A REDESCRIPTION OF TWO PLIOCENE CORMORANTS

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1 A REDESCRIPTION OF TWO PLIOCENE CORMORANTS BERTRAM G. MURRAY, JR.l Section o Neurobiology and Behavior Division o Biological Sciences Cornell University Ithaca, New York Two extinct species o cormorant have been (USNM) 12240, and rom the collection o Pierce described rom the Pliocene o Idaho: Phulu Brodkorb, PB 311; muter, UMMP V33918 (type), and USNM 12827, 12828; au&us, USNM 12239, crocorax idahen& (Marsh), based on the prox UMMP V33908, V I have also examined speciimal 45 mm o a carpometacarpus rom the mens reerable to PhaZucrocorux kennelli Howard rom Castle Creek local auna (Middle Pliocene), the San Diego Pliocene: Los Angeles County Muand Phalacrocorax muter Brodkorb, based on seum (LACM) 2528, 2529, 2566, 2645, 2817, 2833, and a carpometacarpus lacking metacarpals I and For comparison I used six Recent skeletons o III rom the Hagerman local auna (Upper uuritus rom The University o Michigan Museum o Pliocene, see Hibbard et al. 1965). Wetmore Zoology collections (UMMZ 71920, 85465, 99527, (1933) reerred the distal portion o an ulna , , and ) and ive rom the U.S. National Museum (USNM rom the Hagerman local auna to idaherzsis, , and ). Because o the small sample o and Brodkorb (1955) reerred the proximal Recent skeletons, I have used the term dzd /n 1 to portion o another ulna rom the Bone Valley determine the standard deviation o some o the meaormation (Lower Pliocene) o Florida to ida surements. The statistical range reers to six stanhensis, but later (1963) stated that these re dard deviations centered on the mean. Those specimens o iduhensis and mater that exceeded the measured erred specimens probably represent other ranges o skeletons were tested statistically species. Brodkorb (1958) suggested that two (ttest, Simpson et al. 1960: ) to determine i small, unidentiied coracoids rom the Hager they could represent a population, the mean o which man local auna, reported by Wetmore ( 1933)) diered signiicantly rom the mean o the sample population, represent mater. The Recent Phalucrocorax au&us (Lesson) has also been reported rom Phalucrocorax idahen& (Marsh) the Hagerman local auna (Wetmore 1933; O the new material, I reer the ollowing Brodkorb 1958). specimens to icla~sis: two associations o In the collections o avian ossils rom the many bones, each representing a single indi Upper Pliocene Hagerman and Sand Point vidual (UMMP V52472 and LACM 210/ local aunas (Hibbard 1959; Hibbard et al ), parts o our coracoids (UMMP 1965) obtained by Claude W. Hibbard and his V54148, V52440 (2), X3736), scapula (UMMP ield parties o The University o Michigan Mu V48903), humerus (UMMP V52671), radius seum o Paleontology and by Reid Macdonald ( UMMP V45146), o the Los Angeles County Museum o Natural ulna ( UMMP V49637), History are the bones o two species o cormocarpometacarpus (UMMP V55564), tibiotarsus ( UMMP V52418), rant, a larger one and a smaller one. These are a nearly complete tarsoapparently iduhensis and mater, respectively. metatarsus (UMMP V49571), and a cervical Because these species are poorly known, a vertebra ( UMMP V49018). description o this new material is presented. The type o idahen& (YPM 527) is the wellpreserved, proximal 45 mm o a carpometa MATERIALS carpus. Marsh (1870) described the specimen in detail but distinguished it, as Graculus, rom Most o the new material is rom the Hagerman local auna in Twin Falls County, Idaho, in section 5 o Phalucroc~ax by the presence o the anterior Township 8 south, 13_east, and in sections 16, carpal ossa, which is not even a good speciic 17, 21, 28, 29, 32, and 33 o Township 7 south, character. I have ound only two distinguish 13 east (see Murray 1967). The remaining specimens ing eatures. The irst is the shape o meta (The University o.michigan Museum o I%leontology (UMMP) V45146, V45148, V49018, V49020, V52671) carpal I, a eature noted by Howard (1946) are rom the Sand Point local auna in Owyhee when she compared idaheti with Phalucro County, Idaho, in SW y4 o section 1, Township 6 COMX TTUZCTO~S (Cope). The curve between south, 8 east (Hibbard 1959). the extensor attachment and the pollical acet In addition to the new material, I have examined the ollowing ossil specimens:, Yale Peabody has a smaller radius, giving the process o Museum (YPM) 527 (type), U.S. National Museum metacarpal I a squarish appearance and causing it to project orward at a greater angle to Present address: Depatment o Natural Science, Michigan the axis o the shat o metacarpal II than in State University, East Lansing, Michigan r2931 The Condor, 72:293298, 1970

