in lateral view. Posteroventral inflation in female valves; truncated posterior in males. Sulcus along dorsal margin of carapace. Ventral surface planar. Valves strongly ornamented with sub-concentric costae in reduced numbers and more widely spaced than is typical for the genus; marked development of horizontal keel in ventrolateral region; strongly noded. Hinge lophodont: prominent median element, shorter terminal elements. Wide accommodation groove in larger left valve. Radial pore canals short, straight and simple, up to 35 anteriorly. Inner margin and line of concrescence do not coincide. Remarks: Although differences in the strength of costate ornamentation are slight, variations in the strength of noding are more obvious within the sample population (99 valves and carapaces). Some variability in valve outline and carapace shape, independent of sexual dimorphism and similar to that illustrated by Clements in T. mackerrowi Bate (Stereo-Atlas Ostracod Shells, 2, 117-124, 1974) was also observed. Only one A-l and one A-2 specimen were recovered. T. mackerrowi differs on account of its weaker costate ornament and lack of ventrolateral keel, but the positions of nodes and pattern of ornamentation are similar in both species. Timiriasevia sp. A of Bate, 1965 (Palaeontology, 8, 758, pi. 3) possesses a ventrolateral keel but is lozenge shaped, smaller, and un-noded. T. epidiformis Mandelstam, 1947 from the middle Jurassic of the Mangyshlak Peninsular, U.S.S.R. (All-Union Petrol. Scientific Res. Geol. Prosp. Inst. 5, 6, 22-24), is similarly lozenge shaped but lacks a ventrolateral keel. T. principalis Lyubimova, 1956, from the upper Cretaceous of Mongolia (Trudy vses. neft. nauchno — issled. geol. — razv. Inst. [VNIGRI], 93, 129, 130. pi. 24, figs, la, b) is a larger and more weakly ornamented species similarly lacking a ventrolateral keel. T. humilis Zhong, 1964 and T. shensiensis Zhong, 1964, from the middle Jurassic of Shenshi Province, China (Acta Pal. Sinica, 12, 457, pi. 2, figs. 14-16; 456, pi. 2, figs. 1-7) are both weakly ornamented. T. digitalis Govindan, 1975, from the Kota Limestone of India (Palaeontology, 18, 207-216, pi. 13), is strongly costate Explanation of Plate 15, 52 Fig. 1, cf LV, ext. lat. (paratype, OS 12994, 615/am long); fig. 2. cf RV, ext. lat. (paratype, OS 12995, 580/am long). Scale A (100/am; X 155), figs. 1, 2. Stereo-Atlas of Ostracod Shells 15, 50 Timiriasevia uptoni (2 of 8) Stereo-Atlas of Ostracod Shells 15, 52 Timiriasevia uptoni (4 of 8) Stereo-Atlas of Ostracod Shells 15, 53 Timiriasevia uptoni (5 of 8) Remarks ( cont .): yet is larger and lacks a keel. Timiriasevia sp. I of Brenner, 1976, from the Spanish Wealden (Palaeontographica, Abt. A, 152, 113-201), is a keeled species although otherwise not similarly ornamented. Timiriasevia sp. of Malz (Senckenberg. leth., 66, 311, pi. 8, figs. 88-90) from the lower Bajocian of Sardinia is similar though less elongate and with a smaller keel. Timiriasevia sp. I of Rohr (op. cit.) appears to be conspecific with T. uptoni although further examination needs to be made. Similarities between the last two species and T. uptoni might suggest an evolutionary lineage from the lower Bajocian to upper Bathonian. Distribution: Confirmed