No. 152 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES October 26, 2001 LATE CRETACEOUS DIATOMS (BACILLARIOPHYCEAE) FROM THE MARCA SHALE MEMBER OF THE MORENO FORMATION, CALIFORNIA By Vladimir A. Nikolaev, John P. Kociolek, Elisabeth Fourtanier, John A. Barron, and David M. Harwood Stephanopyxis appendiculata Ehrenberg California Academy of Sciences San Francisco, California Late Cretaceous Diatoms (Bacillariophyceae) from the Marca Shale Member of the Moreno Formation, California Paralia crenulata (Grunow) Gleser Late Cretaceous—Oligocene, marine OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES No. 152 October 26, 2001 LATE CRETACEOUS DIATOMS (BACILLARIOPHYCEAE) FROM THE MARCA SHALE MEMBER OF THE MORENO FORMATION, CALIFORNIA By Vladimir A. Nikolaev, John P. Kociolek, Elisabeth Fourtanier, John A. Barron, and David M. Harwood Stephanopyxis appendiculata Ehrenberg California Academy of Sciences San Francisco, California SCIENTIFIC PUBLICATIONS Alan E. Leviton, Editor Katie Martin, Managing Editor Copyright © 2001 by the California Academy of Sciences, Golden Gate Park, San Francisco, California 94118 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage or retrieval system, without permission in writing from the publisher. ISSN 0068-5461 Printed in the United States of America Norcal Printing, Inc., San Francisco, California Table of Contents Page PADSTra Ctr arate oT ee nmr y omen trm Sr ICIC Hen gan NCIS rane ha PON ral meee Gee Gen eee tulsa yan even Cueto qj IrnGineaIDOLAYONNT, 525 essay odes @ o-ceBlG neck tho econ ieeoad iene echt lat carrier aera annie Pre Mined CC i le Os I 7 MateralsvancliVicth ods vertices he rachiecranr seit oc estas Cuceaeatsieccis ay teche tr etas Someta ethael segs 5 axlen tnt, ouclmeeene 8 GeolosicaleScttinaey aac yen et paren acu cep Reena tee peop tence cunssaetorcnen <3.0 eestor uN iniae 8 SelectiontofSamplessforstudy etree acre we near eR rset erst erie arte eraser are 10 NAW ATOYGIS OR ice carer oeee Ge athens cseche eepin aeajr Gucete otek CURE CHGNG ino -NCry FAR ec Cec IEnC eee, CEILS Toman RR io en Males etn 11 MAKOMOml CUIbIS te rey eke tenet cle tem ect e A Oe tn k SUM relusiete rat peer | oom nag ARM ho oe ca fuente cane 12 Subclass -Archaegladiopsophycidacienwr-t-am tetera tte a-eaten ney t-te ine neen eter wee haf -e = etre ene etree 12 Order Archaegladiopsidales: Family Thalassiosiropsidaceae ............. 0.000200 e eee eee 12 (Genuswlhalassiosinopsis: een yee Wctse Rect ee eee cial alah aete Mea ahatises eatin hieeae cae eet een ee meen ae 12 Genus! GIGCIOPSIS err cxco sts scons yer eM Neo eae hes A eae oe ae hsm eat oy hoes onse tee Me eee es 12 Order Stephanopyxales#ramuly,.stephanopyxaceae pas-yeusr-ccr sy ecu ehseperteeeet none eds eee eee ree 13 GEMUSTSTEDNGNODVAISira sey se eens UAT lence at wane iar ce ed PSEC rede ne a UaaTA aT TG cen RNR En EL 13 SubclasssParaliophy cidacssc was -youe cosiepsioth essen alcesyss tcer gouty amore wae Senses eelelouearen sas geseurken een eee 15 OrderParalialesshamilysaraliaceacyy py-sa-t wees eee ence een eke res ane tec ee eee 15 GenuispRaraligy wale 3) Pisces Aes yieh shales Aba ta ees edad tiares tyr tenets etary eeetrew ee Ada baie rey Neve actrees 15 SubclasssHeliopeltophy.cidacw awe anecyeta ess crate cae epoch a roraaerawetonaes Rane Feary seated tre ated. een Ee 15 @rdemHeliopeltalessbamilyahcliopeltaccacimcs-ee rt useuens sete cee se ee eiete chen oe ees cies renee ae 15 (GEMUSBA CLIN OPEV CHUS Taree cae ene enna ete Mie Es aR eG RECO EEE SE ORI Re chen ce a Gee PCE 15 GemUSKE CHILO PONUS Ary eee eee es Ten on ree ey LI rT ere et ne PS gee Le 16 (Gree DY op otis ay sane ates cles Cai TM le esta iehents cl Gam eerin Sareea a aoe ch ON ic ch eam ot EL St 16 GenusiGlO“iopiyehius erence Nr tc ec AOA a see ee TN RUE eet ae EU ER cae na as an nee are 16 Genuseh aya] dicta nesics ee ka uta Heed caer ses ey eset Pe eee oe NE A ee erase oe 16 @rder~AliscalessramilyeAulscace acu nca ey arte tee en ear eee een eee cere ee neuen 17 (Gensel end ey array way sere cde seared Wig Tete te eae Rann Sar ae 6, Aer Re TO ai ata oe ENE 1a. SHWCEES Capeinersiieo iVaGhie Si somoce wa glbdida Hid abe colin Gite Ob 6 eel waldo al Gtolguse Sletgle nets ol 17 Order Coscinodiscales: Hamil ya€oscinodiscaceaes mates Charrette pce rs eee 17 GENnuUSiGOSCINOAIS CLS Warren se terete ee er TOE ent eS Ge RUM es a Na ene ors Oe ae eA ee iff OrderAulacodiscalessskamily Aulacodiscaceacmn. 5 wa etues hie aie ay ice tate nl eee 18 (GENUSHATIGCOGIS CLESIR Rene aks ee oereeT ec tea oe A STEIN ae TT oe Tae eee ae eee 18 OrdemEupodiscalessibupodiscaceacs gerry ety pe tae tant te Sey a ae eet ealicua eye page ger es ewe terete Pees 18 GenuspRatinayell aii ie Wop ke poe ieyete tse etre aetna aber e Se Menge age any oo. Jy tie sci] A) Ate teats ree 18 Orden Stellanmalesshamuily;stellammaceacwaemustes teieeaar ie sera nee ace crane ee eee 18 GenuspStell anim aie cwaierr se pan trae teeter cna sae gen ieee ee Nien ase ea Meee as log re pa 18 Genus¥AZp Cilio SiS Mrs garg ne gry co MaRS MRE Ale cp eset ig ety Saale ae acne e. eigen ne ty ae 19 GeEnUSPROMBHOCISCU Simmer maton tea Wag attain ae Rs geese ele ace emcee che aS Oecd reece aS 19 Ordemstellarmalessramilyalnmeoniuimiaceden! pve ei ernest yar cicce wey see teasers ta tee eens eneee(. GenuUsplriSOnitmuren sce ter creer ase ech aru ereac ee re ape tee ter aa aR Pee et TE tet eRe Sut.) SubclassiBiddulphiophy.cidacimvemmmay yarn steer ae ae rie tercine ne qitces valeitenn mo Roe Neste. cies eects 2-0) Ordemiemiaulales#kamilysiemiaulacedelpew-mne- emir paresis teeter eee ere eneg ees ste eZ) GemUSPETE iA UL US Ug ea ey NR Se eee eR OT EE OE eee en ae? 0) GenusiSpiynciolethustp ins pee aces pepe, tec e ste eran Ae Arcee ene pt ite an rea ee) GSS WRG! on oars 8 ceo a GOO OO ex ORME OT EO NTO Oe CORE SEEN Como Me a Oe ioe cael OrdemiemiaulalesskamilyaSheshukovacedeusepayle-i a teaeteiaciaes cuncheaiencd eine inert isleeen nent GenlUStSHeSHUKOVICRNR Se eI WEE Sean. Crane cen a Ren pe een ene ee tn me eran, Sege ol GremnuseVied lini cite: rr pears renee ceca epee cee tar rasa IR Teer Rea renee pe aca ae Veet ne eee GenUSEE OIC Geen eee MRT Ue CRA eee TNS een MT STE REE OrdemStictodiscalessamilyastictodiscaccdem= earn te Mere ce ee eee ene (GenuSHPSCUdOSTICLOGISCUS pein TT ee eo ee a ee ene Sees GenuspArachnordis cists Bem eaters ee ere recat ee ST Ne ae ne ee EE EE ene