294 BERTRAM G. MURRAY, JR. TABLE 1. Measurements (in mm) o carpometacarpi o some cormorants (Phalacro~~ax). Width through Width metacarpal II Trochlea depth metacarpal I 5 SD SD?

2 294 BERTRAM G. MURRAY, JR. TABLE 1. Measurements (in mm) o carpometacarpi o some cormorants (Phalacro~~ax). Width through Width metacarpal II Trochlea depth metacarpal I 5 SD SD? SD 2 8D males (n = 6) emales (n = 4) iduhetwis (type), YPM ** 7.1** 16.0** UMMP V * 15.0** UMMP X * 5.4** ** mqh?er (type), UMMP V * * UMMP V * 12.7 kenndli LACM * ** Signiicantly dierent rom P. at 0.05 level. au&us; the process o metacarpal I in uzlritus is trapezoidal in shape. Second, the internal rim o the carpal trochlea is less round and orms a less sharp angle with metacarpal III than in. Carpometacarpus V is an almost perect copy o the type (except or being more complete and o a dierent color) in size and eatures. The carpometacarpi o the two associations (UMMP V52472 and ) are smaller but in qualitative eatures are like idahen.& rather than like. Most measurements o carpometacarpi reerable to iinsis are within the statistical range o aur8u.s but are statistically dierent rom au&us means (table 1). On the basis o the carpometacarpi, then, the two associations o bones are reerred to idahe&. Single bones are reerred to idahen& i they resemble the bones o the associated skeletons. The humeri (V52472, V5,2671, and 210/ 17819) do not dier in size rom those o au&us (table 2). However, id&en&s diers rom on the basis o the scar o the inmspinatus attachment, which interrupts the curve rom the distal edge o the bicipital crest to the internal tuberosity in but not in (seen rom ventral view) and the slight dip between the head and the area ventral to the capital groove, which is present in au&us but absent in Wensis (seen on palmar view ). One complete ulna o i&hen& (V52472) is barely outside the statistical range o au&us ulnae in length but does not dier in other measurements (table 3). Despite the greater overall length o the ulna, the scar o brachiulis anticus is not longer than the average or (27.5 mm against a mean o 28.2 or six auri.t itus). In this specimen and in LACM 210/17819 the lange o the proximal radial depression extends outward at a greater angle to the shat and does not extend so ar distally as in. The ratio, ulna length/coracoid length, o specimen V52472 is 2.60, whereas in aurtius it ranges in six males rom, 2.34 to 2.46 (mean, 2.41)) and in our emales rom 2.35 to 2.47 (mean, 2.41). P. idahewia may have been slightly longerwinged than. The irst phalanx o the second digit o the wing (V52.472) diers rom that o au&us in having a ridge extending only ab out onethird the distance rom the metacarpal acet to the digital acet, whereas this ridge extends nearly to the digital acet in. The nearly complete emur (V52472) is slightly but not signiicantly longer than that o mritus (table 4). In both V52472 and the internal and external condyles are separated by a deeper groove (seen rom either anterior or posterior view), a result o the internal condyle being longer than in. Tibiotarsus V52472 is slightly but signiicantly longer than that o uuritus (table 5). In both V52472 and the most anterior portion o the internal articular surace lares upward less sharply than in auritu.s, and the internal edge o the proximal end is not interrupted by a ligamental attachment as it is in. The external ligamental prominence at the distal end does not bulge as markedly as in. Tarsometatarsus V49571 is signiicantly longer than those o (table 6). Other

