'4P

^ifk New Enaliarctos^ (Pinnipedimorpha) from the Oligocene and Miocene of Oregon and the Role of "Enaliarctids" in Pinniped Phylogeny SERIES PUBUCATIONS OF THE SMITHSONIAN INSTITUTION

Emphasis upon publication as a means of "diffusing knowledge" was expressed by the first Secretary of the Smithsonian. In his formal plan for the Institution, Josei;^ Henry outHned a program that irv;luded the following statement: *lt is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in £dl branches of knowledge." This tt^me of t>ask: research has been adhered to through the years by thousarKte of titles issued in series publk^tkjns under the SmithscKuan imprint, (xynmencing with Smithsonian Contributions to Knowlodge in 1848 arKl contirniing wittt the following active series:

Smithsonian Contributions to Anthrc^ogy Smithsonian Contritjutions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Paleobiology Smithsoni^i Contributions to Zoology Smithsonian Folklife Studies Smithsonian Studies in Air and Space Smithsonian Studies in History and Technology In these series, the Institution putilishes small papers arKl full-scale monographs ttiat report the research and collections of its various museums and bureaux or of professkxial colleagues in the worid of science and schdarship. The publications are distrit)uted by mailing lists to NtKaries, universities, and similar institutkins throughout ttie worid. Papers or monographs submitted for series put>licatk>n are received by the Smithsonian tnstitutk>n Press, subject to its own review for format and style, only through departonents of the various SmithscMiian museums or bureaux, where the martuscr^ts are given substantive review. Press recMrements for manuscript and art prepwatton are outlined on the Inside back cover.

Robert McC. Adams Secretary Smithsonian InstltutkMi SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY • NUMBER 69

New Enaliarctos^ (Pinnipedimorpha) from the Oligocene and Miocene of Oregon and the Role of "Enaliarctids" in Pinniped Phylogeny

Annalisa Bert a

SMITHSONIAN INSTITUTION PRESS Washington, D.C. 1991 ABSTRACT Berta, Annalisa. New Enaliarctos* (Pinnipedimorpha) from the Oligocene and Miocene of Oregon and the Role of "Enaliarctids" in Pinniped Phylogeny. Smithsonian Contributions to Paleobiology, number 69, 33 pages, 22 figures, 1991.—Three new species of the pinnipedimorph Enaliarctos* are described from the marine late Oligocene and early Miocene (Arikareean and Hemingfordian or early Barstovian correlatives) of coastal Oregon. Enaliarctos tedfordl, new species, is based on a partial cranium from the late Oligocene Yaquina Fonnation. A related new species, Enaliarctos emlongi, is founded on a nearly complete cranium, jaws, and associated skeletal elements from the late Oligocene to early Miocene Nye Mudstone. A third new species, Enaliarctos barnesi, is based on a partial cranium and jaws from late Oligocene or early Miocene rocks near the contact between the Yaquina Formation and the Nye Mudstone. Another skull, from the Nye Mudstone, is referred to a previously described species, Enaliarctos mitchelli Barnes, 1979. Three of these species, E. mitchelli, E. emlongi, and E. tedfordl form a monophyletic clade, united by reduced cheek teeth cingula and short metacone of the upper camassial. The major trend observed in Enaliarctos over 10 million years of history is an intermediate stage in the transformation to homodonty evidenced by premolarization of the upper camassial and molars and reduction and simplification of cusps on the lower camassial. Cladistic analysis of 52 cranial and dental characters suggests the following phylogenetic hypotheses: (1) the subfamily "Enaliarctinae" (= "Enaliarctidae") is paraphyletic, (2) monophyly of the genus Enaliarctos* is questioned although the status of this taxon as sister taxon to other pinnipeds is affirmed, (3) other "enaliarctid" pinnipeds, Pteronarctos and Plnnarctidlon, are assigned to less inclusive pinniped clades {Pteronarctos -I- all other pinnipeds and Pinnarctidion + Desmatophoca, Allodesmus, and the Phocidae).

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The trilobite Phacops rana Green.

Library of Congress Cataloging-in-Publication Data Berta, Annalisa New Enaliarctos* (Pinnipedimorpha) from the Oligocene and Miocene of Oregon and the role of "Enaliarctids" in Pinniped phylogeny / Annalisa Berta. p. cm.—(Smithsonian contributions to paleobiology ; no. 69) Includes bibliographical references. 1. Enaliarctos. 2. Paleontology—Oligocene. 3. Paleontology—Miocene 4. Paleontology—Ore­ gon. I. Title. II. Series. QE701.S56 no. 69 [Qe882.P51 560 s-dc20 [569'.74] 91-18125

© The paper used in this publication meets the minimum requirements of the American National Standard for Permanence of Paper for Printed Library Materials Z39.48—1984. Contents

Page Introduction 1 Abbreviations 1 Acknowledgments 2 Location, Stratigraphy, and Correlation 3 Previous Work 4 PINNIPEDIMORPHA 4 Enaliarctos* Mitchell and Tedford 5 Enaliarctos emlongi, new species 5 Enaliarctos barnesi, new species 13 Enaliarctos tedfordi, new species 16 Enaliarctos mitchelli Barnes 19 Interspecific Affinities of Enaliarctos* 25 Higher Level Relationships of Enaliarctos* and "Enaliarctids" 27 Conclusions 31 Literature Cited 32

Ul

New Enaliarctos'^ (Pinnipedimorpha) from the Oligocene and Miocene of Oregon and the Role of "Enaliarctids" in Pinniped Phylogeny

Annalisa Berta

Introduction however, that there is no consensus regarding pinniped "Enaliarctids" are basal pinnipeds implicated in the higher relationships. While expressing some reservations, Flynn et al. level phylogeny of all other pinnipeds (including otariids, (1988) endorsed monophyly whereas Wozencraft (1989) odobenids, phocids, and their fossil allies). Initial study rejected Wyss's arguments and concluded that pinnipeds are established "enaliarctids" as an intermediate evolutionary stage diphyletic. Barnes (1989) also contested Wyss's conclusions between ursoids and "otarioids" (including otariids, odobenids, and supported recognition of the "Otariidae" (= "Otarioidea") and the extinct desmatophocids) (Mitchell and Tedford, 1973). comprised of the following subfamilies: Enaliarctinae, Otar- This interpretation was part of a broader, diphyletic view of iinae, Desmatophocinae, Allodesminae, Imagotariinae, Dusig- pinnipeds that proposed that "otarioids" derived from ursids nathinae, and Odobeninae. This latter arrangement follows that whereas phocids originated from mustelids (Mivart, 1885; originally proposed by Mitchell (1968, 1975). McLaren, 1960; Tedford, 1976). This notion was widely A large, diverse, well-preserved collection of fossil pin­ accepted (Repenning, 1976; Repenning and Tedford, 1977; nipeds representing the genus Enaliarctos* found by Douglas Barnes, 1979; de Muizon, 1982; King, 1983). Recently, Emlong from late Oligocene-early Miocene rocks of coastal however, Wyss (1987) rejected the "Otarioidea" as based Oregon formed the basis for this study. This report provides largely on primitive characters and he marshalled osteological, description of Enaliarctos* species new to the published record soft anatomical, and biomolecular evidence to support a and an analysis of their interrelationships. Also considered is monophyletic origin of pinnipeds. He concluded that "enaliarc­ the role of "enaliarctids" in pinniped phylogeny. tids" as traditionally defined are paraphyletic and he recognized This study suggests that Enaliarctos should be regarded as a Enaliarctos as the sister group to the remaining pinnipeds. metataxon, so indicated by an asterisk (*). This convention, an Pinniped monophyly was further strengthened by skeletal asterisk beside the taxonomic name (formulated by Gauthier, evidence provided by Wyss (1988a), Berta et al. (1989), and 1986; see also Gauthier et al., 1988; Donoghue, 1985) is used Berta and Ray (1990). to designate taxa for which there is no unambiguous character Recent reviews of carnivoran phylogeny demonstrate, evidence supporting either monophyly or paraphyly. ABBREVIATIONS.—The following institutional abbreviations Annalisa Berta, Department of Biology, San Diego Stale University. are used: San Diego. California, 92182 (Research Associate in the Department of Paleobiology, National Museum of Natural History, Smithsonian UCMP Museum of Paleontology, University of Institution). California, Berkeley, CA Review Chairman: Clayton E. Ray, National Museum of Natural USNM Collections of the former United States History, Smithsonian Institution, Washington, D.C. 20560. National Museum, now in the National Reviewers: Lawerence G. Barnes, Natural History Museum of Los Angeles County, Los Angeles; and Andre R. Wyss, University of Museum of Natural History, Smithsonian California, Santa Barbara. Institution, Washington, D.C. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

Type Locality Enaliarctos emlongi uSNM 250345

Portland

N

c

O o

o CB CL

Enaliarctos mitchelli USNM 175637

ml.

Type Locality Enaliarctos tedfordl USNM 206273 Type Locality USNM 314295 Enaliarctos barnesi

Seal Rocks

FIGURE I.—^Detail of part of the Yaquina 15-minute quadrangle, USGS, showing the localities discussed in the text. Arrow indicates location of map enlargement.

ACKNOWLEDGMENTS.—Specimens were skillfully prepared History) provided locality information and assistance with the by Ed Pederson (American Museum of Natural History), measurement of specimens. Charles A. Repenning (U.S. Geological Survey, Denver), and Lawrence G. Barnes (Natural History Museum of Los Gladwyn Sullivan and Michael Tiffany (National Museum of Angeles County) provided casts of comparative specimens. For Natural History). Line drawings were made by Christi Endres. permission to study specimens under their care I thank L.G. Michael McCaffery and Nicki Watson (San Diego State Barnes, Clayton E. Ray (National Museum of Natural History), University) greatly assisted with specimen photography. David and Richard H. Tedford (American Museum of Natural Bohaska and Robert Purdy (National Museum of Natural History). NUMBER 69

Benthic Molluscan North American Central Time Epochs Foraminif. Land Mammal Coast Range (mybp) Stages Stages Ages Oregon

BARSTOVIAN ASTORIA FM. •o NEWPORTIAN 9 \ LU ?r Enaliarctos emlongi Z LU HEMINGFORDIAN

20" 8 SAUCESIAN PILLARIAN OJ NYE MUDSTONE Enaliarctos mitchelli LU

ARIKAREEAN Enaliarctos barnesi 25 YAQUINA FM. JUANIAN Enaliarctos tedfordi LU

30 - ZEMORRIAN

WHITNEYAN ALSEA FM. CO LU MATLOCKIAN 35-

FIGURE 2.—Correlation of rock units containing Enaliarctos species (after Berggren et al., 1985 (time scale and correlation of NALMA) and Armentrout et al., 1983).