occurrence only from the type locality and horizon where it occurs in association with other oligohaline-mesohaline ostracods including Timiriasevia triangularis Timberlake (Stereo- Atlas Ostracod Shells 15, 57-68, 1988). T. sp. I of Rohr occurs in a middle Bathonian horizon within a limestone and lignite sequence at Les Grands Causses, southern France. Sex N X L (mm) SD Max Min N M (mm X ) SD N X H (mm) SD Max Min N L/M X [ SD N L/H X SD 99lv 17 0.63 .044 0.74 0.56 10 0.39 .03 17 0.39 .031 0.45 0.34 10 1.74 .088 10 1.66 .098 99rv 18 0.66 .056 0.79 0.60 10 0.39 .036 18 0.35 .03 0.42 0.31 10 1.74 .142 18 1.87 .12 Cf cf LV 10 0.56 .046 0.64 0.48 7 0.33 .024 10 0.35 .02 0.40 0.33 7 1.80 .086 7 1.60 .078 cfcfRV 15 0.55 .023 0.59 0.50 11 0.36 .025 15 0.31 .016 0.35 0.29 11 1.74 .073 11 1.78 .056 Table 1. Measurements on specimens from sample T5BI (type locality). N = no. of specimens; x = mean; SD = standard deviation; for dimensions L, M and H see Text-fig. 1. Explanation of Plate 15, 54 Fig. 1 9 car., ext. dors, (paratype, OS 12996, 645pm long); fig. 2, 9 car., ext. vent, (paratype. OS 12997, 665pm long); fig. 3. cf car., ext. dors, (paratype, OS 12998, 580pm long). Scale A (100p.ru; x 100), fig. 1; scale B (100pm; X 110), figs. 2, 3. Stereo-Atlas of Ostracod Shells 15, 55 Timiriasevia uptoni (7 of 8) Text-fig. 1. Outline of adult cf RV with measured Text-fig. 2. Muscle scar pattern, RV int. lat. dimensions (Table 1) indicated. Explanation of Plate 15, 56 Fig. 1, 9 LV. int. lat. (paratype, OS 13000, 580pm long); fig. 2, 9 RV, int. lat. (paratype, OS 13081, 545p.ru long); fig. 3, cf LV, int. lat. (paratype, OS 13082, 555pm long); fig. 4, cf RV, int. lat. (paratype, OS 13083, 495p.ru long); fig. 5, cf RV, int. muscle scars (paratype, OS 13083); fig. 6, A-2 juv. RV, ext. lat. (paratype, OS 13084, 340pm long); fig. 7, cf car., ext. vent, (paratype, OS 12999, 550p.ru long). Scale A (100pm; x 80), figs. 1-4; scale B (50pm; x 280), fig. 5; scale C (100pm; x 90), fig. 6; scale D (100pm; x 110), fig. 7. Stereo-Atlas of Ostracod Shells 15, 54 Timiriasevia uptoni (6 of 8) Stereo-Atlas of Ostracod Shells 15, 56 Timiriasevia uptoni (8 of 8) Stereo-Atlas of Ostracod Shells 15 (14) 57-68 (1988) Timiriasevia triangularis (1 of 12) 595.337.14 (116.222) (420 : 162.002.51) : 551.312 + 552.52 ON TIMIRIASEVIA TRIANGULARIS TIMBERLAKE sp. nov. by Simon Timberlake (Sedgwick Museum, University of Cambridge) Holotype: Type locality: Derivation of name: Figured specimens: Timiriasevia triangularis sp. nov. British Museum (Nat. Hist.) no. OS 12979; 9 LV. [Paratypes: nos. OS 12980-12991, OS 13065-13080], SE section of old clay pit near the ‘Round House’, Tarlton, Cirencester, Gloucestershire, England (Nat. Grid Ref. SO 970000); non-marine band in Forest Marble Clay. Pale grey marly clay, 23-53cm below base of the Lower Cornbrash Limestone, Bathonian, middle Jurassic. Latin, alluding to the shape of the valves. British Museum (Nat. Hist.) nos. OS 12979 (holotype, 9 LV: PI. 15, 58, fig. 1), OS 12980 (paratype, 9 RV: PI. 15, 58, fig. 2), OS 12981 (paratype, cf LV: PI. 15, 60, fig. 1), OS 12982 (paratype, cf RV: PI. 15, 60, fig. 2), OS 12983 (paratype, 9 car-: PI- 15, 62, fig. 1), OS 12984 (paratype, 9 car-: PI- 15, 62, fig. 2), OS 12985 (paratype, cf car.: PI. 15, 62, fig. 3), OS 12986 (paratype, cf car.: PI. 15, 64, fig. 6), OS 12987 (paratype, 9 RV: PI. 15, 64, fig. 1), OS 12988 (paratype, $ LV: PI. 15, 64, figs. 3, 5), OS 12989 (paratype, cf RV: PI. 15, 64, fig. 2), OS 12990 (paratype, cf LV: PI. 15, 64, fig. 4), OS 12991 (paratype, 9 A-l juv. car.: PI. 15, 66, fig. 1), OS 13065 (paratype, cf A-l juv. car.: PI. 15, 66, fig. 2), OS 13066 (paratype, 9 A-l juv. RV: PI. 15, 66, fig. 3), OS 13067 (paratype, cf A-l juv. RV: PI. 15, 66, fig. 4), OS 13068 (paratype, 9 A-2 juv. car.: PI. 15, 66, fig. 5), OS 13069 (paratype, cf A-2 juv. car.: PI. 15, 66, fig. 6), OS 13070 Explanation of Plate 15, 58 Fig. 1, 9 LV, ext. lat. (holotype, OS 12979, 560 /u.m long); fig. 2, 9 RV, ext. lat. (paratype, OS 12980, 580 yum long). Scale A (100 yu,m; xl60), figs. 1, 2. Stereo-Atlas of Ostracod Shells 15, 59 Timiriasevia triangularis (3 of 12) Figured specimens (paratype, 9 A-2 juv. LV : PI. 15, 66, fig. 7), OS 13071 (paratype, cf A-2 juv. LV : PI. 15, 66, fig. (cont.): 8), OS 13072 (paratype, 9 A-3 juv. car.: PI. 15, 68, fig. 1), OS 13073 (paratype, cf A-3 juv. car: PI. 15, 68, fig. 2), OS 13074 (paratype, 9 A-3 juv. RV: PI. 15, 68, fig. 3), OS 13075 (paratype, cf A-3 juv. RV: PI. 15, 68, fig. 4), OS 13076 (paratype, 9 A-4 juv. LV: PI. 15, 68, fig. 5), OS 13077 (paratype, cf A-4 juv. LV: PI. 15, 68, fig. 6), OS 13078 (paratype, 9 A-5 juv. RV: PI. 15, 68, figs. 7, 9), OS 13079 (paratype, cf A-5 juv. RV: PI. 15, 68, fig. 8), OS 13080 (paratype, cf A-5 juv. car.: PI. 15, 68, fig. 10). The paratypes are from the same sample (T5BI) as the holotype or from sample T6A, both pale grey marly clay, respectively 46-53 and 31-38 cms below the base of the Lower Cornbrash Limestone at the type locality. Diagnosis: A strongly dimorphic Timiriasevia species: females larger than males, carapace ovate (male) or pyriform (female) in dorsal view, with a strong posteroventral inflation beyond the outer margin in the latter. Valves subtriangular in lateral view; greatest height at or near mid-length in male, behind mid-length in female. Valves of both sexes have pronounced anterior marginal flanges. Left valve larger than right. Valves weakly ornamented with ‘finger print’ striations sub -concentric to valve margins, slightly stronger in ventral and posterior regions and more developed in females than males. Hinge simple, lophodont: short median and posterior elements, longer anterior element. Inner margin and line of concrescence do not coincide anteriorly or posteriorly. Radial pore canals few, short, straight and simple. Explanation of Plate 15, 60 Fig. 1, cf LV, ext. lat. (paratype, OS 12981, 535 /urn long); fig. 2, cf RV, ext. lat. (paratype, OS 12982, 525 yum long). Scale A (100 /urn; xl60), figs. 1, 2. Stereo-Atlas of Ostracod Shells 15, 58 Timiriasevia triangularis (2 of 12) Stereo-Atlas of Ostracod Shells 15, 60 Timiriasevia triangularis (4 of 12) Stereo-Atlas of Ostracod Shells 15, 61 Timiriasevia triangularis (5 of 12) L (mm) M ( mm) H (mm) L/M L/H (A) Sex N X SD Max Min N X SD N X SD Max Min N X SD N X SD 99 lv 32 0.61 .043 0.72 0.55 11 0.38 .036 32 0.39 .021 0.44 0.34 11 1.82 .094 32 1.54 .07 99 rv 33 0.61 .041 0.73 0.56 6 0.40 .034 33 0.37 .019 0.43 0.34 6 1.80 .02 33 