'0 ern.\OZP BRITISH MUSEUM (NATURAL HISTORY) Bulletin -4SEP199! PRESENTED MuseumSENERAL LIBRARY British (Natural History) Geology Series Neogene crabs from Brunei, Sabah and Sarawak; New pseudosciurids from the English Late Eocene; Upper Palaeozoic Anomalodesmatan Bivalvia VOLUME NUMBER AUGUST 47 29 1991 1 1 1 The BulletinoftheBritishMuseum (NaturalHistory),institutedin 1949, isissuedin fourscientificseries, Botany,Entomology, Geology(incorporatingMineralogy) and Zoology, and anHistoricalseries. TheGeology SeriesiseditedintheMuseum'sDepartmentofPalaeontology KeeperofPalaeontology: DrL. R. M. Cocks Editorofthe Bulletin: DrM. K. Howarth Assistant Editor: MrD. L. F. Sealy PapersintheBulletinareprimarilytheresultsofresearchcarried outon theuniqueandever- growingcollectionsofthe Museum, both bythescientificstaffand byspecialistsfromelsewhere whomakeuseoftheMuseum'sresources. Many ofthepapersareworksofreferencethatwill remainindispensableforyearstocome. Avolumecontainsabout256pages,madeupbytwonumbers: published SpringandAutumn. Subscriptionsmaybeplaced foroneormoreoftheseriesonan Annual basis. Individual numbers and backnumberscanbepurchasedanda Bulletincatalogue, byseries, isavailable. Ordersand enquiriesshouldbesentto: SalesDepartment, Natural History MuseumPublications, British Museum(NaturalHistory), Cromwell Road, London SW7 5BD Telephone:071-9389386 Fax:071-938 8709 WorldListabbreviation: Bull. Br. Mus. nat. Hist. (Geol.) © British Museum(Natural History), 1991 ISBN 565 07029 Geology Series ISSN 0007-147 Vol47No 1 pp 1-100 British Museum(Natural History) Cromwell Road London SW7 5BD Issued29August 99 1 »611 Bull. Br. Mus.nat. Hist. (Geol.)47(1): 1-33 Issued29August 1991 Neogene crabs from Brunei, Sabah and BRITISH MUSEUM Sarawak (NATURAL HISTORY) -4S£P|99f PRESENTED MORRIS S. F. GENERAL LIBRARY DepartmentofPalaeontology, British Museum (NaturalHistory), CromwellRoad, London~SW75BD J. S. H. COLLINS 63 OakhurstGrove, London SE229AH CONTENTS Introduction 2 Thefaunaanditspalaeoecology 3 Stratigraphy 3 Localities 4 Systematicpalaeontology 4 SectionPodotremata,SubsectionArchaeobrachyuraGuinot 4 SuperfamilyRaninoidea,FamilyRaninidaedeHaan 4 GenusRaninoidesMilneEdwards 4 Raninoidessp 4 SectionHeterotremataGuinot 5 SuperfamilyDorippoidea,FamilyDorippidaedeHaan 5 GenusDorippeWeber,s.str 5 Dorippe(Dorippe)frascone(Herbst)tuberculatassp.nov 5 SuperfamilyCalappoidea,FamilyCalappidaedeHaan 5 GenusCalappaWeber 5 Calappasexaspinosasp.nov 5 SuperfamilyPortunoidea,FamilyPortunidaeRafinesque 6 SubfamilyPodophthalminaeMiers 6 GenusPodophthalmusLamarck 6 Podophthalmusfusiformissp.nov 6 SubfamilyPortuninaeRafinesque 6 GenusCharybdisdeHaan 6 Charybdis(Charybdis)feriata(Linne)bruneiensisssp.nov 7 GenusPortunusWeber 7 Portunusobvallatussp.nov 7 Portunuswoodwardisp.nov 8 SuperfamilyXanthoidea,FamilyXanthidaeDana 8 GenusGalenedeHaan 8 Galenestipatasp.nov 8 SuperfamilyParthenopoidea,FamilyParthenopidaeMacleay 9 GenusParthenopeWeber,SubgenusRhinolambrusMilne-Edwards 9 Parthenope(Rhinolambrus)sublitoralissp.nov 9 SuperfamilyLeucosioidea,FamilyLeucosiidaeSamouelle 10 GenusAmpliuranov 10 Ampliurasimplexgen.etsp.nov 10 GenusDrachiellaGuinotinSerene&Soh 10 Drachiellaguinotaesp.nov 10 GenusIphiculusAdams&White 1 Iphiculusgranulatussp.nov 11 Iphiculusmiriensissp.nov 1 Iphiculussexspinosussp.nov 13 GenusLeucosiaWeber '3 Leucosialongiangulatasp.nov 13 Leucosiasereneisp.nov 13 Leucosiatutongensissp.nov 15 GenusMyraLeach 15 Myrabrevisulcatasp.nov '5 Myrasubcarinatasp.nov ' Myratrispinosasp.nov ' GenusNuciaDana '6 MORRIS&COLLINS Nuciaborneoensissp.nov 19 Nuciacalculoidessp.nov 19 Nuciacoxisp.nov 19 GenusNucilobusnov 20 Nucilobussymmetricusgen.etsp.nov 20 GenusPariphiculusAlcock 21 