one hate gee 6 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 GENUSEBENCLONUS a Pere bes cscs s, ORT IE, BALS Agate es oe ar Ore ee LOE Eee Renee eee 23 laxavotaWncentaimmsoystematlenPOSIMON er yas testcase cece ite eee en 24 A CANINOGISCUSIDALEFUS VAM Tarde tye levy ke eee eal saya es oe el pO ES Sere) eee Re eee 24 PA CANNOGISCUSHININGCUIALUSS 55 a oe PLATES 1-39 42 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 1 Figs. 14 — Thalassiosiropsis wittiana: Fig. 1 — Hypotype, CAS 3394 (Coll. Long, Fuge & Smith 1946); general view. Fig. 2 — External view of the valve face, showing tangential crossing rows of the foramina of loculate areolae, and the tube of the an- nular process (arrow). Fig. 3 — Internal view of the valve face showing the annular process (arrow), tangential arrangement of loculate areolae and cribral pores arranged in an indistinct radial pattern. Fig. 4 — Detail of Fig. 3, central part of the valve face showing cribral pores of the interrupted cribrum, chambers of loculate areolae, and the central annular process (arrow). Fig. 1 — Light micrograph (LM); Figs. 2-4 — Scanning elec- tron micrograph (SEM). Scale bars: Figs. 1-3 = 10 um; Fig. 4 = lum. Figs. 24 — CAS 1144. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 43 PLATE 1 44 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 2 Figs. 1-7 — Gladiopsis speciosa: Figs. 1-2 — Holotype CAS 3441 (Tubularia pistillaris var. grossipunctata in the collection of Long, Fuge & Smith 1946); general view. Figs. 3-4 — External part of the valve mantle showing the longitudinal and diagonal crossing rows of loculate areolae, and the central (terminal) posi- tion of the annular process on the valve face (arrows). Fig. 5 — External view of the valve apex showing the longitudinal and di- agonal crossing rows of areolae on the valve mantle, and the hya- line valve face with the central opening of the annular process (arrow). Fig. 6 — Fragment of the broken valve mantle showing the external foramen and internal cribrum of the loculate areolae. Fig. 7 — Detail of Fig. 6 showing cribral pores of the cribrum and a cross-section of the chambers of the loculate areolae. Figs. 1-2 — LM; Figs. 3—7 — SEM. Scale bars: Figs. 1-3, 5-6 = 10 um; Figs. 4, 7 = 1 um. Figs. 3-7 — CAS 610954. 45 PLATE 2 ete NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION Sea Re A een ies ooo. eM a. nl 46 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 3 Figs. 1-6 — Stephanopyxis appendiculata: Fig. 1 — Two frus- tules connected in a short colony. Fig. 2 — Valve view. Fig. 3 — Two spherical frustules connected by spines (external tubes of labiate processes) and part of the girdle wall of former mother cell (central part of colony). Fig. 4 — External girdle view of a frustule and a valve showing the linking spine attachment and packing arrangement of the foramen of the loculate areolae. Fig. 5 — Valve interiors showing the interrupted cribrum of the locu- late areolae and the apical ring of labiate processes (arrows). Fig. 6 — Detail of Fig. 5 showing the marginal ring of tuberculate labi- ate processes with a slit, located on the cribrum of loculate areo- lae (arrows). Figs. 1-2 — LM; Figs. 3-6 — SEM. Scale bars: Figs. 1-5 = 10 um; Fig. 6 = | um. Figs. 1-2, 5—6 — CAS 1144; Fig. 3 — CAS 610954; Fig. 4 — CAS 610939. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 47 PLATE 3 e of e®? f; 22.2 2827 ~ 48 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 4 Figs. 1-6 — Stephanopyxis barbadensis: Fig. | — Valve face showing the arrangement of loculate areolae and location of the external tubes of labiate processes (arrows). Fig. 2 — Valve man- tle showing convexity of the valve face and arrangement of the areolae. Fig. 3 — External view of the valve face showing the arrangement of the loculate areolae and the ring of external tubes of the labiate process (arrows). Fig. 4 — Internal view of the valve showing the interrupted cribrum of loculate areolae with the first ring of tubercle labiate processes (large arrow), and the second ring of labiate processes that are located on the cribrum of areo- lae (small arrow). Fig. 5 — Detail of Fig. 4 showing the radial ori- entation of the rows of cribral pores and the tuberculate labiate processes with a slit (arrows). Fig. 6 — Broken wall of the valve near the margin showing features of the second ring of labiate processes, such as the location of the external tube of the labiate process on the cribrum of loculate areolae (arrow). Figs. 1-2 — LM; Figs. 3-6 — SEM. Scale bars: Figs. 14 = 10 um; Figs. 5-6 = | pm. Figs. 1-6 — CAS 610939. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 4 200? » PAA evver, 49 50 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 5 Figs. 1-6 — Stephanopyxis discrepans: Fig. | — Holotype CAS 2036; valve of a “regular” cell from the central part of a colony. Figs. 2-3 — External views of a valve. Fig. 2 — Valve face and part of the valve mantle showing the arrangement of areolae and the form of marginal spines (external tube of the labiate processes). Fig. 3 — Detail of Fig. 2, showing the irregular size of areolae and a portion of the marginal ring of spines with small openings (arrows) that are the external tubes of the marginal ring of labiate processes. Fig. 4 — Internal view of the valve face and valve mantle showing the uninterrupted cribrum of the loculate areolae and the location of the labiate processes (arrows). Fig. 5 — Broken wall of the valve mantle showing the external arrange- ment of the loculate areolae and spines, the internal pattern of the uninterrupted cribrum, and the location of labiate processes (arrow). Fig. 6 — External view of the valve mantle showing the arrangement of areolae and the location of the ring of marginal spines. Figs. 1 — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-2, 4-6 = 10 um; Fig. 3 = 1 pm. Figs. 2-5 — CAS 610954; Fig. 6 — CAS 1144. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 51 PLATE 5 52 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 6 Figs. 1-6 — Stephanopyxis discrepans: Fig. | — Paratype CAS 2037; valve of a “terminal” cell. Fig. 2 — External view of the valve face and valve mantle showing the irregular size and form of the foramen of loculate areolae and the ring of spines. Fig. 3 — Broken valve face revealing the cross-sectional form of the external foramina (top) and internal cribrum (base) of the loc- ulate areolae. Fig. 4 — Oblique view of a valve showing the in- ternal and external features of the valve mantle, including unin- terrupted cribrum, rings of labiate processes (arrows), and the form and distribution of the external branching spines. Figs. 5—6 — Internal valve view showing the uninterrupted cribrum of locu- late areolae and the ring of labiate processes (arrows). Fig. 6 — Detail of Fig. 5 showing the quincunx pattern of the cribral pores of the cribrum and the tuberculate form of the labiate processes (arrows). Figs. 1 — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-2, 4-5 = 10 pm; Figs. 3, 6 = 1 pm. Figs. 2-3, 5-6 — CAS 610954; Fig. 6 — CAS 1144. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 6 54 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 7 Figs. 1-4 — Stephanopyxis grunowii: Fig. | — Valve. Fig. 2 (left) — External view of the valve face and mantle showing the irregular form of the external foramen and the ring of labiate processes marked by the external tubes (arrows). Fig. 2 (right) — Internal view of the valve showing broken cribrum and location of labiate processes (arrows). Fig. 3 — External view of the valve face with foramen of irregular form and tubes of labiate process- es (arrows). Fig. 4 — Interior part of the valve margin (lower left) showing the broken cribrum of loculate areolae and the tubercle with a round aperture of the labiate processes (arrows). Figs. 5 — 6 — Stephanopyxis turris: Fig. 5 — External and internal view of the valve mantle showing rows of foramen of the loculate areo- lae, external tubes of the apical labiate processes (large arrow) at the edge of the valve face, and the internal view of the marginal ring of labiate processes on the valve mantle (small arrows). Fig. 6 — Internal view of the valve with a broken wall showing the bro- ken cribrum, the marginal ring of labiate processes with round apertures (small arrows), and the internal form of an apical labi- ate process with a slit (large arrow). Fig. 1 — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-3, 5 = 10 um; Figs. 4,6 = 1 um. Figs. 1-6 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION n n PLATE 7 56 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 8 Figs. 1-8 — Paralia crenulata: Fig. 1 — Girdle view of a colony comprising 3 frustules and one valve. Fig. 2 — Valve face. Figs. 3, 7 — External views of a colony of three central frustules and two valves at each end; connection of the epitheca and hy- potheca is indicated by the small arrow, and the connection of frustules is indicated by the large arrow. Fig. 4 — External view of a colony showing the raised central connecting ribs on the valve face and the structure of the valve margin and valve mantle; mar- ginal linking spines are broken. Fig. 5 — External view of the valve face showing marginal rings of pores with large and small openings (arrows). Fig. 6 — Internal view of the valve face and valve mantle showing the radial and quincunx rows of porous canals on the valve mantle and the hyaline valve face. Fig. 7 — Girdle view of a colony; connection of the epitheca and hypothe- ca 1s indicated by the small arrow, and the connection of frustules by marginal linking spines is indicated by the large arrow. Fig. 8 — External view of a terminal separation valve without marginal linking spines and reduced central connecting ribs. Figs. 1-2 — LM; Figs. 3-8 — SEM. Scale bars: Figs. 1-6 = 10 um; Figs. 7-8 = 1 um. Figs. 1-6 — CAS 610954; Figs. 7-8 — CAS 615990. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 57 PLATE 8 rs kL ery . . — OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 9 Figs. 14 — Actinoptychus packii: Fig. | — Holotype CAS 1993; general view of valve. Fig. 2-3 — External views of valve face showing radial undulations that separate the valve face into 6 sectors (alternating 3 raised and 3 depressed). Elevated sectors are ornamented with numerous shallow depressions, whereas the depressed sectors are ornamented with small siliceous nodes. The undulating sectors are surrounded by a less undulating marginal zone on the valve face, which bears the external openings of the labiate processes (arrows). The border between the valve face and mantle includes a zone with narrow radial ribs that bear small spines. Porous canals are arranged in radial rows on the valve face and in a quincunx pattern on the valve mantle. Fig. 4 — In- ternal view of the valve face showing the central hyaline field, and the alternating depressed and elevated sectors of the valve face, quincunx rows of porous canals, hyaline curved and narrow fields in front of the convex sectors, and the slits of the labiate processes within small hyaline fields (arrows). Fig. 1 - LM; Figs. 2-4 — SEM. Scale bars: Figs. 1-4 = 10 um. Figs. 24 — CAS 610955. 59 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 9 60 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 10 Figs. 1-4 — Actinoptychus taffii: Fig. | — Holotype CAS 1995; general view of the valve with the focal plane on the sur- face of the elevated sectors and labiate processes at 3, 7, and 11 o’clock; note the quincunx arrangement of porous canals and sub-hexagonal packing of the surface ornamentation on the ele- vated sectors. Fig. 2 — External view of the valve face and narrow valve mantle showing the central hyaline field, the radial undula- tion that separates the valve face into six sectors, the radial and quincunx arrangement of porous canals and the net of anasto- mose ribs, and the opening of the labiate processes at the mar- ginal center of the elevated undulations (arrows). Figs. 34 — In- ternal views of the valve; Fig. 3, valve face with radial undula- tions, , the radial and quincunx arrangement of porous canals, the central hexagonal hyaline field, the curved narrow hyaline fields toward the margin of the convex sectors, and the internal slits of labiate processes (arrows); Fig. 4, detail of Fig. 3 showing of the quincunx arrangement of porous canals and slit of labiate processes around by hyaline field; note the correspondence be- tween the close-packing arrangement of the porous canals and the location of the external ornamentation of anastomose ribs (lighter sub-hexagonal areas). Fig. 1 — LM; Figs. 2-4 — SEM. Scale bar: Figs. 1-3 = 10 um; Fig. 4 = 1 um. Figs. 24 — CAS 610954. 