1.64 .05 Cfcf LV 11 0.57 .042 0.63 0.52 11 0.33 .026 11 0.37 .028 0.42 0.33 11 1.76 .126 11 1.53 .10 cf cf RV 35 0.53 .029 0.6 0.49 16 0.34 .016 35 0.34 .022 0.39 0.30 16 1.66 .08 35 1.56 .055 L (mm) G (mm) W ( mm) L/G LAV (B) Sex N X SD Max Min N X SD N X SD Max Min N X SD N X SD 99 c 14 0.70 .066 0.81 0.58 14 0.41 .046 14 0.49 .071 0.60 0.30 14 1.69 .148 14 1.44 .128 cfcf c 23 0.57 .05 0.64 0.48 23 0.33 .028 23 0.38 .035 0.44 0.30 23 1.69 .112 23 1.52 .097 Table 1. Measurements on specimens from sample T5BI (type locality and horizon). N = no. of specimens; x = mean; SD = standard deviation; for explanation of dimensions L, M, H, G, and W see Text-figs. 2, 3. A = valves; B = carapaces. Remarks: Significant variations in the strength of the ornament were observed in the sample populations: at low magnification some valves appeared almost smooth. Apart from sexual dimorphism there is some minor variability in carapace shape plus a wide size range of adult individuals (see Table 1). All juvenile instars down to A-6 appear to exhibit precocious sexual dimorphism, distinguishable on instar diagrams (Text-fig. 1) and from details of shape and position of maximum width and height in valves and carapaces. As a rule, maximum height and width are behind mid-length in proto-females, at or near mid-length in proto-males. Throughout ontogeny proto-males are Explanation of Plate 15, 62 Fig. 1, $ car., dors, (paratype, OS 12983, 675/xm long); fig. 2, 9 car., vent, (paratype, OS 12984, 630 /xm long); fig. 3, cf car., dors, (paratype, OS 12985. 515 /xm long). Scale A (100/xm; xlOO), figs. 1, 2; scale B (100/xm; xll5), fig. 3. Stereo- Atlas of Ostracod Shells 15, 63 Timiriasevia triangularis (7 of 12) Remarks (cont.): slightly higher than females; length and width are not dimorphic until the A-l instar, at which point the proto-female becomes distinctly longer and more inflated than the proto-male. Although similar to T. mackerrowi Bate, 1965 ( Palaeontology , 8, 756-758, pi. 3, figs. 2-12; see R. Clements, Stereo-Atlas Ostracod Shells, 2, 117-124, 1974) in a number of respects, the weaker yet characteristic ornament and triangular profile of T. triangularis suggest that it is a distinct species. Specimens of T. mackerrowi from the Algarve of Portugal (F. F. Helmdach and M. M. Ramalho, Revue Micropaleont. , 19. (3), 1976) exhibit a similar posteroventral inflation and subtriangular outline, but are strongly costate. Timiriasevia ? sp. (H. Malz, Senckenberg. leth., 66, 31, pi. 8, figs. 80-82, 1985), from the Bajocian of Sardinia is smaller and differently ornamented. T. triangularis is easily distinguished from T. humilis Zhong, 1964 and T. shensiensis Zhong, 1964 from the middle Jurassic of Shensi Province, China ( Acta Pal. Sinica, 12, 457, pi. 2, figs. 14-16; 456, pi. 2, figs. 1-7). T. humilis is narrow and lozenge-shaped, and T. shensiensis possesses a somewhat different selvage structure. Carapaces of T. armeniacumiformis Zhong, 1964 ( Acta Pal. Sinica, 12, 456, pi. 2, figs. 8-13) are rather different in outline: sub-elliptical in lateral view and sub-fusiform in dorsal view. T. principalis Lyubimova 1956, from the Cretaceous of Mongolia ( Trudy vses. neft. nauchno - issled. geol. - razv. Inst. (VNIGRI), 93, 129, 