Journal of Paleontology

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New protocetid (Mammalia, ) from the late middle Cook Mountain Formation of Louisiana

Mark D. Uhen

To cite this article: Mark D. Uhen (1998) New protocetid (Mammalia, Cetacea) from the late middle Eocene Cook Mountain Formation of Louisiana, Journal of Vertebrate Paleontology, 18:3, 664-668, DOI: 10.1080/02724634.1998.10011093 To link to this article: https://doi.org/10.1080/02724634.1998.10011093

Published online: 24 Aug 2010.

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Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ujvp20 Journal of Vertebrate Paleontology 18(3):664-668, September 1998 © 1998 by the Society of Vertebrate Paleontology

NOTE

NEW PROTOCETID (MAMMALIA, CETACEA) FROM THE LATE MIDDLE EOCENE COOK MO UNTAIN FORMATION OF LOUISIANA

MARK D. UHEN, Cranb rook Institute of Scie nce, Bloomfi eld Hills, Michiga n 48303-0801

A frag mentary specimen of an archaeocete was discovered and Age-The Cook Mountain Formation is early Bartonian (middle Eo­ co llec ted from the Cook Mountain Formation by P. H. Jones in 194 3 cene) in age (Dockery, 1996), and the Milams Member is in the lower dur ing a gro und water survey south of the city of Natchitoches, Loui­ part of the formation (Huner, 1939). Foraminifera from the foss il lo­ siana (Maher and Jones, 1949; P. H. Jones, pers. comm.). Th e Coo k ca lity identifi ed by H. V. Howe and listed in Maher and Jone s ( 1949) Mountain Formation is compose d of a series of marine sands and cla ys. include Globigerina mexicana, which is now considered to be a junior In part icul ar, the Milam s Member of the Cook Mountain Formation synonym of Orbulin oides beckmanni (Loeblich and Tapp an , 1988); this inclu des calcareo us glauconitic shales, lignitic shales, and marl ; color places the age of the cetacean in Plankt onic Foraminiferal Zo ne P 13. ranges from gray-green to brown-red (Huner, 1939) . Most of the bones Description-Fou r vertebrae of Natchitoc hia are identified as tho­ are dark on both the surface and the inter ior, but a few are pale on the racic vert ebrae based on the presence of rib articular surfaces. It is surface and dark on the interior ; many of the vertebrae have marl y unclear how man y thoracic vertebrae we re present in Na tchitochia, and " plugs" that form cas ts of the neural ca nals. it is also unclear whether the four thoracic vertebrae recovered are con­ The discover y of the speci men was first noted in a water-supply paper sec utive vertebrae. For these reasons, they will be referred to as Ta to dealing with the Natchitoches area (Ma her and Jones, 1949). Th e spec­ Td where Ta is anterior and Td is posterior. Measurement s of all the imen was sent to the United States Natio nal Museum where it was vertebrae are listed in Tabl e I. accessioned as USN M 16805 , and iden tified by Remington Kellogg as The four thoracic vertebrae are arra nged from anterior to posterior a new archaeocete whale (Maher and Jones, 1949), but never described . based on the positions of the rib articular surfaces. In Natchitochia and The specime n was discussed by Uhen ( 1996) , but it was not named in other archaeocetes, the facet for the rib tuberculum is on the transverse that abs tract. It is here described in more detail and given the name process of eac h verte bra , whereas the facet for the rib capitulum is on Natchitochia jo nesi. the anterola teral surface of the cen trum. In more anterior thoracics, the Abbreviations- NHML, The Natu ral Histor y Museum, Lo ndo n; two artic ular surfaces are well separated, with the transverse process GMUI Department of Geology Mu seum, University of Ibadan, Nigeria; arising from the dorsal border of the pedi cle of the neural arc h, while GSM, Georgia Southern Museum, Sta tesboro; GSP-UM, Geological in more posterior thoracic vertebrae, the transverse process arises from Survey of Pakistan -University of Mich igan Museum of Paleont ology, the lateral side of the centru m and the two rib face ts merge into a single Ann Arbor; SMNS, Staatliches Museum fur Naturkunde, Stuttgart ; artic ular surface . Ta and Tb have we ll-se parated rib facets, wh ile in Tc USNM, Unit ed States National Museum of Natura l Histor y, Washing­ they are separated by a narrow fissure, and in Td they are mostly sep­ ton , DC. arate, but touch eac h other directl y at one point. The rib facets, as we ll as the anterio r and posterior faces of the neural spine bases, are some­ SYSTEMATIC PAL EONTOLOGY what irreg ular ly form ed. Mirorder CETE Linnaeus, 1758 Order CETACEA Brisson , 1762 Sub order ARCH AEOCETI Flower, 1883 Famil y Stro mer, 1908 Sub famil y PROTOCETI NAE (Stro mer, 1908) • SHREVEPORT NATCHlTOCHIA. gen. nov. EtymoIogy- Natchitochia. in refere nce to the type local ity, near the city of Natch itoches. Diagnosis- As for the type and only species.

