Basicranial Anatomy of the Living Linsangs Prionodon and Poiana
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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Papers in the Earth and Atmospheric Sciences Earth and Atmospheric Sciences, Department of 2001 Basicranial Anatomy of the Living Linsangs Prionodon and Poiana (Mammalia, Carnivora, Viverridae), with Comments on the Early Evolution of Aeluroid Carnivorans Robert M. Hunt Jr. University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/geosciencefacpub Part of the Earth Sciences Commons Hunt, Robert M. Jr., "Basicranial Anatomy of the Living Linsangs Prionodon and Poiana (Mammalia, Carnivora, Viverridae), with Comments on the Early Evolution of Aeluroid Carnivorans" (2001). Papers in the Earth and Atmospheric Sciences. 549. https://digitalcommons.unl.edu/geosciencefacpub/549 This Article is brought to you for free and open access by the Earth and Atmospheric Sciences, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in the Earth and Atmospheric Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. AMERICAN MUSEUM NoVltates PUBLISHED BY THE AMER I C AN M U SEUM OF NAT U RAL H ISTORY CENTRAL PA RK WEST AT 79T H STREET, NEW YORK. NY 10024 Number 3330, 24 pp., 10 figures, 2 tables April 26, 2001 Basicranial Anatomy of the Living Linsangs Prionodon and Poiana (Mammalia, Carnivora, Viverridae), with Comments on the Early Evolution of Aeluroid Carnivorans ROBERT M. HUNT, JR.' CONTENTS Abstract ................ ............................ , .. , .. , .. , ., .. , .. , . ... 2 Introduction ....... • . • . • . • . • . 2 Abbreviatio ns ... 3 Cranial and Dental Compari sons ............. ... ... ... .. .... • .... 3 Basicranial Anato my of Paiaeoprioll odoll . • . • . • . • . 7 Basicranial Anato my of Priollodoll and Poiana ..... • .... • .......•. • . 11 Discussion and Conclusions . ... .......... .... • ....... • . • . • . • . 17 Acknowledg nlents ... ............... ... ... • ....... • ..•.. • ....•...... 23 References ....................• •. .. • . •• _ . _ • • . • • _ ... • .. ....•.....•.... • ...... 23 , Research Associ3u: . Division of Pal eoll!ology. American Museum of N a tur~l His.tory; Professor. Geological Sciences. and Cur~to r. Ven cbr.ue Paleontology. University of Nebraska. Li ncoln. NE 68588-0549. Copyright C Ameri can MUSoC um of Nmur.l l History 2001 ISSN 0003-0082 I Pri ce $3.00 2 AMERICAN MUSEUM NOVITATES NO. 1 ABSTRACT The living Asian linsang, Prionodon pardicolor, shares marked anatomical similarities in basicranium and dentition with the extinct Oligocene aeluroid, Palaeoprionodon lamandini, from the Quercy ®ssures, France. The living African linsang, Poiana richardsoni, is similar yet slightly more derived in basicranial traits relative to Prionodon pardicolor, and also has basicranial and dental features indicating a relationship to the living genets (Genetta). The basicranial and auditory anatomy of a series Palaeoprionodon-Prionodon-Poiana can be in- terpreted as a morphocline showing the progressive alteration of the form of the petrosal and auditory bulla from the plesiomorphic aeluroid state in the Quercy fossils to a derived con- dition typical of the linsangs (Prionodon, Poiana) and living genets (Genetta). The basicranial anatomy of Genetta, including the structure of the petrosal and auditory bulla, is typical of other species of the Viverridae. The other lineages of living viverrids are believed to have undergone a similar transformation in their basicranial anatomical pattern from the plesiom- orphic state present in Oligocene aeluroids, exempli®ed by Palaeoprionodon, to the modern patterns typical of the living subfamilies (including the endemic Malagasy viverrid genera). INTRODUCTION siomorphic basicranial pattern common to these aeluroid genera (Hunt, 1998). As a re- African and Asian linsangs of the family sult, I became interested to learn whether liv- Viverridae are living, nocturnal aeluroid car- ing linsangs have retained throughout the nivorans, occupying forested environs in the mid- and later Cenozoic the archaic basicra- Old World tropics (®g. 1). The African lin- nial pattern of these Quercy aeluroids, and in sang (Poiana Gray, 1864) is represented by particular, whether they retain the pattern one or at most two species in west Africa. found in Palaeoprionodon, which has often Poina richardsoni and P. leightoni are dis- been allied with the Asian linsangs of the tributed from Liberia to northern Zaire, and genus Prionodon (Teilhard de Chardin, 1915, the island of Fernando Po (Bioko), according to Rosevear (1974). They are considered here Gregory and Hellman, 1939). as a single species, P. richardsoni, following The living African and Asian linsangs are Pocock (1908), who