L.G. Barnes, R.H. Tedford, A.R. Wyss, C.E. Ray, and CR. siltstone of late Oligocene age, overlies siltstone of the Alsea Crumly have provided valuable comments on the manuscript. Formation (Snavely et al., 1980). This formation has been Emlong's field work was supported by the Smithsonian assigned to the Juanian Molluscan Stage (Addicott, 1976; Institution through the Smithsonian Research Foundation and Armentrout, 1981) and Zemorrian Foraminiferal Stage the Walcott and Kellogg Funds. (Armentrout et al, 1983, chart). The Yaquina Formation has I gratefully acknowledge financial support for this research produced, in addition to pinnipeds, desmostylians (Domning et provided by NSF grant BSR 8607061. al., 1986), cetaceans (Emlong, 1966; Barnes, 1987b), and a single land mammal, an anthracothere. The stage of evoludon Location, Stratigraphy, and Correlation of the anthracothere (see Domning et al., 1986) suggests correlation of this formation with the early part of the Marine sedimentary rocks crop out in structural basins along Arikareean land mammal age, approximately 28-25 Ma the Oregon coast at Astoria, Tillamook, Newport, and Coos (Figure 2). Bay (Snavely et al., 1964). Fossil specimens referred to Marine siltsone and fine-grained sandstone of the Nye Enaliarctos* described in this report were collected by Douglas Mudstone overlie by gradational contact the Yaquina Forma­ Emlong from rock units exposed in the Yaquina Bay area tion (Snavely et al., 1980). The Nye Mudstone is late Oligocene between Newport and Waldport in northwestern Lincoln to early Miocene in age and has been assigned to the Pillarian County, Oregon (Figure 1). This region has been mapped Molluscan Stage (Addicott, 1976; Armentrout, 1981), which (Snavely et al., 1976) and more detailed descriptions of the has been correlated with the Saucesian Foraminiferal Stage regional geology are given in Snavely et al., 1980. The fossils (Armentrout et al, 1983, chart). The Nye Mudstone can be described below come from three successive formations of late correlated with the middle and late Arikareean and early Oligocene through early Miocene age. Hemingfordian, approximately 25-18 Ma (Figure 2). The Yaquina Formation, composed of sandstone and Sandstone and siltstone of the Astoria Formation un- SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY conformably overlie the Nye Mudstone (Snavely et al., 1980). TABLE 1.—Previous classifications of "enaliarctids" and selected groups. The holotype of Enaliarctos emlongi, according to Emlong's field notes, was collected "north of the Nye-Astoria contact in 1. MitcheU and Tedford, 1973 the Astoria Formation." Repenning (pers. comm.) has sug­ Family OTARIIDAE SubfamUy ENALIARCTINAE gested that this specimen may actually be from the upper part Enaliarctos mealsi of the Nye Mudstone. A sample of the enclosing matrix of USNM 250345, processed for foraminifera by Kristin 2. Tedford, 1976 Superfamny OTARIOIDEA MacDougall of the U.S. Geological Survey, Menlo Park, Family ENALIARCTIDAE yielded taxa that were not age diagnostic. The Astoria Enaliarctos mealsi Formation spans the late part of the early Miocene through the Family OTARIIDAE (including Odobeninae) early part of the middle Miocene (Barnes, 1987a; Armentrout, 3. Bames, 1979; 1989 1981) and has been assigned to the Newportian Molluscan Family OTARIIDAE Stage (Addicott, 1976; Armentrout, 1981), which has been Subfamily ENALDVRCTINAE correlated with the Saucesian Foraminiferal Stage (Addicott, Enaliarctos mealsi, E. mitchelli 1976; Armenurout et al., 1983, chart). Two other fossil Pinnarctidion bishopi Pteronarctos goedertae pinnipeds have been recovered from the Astoria Formation. Desmatophoca oregonensis was collected from the Astoria Formation, at an unspecified horizon (Barnes, 1987a) and Kamtschatarctinae. Bames reassigned Kamtschatarctos to the Pteronarctos goedertae was collected from a horizon just Imagotariinae, which he recognized as a subfamily of the above the base of the Astoria Formation where it contacts the Otariidae. Thus, Bames recognized the Enaliarctinae including underlying Nye Mudstone (Barnes, 1989). A chalicothere Enaliarctos*, Pinnarctidion, and Pteronarctos as a basal group collected from the Iron Mountain horizon within the Astoria of otariid pinnipeds involved in the ancestry of various otariid Formation together with other biostratigraphic (molluscan and lineages. foraminiferal) and radiometric evidence provided a correlation Aldiough Wyss (1987) proposed no formal classification of of the Astoria Formation with the Hemingfordian or early part pinnipeds, he regarded die "Enaliarctidae" as paraphyletic. of the Barstovian between 19 and 15 Ma (Barnes, 1987a; Enaliarctos was recognized as the sister group of all odier Munthe and Coombs, 1979) (Figure 2). pinnipeds. Pinnarctidion and Allodesmus were regarded as members of a group including odobenids and phocids. My Previous Work analysis agrees widi the latter arrangement, and I provide evidence for recognition of Enaliarctos as a metataxon and Table 1 summarizes previous arrangements of "enaliarctids" Pteronarctos as die sister taxon of a clade that includes otariids, discussed below. Mitchell and Tedford (1973) described a new odobenids, desmatophocids, and phocids. Additional skeletal genus and species of the pinnipedimorph, Enaliarctos mealsi, material referrable to Pteronarctos is presentiy under study from early Miocene rocks widiin the Pyramid. Hill Sandstone (Berta, in prep.). Member of the Jewett Sand at Pyramid Hill, Kern County, California. They erected the new subfamily of the Otariidae, PINNIPEDIMORPHA Enaliarctinae, to accommodate this taxon. As noted previously, Enaliarctos* was viewed as a transitional form, intermediate This taxon includes Enaliarctos*, Pteronarctos, Otariidae, between terrestrial carnivores, especially ursoids, and the Odobenidae, Allodesmus, Desmatophoca, Pinnarctidion, and aquatic Otariidae. Tedford (1976) elevated the Enaliarctinae to Phocidae. familial level and placed die group in the superfamily DEFINITION.—The most recent common ancestor of En­ Otarioidea. aliarctos and all of its descendants. Barnes (1979) described a second species of Enaliarctos*, E. DIAGNOSIS.—^Pinnipedimorphs are distinguished by die mitchelli, and proposed a new genus and species, Pinnarctidion following synapomorphies: posterior extension of the palatine bishopi; both were collected from Pyramid Hill, California, process of the maxilla; large infraorbital foramen; anterior from rocks at a stratigraphically higher level within the palatine foramina positioned anterior to the maxillary-palatine Pyramid Hill Sandstone Member than die deposits that suture; gready reduced or absent lacrimal that does not contact produced E. mealsi. A third new genus and species of die jugal; supraorbital processes absent or large and shelf-like; "enaliarctid" was recently described by Barnes (1989), Pter­ foramen rotundum merged with the anterior lacerate foramen; onarctos goedertae, from the late early Miocene Astoria large epitympanic recess; postglenoid foramen vestigial- Formation near Newport, Lincoln County, Oregon. In this same absent; jugular foramen gready enlarged; enlarged auditory paper, Barnes reviewed the status of anodier taxon, Kamt- ossicles; pseudosylvian sulcus strongly developed; M^'^ small schatarcios sinelnikovae, from die Miocene of die USSR relative to premolars; M, entoconid and hypoconid reduced- proposed by Dubrovo (1981, 1984) as a new genus and species absent; M3 absent; short, robust humerus with strongly of "enaliarctid" for which she established a new subfamily, die developed deltopectoral crest and enlarged tuberosities; loss of NUMBER 69 entepicondylar foramen on humerus; elongation of digit I in the small, Mj metaconid very reduced and close to protoconid. manus and digits I and V in the pes; short ilium; extemely short, Distinguished from all other species except E. mitchelli in anteroposteriorly flattened femur and medially inclined con­ having posterior portion of zygoma that joins palate anterior to dyles; large, broadly developed greater frochanter on the femur; M^. Distinguished from E. barnesi and E. mealsi in having conical patella. reduced cheek teeth cingula, P* with a short metacone. COMMENTS.—Berta et al. (1989) originally proposed die TYPE MATERIAL.—Holotype: USNM 250345 (Emlong name Pinnipedimorpha to include Enaliarctos and all odier field no. E-53), a nearly complete cranium and jaws. Probably pinnipeds and used postcranial synapomorphies (listed above) from the same individual, there is a left femur and right patella, to diagnose this monophyletic group. Barnes' (1989) arrange­ tibia, and fibula (Emlong field no. E-70). Collected by Douglas ment differs in his incorporation of Enaliarctos in a more Emlong, fall, 1961. exclusive group of pinnipeds (Otariidae sensu lato) in which ETYMOLOGY.—The species is named in honor of Douglas die Phocidae were not included. Of the 19 characters used by Emlong for a lifetime devoted to the collection of fossd marine Barnes to support the monophyly of the "Otariidae" most apply mammals from Oregon and his recognition of their value to to more inclusive groups. science. TYPE LOCALITY.—Cranium and jaws found in place in Enaliarctos* Mitchell and Tedford concretionary bank about 2 ft [60 cm] above beach level and 50 ft [15 m] south of highest part of concretionary bluff, and TYPE SPECIES.—Enaliarctos mealsi Mitchell and Tedford, postcranial elements found 5 ft [1.5 m] from skull, approxi­ 1973. mately 74 mi [400 m] south of Big Creek, Lincoln County, INCLUDED SPECIES.—Enaliarctos mealsi Mitchell and Ted­ Oregon. SEV4, SWV4, Sec. 32, T 10 S, R. 11 W, Yaquina ford, 1973, E. mitchelli Barnes, 1979, and three new species: E. Quadrangle, 15 minute series, USGS: 44°39'17"N, tedfordi, E. emlongi, and E. barnesi. 124°04'42"W. DEFINITION.—Enaliarctos* is a metataxon composed of the HORIZON.—^Just north of Astoria Formation-Nye Mudstone common ancestor of Enaliarctos* and all the species listed contact. According to Emlong's field notes this locality is in the above. Enaliarctos* possesses the diagnostic synapomorphies Astoria Formation; Repenning (pers. comm.) suggests it may in of the Pinnipedimorpha but lacks all of die synapomorphies of fact be from the Nye Mudstone. die next most exclusive clade, the Unnamed Taxon that REFERRED SPECIMENS.—USNM 314540 (E-76-38), crushed includes Pteronarctos and all other pinnipeds. snout and palatal portion of cranium with right P, Cs, left P^, REVISED DIAGNOSIS OF GENUS.—The following attributes and M^ collected by Douglas Emlong on 22 May 1976. retained by Enaliarctos are primitive relative to those of odier According to Emlong's field notes this specimen was collected pinnipeds: deep embrasure pit between P* and M^; P^-M^ with in place in bedrock (Nye Mudstone) at floor of beach, 75 ft [23 multiple roots; P^ with shelf-like protocone; Mj widi well- m] out from bank, ^3 mi [1.07 km] south of Big Creek, Lincoln developed cusps on the trigonid and a hypoconid present on die County, Oregon. NWV4, NWV4, Sec. 5, T 11 S, R. 11 W, talonid; six lumbar vertebrae; ulna lacking die posteriorly Yaquina Quadrangle, 15 minute series, USGS: 44°38'58"N, expanded olecranon process; radius lacking a strongly flattened 124°03'36"W. and expanded distal end; fifdi intermediate phalanx of die USNM 314290 (E-71-58), cmshed skull widi left P^, P^, and manus unreduced; femur with well-developed pit on the head M^ collected by Douglas Emlong on 30 November 1971. for the teres femoris ligament; metapodial shafts rounded in According to Emlong's field notes this specimen was collected cross section with keeled heads and strongly trochleated in a fine-grained sandstone layer that altemates widi coarser phalangeal articulations. grey sandstone containing large concretions between typical COMMENTS.—Because diere are no unequivocal synapomor­ Nye Mudstone and Yaquina Formation, approximately 74 mi phies that diagnose Enaliarctos* I have recognized this taxon [400 m] soudi of Beaver Creek, Lincoln County, Oregon. as a metataxon. Enaliarctos* was originally diagnosed by NW74, Sec. 19, T 12 S, R. 11 W, Yaquina Quadrangle, 15 characters that now appear to be apomorphic at a more general minute series, USGS: 44°31'00"N, 124°,04'42'^. level than was evident when Mitchell and Tedford's (1973) DESCRIPTION.—^The pattern of suture closure (see Sivertson, original description appeared. Supplemental descriptions by 1954) in the holotype indicates that it is an adult. The rostrum Bames (1979) do not provide any odier characters that can be is broad and low and the narial opening is ovoid (Figure 3; interpreted as synapomorphies. Tables 2-4 ). The nasals are relatively long and narrow. The fusion of sutures has obscured the frontal-nasal contact The Enaliarctos emlongi, new species nasolabialis fossa is well developed and positioned on the maxilla above the antorbital rim (Figure 3). The posteroventral RGURES 3-10 margin of this fossa forms a strong antorbital ridge whereas the DIAGNOSIS.—Distinguished from other species of En­ anterodorsal margin is produced into a thickened protuberance. aliarctos by having P^ with broadly developed posterolingual The narrow interorbital region is marked by small, rounded shelf, P2-^ with large crest-like metacone, F^_4 metaconid supraorbital ridges (Figure 3). The sagittal crest begins just SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 3.—Enaliarctos emlongi, new species, USNM 250345, holotype, skuU: A, dorsal view; B, ventral view; C, lateral view. (Scale = 2 cm.) NUMBER 69

TABLE 2.—Cranial measurements (mm) of Enaliarctos from coastal Oregon (e = estimated).

E. emlongi E. barnesi E. tedfordi E. mitchelli Measurements USNM 250345 USNM 314295 USNM 206273 USNM 175637 Cranium length (CBL) 228.00 172.06 Greatest width at anterior nares 32.30 37.18' 30.08 Width across antorbital processes 42.40 56.30 43.16 38.24 Width across greatest interorbital constriction 22.26 28.99 21.06 18.83 Width across supraorbital processes 28.97 40.13 28.16 22.86 Width of braincase al anterior edge of glenoid fossa 66.59 63.82 68.59= Postpalatal length (postpalatal notch to basion) 100.82 99.99 76.64= Width of rostrum across canines 55.43 58.39 39.63= Zygomatic width 126.00= 123.70 91.37= Auditory width 87.79 91.85 68.00= Mastoid width 103.14 105.84 Width of zygomatic root of maxilla 16.36 14.92 15.32 13.47 Basion to anterior edge of zygomatic root 152.61 142.90 117.49 Width of palate across anterior root of P" 56.36 49.75= 51.97 43.22 Width between infraorbital foramen 59.31 56.95= 58.95 44.81 Greatest width across occipital condyles 51.12 53.72 Greatest width of foramen magnum 21.08 25.67 24.63 Greatest height of foramen magnum 20.36 16.03 18.62 Transverse diamenter of infraorbital foramen 10.86« 9.83 9.70 10.23 Length of toothrow, C-M^ 78.18 69.27= 63.56=

TABLE 3.—^Measurements (mm) of the upper dentition of Enaliarctos from coastal Oregon (a - alveolus only; e - estimated).