61 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 10 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 11 Figs. 1-5 — Centroporus californicus: Figs. |—2 — Holotype CAS 3387; valve in different focus. Figs. 3—5 Internal views of the valve. Fig. 3 — Valve face and valve mantle showing undula- tions of the valve. Fig. 4 — Central part of the valve face showing the irregular arrangement of porous canals in the center of the valve and the radial rows of porous canals in the bottom of the figure. Fig. 5 — Margin of the valve showing the radial rows of porous canals and the hyaline ray with an opening on the end (arrow). Figs. 1-2 — LM; Figs. 3-5 SEM. Scale bars: Figs. 1-3 = 10 um. Figs. 3-5 — CAS 615988. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 11 63 64 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 12 Figs. 1-6 — Debya californica: Fig. 1— Holotype CAS 3403; general view of the valve. Figs. 2-4 — External views of the valve. Fig. 2 — Valve face and valve mantle showing radial and marginal undulations and the location of labiate processes (ar- rows). Fig. 3 — Detail of Fig. 2 showing the irregular arrangement of porous canal between the anastomose ribs. Fig. 4 — Detail of Fig. 2 showing porous canals and the system of anastomose ribs and the conical tube of the labiate process (arrow). Figs. 5—6 — In- ternal views of part of the valve face. Fig. 5 — Part of the valve face showing undulation of the valve and location of the labiate processes (arrows). Fig. 6 — Detail of Fig. 5 showing the arrange- ment of porous canals and labiate process with a curved slit (arrow). Fig. | — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-2, 5 = 10 um; Figs. 3-4, 6 = 1 um. Figs. 2-6 — CAS 610939. 65 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 12 ETL ee gn a: 66 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 13 Figs. 1-7 — Gloriopthychus callidus: Fig. 1 — Holotype CAS 2007; general view of the valve with focus on the elevated undu- lations. Fig. 2 — External view of the valve face showing undula- tions of the valve, the system of anastomose ribs, and the open- ings of the labiate processes (arrows). Figs. 3-5 — Internal views of the valve. Fig. 3 — Valve face showing undulations of the valve and the location of labiate processes (arrows). Fig. 4 — Detail of Fig. 3 showing the arrangement of porous canals on the valve face and a cross-section of the valve showing the passages of the porous canals in the basal siliceous layer. Fig. 5 — Detail of Fig. 3 showing the arrangement of porous canals at the valve margin, and the form of the labiate process with a curved slit. Fig. 6 — Ex- ternal view of a small, quadrate valve showing undulations of the valve face, the arrangement of the porous canals and the location of labiate processes (arrows). Fig. 7 — Part of the interior of the valve margin, showing the arrangement of porous canals and the slit of the labiate process (arrow). Fig. | — LM. Figs. 2-7 — SEM. Scale bars: Figs. 1-3, 6 = 10 um; Figs. 4-5, 7 = 1 pm. Figs. 2-5 — CAS 610954; Figs. 6-7 — CAS 610955. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 13 67 68 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 14 Figs. 1-5 — Haynaldia strigillata: Fig. | — Valve. Figs. 2-3 — External views of the valve. Fig. 2 — External view of the valve face, showing the gentle undulation of the valve, the system of anastomose ribs and small spines. Fig. 3 — Detail of Fig. 2 show- ing the system of anastomose ribs near the valve margin and mantle. Figs. 4-5 — Internal views of the valve. Fig. 4 — Valve face showing the irregular arrangement of porous canals on the valve face, the zone of porous canals on the valve mantle, and the marginal ring of labiate processes (arrows). Fig. 5 — Detail of Fig. 4 showing scattered porous canals on the valve face and valve mantle, and the horseshoe shape of the labiate processes (ar- rows). Fig. 1— LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-5 = 10 pm. Figs. 1-5 — CAS 615990. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 69 PLATE 14 70 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 15 Figs. 1-5 — Hendeya dehiscens: Fig. 1 — Holotype CAS 3446; general view of the valve; large arrow identifies the ocel- lus and small arrows identify the position of the labiate process- es. Fig. 2 — Paratype CAS 3447; general view of the valve; ar- rows identify the location of the labiate processes. Figs. 3—5 — In- ternal views of the valve. Fig. 3 — Valve face showing undulations of the valve, location of the labiate processes (large arrows) and the ocellus (small arrows). Fig. 4 — Detail of Fig. 3, showing the arrangement of the porous canals and the tubercle which bears a labiate process with a slit (arrow). Fig. 5 — Detail of Fig. 3 show- ing the ocellus (arrow). Figs. 1-2 — LM; Figs. 3-5 SEM. Figs. 1—3 = 10 um; Figs. 4-5 = 1 um. Figs. 3-5 — CAS 615990. 7a NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 15 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 16 Figs. 1-6 — Coscinodiscus marginatus: Fig. | — Hypotype CAS 3396; general view of the valve. Figs. 2-3 — External views of the valve. Fig. 2 — Valve mantle and valve face showing the arrangement of loculate areolae and the opening of the macro- labiate process (arrow). Fig. 3 — Detail of Fig. 2 showing a part of the broken uninterrupted cribrum of the marginal part of the valve face, and the external opening of the macro-labiate process (arrow). Figs. 4-6 — Interior views of the valve. Fig. 4 — Valve face and valve mantle showing the arrangement of the foramen of loculate areolae, and the location of the macro-labiate process (large arrow) and the marginal ring of labiate processes (small ar- rows). Fig. 5 — Detail of Fig. 4 showing the locula of the areolae (top right), the large foramen of the loculate areolae on the valve face and the smaller foramen on the valve mantle, and four labi- ate processes of the marginal ring (arrows). Fig. 6 — Detail of Fig. 4 showing the macro-labiate process (large arrow) and the labiate processes (small arrows). Fig. 1 — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-2, 4 = 10 um; Figs. 3, 5-6 = 1 um. Figs. 2-6 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 7} PLATE 16 i) oh ¥ a4.