NATCHlTOCHIA JONESI. sp . nov. ALEXANDRIA' Etymology-The specific epithet is in honor of Paul H. Jo nes, who Protocetid locality discovered the holotype. Holotype-USNM 16805, three incomplete ribs and 13 verte brae, includi ng four anterior thoracics, five lumbars, one sacral, two cauda ls, and one of questionabl e position . BATON Diagnosis-Significantl y larger than most other protocetines, with ROUGE the exceptio n of Eocetus schweinfurthi and Pappocetus lugardi ; verte­ NEW brae are smaller than those of Eocetus and lack elongation of the lumbar LAKE CHARLES ORLEANS. ce ntra; vertebrae lack the ventra l keel see n in those verte brae ass igned to Pappocetus; ribs are sma ller and more grac ile than those of Pappo­ cetus. Horizon and Locality-The speci men was collec ted in a road cut along Louisiana state highway 478, in sec tio n 10, T. 8 N., R. 7 W., Natch itoche s South Quadrangle (7.5 minut e series) , south of Natchi ­ toches, Natch itoch es Pari sh, Louisiana (Fig. I; Maher and Jone s, 1949; P. H. Jone s, pers. comm.) . It was recovered from the Mil ams Memb er FIGURE 1. Map of Loui sian a showing the locality of the holotype of of the Cook Mountain Formation . Natchitochia jon esi.

664 Published online 24 Aug 2010 NOTES 665

TABLE I. Measurements of vertebral centra of Narchitochia jonesi Measurements are in millimeters. A dash indicates that the measurement could not be taken due to breakage. T is for thoracic. L is for lumbar. S is for sacral. and Ca is for caudal.

Ta Tb Tc Td La Lb Lc Ld Le S Caa Cab Centrum length 50 .1 51.7 53.3 54.1 54.6 57 .8 60 .2 68.4 72.6 77.9 81.2 86.4 Centrum width 72.1 76.2 83.9 86.7 89.2 89.4 90 .2 92.0 99 .2 99 .3 93 .9 Centrum height 55.2 54.3 55 .3 57 .8 - 63 -64 68 .0 - 64 -66 70.1

FIGURE 2. Natchitochia jonesi thoracic vertebra a in A. anterior view and B. posterior view. Scale is in centimeters. Note the heart-shaped centrum and dorsally placed rib articular facet.

FIGURE 3. Narchitochia jon esi lumbar vertebrae a--e in lateral view . Scale is in centimeters. Note the very large and almost vertically oriented pre- and postzygapophyses. 666 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 18, NO. 3,1998

FIGURE 5. Natchitochia jonesi sacral vertebra in left lateral view . Scale is in centimeters and is in the plane of the auricular surface. Note the large . roughly-textured auricular surface.