3 REDESCRIPTION OF TWO PLIOCENE CORMORANTS 295 TABLE 2. Measurements (in mm) o humeri o some cormorants (Phulucrocorax). Breadth distal end Breadth shat Depth shat males (n=7) emales (n = 3) UMMP V52472 UMMP V kennel& LACM 2833 LACM males (n=7) emales (n = 3) id4zken.sis UMMP V52472 UMMP V52671 k&nelli LACM 2833 LACM 2817 a Actual measurement o third specimen. bn=4. Proximal width Head depth Length o ligamental urrow 35 2 z b wise it appears indistinguishable rom au&us tarsometatarsi. The remaining portions o the coracoids (table 7), sternum, urculum, scapulae, radii, synsacrum, and tarsometatarsus o V52472 and the scapulae, urcuhun, coracoids, and tarsometatarsus o are indistinguishable rom these elements o. Unless specimens are signiicantly larger than aurtius, as is tarsometatarsus V4QS71, single ossil bones o these elements can be either or au&us. The only evidence o the presence o au&us in the Pliocene is a tarsometatarsus ( USNM 12239; Wetmore 1933), the distal portion o a carpometacarpus ( UMMP V33QO8; Brodkorb 1958), and the proximal portion o a scapula (UMMP V33913; Brodkorb 1958), all rom the Hagerman local auna. These specimens cannot be distinguished rom either or Recent aurihs, and thus probably represent iduhermis. I recommend that Phulu.crocorax au&us be removed rom the list o Recent species that occur in the Pliocene until unambiguous evidence becomes available. The ulna (USNM 12240) reerred to idahen&s by Wetmore ( 1933) but questioned by Brodkorb (1963) is somewhat larger than ulna V It is the undiagnostic distal end. I reer it to idahetis because it is not so large as to be outside the possible range o ia2zhemi.s. The Bone Valley ulna (PB 311; Brodkorb 1955) is considerably larger than V52472 (maximum shat diameter at distal end o scar o brachia1i.s anticus, 9.0 mm) but there are no,diagnostic eatures remaining on the ragment. I agree with Brodkorb ( 1963) that this specimen probably represents an unknown species. The distal end o an ulna (UMMP V5746Q) rom locality 3 o the Rexroad local auna in Kansas ( Woodbume 1961)) previously unreported, is too ragmentary to permit positive identiication, but its size suggests it is probably idahewsis. That idaheti should occur in the Rexroad local auna is not surprising as species o ossil grebes (Murray lq67), rails (Feduccia lq68), and an owl (Ford and Murray 1967) are common to both the Rexroad and Hagerman local aunas.

4 296 BERTRAM G. MURRAY, JR. TABLE 3. Measurements (in mm) o ulnae o some cormorants (Phducrocorar). Maximum diameter Greatest measurement: o shat at distal Across internal Across internal end o scar o and external cotylae cotyla and olecranon brachialis anticus au&is males (n=6) emales (n=4) UMMP V52472 mizcer UMMP kennelli V48901 LACM 2529 ** Signiicantly dierent rom P. at 0.05 level ** ** Phalacrocorax mater Brodkorb The ollowing specimens are reerred to mater: proximal portion o an ulna ( UMMP V48901), proximal end o a carpometacarpus (UMMP VS2282), a tibiotarsus lacking the condyles (UMMP V48889), and the distal portion o a emur (UMMP V52269). Brodkorb (1958) distinguished the type carpometacarpus (UMMP V33918) by its being slightly smaller than in auritu.s and wetm,orei and by its having a deep but much shorter cuneiorm ossa that extends proximad only to the level o the external ligamental attachment, and a shorter distal ornix. In comparing the type with my series o I have been unable to observe these dierences, except that it is slightly smaller than the smallest measured au&us specimen (table 1). This dierence is not statistically signiicant. Nevertheless, I think the specimen does represent a species o cormorant that is, on the average, smaller than au&us. The only qualitative dierence I have ound is that the internal rim o the carpal trochlea o the type and reerred (V52282) carpometacarpi resembles the carpometacarpi o and diers rom those o and kennelli (LACM 2843) in being less round and orming a less sharp angle with metacarpal III. The process o metacarpal I (in V52282, lacking in V33918) resembles au&us rather than in being trapezoidal in shape and directed more proximad than orward. The ulna ( V48QOl) is at the short end o the range o (table 3). It is like idahen.& and unlike au&us in the shape o the radial depression. The emur (V52269) is smaller than measured wetmorei ( Brodkorb 1955) and and kennel& (table 4) but resembles TABLE 4. Measurements (in mm) o emora o some cormorants ( Phdacrocorux), uuritus Breadth across condyles SD E 8D males (rm=7) emales (n = 4) UMMP V mater UMMP V J3* * kennelli LACM ** Signiicantly diierent rom P. autitw at 0.05 level.