E. emlongi E. barnesi E. tedfordi E. mitchelli USNM 250345 USNM 314295 USNM 206273 USNM 175637 length 5.42 width 2.69 length 5.82 5.01 width 3.33 3.09 length 7.57 6.90 width 5.40 5.00 length 10.65 10.74 7.50= width 7.65 10.74 7.50= length 8.35 8.52 6.25" width 5.74 6.18 3.88' 11.72 11.05 8.74 p2 1^"S^^ width 5.80 6.12 4.50 length 12.10 10.61 7.36" 8.90 width 7.13 7.06 5.25' 5.26 p4 length 12.15 11.94 11.51 9.90 width 9.87 9.01 8.64 7.08 length 6.86" 7.04 5.20" 7.31 M width 9.04" 8.62 7.90" 4.83 length 4.15 3.33" 3.39' ^ width 3.92 2.45' 2.00' SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

TABLE 4.—^Measurements (mm) of the mandible and lower dentition of bone nor a pit for the inferior oblique muscles. The large Enaliarctos from coastal Oregon. infraorbital canal is nearly circular in outiine. The spheno­ palatine foramen is relatively large and ovoid. The smaller E. emlongi E. barnesi posterior palatine foramen is positioned anterior and slightly USNM 250345 USNM 314295 ventral to it. Length of ramus 165.58 The palate is slightiy arched dorsally for its entire length Length of toothrow C-M2 80.09 70.55 (Figure 3). The incisive foramina have large, paired palatal Depth of ramus below P3 24.09 26.03 openings separated by a narrow crest of bone. The anterior length palatine foramina and dieir associated sulci originate medial to ^1 width P^ and terminate medial to P^. Several smaller posterior length foramina are on either side of the palate. Small, rounded ^ width palatine processes of the maxilla extend a short distance behind length 4.55 M^. The posterior border of the palate is U-shaped and a very ^3 width 5.07 small median tuberosity projects slightiy posteriorly. length 11.49 The palatine, alisphenoid, pterygoid strut between die palate width 7.33 and die braincase is inflated with a rounded, convex lateral length 8.44 margin (Figure 3). Most of the pterygoid hamulus is broken off. ^1 width 4.72 The basioccipital is rectangular and characterized by having a length 11.25 9.53 horizontal flange that abuts the entotympanic. Located posteri­ ^2 width 5.05 4.63 orly and separated by a thick median crest are a pair of very length 12.50 11.19 deep depressions for the rectus capitis muscles. Positioned at ^3 width 5.85 5.46 die anterior end of these depressions are a pair of small length 12.60 11.91 ^4 width 5.73 5.13 tuberosities. The presence of similar tuberosities in E. mealsi, Pinnarctidion bishopi, and Pteronarctos goedertae were noted length 12.53 12.12 H width 5.98 5.70 by Barnes (1979:26, 1989:9), who discovered that dorsal to length 3.60 these tuberosities are matrix filled cavities in the basioccipital. •^ width 2.95 Bames suggested that these cavities may be homologous with the embayment of the inferior pefrosal venous sinus for a loop of the intemal carotid artery seen in ursids and amphicyonids behind the supraorbital ridges and extends as a low ridge back (see Hunt, 1974a,b, 1977). A more detailed evaluation of this to the lambdoidal crest. The posterior surfaces of the braincase character and its distribution is currently in progress (Berta, in are elevated above the anterior surface and the parietals are prep.). A pair of ellipsoidal hypoglossal foramina are posi­ raised into a prominent lambdoidal crest. A pair of deep tioned along the posterolateral margin of die basioccipital. pseudosylvian sulci are obliquely positioned on die lateral The tympanic bullae are large, flask-shaped, and medially surface of the braincase above the'squamosal (Figure 3). The inflated (Figure 3). A steep crest of the bulla forms a groove exoccipital portion of the occipital shield is broad and low. A that joins the bulla to die postglenoid process. Posterolaterally, short median supraoccipital crest separates the dorsal portion of the bulla is fused to the mastoid and paroccipital processes. The the shield. Beneath die lambdoidal crest the shield is concave mastoid process is considerably larger than the paroccipital becoming convex above the nearly circular foramen magnum. process and connected to it by a very low, broad ridge (Figures The zygomatic arch is less bowed laterally and less curved 3, 4). The paroccipital process is short, blunt, and directed dorsally dian in E. mealsi (Mitchell and Tedford, 1973, fig. 6). posterovenfrally. Several small foramina pierce the surface of The vend-al portion of die arch is slightly curved anterodorsally diat portion of the bulla diat forms die tubular external auditory where it rises from the side of the skull. The posterior border of meatus. A flange of the bulla appears to have separated die die zygomatic arch joins die palate between M^ and M^. The median lacerate foramen from the eustachian tube aldiough maxillary-jugal suture is fully closed and cannot be traced. The much of die flange is broken away. The posterior opening of narrow tip of the zygomatic process of the squamosal contacts die carotid canal is confluent widi the enlarged jugular die base of die postorbital process of die jugal in a splint-like foramen. The fossa for the tympanohyal is located medial and arrangement. Large postglenoid processes are present. A small slighdy posterior to the large, deep, circular stylomastoid postglenoid foramen is positioned at die lateral termination of foramen. A very thin flange of bone separates diem. a transverse groove across the postglenoid process. The venfral wall of die bulla on die right side of the holotype The entire orbital region is mediolaterally compressed. The was removed to expose the middle ear cavity (Figure 4). The orbital wall is solid with no vacuities. Sutures in this region are venfrolateral wall of the carotid canal creates a shelf in the not preserved. There is no indication of a lacrimal foramen or medial wall of the bulla. The tympanic crest is considerably NUMBER 69

FIGURE 4.—Enaliarctos emlongi, new species, USXM 250345, holotype, ventral view of right side of basicranium with ventral wall of bulla removed. (Abbreviations: ac = posterior opening of ahsphenoid canal; cc = ventral wall of carotid canal; er = epitympanic recess; et = groove for eustachian tube; fo = foramen ovale; hf = hypoglossal foramen; mc = septum of musculotubarius canal; p = promontorium; pc = posterior op)enmg of carotid canal; pf = postglenoid foramen; pif = posterior lacerate foramen; rw = round window; sf = stylomastoid foramen; tc = tympanic crest; if = tympanohyal fossa; llf = tensor tympani fossa. Scale is approximately 5 mm.) 10 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY larger than in E. mealsi and it projects farther into the tympanic cavity. In addition, the tympanic cavity differs from that of E. mealsi in its farther posterior extension. The pear-shaped promontory is broader mediolaterally than in E. mealsi. The round window is posteriorly oriented and the smaller oval window faces laterally. Lateral to die promontory is a deep, elliptical fossa for the tensor tympani. Posterolateral to the fossa for the tensor tympani is the deep, nearly circular epitympanic recess. A shallow groove marks the anterior margin of this fossa and leads to the groove for the eustachian tube; its lateral margin defined by the septum of die musculotubarius canal. Several smaller grooves are developed on the anterior face of the promontory. The lateral groove, the largest, probably housed the intemal carotid artery. A small opening, presumably the promontory foramen is visible in die posteromedial wall of die bulla. The malleus and incus were recovered from die holotype in excellent condition (Figure 5). The muscular process is absent from the malleus. The anterior portion of the mallear head is relatively large and it bears a deep concavity. Although incomplete, it is apparent that a thin anterior lamina extends from the anterior process to the base of die neck. The manubrium is thin and relatively short. The incus is large and slightiy inflated with a short, broad stapedial process and a long, thin posterior cms. RGURE 5.—Enaliarctos emlongi, new species, USNM 250345, holotype, malleus and incus. (Scale = 1 mm.) I^"3 are arranged in a broad transverse arc. I^"^ are distinguished by having a fransverse groove that extends across The canine is relatively large and slighdy recurved. On die die crown creating die effect of a double cusp (Figure 6). I^ is posterior side of the crown is a vertical crest diat extends larger with a nearly cfrcular crown. Deep vertical wear facets medially from the vertical crest to its termination midway are developed on the lateral margins of the crown. around the lingual face of the tooth.

biT^^^^^^^^J

r I M^'^^l w '^^'^ '^^^^H '<• ^/

w'-- i' wBmaim^^^^^

FIGURE 6.—Stereophotographs of palate and upper dentition of Enaliarctos emlongi, new species, USNM 250345, holotype: A, right I'-^, C, pi"''; B, left T'^. C, P^"^. (Scale = 1 cm.) NUMBER 69 11

P^"^ are elongate and posteromedially broad with well- TABLE 5.—^Measurements (cm) of postcranial elements of Enaliarctos developed lingual cingula (Figure 6). P^ positioned directiy emlongi, USNM 250345 (e = estimated). behind the canine, is single rooted with a centrally positioned paracone. The tooth terminates in an upturned cingular heel. Femur P^"^ are similar in size. P^ shows an increase in width length 13.20 proximal width 6.23 posterolingually and a more sfrongly developed crest-like proximal depth 2.26 metacone. P^"^ differ from E. mealsi in having a well-defined distal width 6.09 metacone separated from the paracone by a deep notch. The distal depth 2.49 anterior premolars exhibit relatively litde wear. Tibia length 23.90 P^ is three-rooted with a large conical paracone separated by proximal width 3.90= a well-defined notch from the relatively large metacone (Figure proximal depth 3.81 6). The protocone shelf is more broadly developed than in E. distal width 3.34 distal depth 3.18 mealsi (Mitchell and Tedford, 1973, fig. 15). A large wear facet Fibula extends from the posterior protocone shelf along the occlusal length 20.80 face of the posterior paracone and metacone blades. No proximal width 3.22 parastyle is developed. A lingual cingulum is present, differing proximal depth 1.62 from the condition in E. mealsi in which the tooth is encircled distal width 2.34 distal depth 2.54 by sfrongly developed labial and lingual cingula. A relatively Patella deep embrasure pit is present on the palate between F* and M^ length 3.65 M^, preserved on the right side is single rooted. A small pit in width 3.08 die palate in the position of die anterior root for M^ was judged depth 1.77 pathologic given the presence of similar pits between P^ and P^. The tooth has a circular crown with low, flattened cusps. This developed. The lower premolars differ from those of E. mealsi toodi resembles an isolated M^ referred to E. mealsi by Mitchell in having reduced cingula and a decrease in size of die and Tedford (1973:242). An anteriorly oriented paracone is paraconid and metaconid. separated by a cleft from the medially directed metacone. The Although heavily worn Mj consisted of the same three cusps talon is a broad protocone shelf. and differs from E. mealsi (Barnes, 1979, fig. 2) in having the Associated with the holotype are well-preserved, nearly metaconid not as well separated from the protoconid. The complete mandibular rami (Figures 7, 8). The rami are unicuspid talonid consists of a single, centrally positioned relatively long and slender with teeth well spaced in die hypoconid. The talonid is relatively shorter dian in E. mealsi. toodirow in comparsion to the short crowded toothrow in E. MJ, represented only by an alveolus, indicates diat this toodi barnesi. The symphysis is shallow with a gendy rounded had a single, bdobed root. ventral border. Although not well preserved in the holotype it In addition to E. mealsi, the only other species of this genus is clear that two mental foramina were developed, a larger one represented by postcranial material is E. emlongi. Elements below P2 and a smaller one below the anterior and posterior from the left and right hind leg (left femur, right tibia, fibula, roots of P3. The coronoid process is broad at die base with a and patella) were apparently recovered from the same low, rounded apex. The pterygoid process is short and shallow individual as the holotype, based on locality and horizon and slopes ventromedially. provenance (Table 5). In most respects these elements compare I3 is preserved on the right side (Figure 9). It is small and very favorably widi USNM 374272, a nearly complete skeleton closely appressed to the canine with a triangular crown. The of £. mealsi that has been recentiy described (Berta et al., 1989; canine is relatively small with a recurved crown. A flat wear Berta and Ray, 1990). facet at the apex extends as a narrow, vertical sfrip to die base The femur is missing the anterior surface of the head, shaft, of the posterior part of the labial side of the crown. A large wear and distal end. It shows typical features seen in E. mealsi such facet is also developed on the labial side of the crown extending as well developed foramen on the head for the ligamentum from the apex to die base of die crown. teres, a prominent lesser trochanter, and a strongly produced Pj is single rooted and positioned directly behind die canine. trochanteric fossa (Figure 10). Much of the lateral condyle of The principal cusp is wom nearly to the level of the crown. A die tibia is missing and diere is no evidence of proximal fusion lingual cingulum is present that curves dorsally at the anterior of the tibia and fibula (Figure 10). The morphology of the distal and posterior ends of the tooth. P2_4 are double rooted and P3_4 articular surface of the tibia is better preserved dian in E. are nearly the same size. Each tooth has a crown widi diree mealsi. It is characterized by development of a deep, cusps, arranged anteroposteriorly, a small paraconid, a large rectangular socket for articulation with the astragalas; in this protoconid, and a small metaconid positioned high on die toodi respect it is more similar to ursids than other pinnipeds. Ursids (Figure 9). The metaconid is smaller dian the paraconid and differ, however, in having die lateral margin of the distal positioned close to die protoconid. Lingual cingula are well articular surface elongated whereas that of E. emlongi slopes 12 SMITHSONL\N CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 7.—Enaliarctos emlongi, new species, USNM 250345, holotype, right lower jaw: A, lateral view; B, medial view. (Scale = 2 cm.)