lumbar vertebrae increase in size from anterior to posterior in all di­ mension s. The lumbar vertebrae recovered appear to form a continuous series and are referred to here as La to Le . La has somewhat irregularly formed transverse processes. and it is difficult to be certain that it is an anterior lumbar rather than a posterior thoracic vertebra. The transverse processes on the other lumbar verte ­ brae are mostly broken. but where present. the distal end s are thin. and they lack rib articular surfaces. The anterior and posterior faces of the centra of the lumbar vertebrae are kidney-shaped. and the centra are moderately spool-shaped. The pre- and postzygapophyses are large and steeply inclined toward the midline. The cranial and caud al ends of the centra are concave. The bases of the neural spines are robu st. but all of the neural spin es are broken. so their lengths cannot be determined. A single vertebra from Natchitochia is identified as a sacral vertebra based on the presence of large auricular surfaces on the distal ends of the tran sverse processes (Fig . 4). The left transverse process is almost FIGURE 4. Natchitochia jonesi sacral vertebra in A, dorsal view. B. complete. while the right transverse process is broken, with only the anterior view, and C, posterior view . Anterior is up in A. Scale is in distal part remaining (not figured). The entire neural arch is miss ing. ce ntimeters. Note the size and shape of the centrum as well as the size The centrum is wid e relative to its length and height when compared and orientation of the transverse process. to the thoracic and lumbar vertebrae. There appears to be no connection between the sacral vertebra ad­ jacent anterior or posterior vertebrae via the centrum or transverse pro­ cesses. A small outgrowth of bone arises from the dorsolateral edge of the posterior end of the centrum of the sacral vertebra. A piece of this The centra increase in length and width from anterior to posteri or, area is missing but there is a similar outgrowth of bone on the dorso­ and the anterior and posterior face s of the centra change from heart­ lateral edge of the anterior end of the first caudal vertebra. This may shaped (Fig . 2) to kidney-shaped from anterior to posterior. The ep iph­ have been a small vestige of a connection between the sacral and the yses are fused to the centra and have convex cranial and concave caudal first caudal. surfaces. The pre- and postzygapophyses are inclined toward the mid­ The dorsal surface of the transverse process of the sacral vertebra line . and they increase in size from anterior to posterior. The bases of angles slightly ventrally from the centrum, and the ventral surface is the neural spines are robust. but all neural spines are broken so their expanded ventrally on the distal end to form the auricular surface . The lengths cannot be determined. distal end of the transverse process projects farther anteriorly than the Three rib fragments are included in the holotype. Two of these frag­ anterior end of the centrum. The auricular surface of the left sacral ments retain the proximal end s, and the third is a mid-shaft fragment. tran sverse process is generally oval in outline. with the long axis ori­ One of the proximal ends is a left rib with both a capitulum and a ented anteroposteriorly (Fig . 5). Thi s surface projects farthest laterally tuberculum for articulation with a thoracic vertebra. possibly Tc or one at the anterior end and angles in towards the centrum posteriorly. The nearby in the thoracic series. The other proximal end represents a right auricular surface is roughly textured and covered with small pits. Thi s rib. having a single articular surface that is kidney-shaped. All of the texture is indic ative of a synarthrotic connection to the innominata like rib shafts are thin and none show evidence of pachyosteoslcerosis as that found in terrestrial , , and Protocetus. seen in some other archaeocetes and sirenians (de Buffrenil et al., 1990) . Two vertebrae of Natchitochia are identified as caudal vertebrae. The Five vertebrae of Natchitochia are identified as lumbar vertebrae caudal vertebrae are similar in size and centrum shape to the sacral based on the presence of transverse processes that arise from the centra vertebra. The caudals have double hypapophyses on the posterior end and that lack articular surfaces for ribs (Fig. 3). The vertebrae have of the ventral side of their centra for the articulation of chevron bones. been arranged from anterior to posterior based on the positions of the Discussion-Natchitochia jonesi clearly belongs in the family Pro­ bases of the tran sverse processes . More anterior lumbar vertebrae have tocetidae (sensu Thewissen et al., 1996) based on the size and mor­ the tran sverse processes arising more dorsally on the centra than those phology of the vertebrae, and its stratigraphic position. The zygapophy­ from more posterior positions in the lumbar series . In addition, the ses of the vertebrae are steeply inclined towards the midline. and the NOTES 667

TA BLE 2. Comparison of skeletal elements of a num ber of pro tocetine archaeocetes . So me of the spec ies . like Natchitochia jonesi, are known only fro m vertebrae. while others. like Pap pocetus lugardi, are known only fro m cra nial or dental remai ns. Usi ng another species for co mpariso n that has all of the elements. like vogtlensis, one ca n co ncl ude that the only species that app roac hes the size of Natc hitochia jo nes i is Pappocetus lugardi.