5 REDESCRIPTION OF TWO PLIOCENE CORMORANTS 297 TABLE 5. Measurements (in mm) o tibiotarsi o some cormorants (Phahrocoraz). Breadth across Narrowest measurement: overall length condyles Shat breadth Shat depth SD 2 SD SD males (n=7) emales (n = 4) S UMMP V52472 UMMP V ** ** * 5.3 mucec UMMP V48889 kennelli LACM 2566 LACM ** 3.9** ** Signiicantly dierent rom P. au&us at 0.05 level. * Not signiicant. All other values not bested. and not azlrizus or kenndli in having a deep groove between the internal and external condyles. The tibiotarsus (V48889) is smaller than the statistical range o tibiotarsi o (table 5) and wetwei (Brodkorb 1955). The ligamental attachment interrupts the inner edge o the proximal end, and the anterior portion o the internal articular surace lares upward sharply, resembling and kennelli rather than id&en&. The two coracoids (USNM and 12828) reported by Wetmore (1933) and reerred to mater by Brodkorb ( 1958) are more lightly built than and probably do rep resent ma.133. UNIDENTIFIED MATERIAL One carpometacarpus (UMMP V49576) is the size o muter but its metacarpal I is more like that o z&hen&s. Either and mater overlap in size, or the shape o metacarpal I is variable in mater. I think the ormer is probably the case, judging rom the small amount o variation in the shape o metacarpal I in Recent skeletons. There are a ew other specimens I have not identiied: the sternal portions o two coracoids ( UMMP V and V56014), two ulnae (UMMP V49637 and LACM 210/22217), a tarsometatarsus ( UMMP V49020), and a complete quadrate (UMMP V53702). DISCUSSION There were at least two species o cormorants living in the Late Pliocene o Idaho. Phalucracorax idahen.& was slightly larger than, and rnmr was smaller than auritzrs, but specimens o each broadly overlap and may even overlap each other. P. kenndli (Howard 1949; Miller and Bowman 1958) and wetmorei (Brodkorb 1955) overlap mater and probably overlap idahen& These cormorants point up the diiculties o studying single bones o ossil species in comparison with a small series o Recent skeletons. By assuming that large specimens o cormorants were idaherbs and smaller specimens in the same deposit were, idahen& has been considered larger than it really is (Wetmore 1988; TABLE 6. Measurements (in mm) o tarsometatarsi o some cormorants (Ph&croco~ax). Trochleae breadth Proximal breadth d SD z SD z SD males (n=7) emales ( l = 4) S kikhen& UMMP V ** 16.2* 14.4* ** Signiicantly dierent rom P. at 0.05 level.