FIGURE 8.—Enaliarctos emlongi, new species, USNM 250345, holotype, left lower jaw: A, medial view; B, lateral view. (Scale = 2 cm.) NUMBER 69 13

FIGURE 9.—Stereophotographs of lower dentition of Enaliarctos emlongi, new species, USNM 250345, holotype: A, right I3, C, P^^, M^; B, left C, P,^, M,. (Scale = 1 cm.)

off abruptly. The fibula displays a well-defined processus TYPE MATERIAL.—//o/orype: USNM 314295 (Emlong lateralis fibulae at its distal end. The patella preserves an Field no. E-71-63), anterior half of cranium and associated ossified portion of the patellar ligament on its anterior surface. mandibular rami; collected by Douglas Emlong on 13 The referred snout and palate of £. emlongi (USNM 314540) December 1971. is the same size as the skull of die holotype. P^ is ETYMOLOGY.—^The species is named in honor of Lawrence posterolingually broad with a large protoconid and well- G. Bames for his longstanding interest, collection, and study of developed metacone on the heel. A large parastyle is present on fossd pinnipeds. MK TYPE LOCALITY.—Approximately 74 mi [400 m] south of The referred crushed skull (USNM 314290) is considerably Beaver Creek, Lincoln County, Oregon. NE comer Sec. 24, T. smaller than either die holotype (USNM 250345) or die 12 S, R. 12 W, Yaquina Quadrangle, 15 minute series, USGS: referred snout (USNM 314540) and undoubtedly represents an 44°31'06"N, 124°04'40"W. immature individual. The dentition is very similar to die HORIZON.—In place in sandstone near the contact between holotype. die Nye Mudstone and the Yaquina Formation. DESCRIPTION.—^The cranium is broken obliquely dirough Enaliarctos barnesi, new species die anterior portion of die brain case and cmshed and deformed dorsoventrally (Figure 11). All sutures except those bordering FIGURES 11-15 die nasals are fused, indicating that this animal was an adult. DIAGNOSIS.—Distinguished from all other species of En­ Measurements are listed in Tables 2-4. aliarctos in having spur-like palatine processes on maxilla, and The snout is similar in most respects to E. emlongi. The short lower cheek tooth row. Distinguished from all species narial opening although distorted appears to have been low and except E. emlongi in having a posterolingual shelf on P^. ovoid. The nasals differ, however, in being short and broad, Distinguished from E. tedfordi, E. emlongi, and E. mitchelli in especially anteriorly (Figure 11). The nasal-frontal contact primitively retaining well-developed cheek teeth cingula, and presents a fruncate margin. Nasolabialis fossae are deep and having F* with a long metacone. their anterior margins form a very pronounced ridge on the 14 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 10.—Enaliarctos emlongi, new species, USNM 250345, holotype, associated postcranial elements: A, B, left femur, anterior and posterior views; C, right tibia and fibula, anterior view. (Scale = 2 cm.) dorsal face of die maxillary in addition to creating the more Both I^ and left I^ are preserved and positioned around a typical antorbital fossa posteriorly. narrower arc than in E. emlongi (Figure 12). I^ is distinguished The interorbital region is narrow widi small, inflated in having a fransverse groove mnning across the crown. Incisive foramina are large and broad. The palate is cmshed supraorbital processes anteriorly positioned (Figure 11). The aldiough it appears as though a single pair of anterior palatine sagittal crest begins posterior to the supraorbital ridges and foramina were present extending from P"^ to P^. The palatine extends posteriorly as a diin elevated ridge. The orbital region process of the maxilla projects as a spur of bone a short distance is solid and there is no indication of a lacrimal foramen. The behind M^ (Figure 11). infraorbital canal is narrowly ovoid and broader dian it is high. The teeth are well-preserved and show relatively littie wear. Although distorted, it appears as diough the zygomatic arch Coarsely crenulate enamel especially on die labial portions of joins die palate between P^ and M^. The postorbital process of die tooth crowns is evident as are well-developed labial and die jugal is dorsally curved; in this respect it is similar to E. lingual cingula completely encircling the teeth (Figure 12). mealsi (Mitchell and Tedford, 1973, fig. 6). The lingual cingulum and vertical crest are prominent NUMBER 69 15

FIGURE U.—Enaliarctos barnesi, new species, USNM 314295, holotype, anterior skull: A, dorsal view; B, ventral view; C, lateral view. (Scale = 2 cm.) 16 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 12.—Stereophotographs of palate and upp)er dentition of Enaliarctos barnesi, new species, USNM 314295, holotype: A, right P. C, P'-^, pi, M'; B, left l\ P, C. P'^, M\ (Scale = 1 cm.) features of the canines. Along the anteromedial side of die incisors, and Mj whereas the right side is missing the ramus canine is a large, rectangular vertical wear facet that extends anterior to Pj. The ramus differs from E. emlongi in being more from the base of the crown to the flattened apex. robust, especially along the ventral border and in having a The premolars differ from those of E. emlongi in being relatively short toodirow. Two mental foramina are preserved relatively shorter and broader posterolingually (Figure 12, just below the midpoint of the horizontal ramus. The larger one Table 3). P^ and P^ are simpler in construction'than diose ofE. is positioned below die posterior root of Pj and the smaller one emlongi and consist of a single cusp, die paracone. In this is below the anterior and posterior roots of P3. feature E. barnesi differs from E. mealsi, which possesses a The alveoli for Ij.s indicate that these teeth were positioned very small metacone, and E. emlongi, in which diis cusp forms very close to the canine. The canine is similar to that of E. a large, weU-developed crest. P^ differs from diat ofE. emlongi emlongi but differs in being proportionally broader at the base, in having a relatively longer metacone, in this feature E. especially across die posterior part of the tooth. barnesi resembles E. mealsi. A deep embrasure pit is present The Pj is missing and the alveolus is resorbed. P2-4 differ betwen F* and M^ (Figure 12). The first upper molar is from that of E. emlongi in having more sfrongly developed considerably smaller than P^. It is double rooted with a single cingula and larger paraconids and metaconids (Figure 15); in large anterior root and fused posterior roots. In most respects it diese features resembling E. mealsi. compares well with that of E. mealsi widi a parastyle, large The MJ is distinguished in having a large frenchant paracone, small metacone, and protocone; the latter cusp paraconid and protoconid and a smaller metaconid medially largely obscured by wear. This toodi differs from its positioned just behind the protoconid. The talonid is longer counterpart in die holotype of E. mealsi in having a reduced dian in E. emlongi and it consists of a single central cusp, die protocone shelf and in having the entire talon shifted further hypoconid. The Mj alveolus indicates that this tooth had a posteriorly. The M^ is, however, similar in morphology to an single bdobed root. isolated specimen referred to E. mealsi by Bames (1979, fig. 2). The M^ alveolus is preserved on die right side and it indicates Enaliarctos tedfordi, new species diat diis tooth was single rooted and elongate. Left and right mandibular rami are associated widi USNM FIGURES 16.17 314295 (Figures 13, 14). The left side lacks die condyle, die DIAGNOSIS.—Distinguished from odier species of En- NUMBER 69 17

FIGURE 13.—Enaliarctos barnesi, new species, USNM 314295, holotype, right lower jaw: A, lateral view; B, medial view. (Scale = 2 cm.) aliarctos by having smaller, less well-developed metacone Oregon. Near NW corner Sec. 19, T 12 S, R. 11 W, Yaquina crests on P^"^. Distinguished from E. mitchelli in primitively Quadrangle, 15 minute series, USGS: 44°3r09"N, retaining dorsally arched ventral portion of zygoma and having 124°04'40"W. posterior portion of palate joining palate between die roots of HORIZON.—According to Emlong's field notes this speci­ M^ Distinguished from E. mealsi and E. barnesi in having men was found "from drift concretion in the Yaquina reduced cheek teeth cingula, P* with a short metacone. Formation." TYPE MATERIAL.—//o/orype: USNM 206273 (Emlong DESCRIPTION.—^The cranium lacks most of die rostrum field no. E-225), cranium lacking rosfrum and left jaw (Figure 16). The animal was an adult as evidenced by die fragment; collected by Douglas Emlong, spring, 1964. degree of suture closure. Tables 2-4 list skull and toodi ETYMOLOGY.—The species is named in honor of Richard H. measurements. Tedford who together widi Edward D. Mitchell initially The interorbital region is very narrow and small supraorbital described specimens referred to this genus and recognized die ridges are on the anterolateral margins (Figure 16). The sagittal significance of these fossils to pinniped evolution. and lambdoidal crests are well developed. The supraoccipital TYPE LOCALTTY.—Nordi of Seal Rock about 300 yds [275 shield is broad and low. The foramen magnum is wider than it m] soudi of the mouth of Beaver Creek, Lincoln County, is high, differing from die nearly circular condition in E. 18 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 14.^—Enaliarctos barnesi, new species, USNM 314295, holotype, left lower jaw: A, lateral view; B, medial view. (Scale = 2 cm.) emlongi. The condyloid foramen is deeply recessed within die The basioccipital is marked posteriorly by a pair of deep foramen magnum. depressions, separated by a median crest, for die rectus capitis No orbital vacuities are developed and there is no frace of a muscles. The presence of basioccipital tuberosities cannot be lacrimal foramen. A well-defined circular pit is present lateral ascertained owing to incomplete preservation. Hypoglossal to the infraorbital foramen for the inferior oblique muscles. The foramina are positioned at the posteromedial margin of die infraorbital foramen is ovoid and broader than it is high. The basioccipital. zygomatic arch is simdar to that of E. mealsi (Mitchell and The mastoid process is enlarged and knob-like (Figure 16). Tedford, 1973, fig. 6) but differs in being less bowed laterally The smaller paroccipital process is joined to it by a very low, and less arched dorsally. The posterior border of the arch joins broad ridge. The paroccipital process differs from E. emlongi in the palate at the posterior root of M^. The squamosal and jugal being relatively larger and projecting further posteriorly. The contact one another in a splint-like arrangement. fragmentary posterior carotid canal is adjacent to die enlarged The anterior palatine fossa and dieir associated sulci are jugular foramen. prominent on either side of die palate and extend from P^ Tympanic bullae are poorly preserved; the right bulla is anteriorly. The palatine processes of die maxilla are developed entirely missing and die left bulla, afready partially broken, was as short, rounded processes of bone that extend a short distance removed. The tympanic crest is simdar to E. mealsi but differs behind M^. from E. emlongi in its smaller size and shelf-like proportion NUMBER 69 19

FIGURE 15.—Stereophotographs of lower dentition of Enaliarctos barnesi, new species, USNM 314295, holotype: A, right P^^, M,: B, left C, ?2_4, Mj. (Scale = 1 cm.)