PariphiculusgselliBeetsbeetsissp.nov 21 Pariphiculuspapillosussp.nov 21 Pariphiculusverrucosussp.nov 21 GenusPhilyraLeach 23 Philyragranulosasp.nov 23 GenusTypilobusStoliczka 23 Typilobusmarginatussp.nov 23 Typilobussp 24 SectionThoracotremataGuinot 24 SuperfamilyGrapsoidea,FamilyGrapsidaeMacleay 24 GenusPalaeograpsusBittner 24 Palaeograpsusbittnerisp.nov 24 SuperfamilyPinnotheroidea,FamilyPinnotheridaedeHaan 26 SubfamilyPinnotherinaedeHaan 26 GenusPinnixaWhite 26 Pinnixaaequipunctatasp.nov 26 Pinnixaomegasp.nov 26 SuperfamilyHexapodoidea,FamilyHexapodidaeMiers 28 SubfamilyHexapodinaeMiers 28 GenusPrepaedumanov 28 Prepaedumadecapodagen.etsp.nov 28 SubfamilyXenophthalminaeAlcock 29 GenusXenophthalmusWhite 29 Xenophthalmussubitussp.nov 29 SuperfamilyOcypodoidea,FamilyOcypodidaeRafinesque 29 SubfamilyMacrophthalminaeDana 29 GenusMacrophthalmusLatreilleinDesmarest,SubgenusMareotisBarnes 29 Macrophthalmus(Mareotis)wilfordisp.nov 29 References 32 SYNOPSIS. Thirty-six species of fossil crab are described and figured from the Neogene of Sabah, Sarawak and Brunei. The following 3 genera, 31 species and 3 subspecies are new: Dorippe frascone tuberculata, Calappa sexaspinosa, Podophthalmusfusiformis, Charybdisferiata bruneiensis, Portunusobvallatus, P. woodwardi, Galene stipata, Parthenope (Rhinolambrus) sublitoralis, Ampliura (gen. nov.) simplex, Drachiella guinotae, Iphiculus granulatus, I. miriensis, I. sexspinosus, Leucosia longiangulata, L. serenei, L. tutongensis, Myra brevisulcata, M. subcarinata, M. trispinosa, Nucia borneoensis, N. calculoides, N. coxi, Nucilobwi (gen. nov.) symmetricus, Pariphiculus gselli beetsi, P. papillosus, P. verrucosus, Philyra granulosa, Typilobus marginatus, Palaeograpsus bittneri, Pinnixa aequipunctata, P. omega, Prepaeduma (gen. nov.) decapoda, Xenophthalmussubitus, Macroph- thalmus (Mareotis) wilfordi. Liechti (1960). LocalityS.4918 (see p. 4), originallysurveyed INTRODUCTION by the Geological Survey as Miri Formation (Pliocene) age, was laterre-assessed as beingof?late middle Pleistocene age (Wilford 1961). It is probable that locality S.5545 (=S.4965) Mostofthe material formingthe basisofthe present descrip- isofsimilar age, containing as it does Charybdis, an in-shore tionswascollected bythe Geological Survey Departmentsof genus with a modern aspect. The Pleistocene horizons were Brunei, Sarawak and Sabah (formerly British Territories in deposited in valleys which were cut into older strata and Borneo) during the 1950s, and sent to the British Museum later flooded. The Pleistocene horizons represent shallower (Natural History) in 1958 and 1963-64. A small quantity of water than the Mio-Pliocene. Barnes (1968: 337) comments: material was subsequently supplied by the Brunei Shell 'Macrophthalmusistodaylittoral,essentiallysub-tropicaland Petroleum Company Ltd. The material is only of broad tropical frequently brackish or estuarine'; there is no reason stratigraphical value because of its uniqueness in the fossil to supposethat the fossilsfrom Brunei came from adifferent record. Reliance was placed on the published ages for the sort ofenvironment. beds by foraminiferal and molluscan workers (Nuttall 1961, A few leucosiids were earlier collected by members ofthe Haile & Wong 1965). Geological Survey of North Borneo from isolated areas in A general description of the geology of Sarawak, Brunei the north-east of Borneo; they are clearly from the older and the western part of North Borneo was published by Miocene deposits but their stratigraphical control is poor. NEOGENECRABSFROMBRUNEI,SABAHANDSARAWAK Thegeological agesforthesespecimensaregiven in Collenette Thesesuggestedconditionsinvitecomparisonwiththecrab (1954) and