130, pi. 24, figs, la, b), differs in its pattern of ornament and lack of any pronounced anterior marginal flange. Distribution: Known only from the type locality and horizon, where it occurs with T. mackerrowi , T. uptoni Timberlake ( Stereo-Atlas Ostracod Shells, 15, 49-56, 1988), an unnamed Timiriasevia species, Theriosynoecum kirtlingtonensis Bate, Bisulcocypris anglica Bate, plus a number of darwinulacean and cypridacean ostracods, charophytes and non-marine gastropods; marine/brackish elements are also present. T. mackerrowi and T. triangularis, along with Theriosynoecum kirtlingtonensis, are the most certainly autochthonous species. The salinity range represented is probably oligohaline-mesohaline. Explanation of Plate 15, 64 Fig. 1, 9 RV, int. lat. (paratype, OS 12987, 555/xm long); fig. 2. cf RV, int. lat. (paratype, OS 12989, 505 /xm long); fig. 3, 9 LV, int. lat. (paratype, OS 12988, 640 /xm long); fig. 4, cf LV, int. lat. (paratype, OS 12990, 510/xm long); fig. 5, 9 LV, detail of muscle scars (paratype, OS 12988); fig. 6, cf car., vent, (paratype, OS 12986, 540 /xm long). Scale A (100/xm; x90), fig. 1; scale B (100 /im; x80), figs. 2, 3, 4; scale C (50 /xm; xl90), fig. 5; scale D (100 /xm; xll5), fig. 6. Stereo- Atlas of Ostracod Shells 15, 64 Timiriasevia triangularis (8 of 12) Timiriasevia triangularis (6 of 12) Stereo-Atlas of Ostracod Shells 15, 62 Stereo- Atlas of Ostracod Shells 15, 65 Text-fig. 1. Ontogeny of T. triangularis ; all left valves. O = cf ; • = $ ; sample T5BI. Timiriasevia triangularis (9 of 12) Height in mm Explanation of Plate 15, 66 Fig. 1, 9 A-l juv. car., dors, (paratype, OS 12991, 450/xm long); fig. 2, cf A-l juv. car., dors, (paratype, OS 13065, 400 /am long); fig. 3, $ A-l juv. RV, ext. lat. (paratype, OS 13066, 420 /rm long); fig. 4, cf A-l juv. RV, ext. lat. (paratype, OS 13067. 360/am long); fig. 5, 2 A-2 juv. car., dors, (paratype, OS 13068, 330 /urn long); fig. 6, cf A-2 juv. car., dors, (paratype, OS 13069, 340 /am long); fig. 7, $ A-2 juv. LV, ext. lat. (paratype, OS 13070, 340 /am long); fig. 8, cf A-2 juv. LV, ext. lat. (paratype, OS 13071, 330 /am long). Scale A (100 /am; X100), figs. 1-8. Stereo- Atlas of Ostracod Shells 15, 67 Timiriasevia triangularis (11 of 12) Text-fig. 2. Adult cf RV ext. lat. in transmitted light showing muscle scars, normal pores and marginal pore canals; measured dimensions (Table 1) indicated. Text-fig. 3. Outline of adult 2 car- 1 measured dimensions (Table 1) indi- cated. Text-fig. 4. Muscle scar pattern, cf RV int. lat. Explanation of Plate 15, 68 Fig. 1, 2 A-3 juv. car., dors, (paratype, OS 13072, 285 /am long); fig. 2, cf A-3 juv. car. dors, (paratype, OS 13073, 290 /urn long); fig. 3, 2 A-3 juv. RV, ext. lat. (paratype, OS 13074, 275/um long); fig. 4, cf A-3 juv. RV, ext. lat. (paratype, OS 13075, 290 /am long); fig. 5, 2 A-4 juv. LV, ext. lat. (paratype, OS 13076, 245/um long); fig. 6, cf A-4 juv. LV, ext. lat. (paratype, OS 13077, 245 /am long); fig. 7, 2 A-5 juv. RV, ext. lat. (paratype, OS 13078, 195 /am long); fig. 8, cf A-5 juv. RV, ext. lat. (paratype, OS 13079, 195 /am long); fig. 9, § A-5 juv. RV, vent, (paratype, OS 13078, 195 /am long); fig. 10, cf A-5 juv. car., dors, (paratype, OS 13080, 205 /am long). Scale A (100/am; X120), figs. 1-4; scale B (100/am; x 140), figs. 5-10. Stereo- Atlas of Ostracod Shells 15, 66 Stereo-Atlas of Ostracod Shells 15, 68 Timiriasevia triangularis (12 of 12) Timiriasevia triangularis (10 of 12) Stereo-Atlas of Ostracod Shells 15(15) 69-72 ( 1988) Amphiexophthalmocythere oertlii ( 1 of 4) 595.337.14 (44.161.003.47) : 551.351 + 552.54 ON AMPHIEXOPHTHALMOCYTHERE OERTLII (BABINOT) by J. F. Babinot & J. P. Colin (Universite de Provence, Centre St. Charles, Marseille & Esso Research, Begles, France) Genus AMPHIEXOPHTHALMOCYTHERE Grundel, 1975 Type-species (by original designation): Exophthalmocythere oertlii Babinot, 1971 Diagnosis: Medium-sized carapace, flattened; posterior end acuminate in the upper half of valve height. Valve surface reticulate with strongly developed nodes and spines. Prominent nodes occur especially at the posterodorsal angle and (two) along the ventral margin. Eye tubercle well developed; subcentral tubercle more or less well developed; hinge amphidont (heterodont/slightly hemiamphidont). Marginal zones moderately wide without vestibulum. Remarks: The type-species has been originally assigned to the late Jurassic/early Cretaceous genus Exophthalmocythere Triebel, 1938 on the basis of its overall shape, ornamentation and prominent eye-tubercle. In fact this genus is more rectangular, less ornamented (absence of strong nodes and long spines) and the anterior tooth on the right valve is crenulate. The early Cretaceous genus Parexophthalmocythere Oertli, 1959, has no subcentral tubercle, its ornamentation is less developed and its hinge has more crenulate elements. We therefore think that Amphiexophthal- mocythere should be considered as a genus, not a subgenus of Parexophthalmocythere Oertli, 1959. Moreover, it belongs to the family Trachyleberididae, not the Progonocytheridae as previously suggested; it is related to the genus Navarracy there Colin & Rodriguez-Lazaro, also from the north Tethyan Cretaceous (see Stereo-Atlas Ostracod Shells 13 (13), 63-66, 1986). Explanation of Plate 15, 70 Fig. 1, cf car., ext. It. lat. (EPR-E 23458, 720 pm long); fig. 2, 9 car. ext. rt. lat. (EPR-E 23459, 720 jam long); fig. 3, cf car. ext. dors. (EPR-E 23460, 730 pm long). Scale A (100 pm: x 86), figs. 1-3. Stereo- Atlas of Ostracod Shells 15, 71 Amphiexophthalmocythere oertlii (3 of 4) Amphiexophthalmocythere oertlii (Babinot, 1971) 1959 Cythereis sp. H. J. Oertli, Paldont. Z., 33, 4, 246, pi. 32, fig. 9. 1965 Cythereis sp. 1 Oertli; P. Saint-Marc, Thesis Univ. Paris, 156, pi. 22, fig. 10, pi. 19, fig. 20. 1971 Exophthalmocythere oertlii n.sp. J. F. Babinot, Rev. Micropaleontol., 13, 4, 237, pi. 1, figs. 1, 2. 1971 Parexophthalmocythere oertlii (Babinot) (sic); R. Damotte, Rev. Micropaleontol. , 14, 1, 18, pi. 3, figs. 19a-d. 1973 Exophthalmocythere oertlii Babinot; J. P. Colin, Thesis Univ. Paris, 181, pi. 19, fig. 4. 1975 Parexophthalmocythere ( Amphiexophthalmocythere ) oertlii (Babinot); J. Grundel, Freiberger ForschHft, C 304, 34, fig. 2. 1980 Parexophthalmocythere ( Amphiexophthalmocythere ) oertlii (Babinot); J. F. Babinot, Trav. Lab. Geol. hist. Paleontol. Univ. Provence, 10, 119, pi. 15, figs. 4-10. 