6 298 BERTRAM G. MURRAY, JR. TABLE 7. Measurements (in mm) o coracoids o some cormorants (Phalacrocorax). auriths males (n=7) emales (n = 4) UMMP V52472 Head to Head to internal tip sternal ed e o sternal acet scapular acet 32 li z Dormventral head depth Howard 1946; Brodkorb 1956). In one individual o i&hen.s% (UMMP V52472) the coracoid is near the mean size o male coracoids (table 7), whereas its ulna exceeds the mean o male ulnae by more than three standard deviations (table 3). Without having an associated skeleton, the dierence in proportions could not have been known, and so the ossil record o was extended erroneously back into the Pliocene. Another aspect o interest is that a species may have characteristics in common with two or more species. For instance, in the characteristics I ound, the emur o muter is like that o iceahensi.s and dierent rom au&us and lcennelli, whereas the tibiotarsus od mater is more like those o and kennelli than like that o id&emis. Characterization and identiication o species on the basis o a single bone, or even a ew bones, should be tentative, especially when the variation within related Recent species is not well known. ACKNOWLEDGMENTS I want especially to thank C. W. H&bard or permitting me to study these ossils and or his continued encouragement during the course o the work. There are others to whom I also owe thanks: H. Howard and J. R. Macdonald o the Los Angeles County Museum o Natural History, C. E. Ray and R. L. Zusi o the U. S. National Museum, P. M. Galton o the Peabody Museum o Natural History at Yale University, P. Brodkorb o the University o Florida, and R. W. Storer o The University o Michigan Museum o Zoology or the loan o additional specimens; and H. Howard and J. A. Feduccia or critically reading the manuscript. C. W. Hibbard s ield work in Idaho was supported by NSF grant GB1528. LITERATURE CITED BRODKORB, P The aviauna o the Bone Valley ormation. Florida Geol. Surv., Rept. Invest. 14: l57. BRODKORB, P Fossil birds rom Idaho. Wilson Bull. 70: BRODKOFIB, P Catalogue o ossil birds. Bull. Florida St. Mus. Biol. Sci. 7: FEDUCCIA, J. A The Pliocene rails o North America. Auk FORD, N. L., AND B. G. MURRAY, JR Fossil owls rom the Hagerman local auna (Upper Pliocene) o Idaho. Auk 84: HIBBARD, C. W Late Cenozoic microtine rodents rom Wyoming and Idaho. Papers Michigan Acad. Sci. Arts Letters HIBBARD, C. W., C. E. RAY, D. E. SAVAGE, D. W. TAYLOR, AND J. E. GIJILDAY Quaternary mammals o North America. p In H. E. Wright, Jr., and D. G. Frey [eds.] The Quaternary o the United States. Princeton Univ. Press, Princeton, New Jersey. HOWARD, H A review o the Pleistocene birds o Fossil Lake, Oregon. Carnegie Inst. Wash. Publ. no. 551: HOWARD, H New avian records or the Pliocene o Caliornia. Carnegie Inst. Wash. Pub]. no. 584: MARSH, 0. C Notice o some ossil birds, rom the Cretaceous and Tertiary ormations o the United States. Amer. J. Sci. 49: MILLER, L., AND R. I. BOWMAN Further bird remains rom the San Diego Pliocene. Los Angeles Co. Mus. Contrib. Sci. no. 2&l15. MURRAY, B. G., JR Grebes rom the Late Pliocene o North America. Condor 69: SIMPSON, G. G., A. ROE, AND R. C. LEWONTIN Quantitative zoology. Harcourt, Brace, and Co., New York and Burlingame. WETMO~E, A Pliocene bird remains rom Idaho. Smithsonian Misc. Coll. 87( 20 ) : l12. WOODBV~UVE, M Upper Pliocene geology and vertebrate paleontology o part o the Meade Basin, Kansas. Papers Michigan Acad. Sci. Arts Letters 46: Accepted or publication 16 July 1969.

GREBES FROM THE LATE PLIOCENE OF NORTH AMERICA

GREBES FROM THE LATE PLIOCENE OF NORTH AMERICA BERTRAM G. MURRAY, JR. The Pliocene grebe fauna of North America is not well known. Brodkorb (1963a) lists two extinct species, Pliodytes lanquisti Brodkorb