Haile & Wong (1965). fauna collected from the Gulf of Siam (Thailand) by the All the material described in this paper is deposited Danish Expedition to Siam (1899-1900) and described by in the British Museum (Natural History), Department of Rathbun, 1910. She (1910: 303) notesthepositionoftheGulf Palaeontology: register numberprefix In. of Siam midway between the Indian Ocean and the West Pacific Ocean, and goes on to comment on the high number ofnewgeneraandspecies.Thissuggestedanareaparticularly suited to speciation, a comment which might be equally true THE FAUNA AND ITS PALAEOECOLOGY forthecrabsofthe PlioceneofBorneo. Shefurthernotedthe abundance ofsmall forms, especially Goneplacidae (s.l.) and Leucosiidae,whichalsoshowthesamedominancein Borneo. The successive Mio-Pliocene crab faunas from north-west Initially Rathbun attributed this bias to 'the zeal of the Borneo are unusual, in that they contain an abnormally high collector' but later came to realise that it was because the proportion of leucosiids (species and specimens) compared collectionwastakenfromashelteredarmofthesea. Rathbun with the average of the Indo-West Pacific faunas. Table 1 recorded 204 species (of which 55 are inshore/estuarine comparesthefossilfaunaswithdataforthe Indo-WestPacific species) in her report, compared with the 36 fossil species region as a whole (taken from Serene 1968: 2804 species in (2 inshore/estuarine) in the Borneo fauna here reported. 462 genera) at the present day, and for the nearest com- Some crab groups are clearly underrepresented in the parable Recent fauna, that ofthe GulfofThailand (Rathbun Borneofauna,particularlytheXanthoideaandMajoidea,but 1910: 207 species in 104 genera). The Gulf ofThailand was in the Gulf of Siam these are either associated with a very chosenbecause itmostcloselycompareswiththequietwaters inshore position or found in close association with algae that ofBorneo and also hasahigherproportion ofleucosiidsthan appear to be absent in Borneo. Serene & Soh (1976), the normal shelf. The Gulf of Thailand fauna was largely reportingon the Brachyuracollected duringtheThai-Danish taken by dredge from between the coast and the off-shore Expedition (1966) from approximately the same area as fringing islands, an area protected from the high energies of Rathbun'smaterial,commentedparticularlyonthesmallsize the open shelf with depths ranging from shoreline to about ofthe specimens. The great majority did not exceed 10 mm. 50 m. The bottom is largely composed of sand and broken This is also true ofmany ofthe species from Borneo, so it is shell. Leucosiids generally live in such areas in relatively not considered that the Borneo faunas contain a preponder- shallow water. They are weak, sluggish back-burrowers, ance ofjuvenile forms. lurking half-buried forpassingprey. It istherefore suggested The two genera Macrophthalmus and Charybdis from that the Mio-Pliocene horizons of Borneo were deposited in the Pleistocene of Borneo are found in many sublittoral, similar shallow (5-50 m), low-energy areas. The lithology of estuarine or brackish waters around the Indo-Pacific, the the rock confirms that the bottom was of sand and broken predatory Charybdisbeingthe morefully marine. shell, particularly suitedto the back-burrowingleucosiids. The environment during the Pliocene remained relatively steady. One species (out of29) survivedfrom the LowerMiri Table 1 Distribution, bypercentagesinfamilyofsuperfamily,of to the Seria and 10 species survived from the Lower Miri to crabsfromtheRecentoftheIndo-WestPacific(n =2804speciesin the Upper Miri; one speciesthat appeared in the Upper Miri 4in6222gegneenrear;a;Sehreerneien)19a6n8)d,tthheeRNeecoegnetnoefotfheBoGurlnfeoof(nTh=ail36ansdpe(cnie=s