with only a slight projection into the tympanic cavity. Much of a notch from a crest-like metacone (Figure 17). Wear facets are die posteromedial waU of the bulla is broken away. Beneath the along the shearing surfaces of the paracone and metacone. The remaining ledge of die bulla is the wall of the carotid canal. protocone is a broadly developed shelf centrally positioned. The abraded surface of the tympanic cavity obscures much Wear has created an ovoid pit in the middle of die shelf. of the detail of this region. The promontorium is similar in size As judged from the alveolus, M^ is double rooted with a and morphology to E. emlongi. The round window is small anterior root and a large posterior root. The alveolus for distinguishable as a posterolateral opening at the base of die M^ is only preserved on die left side; although most of die promontorium. The fossa for the tensor tympani is a shallow, labial portion is broken away it appears to have been relatively elUptical pit situated anterolateral and ventral to die promonto­ smaU. rium. The epitympanic recess is largely filled with hard mafrix. Associated with the cranium was a fragment of the left jaw The malleus and incus were recovered in poor condition. The consisting of a portion of the ascending ramus including the malleus is small. The head is uninflated and lacks a deep coronoid process and condyle. The specimen is similar to E. concavity. Neither an anterior lamina nor anterior process were emlongi and E. barnesi in having a relatively broad coronoid developed. The manubrium is relatively short and broad. The process. incus is also smaU and uninflated. The holotype bears the posterior portion of the right and left Enaliarctos mitchelli Barnes P^ right P^, and left P*, and the alveoli of right F*, left and right FIGURES 18-20 M^ and left M^ (Figure 17). P^"^ consist of a large central paracone followed by a short crest-like metacone. The EMENTDED DIAGNOSIS OF SPECIES.—Distinguished from all metacone is larger in P^. Lingual cingula are well developed. A other species of Enaliarctos by having a high narrow rosfrum, principal difference between the anterior premolars of E. ventral portion of zygoma flat with fossa, zygomatic arches emlongi and E. tedfordi is die degree of development of die lower on skull, high circular anterior narial opening, and M^ metacone. E. tedfordi is distinguished by having a large with reduced protocone. Distinguished from all other species metacone. except E. emlongi in having posterior portion of zygoma P^ is diree-rooted with a large conical paracone separated by joining palate behind M^. Distinguished from E. barnesi and E. 20 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 16.—Enaliarctos tedfordi, new species, USNM 206273, holotype, skull: A, dorsal view; B, ventral view; C, lateral view. (Scale = 2 cm.) NUMBER 69 21

FIGURE 17.—Stereophotographs of palate and upper dentition of Enaliarctos tedfordi, new species, USNM 206273, holotype: A, left P^. P"; B, rightP^' l (Scale = 1 cm.)

mealsi in having reduced cheek teeth cingula, P^ widi a short on the right side have been sheared off along thefr labial metacone. margins. P^""^ and M^ are well preserved on the left side and the TYPE MATEmAL.—Holotype: UCMP 100391, anterior alveoli of right M^ and right and left M^ are present. This half of cranium. specimen was an adult; aU of die sutures except those bordering Paratype: UCMP 80943, partial palate, bearing parts of the nasals are fused. both canines. The referred cranium of E. mitchelli is comparable in size to TYPE LOCALITIES AND HORIZONS.—As described by Barnes the holotype (Tables 2-3). The rostrum is deeper dorsoven­ (1979:12) the holotype was collected in loose rock but trally. In anterior view, the narial opening is more nearly ovoid probably from the "upper fossdiferous, concretion-bearing and not circular as in the holotype (Bames, 1979, fig. 3). The bed" on the south face of Pyramid Hill; collected by Daryl P. nasals are relatively short. The nasolabialis fossa is pronounced Domning, 6 May 1972. The paratype is presumably from the and vertically oriented as in the holotype. A strong antorbital same locality as the holotype; collected by J. Howard ridge is developed along the posterior rim of die fossa, which is Hutchison, 18 May 1968. continuous with a ridge that defines die anterior margin of die REFERRED SPECIMEN.—USNM 175637, nearly complete fossa (Figure 18). cranium missing anteriormost portion of rosfrum, squamosals, The interorbital region is narrow. Supraorbital ridges are and right wall of the braincase; collected in two parts by weakly developed. Bodi the sagittal and lambdoidal crests are Douglas Emlong. According to Emlong's field notes the heavily abraded. The braincase has squared anterolateral braincase (E-74-8) was coUected in 1970 in float from the Nye margins with well-marked oblique depressions on either side Mudstone, about 73 mi [530 m] south of the mouth of Thiel for the sylvian sulcus. The surface of the braincase is irregular Creek, Lincoln County, Oregon. NE comer Sec. 24, T 12 S, R. and pitted by numerous small foramina. The occipital condyles 12 W, Yaquina Quadrangle, 15 minute series, USGS: are missing. A pair of deep fossae are positioned at the 44°33'28"N, 124°04'18"W. Emlong collected the anterior half dorsolateral margins of the foramen magnum. The occipital of the skull (E-597) in 1974 from near the same locality and shield is broad and low. It is slightiy concave dorsally and it recognized that it probably belonged to the braincase he had becomes convex above the foramen magnum. Within the previously collected. foramen magnum is the condyloid foramen with a thin medial DESCRIPTION.—The specimen referred to E. mitchelli, wall. USNM 175637, is a well-preserved cranium lacking squamosal The zygomatic arch is more dorsally curved than in the portions of die zygomata (Figure 18). Much of the wall of die holotype (Barnes, 1979, fig. 3) and the postorbital process of braincase on the right side is missing and the specimen has die jugal at its juncture widi the skull is elevated higher above been prepared on diat side exposing the floor of the braincase the toothrow (Figure 18). The ventral surface of the arch is (Figure 19). The anteriormost portion of die snout is missing nearly horizontal at its juncture widi die skull and produced but the portion posterior to die incisive foramina, die canine into a shallow fossa. The posterior border of die zygomatic arch roots, and a small portion of die left canine are preserved. Bodi joins the palate between M' and M^. die right and left P^ are represented by alveoli. The cheek teeth The fusion of sutures in the orbital region makes it 22 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

FIGURE 18.—Enaliarctos mitchelli, USNM 175637, referred specimen, skull: A, dorsal view; B, ventral view; C, lateral view. (Scale = 2 cm.) NUMBER 69 23

FIGURE 19.—Enaliarctos mitchelli, USNM 175637, referred specimen, dorsal view of floor of braincase. Cross hatched area is filled with matrix. Abbreviations: eb = embayment ia basioccipital; iam = intemal auditory meatus; pa = petrosal apex; plf = posterior lacerate foramen; sf = subarcuate fossa. (Scale is approximately 5 mm.)

impossible to determine if a lacrimal bone was present. A small central pair with associated shallow furrows is located smaU, circular lacrimal foramen is discernible. The orbital posterolateral to the anterior pair, and posteromedial to the region is solid with no vacuities. The enlarged infraorbital central pair are several randomly disfributed very small foramen is roughly triangular and higher than it is wide. A pit foramina. The palatine process of the maxilla is a rounded for the inferior oblique muscle is positioned medial to the projection that terminates a short distance behind the M^ anterior rim of the infraorbital foramen. The large spheno­ alveolus. The palate has a U-shaped smooth margin. palatine foramen is situated dorsal to the termination of die The palatine and alisphenoid are inflated sfruts between the palatine process of the maxilla. Anteroventral to it is a small palate and the braincase. The delicate pterygoid hamulus is posterior palatine foramen. The circular ethmoidal foramina preserved on the left side of USNM 175637. lies 11 mm from the optic foramina. The large optic foramina The basicranial region is similar to that of other species of is located below the interorbital septum and dorsal to the the genus. A deep trough formed largely of the basisphenoid is braincase. The anterior lacerate foramina emerge from the separated by a V-shaped ridge from the basioccipital, which is braincase lateral and posterior to the optic foramina, separated marked by a pair of depressions for die rectus capitis muscles. from the alisphenoid by a bony vertical septum. Lateral to these depressions are a pair of large tuberosities that The incisive foramina are similar in shape and orientation to are further discussed below. die holotype. A groove runs down the middle of die palate Tympanic bullae are flask-shaped and medially inflated surrounded on eidier side by a pair of anterior palatine foramina (Figure 18). Anterolaterally the bulla is fused to the postglenoid with associated sulci originating medial to F* and terminating process. The paroccipital and mastoid processes are broken medial to P^. USNM 175637 differs from die holotype and away near die base of the skull. A short flange of bone separates paratype ofE. mitchelli (Bames, 1979, fig. 3) in having several die opening for die eustachian tube from the median lacerate smaller posterior foramina in addition to the anterior pair. A foramen. The posterior carotid foramen lies slightiy anterior to 24 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

^^p m^^-y^^ M^^'^\ ' BJ|L; : h 4^ 'l^' ' • ' p#1 ^ ''•'•-'hmi fi^Jl^^K^ lr<2i^8 fSSIm^St^M r^^BK^M ^KSI^^" <

\r.^mr •'-:• -.v

FIGURE 20.—Stereophotographs of palate and upper dentition of Enaliarctos mitchelli, USNM 175637, referred specimen: A, right P^; B, left P^-M'. (Scale = 1 cm.) die large opening for the posterior lacerate foramen and P* is large relative to M^ three-rooted, and encircled by a separated from it by a bony bridge. As preserved on die right well-defined cingulum that is especially prominent linguaUy. side, the circidar stylomastoid foramen lies in a deep pit. The The paracone is much larger than the metacone and separated pit for the tensor tympani lies posterior to the stylomastoid from it by a sharp notch (Figure 20). The protocone is shelf-like foramen, separated from it by a narrow crest of bone. and cenfrally positioned. A large wear facet extends from the Preparation of the dorsal surface of the braincase provides posterior protocone shelf across the posterior surface of die evidence of an excavation in the lateral edge of the basioccipital paracone and metacone. As in the holotype, the three roots of P^ (Figure 19). On the venfral surface of the skull these are positioned closer together than in E. mealsi (Barnes, 1979, excavations appear as large tuberosities that are deflected fig. 5). A deep embrasure pit in die palate is developed between medially at their posterior termination. As noted previously, P4 and Ml. these tuberosities may indicate die presence of die basioccipital Ml is double rooted. The crown is elongate with a long, low embayment and presumed loop of die intemal carotid artery. paracone separated from the labial tooth margin by die Anterior to the cochlea the pefrosal apex is sharply pointed. The parastyle. A wear facet is present on the anteromedial margin of subarcuate fossa is deep and circular. The intemal acoustic the parastyle. The paracone is separated from the small, conical meatus is a relatively large, flattened single opening. metacone by a shallow notch. The protocone is developed as a low posterolingual shelf. The cheek teeth of E. mitchelli are represented in USNM M^, as judged from the alveolus, was single rooted and 175637, which preserves P^""* and M^ (Figure 20). Previously differs from the holotype in being relatively larger. no cheek teeth were known for this species. Only a small COMMENTS.—Of die characters used by Barnes (1979) to fragment of die left canine is preserved. The alveolus for P' is distinguish E. mitchelli from E. mealsi in his original positioned direcdy behind the canine and indicates this toodi description, most are diagnostic: narrow, high rosfrum; high, had a relatively large single root. anterior narial opening that is nearly circular in anterior view; p2"^ are double rooted, high crowned, and posteromedially zygomatic arches relatively lower on skull and not gready broad. Well-developed lingual cingula are present extending arched at midpoint; and ventral surface of zygomatic arch onto die labial side of die toodi at the anterior and posterior ventral to the infraorbital foramen more nearly horizontal and toodi margins. The anterior premolars consist of a single large not as steeply inclined anteriorly. The narrow interorbital paracone followed by a very small metacone, faintly indicated region and the single paired posterior palatine foramina on die posterior slope of the paracone. The degree of (probably homologous with the anterior palatine foramina = development of die metacone resembles that in E. mealsi anterior opening of the palatine canal) of E. mitchelli cited by (Bames, 1979, fig. 2a). Wear is apparent along the pos­ Barnes as diagnostic features were here determined not useful teromedial margin of P^. to distinguish Enaliarctos species. NUMBER 69 25