Skeletal eleme nt mea sur em ent (mm) Ant. thoracic Post. thoracic Ant. lumbar Species Specimen number P' len gth M , length ce ntrum len gth ce ntrum length ce ntrum len gth Na tchitoch ia jonesi USNM 16805 50. 1 54 .1 57.8 Eocetus schweinfu rthi SM NS 10986 4 1 Eocetus schweinfurthi SMNS 10934 119 Protocetus atavus SMNS 11084 24 Protocetus atavus SMNS 11086 49.8 Georgiacetus vog tlensis GSM 350 39.9 50 .3 Pappocetus lugardi NHML 11414 Pappocetus lugardi GM UI spec ime n 48' Babiacetus indicus GSP-UM 3005 36.8 ' Missing both epiphyses. dorsal margin s of the anterior faces of the zygapophyses flare anteriorly . I thank F. C. Whitmore Jr.• J. G. Mead. and D. J. Bohaska for di scussion Both of these charac ters are shared primitive charac ters of non-basilo­ of ce tacean sac ral verte brae. I also than k W. C. Clyde and J. I. Bloch saurid arc haeocetes . Havin g a single sacral verte bra clearly distingu ish­ for accompa nyi ng me to Lo uisiana to try to find more of the type spec ­ es Na tchitoc hia fro m rem ingtonocetid s. whic h have four vertebrae firm­ ime n. eve n though we were unsuccessful. Las tly I tha nk the Horace H. ly fuse d via the ce ntra in their sacra (Gi nge ric h et al., 1995) . There are Rackh am School of Graduate Studies. Th e University of Mich iga n. for no pak icetid. am buloce tid, or remington ocet id vertebrae tha t approach suppo rting the field wor k in Lou isiana. the size of the vertebrae of Na tchitochia. In additio n. the age of the Cook Moun tain Formation overlaps with that of remingtonocet ids and LIT ER ATURE CITED protocetids from the Old World. but not with pakicet ids and arnbulo­ cetids , whi ch are unkn own from North America (Gi nge rich et al.. 1995 ). Albright . L. B. 199 6. A protocet id ce tacean from the Eocene of South Oth er described protocetines include Protocetus and Eocetus from Carolina. Journal of Paleontology 70 :5 19-522. the Mokattam Hills. Egypt (F raas . 1904); (Sahni and Mishr a, Andrew s. C. W. 1920. A description of new spec ies of ze uglodo nt and 1975 ). Bab iacetus (Trivedy and Satsangi, 1984 ). Rodh ocetu s (Gi nge rich of leath er y turtl e fro m the Eocene of so uthern Nigeria. Proceedings et al., 1994 ). Tak racetus, and Gaviacetus (Gi nge ric h et al., 1995) fro m of the Zoological Society of Lond on 191 9:309- 319. Indo-Pak istan ; Pappocetu s (A ndrews. 1920) from Nige ria. Wes t Africa; Buffren il, V. d.• A. De Ricqles, C. E.Ray. and D. P. Domning. 1990. and Georgiacetus vogtlensis, a new protocet id fro m Georgia and pos­ Bon e histology of the ribs of the archaeocetes (Ma mmalia: Ce ta­ sibly South Carolina (Hulbert and Petkewich , 199 1; Albrig ht. 1996; cea).Journal of Vertebra te Paleont ology 10:455-466. Hulbert. 1998). The verte brae indicate that Natchitochia is co nside rably Dock er y III. D. T. 1996. Toward a revision of the ge neralized strati­ larger than all other protocet ines but Pappocetus and Eocetus. Tabl e 2 graphic co lumn of Mississippi. Mississippi Geology 17:1- 9. sho ws a co mpa riso n of a num ber of skele tal eleme nts of Na tchitochia Fraas . E. 1904. Ne ue Zeu glodont en aus dem unteren Mittelecocan vom with other protocetin es. Th e vertebrae of Natchitoc hia are ve ry different Mok attam bei Cairo. Geolog ische und Palseont ologische Abhand­ in morphology and bon e texture from those that have been ass igned to lungen, Jena, Neue Folge 6: I99-220. Eocetus (Stro me r. 1903. 1908). T he lumbar vertebrae of Eocetus have Ginger ich. P. D.. M. Arif, and W. C. C lyde . 1995 . New archaeocetes elongated ce ntra and pro cesses in additio n to being much larger than (Ma mmalia. Cet acea) fro m the middle Eocene Domanda Forma tion those of Nat ch itochia. of the Sulaima n Range. Punjab (Pa kistan). Contribution s from the Possession of a single sac ral vert ebra clearly distingu ishes Natchi­ Mu seum of Pale ont ology. Univers ity of Mich igan 29 :29 1- 330. tochia from Rodhocetu s, whi ch has four verte brae loosely co njo ined via ---. S. M. Raza, M. Arif, M. Anwa r. and X. Zh ou . 