scoulrlveicvteeddfirntoomtthheetoSeprmioastFoserrmiaetsioofnt.heNBoorcnreaobsPlihoacveene,betehne 204speciesin 107genera; Rathbun 1910). Liang Formation. Indo-WestPacific Borneo(Neogene) Thailand Dromiacea 3.4 3.0 STRATIGRAPHY Raninoidea 0.7 3.0 - Dorippoidea 1.6 3.0 1.0 Calappidae 1.3 3.0 3.0 AccordingtoVan Bemmelen (1970), the geosyncline formed Leucosiidae 10.0 65.0 16.0 Majoidea 27.7 3.0 16.0 on the base-levelledCretaceouswassinkingbytheendofthe Portunoidea 7.8 9.0 10.0 Lower Tertiary, with subsidence continuing into the Upper Xanthoidea 22.5 3.0 22.0 Tertiary. The basin wasbeingfilled byclasticsedimentsfrom Hexapodidae 4.7 3.0 13.0 the central Borneo mountainous spine to the south and from POicnynpootdhoeirdideaae 47..33 9-.0 56..00 surrounding land masses to the north (Sunda Continent). Grapsoidea 11.7 3.0 10.0 Umbgrove (1933) called this late cycle geosyncline, in which it lies between stable and mobile areas resulting in weak folding, an ideogeosyncline. Haile (1969) described the for- In addition, there are present in Borneo more commensal mations that make up what he called the North-west Borneo species of crabs than would be expected, since many are soft- Geosyncline, goingon to describe itsorganization andevolu- shelled and consequently easily damaged or destroyed before tionary history. He compared and contrasted it with burial. Althoughthere is nodirectfossilevidence, annelidsand Aubouin's (1965) geosynclinal couple model. Bol & van holothuriansprobablyalsothrived,whichwouldaccountforthe Hoorn (1980) believed thatthe parallel ridgeswere the result presence ofa higher than average proportion ofspecies (and of mild compressional movements related to basement specimens)ofcrabscommensalwiththese animals. Thetube- wrench faulting. These weak positive areas paralleling like enrollment of the fossil commensal crabs suggests that the present north-western coastline of Borneo probably sidewayswalkingwas alreadywell established. acted as barriers to strong wave action, thus having the MORRIS&COLLINS same effect as the fringingislands alongthe GulfofThailand Muara Road, 8 km north of Brunei Town, Brunei (?late today. middle Pleistocene-Wilford 1961: 102). The Miri and Seria Formations ofthe Belait Group under- S.4965. See S.5545. lie about 647 km2 of Quaternary in Sarawak and Brunei. 5.5536. Clay ironstone nodules in road cutting Mile 24! on Outcrops are mostly to be found in sea cliffs and road Tutong Road from Brunei Town, Brunei. Pliocene, Seria cuttings. The Belait Group consists of alternations of clays, Formation. sandy clays and sandstones. The main feature-forming beds 5.5537. Clay ironstone nodules in road cutting Mile 211 on are the thick sandstone sequences, from which much of the Tutong Road from Brunei Town, Brunei. Pliocene, Seria fossil crab fauna has come. The Miri Formation is 1954 m Formation. thickatMiri anditcanbe lithologicallyand(basedonsmaller 5.5538. Mile 19! on Tutong Road to Brunei Town, Brunei. benthonic foraminifera) palaeontologically divided into an Pliocene, UpperMiri Formation. upper (1323 m) and a lower (631 m) sequence. The Upper 5.5539. Mile 17| on Tutong Road to Brunei Town, Brunei. Miri isthe more arenaceous, with more rapidbutlessregular Pliocene, UpperMiri Formation. alternations. The Seria Formation (up to 2000 m thick) is S.5544. Mile 13! on Tutong Road to Brunei Town, Brunei. conformable with the underlying Miri Formation and is Pliocene, LowerMiri Formation. structurally and lithologically similar. It can be separated S.5545 (= S.4965). Near Mile 13 on Tutong Road to Brunei palaeontologically by the appearance of the foraminifer Town, Brunei. Late Middle