Interspecific Affinities of Enaliarctos* contrast, the cingula are reduced in E. tedfordi, E. emlongi, and E. mitchelli. Currendy five species of the genus Enaliarctos* are 6. P'^ metacone short. Aldiough de Beamont (1965) de­ recognized: E. mealsi, E. mitchelli, E. barnesi. E. tedfordi, and scribes the metacone blade in Cephalogale minor as short, it is E. emlongi. Assignment of these species to Enaliarctos was in fact relatively long (pers. observ.) and comparable in length based on a phylogenetic analysis of 16 cranial and dental to that oiE. mealsi (Mitchell and Tedford, 1973, fig. 15) and E. characters (Table 6). Two equally parsimonious d^ees were found by the branch and bound option of PAUP (Phylogenetic barnesi. In contrast, E. tedfordi, E. emlongi, and E. mitchelli are Analysis Using Parsimony) version 3.0 (Swofford, 1989) with all characterized by having a short metacone on the upper a branch lengdi of 20 and a consistency index (C.I.) of .900. camassial. The sfrict consenus free is shown in Figure 21. For all Four additional characters were identified by PAUP as characters it was possible to use the most proximate outgroup, potential synapomorphies at this level, but with equally the Ursidae. Primitive ursids examined included Cephalogale, parsimonious explanations also available. Because three of Amphicynodon, Pachycynodon, and Allocyon. Cephalogale has diese (SYNAPOMORPHIES 7, 8, 10) were scored as missing data been previously aUocated to the Hemicyoninae (Mitchell and (?) among two of the three species, I freatthe m as apomorphies Tedford, 1973) and Amphicynodon and Pachycynodon have at die minimum levels at which observation confirms their been included within the paraphyletic Amphicynodontinae disfribution (see Figure 21). Another character, P3_4 with large (Flynn et al., 1988). Recognition of Allocyon as an ursid paraconids well separated from protoconid (SYNAPOMORPHY follows the suggestion of Tedford (pers. comm.). 16) is equivocally assigned to this clade as a reversal. Enaliarctos mealsi* is here identified as a metaspecies based Within this group, a sister group relationship between £. on its lack of diagnostic atfributes. A number of features were emlongi and E. mitchelli is supported by one synapomorphy. listed by Barnes (1979) in his revised diagnosis of die species. 3. Posterior portion of zygoma joins palate posterior to M^. Of these, most are symplesiomorphies. The remaining species This is another feature originally used by Bames (1979) to of Enaliarctos* comprise two intemested monophyletic groups distinguish E. mitchelli from E. mealsi. As determined by this (Figure 21). The first group is comprised of the recent common study, the primitive condition in which die zygoma joins the ancestor of E. barnesi and the Unnamed Taxon that includes E. palate between die roots of M^ is seen in E. mealsi and E. tedfordi, E. emlongi, and E. mitchelli. A single synapomorphy tedfordi as well as primitive ursids. unites this group: short nasal bones (SYNAPOMORPHY 12). Characters that distinguish E. mitchelli from E. emlongi Insofar as long nasal bones are present in die outgroup, I regard include die following. diis condition as ancesfral in Enaliarctos, with its subsequent 2. Ventral portion of zygoma flat with fossa. This feature reversal in E. emlongi. Enaliarctos barnesi is diagnosed on die was originally used by Bames (1979) to distinguish E. mitchelli basis of two unequivocal characters and one equivocal from E. mealsi. As observed by Bames in E. mealsi, the ventral character briefly discussed here. surface of die zygomatic arch beneath the infraorbital foramen 14. P^ lingual shelf. A lingual shelf is absent among is inclined anterodorsally and lacks a fossa. Although die primitive ursids. Among Enaliarctos species only E. barnesi zygomatic arch is not completely preserved among primitive and E. emlongi have lingual shelves developed; E. emlongi is ursids (e.g., Cephalogale de Beaumont, 1965, fig 24; Allocyon distinguished by having a more broadly developed shelf. Merriam, 1930, fig. 1) they possess inclined zygoma. Based on 15. Short lower cheek tooth row. The lower cheek teeth in E. additional material of Enaliarctos described herein, I regard the barnesi are arranged very close to one another with no flat condition of the zygoma as diagnostic at this level. diastemata, and die lengdi of tooth row is short in comparison 13. Zygomatic arches lower on skull. As observed by to that of £. emlongi and primitive ursids (Table 4). Barnes (1979:12, figs. 18a,b) in E. mealsi the zygomatic arch One odier character was equivocally assigned to this level: has a continuous dorsal curvature in lateral view in contrast to rounded palatine processes (SYNAPOMORPHY 1). The spur-like E. mitchelli, in which the arch "makes a more acute angle in die condition of these processes in E. barnesi are interpreted as a horizontal plane where it joins the skull. Consequendy die reversal to the primitive condition based on outgroup compar­ postorbital process of the jugal is lower on the skull in E. sion. mitchelli." The disfribution of this feature among primitive The second monophyletic Enaliarctos clade is defined as the ursids indicates that die flat, low condition of the arch is recent common ancestor of the Unnamed Taxon that includes derived. E. tedfordi, E. emlongi, and E. mitchelli. As described below Among species of Enaliarctos* several dental trends can be two unequivocal synapomorphies diagnose diis group with noted. The presence of cheek teeth widi sectorial features, four additional characters freated as ambiguous. namely large, blade-like cusps, the lingual position of enlarged 4. Reduced cheek teeth cingula. Well-developed labial and protocone shelves, the elevation of molar trigonids, and a long lingual cingula surrounding the cheek teeth have been talonid, exemplified by E. barnesi and E. mealsi*, represent die identified in ursids (e.g., Cephalogale de Beaumont, 1965), E. primitive pinniped morphotype. This conclusion stems from mealsi (Mitchell and Tedford, 1973), and E. barnesi. In recognition of the disfribution of "sectorial" dental features 26 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

TABLE 6.—Distribution of cranial and dental features among Enaliarctos species and the outgroup Ursidae. (Symbols: 0 = primitive; 1-2 = derived states; ? = not known.) barnesi tedfordi emlongi mealsi mitchelli rsida e D t*5 bj tq bj bi 1. Rounded palatine processes 0 1 0 1 1 1 2. Ventral portion 2ygoma flat with fossa 0 0 0 0 0 1 3. Posterior portion of zygoma joins palate posterior to M' 0 0 7 0 1 1 4. Reduced cheek teeth cingula 0 0 0 1 1 1 5. P^"^ metacone large, crest-Hke 0 0 0 1 2 0 6. P^ metacone short 0 0 0 1 1 1 7. P3_4 metaconid small 0 0 0 ? 1 ? 8. MJ, metaconid very reduced, close to protoconid 0 0 0 ? 1 ? 9. High, narrow rostrum 0 0 0 0 0 1 10. M^ very reduced protocone 0 0 0 ? ? 1 11. High, circular anterior narial opening 0 0 ? ? 0 1 12. Short nasal bones 0 0 1 ? 0 1 13. Zygomatic arches lower on skiill 0 0 ? 0 0 I 14. P3 lingual shelf 0 0 1 0 2 0 15. Short lower cheek tooth row 0 ? 1 ? 0 ? 16. Pj^ large paraconids, weU separated from protoconids 0 1 1 ? 0 7

•§ "5) alsi CO Ion chelli s •Q S E

1 mit S (b (0 M M 0) o fiss

o rcto a rcto arct .ra .ra c ra ra S rsid a

naliai naliai S ,c c: c ZD UJ Hi LU LU Uj a:

see text

FIGURE 21.—^Phylogeny of Enaliarctos species. Numbers refer to derived characters listed in Table 6 and discussed in text. NUMBER 69 27 among primitive ursids and amphicyonids (see following (Figure 22, node 1) can be distinguished from dieir closest section). All other species of the genus possess cheek teeth with relatives, die Ursidae, on die basis of 15 unequivocal characters reduced cingula and a reduced metaconid on Mj suggesting a and 5 equivocal characters (Table 7) discussed below. decreased camassial function of die cheek teeth. A continuation 1. Palatine process of maxilla extends behind last molar. of the frend toward loss of "fissiped-like" camassials distin­ The configuration of die palatal portion of die maxilla differs guished by taxa having a short metacone on F* is seen among among pinnipedimorphs and ursids. In ursids the maxilla members of Group 2: E. tedfordi, E. emlongi, and E. mitchelli. terminates at or slightiy behind the last molar. In Enaliarctos and odier pinnipeds the palatine process of die maxilla extends behind the last molar. Higher Level Relationships of 4. Large infraorbital foramen. Ursids and amphicyonids Enaliarctos* and "Enaliarctids" possess a small, slit-like infraorbital foramen. In pinnipedi­ Forty-two binary and 10 multistate characters among morphs the infraorbital foramen is large. pinnipedimorphs {Enaliarctos, Pteronarctos, Otariidae, Odo­ 5. Anterior palatine foramina anterior of maxillary-palatine benidae, Allodesmus, Desmatophoca, Pinnarctidion, and Pho­ suture. In ursids and most other terresfrial camivorans the cidae) were scored on a taxon-character mafrix (Table 7). All anterior palatine foramina are on the suture as observed by multistate characters were entered as unordered, and missing Wyss (1988b:30). A distinctive feature of pinnipedimorphs is data were entered as ?. The branch and bound option of PAUP the anterior position of the anterior palatine foramina relative to (Swofford, 1989) resulted in a single most parsimonious tree the maxillary-palatine suture. with a branch lengdi of 75 and a consistency index (C.I.) of 7. Supraorbital processes very reduced-absent or large and .840 (Figure 22). shelf-like. As noted by Wyss (1987) die absence of large As previously mentioned, the Ursidae was employed as the supraorbital processes may be primitive for pinnipeds or lost first outgroup. Following the suggestion of Maddison et al. independendy in Enaliarctos and "phocoids." Although I (1984) a second outgroup was also employed, the extinct concur with Wyss that the absence of large supraorbital Amphicyonidae. Flynn et al. (1988) provided diree altemate processes is the derived condition, I regard the condition of the hypotheses for relationships of the Amphicyonidae: (1) supraorbital processes in Enaliarctos and phocoids differendy. amphicyonids as arctoids (relationships unresolved among The supraorbital processes in Enaliarctos though very reduced arctoids), (2) amphicyonids as sister group of other arctoids, or are still consistendy present as ridges or protuberances. In (3) amphicyonids as sister taxon to die Ursidae. My analysis contrast, among odobenids, phocoids, and Allodesmus die supports the view that the Amphicyonidae are the sister taxon processes are completely lacking. to the Ursidae. Retention of die excavated basioccipital and 8. Foramen rotundum merged with anterior lacerate fora­ presumed loop of the intemal carotid artery in Enaliarctos men. The primitive condition in which die foramen rotundum supports consideration of this feature as a synapomorphy is separate from the anterior lacerate foramen is seen in ursids uniting the Ursida clade (including Amphicyonidae, Ursidae, and amphicyonids, as well as the "enaliarctid" Pinnarctidion. and Pinnipedimorpha). As noted by Bames (1979:24) in Enaliarctos, otariids, and Flynn et al., (1988) briefly reviewed possible relationships of odobenids the foramen rotundum is merged with the anterior pinnipeds to other arctoids. One view holds that pinnipeds are lacerate foramen. As discerned in the present study, the derived the sister group of ursids while in the second arrangement condition is more broadly distributed among other pinnipeds pinnipeds are part of a multichotomy with other arctoid including phocids. families. Their support for an ursid-pinniped alliance is based 10. Large round window. All pinnipeds including En­ on two dental synapomorphies: shelf-like anteromediaUy aliarctos share a large round window (Wyss, 1987). placed F* protocone and a narrow M^ with longitudinally 12. Epitympanic recess large. As noted by Mitchell and elongated protocone. In addition, Wyss (1987) noted that Tedford (1973) the epitympanic recess in Enaliarctos mealsi pinnipeds and ursids are unique among camivorans in lacking was large relative to the size of die middle ear cavity in a muscular process on the malleus. As I have indicated comparison to Cephalogale. Wyss (1987) recognized this elsewhere (Berta et al., 1989; Berta and Ray, 1990) to die list feature as a synapomorphy uniting all pinnipeds. above may be added die following postcranial characters: 13. Postglenoid foramen vestigial-absent. In Cephalogale a knob-like acromion process of the scapula and ulna with a large postglenoid foramen is present (Mitchell and Tedford, robust olecranon process. Thus, considerable evidence supports 1973). The postglenoid foramen is, in contrast, smaU or absent pinnipeds as having shared a most recent common ancesfry in pinnipedimorphs. with terresfrial arctoids, widi ursids considered as the most 14. Jugular foramen greatly enlarged. The jugular foramen likely sister group. (= posterior lacerate) is enlarged in all pinnipeds including Enaliarctos* is recognized as the sister taxon of all odier Enaliarctos as noted by Wyss (1987). pinnipeds as originally proposed by Wyss (1987). The 75. Enlarged auditory ossicles. As is true for odier Pinnipedimorpha clade {Enaliarctos plus all other pinnipeds) pinnipeds, the malleus and incus of Enaliarctos are relatively 28 SMITHSONLMSf CONTRIBUTIONS TO PALEOBIOLOGY

TABLE 7.—^Distribution of cranial and dental features discussed in text. (Symbols: 0 - primitive state; 1-2 = derived states; ? = not known.)