1983 Parexophthalmocythere ( Amphiexophthalmocythere ) oertlii (Babinot); J. F. Babinot & J. P. Colin, in R. F. Maddocks (ed.). Applications of Ostracoda, fig. 10A, Univ. Houston Geosciences, Texas. 1985 Parexophthalmocythere (Amphiexophthalmocythere) oertlii (Babinot); J. F. Babinot, J. P. Colin & R. Damotte, Bull. Centres Rech, Explor.-Prod. Elf- Aquitaine, Mem., 9, pi. 58, figs. 10-12. 1985 Amphiexophthalmocythere oertlii (Babinot); J. P. Colin & R. Damotte, Cretaceous Research, 6, 158, fig. 1. Holotype: Type-locality: Figured specimens: Diagnosis: Distribution: Universite de Provence, Marseille, Laboratoire de Stratigraphie et Paleoecologie, no. HCE7; carapace. La Begude, 3 km S of Le Camp-du-Castellet, Var, SE. France; approx, lat. 47° 55' N, long. 3° 45' E. Late Cenomanian, upper Cretaceous. In marly limestone with benthic larger foraminifera (alveolinids), oysters and organic matter. Esso Production Research-European, Begles, France, nos. 23458 (cf car.: PI. 15, 70 fig. 1), 23459 (9 car.: pi. 15, 70, fig. 2), 23460 (cf car.: PI. 15, 70, fig. 3), 23461 (9 LV: PI. 15, 72, fig. 1), 23462 (cf RV: PI. 15, 72, fig. 2), 23463 (9 car.: PI. 15, 72, fig. 3). All the figured specimens are from the late Cenomanian of the type-locality. As for the genus (monotypic). Known only from Cenomanian inner neritic deposits of southern France (Provence, Touraine, Aquitaine Basin, Languedoc) and the Iberian Peninsula (northern Spain, Portugal). Explanation of Plate 15, 72 Fig. 1, 9 LV, int. lat. (EPR-E 23461, 720 Aim long); fig. 2, cf RV, int. lat. (EPR-E 23462, 690 pm long); fig. 3, 9 car. vent. (EPR-E 23463, 755 pm long). Scale A (100 /urn; X 86), figs. 1-3. Stereo-Atlas of Ostracod Shells 15, 70 Amphiexophtalmocythere oertlii (2 of 4) Stereo-Atlas of Ostracod Shells 15, 72 Amphiexophtalmocythere oertlii (4 of 4) Stereo- Atlas of Ostracod Shells: Vol. 15, Part 1 CONTENTS 15 (1) 1- 4 15 (2) 5- 8 15 (3) 9-12 15 (4) 13-16 15 (5) 17-20 15 (6) 21-24 15 (7) 25-28 15 (8) 29-32 15 (9) 33-36 15 (10) 37-40 15 (11) 41-44 15 (12) 45-48 15 (13) 49-56 15 (14) 57-68 15 (15) 69-72 On Loxoconcha praepontica praepontica Maybury & Whatley subsp. nov.; by C. A. Maybury & R. C. Whatley. On Loxoconcha praepontica magna Maybury & Whatley subsp. nov.; by C. A. Maybury & R. C. Whatley. On Loxoconcha pararhomboidea Whatley & Maybury sp. nov.; by R. C. Whatley & C. A. Maybury. On Pahnoconcha hornei Maybury & Whatley sp. nov.; by C. A. Maybury & R. C. Whatley. On Webbylla cyma Schallreuter & Siveter gen. et sp. nov.; by R. E. L. Schallreuter & D. J. Siveter. On Webbylla reticulata Schallreuter & Siveter sp. nov.; by R. E. L. Schallreuter & D. J. Siveter. On Pilla piformis Schallreuter & Siveter gen. et sp. nov.; by R. E. L. Schallreuter & D. J. Siveter. On Tricornia ( Bohemia ) paragracilis (Blumenstengel); by G. Becker. On Bradleya normani (Brady); by D. W. Foster & R. L. Kaesler. On Reticulocosta ornatoreticulata (Reyment); by R. Reyment. On Quadracythere keeni Slipper sp. nov.; by I. J. Slipper. On Quadracythere nodosa Haskins; by D. J. Horne & I. J. Slipper. On Tinririasevia uptoni Timberlake sp. nov.; by S. Timberlake. On Tinririasevia triangularis Timberlake sp. nov.; by S. Timberlake. On Amphiexophthalmocy there oertlii (Babinot); by J. F. Babinot & J. P. Colin. 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