> 74 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 17 Figs. 1-6 — Aulacodiscus archangelskianus: Figs. 1-4 — Views of the valve face showing morphological variability. Fig. | — Paratype CAS 1997. Fig. 2 — Paratype CAS 1998. Fig. 5 — Ex- ternal view of the valve face showing radial undulations with tubes of the labiate processes, the arrangement of loculate areo- lae and ribs between the valve face and valve mantle. Fig. 6 — In- ternal view of the valve face showing radial undulations with the labiate processes visible on the bottom of the depression (arrows) and arrangement of the foramen of loculate areolae on the valve face and valve mantle. Figs. 1-4 — LM; Figs. 5—6 — SEM. Scale bar: Figs. 1-6 = 10 um. Figs. 3-6 — CAS 610954. 75 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 17 76 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 18 Figs. 1-6 — Rattrayella churchii: Fig. | — Holotype CAS 3541, general view of the valve. Figs. 2-4 — External views of the valve. Fig. 2 — Valve showing undulations of the valve face, three marginal elevations with ocelli, marginal ring of spines and tubes of the labiate processes (arrows). Fig. 3 — Detail of Fig. 2 show- ing the uninterrupted cribrum with small tubercles, ocellus and part of the ring of marginal spines. Fig. 4 — Part of the valve mar- gin with a broken cribrum to illustrate the structure of the locu- late areolae with an external uninterrupted cribrum, tube of a labiate process (arrow) and marginal spines. Fig. 5 — Internal view of the valve showing undulations of the valve face, location of the ocelli (large arrows) and the location of labiate processes (small arrows). Fig. 6 — Detail of Fig. 5 showing the radial rows of foramen of the loculate areolae, two tubercle labiate processes (arrows) and the hyaline margin of the valve mantle. Fig. 1 — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-2, 5 = 10 um; Figs. 3-4, 6 = 1 um. Figs. 2-6 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 77 PLATE 18 78 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 19 Figs. 1-5 — Stellarima distincta: Fig. 1 — Holotype CAS 3391; general view of the valve. Figs. 2-3 — External views of the valve. Fig. 2 — Valve showing the arrangement of loculate areo- lae on the valve face and valve mantle, and location of the cen- tral, slit-form labiate process (arrow). Fig. 3 — Part of the valve face showing the honeycomb structure of the chamber of loculate areolae, and the location of the slit-form labiate process (arrow). Figs. 4—5 — Internal views of the valve. Fig. 4 — Valve showing the arrangement of foramen of the loculate areolae on the valve face, valve mantle, and the location of the labiate process (arrow). Fig. 5 — Detail of Fig. 4 showing the different sizes of foramen of the loculate areolae in the center of the valve face, and the slit of the labiate process (arrow). Fig. |— LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-4 = 10 um, Fig. 5 = 1 um. Figs. 2-5 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 79 PLATE 19 80 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 20 Figs. 1-6 — Stellarima steinyi: Fig. | — Holotype CAS 2006; general view of the valve. Figs. 24 — External views of the frus- tule and valve. Fig. 2 — Frustule showing the epivalve (top) with epicingulum and hypovalve (bottom). Fig. 3 — Valve, showing the arrangement of loculate areolae in radial rows with a fasciculate pattern, small central hyaline field with a slit-form labiate process (arrow). Fig. 4 — Detail of Fig. 4 showing the arrangement of the loculate areolae with broken cribrum, and the slit of the labiate process (arrow). Figs. 5—6 — Internal views of the valve. Fig. 5 — Part of a broken valve, showing the cross-sectional form of the ovoid chamber of the loculate areolae, arrangement of foramen of the loculate areolae, and the labiate process (arrow). Fig. 6 — Part of the valve showing the arrangement of foramen of the loculate areolae, the central location of the labiate process with a slit (arrow), and the hyaline valve mantle (right). Fig. 1 — LM; Figs. 2-6 — SEM. Scale bars: Figs. 1-3, 6 = 10 um; Figs. 4-5 = 1 um. Figs. 2-6 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 81 PLATE 20 . Ce ee OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 21 Figs. 1-6 — Azpeitiopsis morenoensis: Fig. 1 — Holotype CAS 2004; general view of the valve showing radial fasciculate arrangement of loculate areolae, with rows of areolae in each fas- cicle parallel to the longest central row, and the central crescen- tric flexure of the valve. Figs. 2-3 — External views of the valve. Fig. 2— Valve showing the arrangement of loculate areolae on the valve face, small central depression and the location of the exter- nal tube of the labiate process (arrow). Fig. 3 — Detail of Fig. 2 showing the central depression and tube of the labiate process. Figs. 4-6 — Internal views of the valve. Fig. 4— Valve view show- ing the arrangement of foramen of the loculate areolae in radial rows on the valve face, radial and secondary crossing rows of foramen near the valve margin, one row small areolae on the valve mantle, and the internal slit of the labiate process on the central depression (arrow). Fig. 5. — Detail of Fig. 4 showing the foramen of loculate areolae and the slit of the labiate process. Fig. 6 — Part of a broken valve showing the form of the chamber of loculate areolae in the basal siliceous layer and part of the slit of the labiate process. Fig. 1—- LM; Figs. 2-6— SEM. Scale bars: Figs. 1-2, 4 = 10 um; Figs. 3, 5—6 = 1 um. Figs. 2-6 — CAS 610954. 83 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 21 84 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 22 Figs. 1-5 — Pomphodiscus morenoensis: Fig. | — Holotype CAS 34022; general view of the valve; arrow marks the location of the labiate process. Figs. 2—3 — External views of the valve. Fig. 2 — Valve view showing the arrangement of loculate areolae in radial rows, the convex wall of the central chamber with an ovoid opening (large arrow), the slit of the labiate process (small arrow), low marginal ridge, and two rows of smaller loculate are- olae on the valve mantle. Fig. 3 — Detail of Fig. 2 showing the ovoid opening of the central chamber and the slit of the labiate process (arrow). Fig. 4 — Internal view of valve showing arrange- ment of foramen of loculate areolae on the valve face, convex wall of the central chamber with a small depression in the center of the valve, slit of the labiate process (arrow), and smaller rows of foramen on the valve mantle. Fig. 5 — Center of valve face showing the flattened tube of the labiate process with slit. Fig. 6 — Pomphodiscus craspedodiscoides — Holotype CAS 3397; gen- eral view of the valve showing the circular central chamber, labi- ate process (arrow), and radial fasciculate arrangement of areo- lae. Figs. 1, 6 — LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-2, 4, 6 = 10 um; Figs. 3, 5 = 1 um. Figs. 2-5 — CAS 610955. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 85 PLATE 22 86 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 23 Figs. 1-6 — Trigonium hertleinii: Figs. |\-2 — CAS Holotype 2041; general view of the valve in different focus. Fig. | — Focus on the margin part of valve face. Fig. 2— Focus on the central part of valve face. Fig. 3 — Valve. Figs. 4-5 — External views of the valve. Fig. 4 — Valve showing the central round depression of the valve face, irregular arrangement of the loculate areolae, margin- al part of valve with irregular rows of smaller loculate areolae, and the different sizes of the pseudocelli on the corners of valve (arrows). Fig. 5 — Detail of Fig. 4 showing the smaller size of the foramen of the loculate areolae (visible inside the holes) and the larger size of the opening with a broken velum; large pseudocel- lus with rows of smaller areolae. Fig. 6 — The same valve, inter- nal view, showing the irregular arrangement of the foramen in the central part of the valve and the radial rows of foramen in the marginal part of the valve. Figs. 1-3 — LM; Figs. 4-6 — SEM. Scale bars: Figs. 1-4, 6 = 10 um; Fig. 5 = 1 um. Figs. 3-6 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 23 87 88 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 24 Figs. 1-5 — Sphynctolethus monstrosus: Fig. 1 — Holotype CAS 2034; general view of the valve face. Fig. 2 — Two valves connected in a colony. Fig. 3 — External view of the valve with a broken valve face showing the polar elevations with ocelli, mar- ginal ridge, radial arrangement of poroid areolae and vertical rows porous canal on valve mantle. Fig. 4 — Internal view of the valve showing undulations of the valve face, location of the mar- ginal ridge, arrangement of poroid areolae in radial rows, and the central location of the labiate process (arrow). Fig. 5 — Detail of Fig. 4 showing the foramen of poroid areolae and porous canal in central part of valve and the tuberculate labiate process with a slit (arrow). Fig. 6 — Hemiaulus polymorphus: General view of the valve. Figs. 1, 6 — LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-4, 6 = 10 um; Fig. 5 = 1 um. Figs. 2, 4-5 — CAS 610954; Fig. 6 — CAS 610955. NIKOLAEV ET AL:: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 24 89 90 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 25 Figs. 1-3 — Hemiaulus polymorphus: Fig. | — Girdle view of two frustules connected by horns of the linking apparatus with short spines, external tubes of the labiate processes are visible in the center of the top an bottom valves. Fig. 2 — External view of the valve showing the arrangement of poroid areolae, polar horns, marginal ridge, and the opening of the central labiate process (arrow). Fig. 3 — Internal oblique view of the valve show- ing undulations of the valve face separated by pseudosepta and the location of the labiate process ( arrow). Figs. 4-6 — Trinacria aries: Fig. 4 — Plesiotype CAS 2042 is at right; two valves. Fig. 5 — External view of the valve showing the irregular arrangement of poroid areolae on the valve face and the horizontal rows of poroid areolae on the valve mantle, polar elevations bear pseudoocelli and small spines, low marginal ridge. Fig. 6 — Inter- nal view of the valve showing the arrangement of the foramen of poroid areolae on the valve face, and the location of the labiate process with a slit ( arrow). Fig. 4 — LM; Figs. 1-3, 5-6 — SEM. Scale bars; Figs. 1-6 = 10 pm. Figs. 1-2 — CAS 615978; Figs. 4-5 — CAS 610955. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 91 PLATE 25 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 26 Figs. 1-4 — Trinacria insipiens: Figs. 1, 3 — External views of valves showing polar elevation with pseudoocelli and small spines, arrangement of poroid areolae in radial rows on the valve face, the tube of the labiate processes (arrows), and a marginal ridge. Figs. 2, 4 — Internal views of the valves showing the arrangement of the foramen of poroid areolae in radial rows on the valve face, one row of larger poroid areolae on the valve man- tle, and the location of labiate processes with a slit (arrow). Figs. 5—6 — Medlinia mucronata: Fig. 5 — Plesiotype CAS 2051; gen- eral view of the valve. Fig. 6 — External view of the valve show- ing the irregular rows of poroid areolae on the valve face, low marginal ridge, one row of larger poroid areolae on the valve mantle, and the location of the external tube (broken) of the labi- ate process (arrow). Fig. 5 — LM; Figs. 1-4, 6 — SEM. Scale bars: Figs. 1-6 = 10 um. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 93 PLATE 26 94 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 27 Figs. 1-3 — Euodiella tristictia: Fig. 1 — Holotype CAS 2052, general view of the valve with focus on the elevations and the central part of the valve. Fig. 2 — External view of the valve showing undulations of valve face, the arrangement of poroid areolae in radial rows on the valve face, small isolated porous canals between the rows of poroid areolae, small elevations at the angles, the marginal ridge, scattered slit of the labiate process (small arrow), and two pseudoocelli located on the valve mantle (large arrows at the bottom). Fig. 3 — Internal view of valve showing undulations of the valve, arrangement of the foramen of poroid areolae in radial rows on the valve face and vertical rows of poroid areolae on the valve mantle, and the tubercle labiate process with a slit (arrow). Figs. 4-6 — Medlinia deciusii: Fig. 4 — General views of two valves on slide CAS 201069; valve on the right is syntype specimen CAS 2044. Fig. 5 — External view of the valve showing the irregular arrangement of poroid areolae on the valve face, polar elevations, and the location of tube of the labiate process (arrow). Fig. 6 — Internal view of the valve show- ing the irregular arrangement of the foramen of poroid areolae on the valve face and the linear rows of poroid areolae on the valve mantle, and the location of labiate process (arrow). Figs. 1, 4 LM; Figs. 2-3, 5-6 — SEM. Scale bars: Figs. 1-6 = 10 um. Figs. 2-3, 5—6 — CAS 610955. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 95 PLATE 27 96 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 28 Figs. 1-5 — Euodiella bicornigera: Fig. 1 — Holotype CAS 2039; general view of the valve. Figs. 2-3 — External views of the valve. Fig. 2 — Valve view showing two polar elevations with pseudoocelli, marginal ridge, arrangement of poroid areolae in radial rows with a focal center of the rows near the rounded cor- ner that lacks an elevation and bears the flattened tube of the labi- ate process (arrow). Fig. 3 — Detail of Fig. 2 showing the cribrum of poroid areolae, the pseudoocelli on the polar elevation, and part of the marginal ridge. Figs. 4-5 — Internal views of the valve. Fig. 4 — Valve view showing the arrangement of the foramen of poroid areolae of the valve face, tubercle labiate process (arrow), and the external and internal structure of the poroid areolae on the valve mantle. Fig. 5 — Detail of Fig. 4 showing the tuberculate labiate process with a slit. Fig. 1 — LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-2, 4 = 10 um; Figs. 3, 5 = 1 um. Figs. 2-5 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 97 PLATE 28 98 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 29 Figs. 1-5 — Sheshukovia excavata: Fig. 1 — Plesiotype CAS 2047; general view of the valve face. Figs. 2-4 — External views of two valves, showing the arrangement of poroid areolae in ra- dial rows, polar elevations with pseudoocelli, marginal ridge, and the location of labiate processes (arrows). Fig. 3 — Detail of Fig. 2 showing part of the valve, a polar elevation with a pseudoocel- li, the radial rows of poroid areolae on the valve face, marginal ridge, one row of larger poroid areolae on the valve mantle, and external tubes of the labiate processes (arrows). Fig. 5 — Internal view of the valve showing the arrangement of the foramen of poroid areolae, and the location of labiate processes (arrows). Fig. 1 —- LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-5 = 10 pm. Figs. 2-5 — CAS 610954. 99 MORENO FORMATION CRETACEOUS DIATOMS FROM THE NIKOLAEV ET AL:: PLATE 29 100 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 30 Figs. 1-5 — Pseudostictodiscus picus: Figs. 1-2 — Holotype CAS 2011; valve in different focus, Fig. 1 focus is on the central part of the valve and in Fig. 2 the focus is on the margin of the valve. Fig. 3 — External views of the valve showing the central concave depression of the valve face with a central hyaline field, the irregular radial rows of poroid areolae, slit of the labiate process (small arrow), the marginal part of valve face bears radi- al rows of poroid areolae, a narrow circular ridge separates the central and marginal parts of valve face, narrow hyaline edge of the valve mantle with two small angular projections (large ar- rows). Fig. 4 — Internal view of the valve showing the central hyaline field, the elongate foramen of poroid areolae that are arranged radially near the margin of central elevation, slit of the labiate process (small arrow), radial rows of foramen on the mar- gin of valve face, and two small angular projections on the edge of valve mantle (large arrows). Fig. 5 — Girdle view of the man- tle showing the elevation of the central part of the valve face and the irregular rows of poroid areolae on the steep valve mantle. Figs. 1-2 — LM; Figs. 3-5 — SEM. Scale bars: Figs. 1-5 = 10 um. Figs. 3-5 — CAS 610939. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 101 PLATE 30 102 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 31 Figs. 1-5 — Arachnoidiscus ehrenbergii: Fig. 1 — Hypotype CAS 3356, general view of the valve. Fig. 2 — External view of part of the valve showing the central hyaline field surrounded by a ring of labiate processes , and radial rows of poroid areolae with small vola. Figs 3—S — Internal views of valves. Fig. 3 — System of central round hub which connects the radial ribs, short sec- ondary ribs are restricted to the margin area, foramen of poroid areolae, and a ring of labiate processes that surround the hyaline center of the valve (arrow). Fig. 4 — Part of the valve showing the system of radial ribs, rows of foramen of poroid areolae and cen- tral hyaline field with ring of slit labiate processes (arrow). Fig. 5 — Detail of Fig. 4 showing central hyaline field with ring of slits labiate processes. Fig. | — LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-4 = 10 um; Fig. 5 = 1 um. Fig. 2— CAS 610939; Fig. 3 — CAS 615990; Figs. 4-5 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 103 PLATE 31 104 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 32 Figs. 1-7 — Benetorus fantasmus: Fig. | — Holotype CAS 2000, general view of the valve, showing the radial rows of poroid areolae outside of the central ring-shaped chamber, posi- tion of the ‘isthmus’ marked by the arrow. Fig. 2 — Valve view, ar- rows indicate the location of the isthmus. Figs. 3—5 — External views of the valve. Fig. 3 — Valve view showing the mid-radius ring-shaped hyaline chamber with an ‘isthmus’ (large arrow), the central part of the valve face perforated by porous channels, ra- dial rows of poroid areolae on the valve face, marginal ridge, the valve mantle with one rows of porous canals, and the tube of the labiate process (small arrow). Fig. 4 — Broken part of the valve showing a cross-section of the poroid areolae with a small rota (arrow). Fig. 5 — Part of the ring-shaped chamber with a broken external hyaline layer exposing the internal layer of the chamber (perforated by porous canals), and the opening of the labiate process (arrow). Figs. 6—7 — Internal views of the valve. Fig. 6 — valve view showing undulations of the of valve face, the central part of the valve with porous canals, the wall of the ring-shaped chamber perforated by pores that continued as foramen of poroid areolae on the valve face, and the labiate process (arrow). Fig. 7 — Detail of Fig. 6 showing the labiate process with a slit sur- rounded by a hyaline field and two linear pores. Figs. 1-2 — LM; Figs. 3-7 — SEM. Scale bar: Figs. 1-3, 6 = 10 um; Figs. 4-5, 7 = 1 pm. Figs. 2-5 — CAS 610955; Figs. 6-7 — CAS 615990. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 105 PLATE 32 106 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 33 Figs. 1-5 — Acanthodiscus paterus: Fig. | — Holotype CAS 3416; view of part of the valve. Figs. 2-3 — External views of a valve. Fig. 2 — Valve showing the hyaline valve face and ring of short ribs oriented radially on the valve margin. Fig. 3 — Detail of Fig. 2 showing the marginal part of the valve and features of the ornamentation. Figs. 4-5 — Internal views of parts valves. Fig. 4 — Part of the valve margin showing the hyaline and non-perforate structure of the basal siliceous layer. Fig. 5 — Part of the valve face and valve mantle showing the hyaline structure of both. Fig. 1— LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-3, 5 = 10 um; Fig. 4 = 1 pm. Figs. 2-3, 5 — CAS 610954; Fig. 4 — CAS 610939. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 107 PLATE 33 108 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 34 Figs. 1-4 — Acanthodiscus immaculatus: Fig. 1 — Holotype CAS 2003; general view of the valve. Fig. 2 — External view of the valve showing the hyaline non-perforate structure of the valve face and valve mantle. Figs. 3-4 — Internal view of the valve at different magnification showing the hyaline nature of the basal siliceous layer. Fig. | — LM; Figs. 2-4 SEM. Scale bars: Figs. 1-3 = 10 um; Fig. 4 = 1 um. Figs. 2-4 — CAS 610955. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 109 PLATE 34 _— 110 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 35 Figs. 1-2 — Pseudopyxilla russica: Girdle view of a valve showing the hyaline structure of the mantle and valve face. Fig. 3 — Pseudopyxilla sp.: Girdle view showing the hyaline structure of the mantle and part of the valve face that is perforated by porous canals (arrow). Figs. 4-6 — Odontotropis galleonis: Fig. 4 — Holotype CAS 2028; girdle view showing the epivalve (lower valve) with a perforate mantle and the hypovalve (upper valve). Fig. 5 — Epivalve with a trapezium-shaped longitudinal costa. Fig. 6 — Hypovalve with longitudinal costa, two curved spines and scattered small spines on the valve face. Fig. 4 — LM; Figs. 1-3, 5-6 — SEM. Scale bars: Figs. 1-6 = 10 um. Figs. 1-2 — CAS 610955; Fig. 3 — CAS 610954; Figs. 5—6 — CAS 610939. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 111 PLATE 35 112 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 36 Figs. 1-5 — Kentrodiscus blandus: Fig. 1 — Holotype CAS 3409; girdle view of a frustule; epivalve is funnel-shaped and hy- povalve is circular, slightly convex and covered with scattered small spines. Figs. 2-5 — External views of the frustule and valve. Fig. 2 — Girdle view of a frustule showing the hyaline epivalve with a long conical elevation that bears longitudinal ribs and a zone of porous canals near the margin, and the low convex hypo- valve with small spines (bottom right). Figs. 3-4 — Epivalve in different positions showing the central conical elevation with longitudinal curved ribs and the location of a slit labiate? process (arrow). Fig. 5 — Detail of Fig. 4 showing the slit of a labiate? process located on the top of the elevation (arrow). Figs. 6-7 — Kentrodiscus andersonii: Fig. 6 — Holotype CAS 2016; girdle view of a frustule. Fig. 7 — External view of a frustule showing the girdle and epivalve/hypovalve with a system of spines. Figs. 1, 6 — LM; Figs. 2-5, 7 = SEM. Scale bars: Figs. 1-4, 6-7 = 10 pm. Fig. 5 = 1 pm. Figs. 2-5 — CAS 610955; Figs. 6-7 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 113 PLATE 36 114 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 37 Figs. 1-5 — Kentrodiscus aculeatus: Fig. | — Holotype CAS 2015; girdle view of a frustule. Figs. 2-3 — External views of a frustule showing the epivalve (top) and hypovalve (bottom) bear- ing small spines on the valve faces and the conical elevation of the hypovalve. Figs. 4-5 — Internal views of the epivalve show- ing the hyaline basal siliceous layer. Fig. 1 — LM; Figs. 2-5 — SEM. Scale bars: Figs. 1-5 = 10 um. Fig. 2 — CAS 610939; Figs. 3-5 — CAS 610954. NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION 115 PLATE 37 116 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 38 Figs. 1-7 — Liradiscus ovalis: Figs. 1-2 — Valve of the same specimen in different focus. Fig. | — Focus on the valve margin. Fig. 2 — Focus on the center of the valve face. Figs. 3, 5, 7 — Ex- ternal views of the valve face valve showing the system of anas- tomose ribs on the valve face. Figs. 4, 6 — Internal views of valve showing the hyaline basal siliceous layer and the marginal ring of short teeth. Figs. 1-2 — LM; Figs. 3—7 — SEM. Scale bars: Figs. 1-7 = 10 um. Figs. 1-7 — CAS 1144. 117 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 38 118 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, NO. 152 Plate 39 Figs. 1-5 — Xanthiopyxis grantii: Figs. 1-2 — Holotype CAS 2054; Valve views of the same specimen in different focus. Fig. | — Focus on the valve margin. Fig. 2 — Focus on the valve face. Figs. 3-4 — External views of the valves. Fig. 3 — valve view showing the arrangement of spines on the valve face. Fig. 4 — valve view showing the irregular perforations of the valve face by porous canal and presence of small spines. Fig. 5 — Internal view of the valve. Figs. 6-7 — Pterotheca evermannii: Fig. 6 — Holotype CAS 2033; girdle view of cylindrical epivalve with an hyaline tapering spine with lateral extensions near the apex. Fig. 7 — External girdle view showing the hyaline structure of the basal siliceous layer. Figs. 8, 9 — Pterotheca crucifera: Fig. 8 — Holotype CAS 2030; girdle view of epivalve with an hyaline ter- minal spine bearing costae with lateral extensions. Fig. 9 — Ex- ternal girdle view of the epivalve showing the hyaline structure of basal siliceous layer with sub-radial costae on the valve face. Figs. 10-11 — Micrampulla parvula: Fig. 10 — Holotype CAS 2025; side view. Fig. 11 — External side view showing a system of anastomose ribs on the inflated part of the cell, and the hyaline structure of the cylindrical part of the cell. Figs. 1—2, 6, 8, 10 — LM; Figs. 3-5, 7,9, 11 — SEM. Scale bars: Figs. 1-11 = 10 um. Fig. 3 — CAS 615990; Figs. 4-5 — CAS 610954; Figs. 6, 9 - CAS 610955; Fig. 11 — CAS 610939. 119 NIKOLAEV ET AL.: CRETACEOUS DIATOMS FROM THE MORENO FORMATION PLATE 39 i‘ [= io tpi Tea SOP ai oh PYF ey SMITHSONIAN INSTITUTION LIBRARIES INIT 3 9088 01302 64.