Pleistocene? Triloculina 18 (Wilford 1961: 73). The lowerbedsoftheSeria 5.5548. Mile 12! on Tutong Road to Brunei Town, Brunei. Formation are arenaceous, givingwaytosandyandsiltyclays Pliocene, LowerMiri Formation. in the higher beds. The Seria Formation was deposited in a 5.5549. Mile 12! on Tutong Road to Brunei Town, Brunei. very shallow seaway, with even inshore lagoonal conditions; Pliocene, LowerMiri Formation. it was certainly shallower than the preceding Miri Formation 5.5550. Mile 12 on Tutong Road to Brunei Town, Brunei. sea. Pliocene, LowerMiri Formation. Nearly 4000 m of sediment was deposited during the late S.10474. Sea cliffc. 1.5 km north-east ofthe mouth ofRiver Miocene and Pliocene filling of the geosyncline. An unsub- Trusan, south-west of Miri, Tanjong Batu area, Sarawak. stantiated estimate by Schuppli (1946: 4) suggeststhatduring Pliocene, Lower Miri Formation. the Neogene ofnorth-west Borneo 50,000ft (c. 15,000 m) of S.10475. In sea cliffs. 0.8 km north-east of the mouth ofthe sediment wasdeposited. Batang River, south-west of Miri, Sarawak. Pliocene, The Liang Formation, which is up to 3000 ft (c. 920 m) LowerMiriFormationbuthigherinsuccessionthanlocality thick, overlies the Seria Formation, andwasdepositedon an S.10474. erosional surface. The Liang is predominantly a marine transgressive series of poorly consolidated sands and clays, changing upwards into similar, but lagoonal or deltaic, sedi- ments. No fossil crabs have been collected from the Liang SYSTEMATIC PALAEONTOLOGY Formation. The top boundary of the Liang is an unconformable erosional surfacewith the overlyingPleistocene terraces. The PODOTREMATA Section Guinot, 1977 cause of this was structural, following uplift en bloc of the coastal region of north-west Borneo. The denudation was Subsection ARCHAEOBRACHYURA Guinot, 1977 followed by the Jerudong Cycle, which produced a system of Superfamily RANINOIDEAde Haan, 1841 mature valleys in which are deposited the Jerudong Terrace sands of ?late Middle Pleistocene age, estuarine or fluviatile FamilyRANINTOAEde Haan, 1841 in character. This deposit is never more than 10 m in GenusRANINOIDESH. Milne Edwards, 1837 thickness. Type species. By monotypy Ranina laevis Latreille, 1825, from the Recent (type locality unknown). Range. Eocene to Recent. LOCALITIES Raninoidessp. Fig.39 J.771. Mile 3| on Labuk Road from Sandakan, Sabah. Material. Two fragmentary external moulds from locality Undifferentiated Miocene Tes-f (?Lower Miocene) (Fitch S.5539. UpperMiri Formation: In 61915 (Fig. 39), In 61916. 1958). Description. Thefulllengthofneithercarapaceispreserved, NB.130, NB.132. South-east part of Silimpopon region near but it probably equalled twice the maximum width which Tawau, Sabah. Silimpopon horizon of Wenk (1938) which occursataboutmidlength;itismoderatelyroundedtoweakly is aclay band lying between the Simengaris Formation and subcarinate in transverse section and longitudinally nearly Kapilit Formation, ?LowerMiocene (Tes-f). flat. Gently convex posterolateral margins converge to a NB.11541. Headwaters of Silabukan River, c. 14 km east of posterior margin somewhat narrower than the orbitofrontal Silabukan, Sabah. Segama Group, Tungku Formation, margin, which occupies about three-quarters of the width. Middle Miocene (upperTf). The very short anterolateral margins terminate at the basal S.4807. Calcareous nodules in sea cliffs at Penanjong, 5 km scars of apparently rather small, obliquely-directed spines north-eastofTutong, Brunei. Pliocene, Seria Formation. probably weaker than the flattened outer orbital spine. S.4918. Base of marine alluvium in road cutting, Mile 3\ on Posterior to the lateral spine the lateral edges are