u OJ .y i; c: ^ '-5 -S DiiiOCL,Oa,a,Q-<.S 2 -- ; 1. Posterior extension of palatine process of maxilla 0 1 1 0 1 2 2 2 2. NasolabiaUs fossa absent 0 0 1 1 0 0 1 3. MaxiUa makes a significant contribution to orbital wall 0 7 1 1 1 1 1 4. Large infraorbital foramen 0 1 1 1 1 1 1 5. Anterior palatine foramina anterior of maxillary-palatine suture 0 1 1 1 1 1 1 6. Lacrimal fuses early lo maxiUa, greatly reduced or absent; does not contact jugal 0 7 1 1 1 1 1 7. Supraorbital processes reduced-absent or large and sheLf-Like 0 1 3 2 2 1 1 1 8. Foramen rotundum merged with anterior lacerate foramen 0 1 1 1 1 0 c 9. Mastoid process distant to paroccipital process 0 0 0 1 0 0 1 1 10. Large round window 0 1 1 1 1 7 1 11. Enlarged basal whorl of scala tympani 0 7 1 1 7 ? 1 12. Epitympanic recess large 0 1 1 1 1 1 1 13. Postglenoid foramen vestigial-absent 0 1 1 1 I 1 1 14. lugular foramen greatiy enlarged 0 1 1 1 1 1 1 15. Enlarged auditory ossicles 0 1 1 1 1 7 7 16. Middle ear cavity and EAM lined with distensible cavernous tissue 0 7 1 1 7 ? 1 17. Pseudosylvian sulcus strongly developed 0 1 0 0 1 0 c 18. Deciduous dentition reduced 0 7 1 1 7 7 1 19. M^"^ smaU-subequal relative to premolars 0 1 1 1 7 7 20. MJ entocoiud reduced-absent 0 1 2 2 ? ? 7 21. MJ hypoconid reduced-absent 0 1 2 2 ? 7 2 22. MJ absent 0 1 1 1 1 ? ] 23. Nasal processes of premaxilla, prominent protrude above alveolar margin 0 0 1 0 1 7 ( 24. Canal for cochlear aqueduct merged with round window 0 0 0 1 7 ? " 25. Paroccipital process enlarged 0 0 0 1 1 1 ] 26. P^, two-roots-single rooted 0 0 1 1 1 7 ] 27. M^ two-roots-single rooted 0 0 1 1 1 0 : 28. M^"^ cingulum reduced-absent 0 1 1 1 1 7 29. MJ 2 trigonid suppressed 0 0 1 1 ? 7 30. M] metaconid greatiy reduced-absent 0 0 1 1 7 7 31. MJ absent 0 0 1 1 0 7 32. Fossa muscularis absent 0 0 1 1 0 1 33. Large orbital vacuities present 0 0 1 1 0 0 ( 34. Embrasure pit l>etween P^-M', shaUow-absent 0 0 1 1 1 1 35. Pit for tensor tympani reduced-absent 0 0 1 1 0 1 36. Processus gracUis and anterior lamina of malleus reduced 0 0 1 1 1 ? ' 37. P^ enlarged protocone shelf absent 0 0 1 0 0 0 38. Narrow contact between nasals and premaxUla 0 0 0 1 0 7 39. Ascending process of premaxUla-maxiUa dips into nasal aperture 0 0 0 1 0 7 40. Canals for CN VII and VIII widely separate 0 0 0 2 7 2 : 41. Auditory bulla underlaps basioccipital 0 0 0 1 0 1 42. Petrosal visible through posterior lacerate foramen 0 0 0 1 0 1 43. Caudal entotympanic inflated 0 0 0 2 0 1 44. Basioccipital short, broad, widened posteriorly 0 0 0 1 0 7 45. Reduced coronoid process 0 0 0 1 0 7 46. P caniniform with circular cross-section 0 0 0 0 7 7 2 2 47. P lingual cingulum absent 0 0 0 1 7 7 48. Nasals terminate posterior to frontal-maxUlary contact 0 0 0 1 0 0 7 49. Posteriorly wide palate 0 0 0 1 0 0 1 50. Squamosal-jugal, mortised contaa 0 0 0 2 0 0 1 1 2 51. Flange below ascending ramus of mandible 0 0 0 1 0 0 ? 1 1 52. Lower premolars with large paraconids 0 1 0 0 7 7 7 1 0 NUMBER 69 29

PINNIPEDIMORPHA PINNIPEDIA

CO ida e tos

tidion Q> rotas a> ophoc dobe n Hades tariid a innarc hocid a rsida e esmat naliarc terana =) LU 0. O O '^ Q CL a.

(2Z.43')

(1',7',S,27',46')

(1,9,23,25,39,40',41, 45,48,49,50',51) 4 (24,38.40,42-44,47)

3 (2,7',17,31,32,33,35,37)

2 (20'.21',23,26,27,29,30,34,36)

1 (1,3-8,10-22,28)

FIGURE 22.—Higher level relationships of Enaliarctos and "enaUarctids." Numbers refer to derived characters listed in Table 7 and discussed in text. Characters marked with a tick (') designate a multistate character. Postulated reversals lo ancestral character states are underlined.

larger than in terresfrial camivorans (Wyss, 1987, table 1). and Tedford (1973) Enaliarctos can be distinguished from 17. Pseudosylvian sulcus strongly developed. As described Cephalogale in having the hypoconid centrally positioned and by Mitchell and Tedford (1973:237) in Enaliarctos mealsi die separated from the trigonid by a broad groove. This cusp is pseudosylvian (= sylvian) fossa is enlarged to a broad and deep suppressed in all later pinnipeds. crease down the side of the brain. Judging from the skull and 22. MJ absent. Among primitive lu-sids, Amphicynodon, endocranial cast of Cephalogale figured by de Beaumont Pachycynodon, Allocyon, and Cephalogale, M3 is present This (1965) the pseudosylvain sulcus does not appear to be sfrongly tooth is absent in Enaliarctos and later pinnipeds. developed. According to Bames (1989, fig. 9) Pteronarctos can 28. M^'^ cingulum reduced-absent. In the primitive condi­ be distinguished from Enaliarctos by its shallower pseu­ tion, seen in Cephalogale and amphicyonids, an enlarged dosylvian sulcus. Comparisons with additional specimens of cingulum encircles the upper molars. This cingulum is reduced Pteronarctos from die Emlong collection (Berta, in prep.) or absent in Enaliarctos and all later pinnipeds (Mitchell and indicate that this is not die case. The presence of a strongly Tedford, 1973). developed sulcus is recognized here as having evolved in The polarity of five other features, although unknown in pinnipedimorphs ancesfrally and having subsequendy been lost Enaliarctos, have been assigned a most parsimonious distribu­ in pinnipeds. tion at this node. I treat three of these features, enlarged basal 19. M^'^ small relative to premolars. The primitive pin­ whorl of scala tympani (SYNAPOMORPHY 11), middle ear cavity niped dentition as exemplified by Enaliarctos is characterized and external auditory meatus presumably lined with distensible by having M^"^ reduced relative to the premolars. As cavernous tissue (SYNAPOMORPHY 16), and deciduous dentition commented by Mitchell and Tedford (1973:251), "the degree reduced (SYNAPOMORPHY 18), as apomorphies of the Pinnipe- of reduction of the upper molars in Enaliarctos compared with dia clade, die minimum level at which observation confirms die premolars is greater dian diat of any known early arctoid." their distribution. Two additional features, maxilla makes a In all later pinnipeds the molars and premolars are subequal. significant conu-ibution to die orbital wall (SYNAPOMORPHY 3), 20. MJ entoconid reduced-absent. An entoconid is present and lacrimal fuses early to maxilla, greatly reduced or absent; in primitive ursids. This cusp is reduced to a crest in does not contact jugal (SYNAPOMORPHY 6), are assigned as Enaliarctos as noted by Mitchell and Tedford (1973) and apomorphies at the level of the Unnamed Clade that includes suppressed in all later pinnipeds. Pteronarctos and all other pinnipeds. One additional character 21. MJ hypoconid reduced-absent. According to Mitchell hsted by Wyss (1987) as a potential pinniped synapomorphy 30 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY

(large cochlear aqueduct) requires further comparative study The derived pinniped palate lacks an embrasure pit on die and measurement before it can be definitively assigned at this palate between P^ and M^ to receive the crown of the lower or any other level (Wyss, pers. comm.). camassial, a conspicuous feature in Pteronarctos, Enaliarctos, In addition to cranial and dental features the pinnipedi­ and terresfrial camivorans (SYNAPOMORPHY 34). This character morphs are distinguished by a large number of synapomorphies together with a number of dental modifications including of the postcranial skeleton reviewed elsewhere (Berta et al., reduction or loss of F* protocone (SYNAPOMORPHY 37), loss of 1989; Berta and Ray, 1990). Derived features of die forelimb MJ metaconid, entoconid, and hypoconid (SYNAPOMORPHIES include short, robust humems widi sfrongly developed del­ 20, 21, 30), and loss of M2 (SYNAPOMORPHY 31) indicate topectoral crest and enlarged tuberosities; elongation of digit I suppression of the camassial function of these teedi, which is in the manus and digits I and V in the pes; loss of supracondylar viewed as a frend toward homodonty exemplified by modem foramen on humems ( a reversal in phocines). Shared derived pinnipeds. features of the hindlimb include short ilium; extremely short Synapomorphies of the pinniped postcranial skeleton (see anteroposteriorly flattened femur and medially inclined con­ also Berta et al, 1989; Berta and Ray, 1990) include, for die dyles; large, broadly developed greater frochantero n the femur forelimb, flattening and posterior expansion of the olecranon and conical patella. In the axial skeleton, pinnipedimorphs process of the ulna and sfrong reduction of fifdi intermediate share with all arctoids except ursids possession of an alar notch phalanx of the manus. Pelvic girdle and hindlimb spe­ radier dian a foramen on die adas. cializations include unfused pubic symphysis, loss of pit for The next more restrictive clade is an unnamed group that ligament on femoral head, reduction or loss of frochanteric includes the fossd taxon Pteronarctos and all other pinnipeds fossa on femur, and reduction of processus lateralis on die and is defined by nine cranial characters (Figure 22, node 2; fibula. Both the manus and pes display hinge-like phalangeal Table 7). Because relationships among more inclusive pinniped articulations, flattened phalanges, and non-trochleated clades were not die principal focus of diis study, descriptions of interphalangeal articulations. All pinnipeds (except living characters as were provided in the preceding section for walruses) are characterized by having five lumbar vertebrae. diagnosis of Pinnipedimorpha are not detailed here. Pter­ Monophyly of the Otariidae (= Otariinae Mitchell, 1968, onarctos and all odier pinnipeds are characterized dentally by a 1975; Barnes, 1989) has fraditionally been accepted (Repen­ reduction in the number of roots on the upper molars ning and Tedford, 1977; Berta and Demere, 1986; Barnes, (SYNAPOMORPHY 27). The upper molars of Enaliarctos and 1989). This analysis identified only a single character reversal, ursids have three separate roots. This number is reduced to two the presence of large shelf-like supraorbital processes as in Pteronarctos and phocids and one in all other pinnipeds. uniting otariids (SYNAPOMORPHY 7). Relationships among die The Pinnipedia clade is defined by 8 cranial characters Otariidae are discussed further elsewhere (Berta and Demere, (Figure 22, node 3). The fossa muscularis (SYNAPOMORPHY 1986; Berta, in prep.). 32), prominent in Pteronarctos, Enaliarctos, and ursids, is As proposed by Wyss (1987) odobenids and phocids and absent in members of this group. This character and its their fossil allies are sister taxa (Figure 22, node 4). Cranial proposed fransformation warrant a few additional comments. features that support this clade include reduced contact between As defined by Davis (1964:49) immediately behind die the premaxilla and nasals (SYNAPOMORPHY 38), and pefrosal lacrimal fossa is a shallow pit, the fossa muscularis, in which visible through posterior lacerate foramen (SYNAPOMORPHY the inferior oblique muscle of the eye arises; the thin floor of 42). In addition, there are numerous derived features of the ear diis pit is usually broken through on dry skulls, and dien region diat are more fully described by Wyss (1987). Among resembles a foramen. This fossa in Ursus is relatively postcranial synapomorphies defined by Wyss in the previously enormous, as large as the lacrimal fossa. Examination of die mentioned paper are development of an at least incipientiy skull of Cephalogale minor (Vienna Natural History Museum, caudally directed process on the asfragalas, short calcaneal Vienna A4445) reveals the presence of a slight depression tuber, and enlarged baculum. behind the lacrimal fossa delimited by a venfraUy floored ridge. A more inclusive clade of pinnipeds including Pin­ A possible interpretation is diat the condition in Cephalogale narctidion, Desmatophoca, Allodesmus, and Phocidae is united might be an intermediate stage in development of the deep, by 12 derived cranial features (Figure 22, node 5). These posteriorly positioned fossa seen in Enaliarctos and Pter­ pinnipeds display a mortised contact between the squamosal onarctos. Following diis fransformation sequence, odier pin­ and jugal (SYNAPOMORPHY 50), posteriorly wide palate nipeds are hypothesized to have lost this fossa. (SYNAPOMORPHY 49), and nasals that terminate posterior to die As noted by Wyss (1987:16) another pinniped synapomor­ frontal-maxillary contact (SYNAPOMORPHY 48). The lower jaw phy is "die presence of of an unossified space (often termed has a reduced coronoid process (SYNAPOMORPHY 45) and a orbital vacuity) in die venfral wall near the juncture of die mandibular flange developed below the ascending ramus frontal, maxilla, and palatine bones...associated with die (SYNAPOMORPHY 51). Relationships among these taxa are pinniped configuration of the maxilla" (SYNAPOMORPHY 33). represented in Figure 22, in which Desmatophoca + Pinnarc- NUMBER 69 31 tidion + Allodesmus form an unnamed clade widi Desmato­ Conclusions phoca and Pinnarctidion linked as sister taxa, Pinnarctidion Three new species of the archaic pinniped Enaliarctos* from and Desmatophoca possess a squamosal-jugal articulation that the marine late Oligocene and early Miocene (Arikareean and is less modified than diat displayed by Allodesmus and phocids Hemingfordian or early Barstovian correlatives) of coastal in which diis contact is dorsoventrally expanded (SYNAPOMOR­ Oregon are described based on well-preserved crania and PHY 50). These taxa also lack development of large orbital dentitions: E. barnesi (near Yaquina Formation-Nye Mudst­ vacuities (SYNAPOMORPHY 33) that are present in both one contact), E. emlongi (Nye Mudstone or Astoria Formation), Allodesmus and phocids. The Phocidae are monophyletic (for a and E. tedfordi (Yaquina Formation). An additional skull is recent systematic freatment see Wyss, 1988b). referred to a previously described species, E. mitchelli (Nye The above analysis clearly shows that "enaliarctids" are Mudstone). These taxa differ principally in facial morphology paraphyletic. Enaliarctos* is the sister group of the remaining and details of the dentition. Phylogenetic analysis of cranial pinnipeds, and Pteronarctos and Pinnarctidion are placed in and dental characters among these species and die genotype E. less inclusive clades. This is in contrast to the traditionally mealsi results in recognition of Enaliarctos as a metataxon, accepted phylogeny of "enaliarctids" as basal otariids involved since monophyly of this taxon cannot be unambiguously only in the ancesfry of some pinnipeds (sea lions, walruses, and determined. Relationships among Enaliarctos species are their fossil allies (desmatophocids and allodesmids), but not largely unresolved aldiough there is some character evidence to true seals) (Bames, 1979, 1989). According to Bames support die common ancestry ofE. tedfordi, E. emlongi, and E. (1989:19) the "Enaliarctinae are a horizontal group,...a grade mitchelli. rather than a clade." Recognition of the paraphyletic grade Phylogenetic analysis of 52 cranial and dental features "Enaliarctinae" is an inappropriate systematic procedure. Such among fossil taxa {Enaliarctos, Pteronarctos, Desmatophoca, an approach is undesirable for many reasons, die most Allodesmus, and Pinnarctidion) and extant pinniped families important of which is that it misrepresents the evolutionary (Otariidae, Odobenidae, and Phocidae), supports die view that history of pinnipeds. If one accepts the evidence reviewed here, the "Enaliarctinae" (= "Enaliarctidae") is paraphyletic as well then the phylogenetic arrangement of diese taxa should reflect as the recognition that Enaliarctos* is the sister taxon of all that knowledge. By grouping Pteronarctos and Pinnarctidion other pinnipeds. Other taxa previously included in the in the "Enaliarctinae" and arguing for "die taxonomic utility [of "Enaliarctidae" {Pteronarctos and Pinnarctidion) show differ­ doing so], considering the still comparatively meager state of ent relationships: Pteronarctos + all other pinnipeds form one our knowledge of early otariid evolution," Bames (1989:19) monophyletic clade and intemested within diis clade are obscures what we do know about the interrelationships of these several other clades, one of which includes Pinnarctidion + taxa. Desmatophoca, Allodesmus, and the Phocidae. Literature Cited