recognized leightoni as rare animals: Prionodon pardicolor and P. a subspecies of richardsoni. The Asian lin- linsang are listed as endangered (by the Con- sangs (Prionodon Hors®eld, 1822) are con- vention on International Trade in Endangered sidered to be more diverse: one species (the Species, and by the U.S. Department of the spotted linsang, P. pardicolor) is found from Interior). Although the eastern population of Nepal to Indochina, and a second species Poiana richardsoni is not reported as endan- (the banded linsang, P. linsang) reported gered, the western population is listed by the from Thailand and the Malay Peninsula into IUCN (International Union for Conservation Sumatra, Java, and Borneo (Nowak, 1991). of Nature) as of indeterminate status (No- Linsangs nest above ground and eat insects, wak, 1991); whether these eastern and west- small vertebrates, and some plant material ern groups are in contact through the tropical (Rosevear, 1974). forest belt is uncertainÐRosevear (1974) The Old World linsangs are of particular considered them among the rarest of African interest because of their evident anatomical mammals. Therefore, the opportunity to dis- similarity in cranial and dental features to sect the auditory region and describe the ba- one of the oldest fossil representatives of the sicranial anatomy of both Poiana richard- aeluroid Carnivora, Palaeoprionodon laman- soni and Prionodon pardicolor was fortu- dini, from the Oligocene ®ssure deposits of itous and timely. Are the linsangs ``living Quercy, France (Teilhard de Chardin, 1915; fossils''? This study considers the possibility Gregory and Hellman, 1939). A recent study that linsangs are relicts of the Oligocene ae- of Palaeoprionodon and other closely related luroid fauna, preserving a basicranial mor- primitive aeluroids (Stenoplesictis, Stenoga- phology from a time when the Aeluroidea le, Proailurus) from the Oligocene and early were in an initial phase of their great Eur- Miocene of western Europe identi®ed a ple- asian radiation. 2001 HUNT: AELUROID CARNIVORE EVOLUTION 3 Fig. 1. Geographic distribution of the living Asian linsangs (Prionodon pardicolor, P. linsang) and African linsang (Poiana richardsoni), and the Eurasian localities that have produced fossils of the Oligocene aeluroid Palaeoprionodon. 1, Palaeoprionodon lamandini, Quercy ®ssures, France; 2, Hsanda Gol, Mongolia (?Palaeoprionodon); 3, Poiana richardsoni leightoni (western area), P. r. richardsoni (eastern area); 4, Prionodon pardicolor (northern area), Prionodon linsang (southern area). ABBREVIATIONS h hypoglossal (condyloid) foramen ic internal carotid artery Anatomical L middle lacerate foramen m mastoid A alisphenoid P petrosal a ``apron'' of petrosal plf posterior lacerate foramen ac alisphenoid canal (posterior opening) pp paroccipital process of the exoccipital BO basioccipital R rostral entotympanic BS basisphenoid rp rugose surface of petrosal promonto- c common opening for the hypoglossal and rium for attachment of the caudal en- posterior lacerate foramina in Poiana totympanic in Nandinia d depression in basisphenoid for internal SQ squamosal carotid loop T ectotympanic E caudal entotympanic tf ¯ange of the ventral process thinned by F facet on petrosal promontorium for ec- appression of the caudal entotympanic totympanic tt tensor tympani fossa fo foramen ovale V ventral process of the petrosal promon- gf postglenoid foramen torium 4 AMERICAN MUSEUM NOVITATES NO. 1 x line of caudal entotympanic attachment (formed by the right and left orbitosphe- to ectotympanic noids) is thin and narrow at this locus and Z contact of ectotympanic ¯ange with pe- probably represents the primitive aeluroid trosal promontorium condition for the emergence of cranial nerves V1,V2, and the optic nerve from the brain- Institutional case. The optic foramen lies in close prox- AMNH American Museum of Natural History, imity to the orbital ®ssure in these aeluroids, New York (Department of Mammalo- in contrast to many arctoid carnivorans in gy) which the optic foramen is placed farther for- FMNH Field Museum of Natural History, Chi- ward along the orbital wall. cago (Department of Mammals) An alisphenoid canal is present, its poste- MNHN MuseÂum National d'Histoire Naturelle, rior opening placed a few millimeters ante- Paris rior to the foramen ovale. In Prionodon and Poiana the maxillary branch of the trigemi- CRANIAL AND DENTAL nal nerve (V ) exits the braincase through the COMPARISONS 2 small foramen rotundum in the cranial wall Cranial measurements of Prionodon, and emerges within the alisphenoid canal. Poiana, and two skulls of Quercy Palaeo- Both V2 and the blood vessels traveling in prionodon illustrate their similarity in size the canal exit the skull