1994 . New the transverse processes in the sac rum (Gingerich et al ., 1994 ). T his whale fro m the Eocene of Pak istan and the origin of ce tacean fea ture also places Na tchitochia in the subfamily Protocetin ae. since the swi mming. Nature 368:844 - 847 . only other cetacean known with a single sac ral vertebra is Protocetus Halstead. L. B.• and J. A. Middleton. 1974 . New mater ial of the ar­ fro m the Mokau am Hill s. Egypt (Fraas. 1904) and this feature has been chaeocete whale. Pap pocetus lugardi Andre ws . fro m the middle suggested to be a characteristic of the subfamily (The wissen et al., Eocene of Nigeria. Journ al of Mining and Geology 8:81 -85. 1996 ). Rodhocetus is a member of the other su bfa mily of protocet ids, Hu lbert. R. c.. Jr.• and R. M. Petkew ich . 199 1. Innom inate of a middle the Indocet inae, which may be characterized by the possession of fo ur Eocene () protocetid whale fro m Georgia . Journal of Ver­ unfused sac ral vertebrae . Na tchitochia is also unl ikely to be co nspec ific teb rate Paleont ology (Suppleme nt to Number 3) II :36A. with Geo rgiace tus becau se Geo rgiace tus incl udes an innominate that ---.---. G.A. Bishop. D. Bu kry, D. P. Aleshire. 1998. A new lacks an auric ular surface for articulation with the sac rum (Hulbe rt and middle Eocene protocetid whale (Mamma lia: Cetacea: Archaeo cet i) Petkewich , (991) . and associated biota from the Middle Eoce ne of Georgia. Journal The vertebrae of Natchitochia could have co me from Papp ocetus of Vertebrate Paleont ology 72 :905 - 925. lugardi, as it is a large protocetin e speci es. but neither species has been Hun er, J. J. 1939 . Geolog y of Caldwell and Winn Parish es. State of found with vertebrae and cra nial material associated. A set of vertebrae Louisiana Department of Co nse rvation Geological Bull etin 15:1­ that were recovered fro m the A meki Formation of Nigeria has bee n 356. assigned to Pappocetu s lugardi (Halstead and Middleton . 1974 ). Th ese Loebl ich, A. R. J.. and H. Tap pa n. 1988. Foraminifera l Gen era and their vertebrae are so mew hat smaller than those of Natchitochia, but they are C lassificatio n. Van Nos trand Re inhold. New York. 970 pp. diffic ult to compare. since they are fro m a very young individual. In Maher. J.C.; and P. H. Jones. 1949. Ground-wa ter exploration in the additio n. an axis vertebra (N HM L 11089) and a number of ribs (N HML Natchi toc hes area Lou isiana. United States Geological Survey Wa­ 11088) have been assigned to Pappocetus lugardi. Th e rib s are larger ter Supply Paper 968-D: 159- 211. and more robust than those of Natchitoc hia , suggesting that they are Sahni, A.• and V. P. Mishra. 197 5. Lower Tert iar y fro m not the sa me spec ies. Until cranial material of Na tchitochia is found western Ind ia. Mon ograph of the Palaeont ological Society of Ind ia associ ated with vertebrae or vertebral mater ial of Pappo cetus is found 3: 1-48. assoc iated with cranial material. thi s question must remain unanswered. Strom er. E. 1903 . Zeu glodon-reste aus dem Oberen Mitteleocan des Acknowledgments-I thank Paul H. Jones. who discovered the type Faj um. Beitrage zur Palaontologie und Geologie Osterreich-Un­ spec imen of Na tchitoch ia jonesi and don ated it to the Na tio nal Mu seum. ga rns und des Orient s 25:65- 100. 668 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 18, NO.3, 1998

--- 1908. Die Urwale (). Anatomischer Anzeiger 33: Uhen, M. D. 1996. New protocetid archaeocete (Mammalia, Cetacea) 81-88. from the late middle Eocene Cook Mountain Formation of Loui­ Thewissen, J. G. M., S. I. Madar, and S. T. Hussain. 1996. siana . Journal of Vertebrate Paleontology (Supplement to Number natans, an Eocene cetacean (Mammalia) from Pakistan. Courier 3) 16:70A. Forschungsinstitut Senckenberg 191:1-86. Trivedy, A. N., and P. P. Satsangi. 1984. A new archaeocete (whale) from the Eocene of India . Abstracts of the 27th International Geo­ logical Congress, Moscow 1:322-323. Received 14 April 1997; accepted 16 October 1997.