Addicott, W.A. Donoghue, M.J. 1976. Neogene MoUuscan Stages of Oregon and Washington. In A.E. 1985. A Critique of the Biological Species Concept and Recommendation Fritsche, H. Ter Best, Jr., and W.W. Womardt, editors, The Neogene for a Phylogenetic Alternative.Bryolog'ist, 88:172-181. Symposium, pages 95-116. San Francisco: Society of Economic Dubrovo, LA. Paleontologists and Mineralogists [Armual Meeting, Pacific 1981. A New SubfamUy of FossU Seals (Pinnipedia Kamtschatarctinae Section]. subfam nov.) Proceedings ofthe Academy of Sciences ofthe USSR, Armentrout, J.M. 256:970-974 [in Russian]. 1981. Correlation and Ages of Cenozoic Stratigraphic Units in Oregon and 1984. Miocene Seals from the Pacific Region. Paleontological Journal, Washington. Geological Society of America Special Paper, 184: 18(l):50-60 [in Russian]. 137-148. Emlong, D. Armentrout, J.M., D.A. HuU, J.D. BeauUeu, and W.W. Rau, editors 1966. A New Archaic Cetacean from the OUgocene of Northwest Oregon. 1983. Correlation of Cenozoic Stratigraphic Units of Western Oregon and Bulletin of the Museum of Natural History. University of Oregon, Washington. Oregon Department of Geology and Mineral Industries 3:1-51. Oil and Gas Investigations, 7: 90 pages, 1 chart. Hynn, J.J., N.A. Neff, and R.H. Tedford Barnes, L.G. 1988. Phylogeny of the Carnivora. In M.J. Benton, editor, The Phylogen­ 1979. Fossil Enaliarctine Pinnipeds (MammaUa: Otariidae) from Pyramid etic Classification of the Tetrapods. Volume 2 (Mammals), pages HUl, Kern County, California. Contributions in Science. Natural 73-116. Oxford: Qarendon Press. History Museum of Los Angeles County, 318:1-41, figures 1-22, Gauthier, J.A. tables 1-4. 1986. Saurischian Monophyly and the Origin of Birds. In K. Padian, editor, 1987a. An Early Miocene Piimiped of the Genus Desmatophoca (Mam­ The Origin of Birds and the Evolution of FUght. Memoirs of the maUa: Otariidae) from Washington. Contributions in Science. California Academy of Sciences, 8:1-55. Natural History Museum of Los Angeles Couniy, 382:1-20, figures Gauthier, J.A., R. Estes, and K. de Quieroz 1-9, 1 table. 1988. A Phylogenetic Analysis of Lepidosauromorpha. In R. Estes and G. 1987b. Aetiocetus and Chonecetus, Primitive OUgocene Toothed Mysticetes PregUl, editors, Phylogenetic Relationships of Lizard Families: and the Origin of Baleen Whales. [Abstract.] Journal of Vertebrate Essays Commemorating Charles L. Camp, pages 15-98. Stanford Paleontology, 7 (Supplement to no. 3), lOA. Univ. Press. 1989. A New EnaUarctine Pimuped from the Astoria Formation, Oregon, Hunt, R.M., Jr. and a Classification of the Otariidae (MammaUa: Carnivora). 1974a. The Auditory BuUa in Carnivora: An Anatomical Basis for Contributions in Science. Natural History Museum of Los Angeles Reappraisal of Carnivore Evolution. Journal of Morphology, County, 403:1-26, figures 1-9, tables 1-2. 143(l):21-76. Berggren, W, D.V. Kent, J.J. Flynn, and J.A. Van Couvering 1974b. Daphoeniclis, a Cat-Uke Carnivore (MammaUa, Amphicyonidae) 1985. Cenozoic Geochronology. Geological Society of America Bulletin, from the Oligcxene of North America. Journal of Paleontology, 96:1407-1418. 48(5): 1030-1047. Berta, A. 1977. Basicranial Anatomy of Cynelos Jourdan (MammaUa: Carnivora), In prep. [New specimens of Pteronarctos (Pinnipediformes) from the an Aquitaiuan Amphicyonid from the AlUer Basin, France. Journal Miocene of Oregon and Its relationship to the Otariidae.] of Paleontology, 51(4):826-843. Berta, A., and T.A. Demere King, J.E. 1986. Callorhinus gilmorei n. sp., (Carnivora: Otariidae) from the San 1983. Seals of the World. Second edition, 240 pages. Ithaca, New York: Diego Formation (Blancan) and its ImpUcations for Ouriid ComeU University Press. Phylogeny. Transactions of the San Diego Society of Natural Maddison, W.P, M.J. Donoghue, and D.R. Maddiscwi History, 2l{l):lll-l26. Berta, A., and C.E. Ray 1984. Outgroup Analysis and Parsimony. Systematic Zoology, 33:83-103. 1990. Skeletal Morphology and Locomotor CapabUities of the Archaic McLaren, LA. Piimiped, Enaliarctos mealsi. Journal of Vertebrate Paleontology, 1960. Are the Pinnipedia Biphyletic? Systematic Zoology. 9:18-28. 10(2):141-157. Merriam, C.W. Berta, A.. C.E. Ray, and A.R. Wyss 1930. Allocyon, a New Canid Genus from the John Day Beds of Oregon. 1989. Skeleton of the Oldest Known Pinniped, Enaliarctos mealsi. University of California Publications in Geological Sciences, Science, 244:60-62. 19:229-243, figures 1-5, plates 35, 36. Davis, D.D. MitcheU, E.D. 1964. The Giant Panda: A Morphological Study of Evolutionary Mecha­ 1968. The Mio-Pliocene Pinniped Imagotaria. Journal of the Fisheries nism. Fieldiana: Zoology Memoirs, 3:1-334. Research Board of Canada, 25:1843-1900. De Beaumont, G. 1975. ParalleUsm and Convergence in the Evolution of Otariidae and 1965. Contribution a I'etude du genre Cephalogale Jourdan (Carnivora), Phocidae. Rapports et Proces-verbaux des Reunions, Conseil Schweizerische Paldontologische Abhandlungen, 82:1-34, figures International pour I'Exploration de la Mer, 169:12-26. 1-28. MitcheU, E., and R.H. Tedford Domning, D.R, C.E. Ray, and M.C. McKenna 1973. The EnaUarctinae: A New Group of Extinct Aquatic Carnivora and 1986. Two New OUgocene DesmostyUans and a Discussion of Tethyth­ a Consideration of the Origin of the Otariidae. Bulletin of the erian Systematics. Smithsonian Contributions to Paleobiology. 59: American Museum of Natural History, 151(3):201-284, figures 56 pages. 1-27 tables 1-4.

32 NUMBER 69 33

Mivart, G. Snavely, RD., Jr., N.S. MacLeod, H.C. Wagner, and W.W. Rau 1885. Notes on the Pinnipedia. Proceedings of the Zoological Society of 1976. Geology of the Yaquina and Toledo Quadrangles, Oregon. United London, 1885:484-500. States Geological Survey MisceUaneous Investigations Series Map Muizon, Ch. de 1-867, scale 1 : 62,500. 1982. Les relations phylogenetiques des Lutrinae (MusteUdae, Mam­ Snavely, RD., Jr.. W.W. Rau. and H.C. Wagner maUa). Geobios. Memoire Special. 6:259-277. 1964. Miocene Stratigraphy of the Yaquina Bay Area. Newport, Oregon. Munthe, J., and M.C. Coombs OreBtn, 26(8):133-151. 1979. Miocene Dome-skuUed ChaUcotheres (MammaUa, Perissodactyla) Swofford, D.L. from the Western Uruted Slates: A PreUminary Discussion of a 1989. Phylogenetic Analysis Using Parsimony (PAUP), Version 3D. Bizarre Structure. Journal of Paleontology, 53(1):77-91. Champaign: DUnois Natural History Survey. Repenning, CA. Tedford. R.H. 1976. Adaptive Evolution of Sea Lions and Walruses. Systematic Zoology. 1976. Relationship of Pinnipeds to Other Carnivores (MammaUa). System - 25(4):375-390. alic Zoology. 25(4):363-374. Repenning, C.A., and R.H. Tedford Wozencraft, C. 1977. Otarioid Seals of the Neogene. Professional Papers of the United 1989. The Phylogeny of the Recent Carnivora. In John L. Gittleman, Stales Geological Survey, 992: 93 p)ages. editor. Carnivore Behavior, Ecology, and Evolution, pages 495- Sivertson, E. 535. New York: ComeU University Press. 1954. A Survey of the Eared Seals (FamUy Otariidae) with Remarks on the Wyss. A.R. Antarctic Seals CoUected by M/K "Norvegia" in 1928-1929. Det 1987. The Walrus Auditory Region and Monophyly of Pinnipeds. Norske Vedenskaps-Akademii Oslo, 36:1-76. American Museum Novitates, 2S71:1-31, figures 1-7, tables 1-2. Snavely, P.D., Jr., N.S. MacLeod, H.C. Wagner, and D.L. Lander 1988a. Evidence from FUpper Structure for a Single Origin of Pinnipeds. 1980. Geology of the West-central Part of the Oregon Coast Range. In Nature, 334:427-428. Geologic Field Trips in Western Oregon and Southwestem 1988b. On "Retrogression" in the Evolution of the Phocinae and Phylogen­ Washington, Bulletin of the Oregon Department of Geology and etic Affinities of the Monk Seals. American Museum Novitates, Mineral Industries, 101:39-58. 2924: 38 pages.

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