MUS. COM9. ZOOL £/Xg LIBRARY OCCASIONAL PAPERS OCT 2 3 1978 Of the HARVARD LnC UNIVERSITY MUSEUM OF NATURAL HISTORY The University of Kansas Lawrence, Kansas NUMBER 75, PAGES 1-20 OCTOBER 3, 1978 AN EARLY MIOCENE (ARIKAREEAN) FAUNA FROM XORTHCEXTRAL FLORIDA (THE SB-1A LOCAL FAUNA) By David Frailey 1 The history of terrestrial vertebrates on the Florida peninsula after its presumed emergence in the Oligocene (White, 1942) is recorded in beach strand-line deposits and scattered karst fillings in the widespread marine limestones (see Olsen, 1965, 1968, for & a review of Tertiary localities). The fragmentation of specimens inherent in beach deposits and the rarity of known bone-bearing sinkholes, either through their absence or through lack of discovery, has created a situation in which a few small localities, often with poorly preserved specimens, achieve great importance in any recon- struction of mid-Tertiary faunal diversity in Florida. For example the Late Oligocene-Early Miocene North American Land Mammal Age, the Arikareean, is presently represented in Florida by only three local faunas: Brooksville (Patron, 1967a), Franklin Phosphate Pit No. 2 (Simpson, 1930), and SB-1A, the subject of this paper. Of these three, SB-1A has yielded the most diverse fauna and the greater number of taxonomically useful specimens. Each of the three known Arikareean local faunas of Florida presents a slightly different aspect of faunal diversitv in Florida in that each contains elements not found in the other three. SB-1A is the most unusual in this respect, and the most indicative of our present state of knowledge on this subject, in that none of its faunal members (with the possible exception of the higher taxon Anchi- tneninae) are found in any of the other two local faunas; all are newjidditions to the Arikareean record of Florida. T7n,!^ U r Un f t XatUr ?' HiSt0ry and Dt 'P art ment of Systematic* and Ecology \Z*T Y V, n maS : Lawrence ' KS 6604 '5; and, Research Associate, Timber- lane Research Organization, Route 2, Box 212B, Lake Wales FL 33853 2 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY The SB-1A Local Fauna was first discovered by Mr. Wesley Hunt during a routine survey of quarries in North Florida in July, 1972, by the Timberlane Research Organization. A small amount of material was collected at this time but its significance was over- looked. Shortly thereafter, the site was rediscovered and brought to the attention of personnel in the Florida State Museum who re- ferred to it as the Live Oak Locality. Both groups made sporadic superficial collections until December, 1974, when Mr. John S. Waldrop received word that the area was being planned for use as a dump for compacted garbage. During December, 1974, and March, 1975, with intermittent trips in between, Mr. Waldrop and field crews from the Timberlane Research Organization removed, washed, and sorted the material that forms the basis of this study. Recent work has not added to the taxonomic diversity of the fauna nor added to the representation of the rarer elements and justifies a systematic description of the fauna at this time. The SB-1A Local Fauna occurs in an unstratified conglomeratic sequence above the Suwannee Limestone (Oligocene). The locality was exposed by limestone mining operations of Florida Rock Prod- ucts, Inc., Shands and Baker Division, from which the S and B of the faunal name is derived. The site is located about one mile north of the small town of Live Oak, Suwannee County, Florida. Tooth nomenclature follows that of Szalay (1969) and P* tton , and Taylor (1971). All measurements are in millimeters. "( )" indicates an approximate measurement. The following institutional abbreviations are used: AMNH, American Museum of Natural History; CM, Carnegie Museum; F:AM, Frick American Mammals, American Museum of Natural Historv; TRO, Timberlane Research Organization, Rt. 2, Box 212B, Lake Wales, FL 33S53; UF, Uni- versity of Florida; UOMNH, University of Oregon, Museum of Natural History. Acknowledgements I am indebted to Mr. John S. Waldrop, Coordinator of Research, Timberlane Research Organization, for permission to study and report on this material. Individuals who have aided in the collection of this material include: Fred Barrett, Fred Helsel, Wesley Hunt, John Iskra, Greg Lail, Steve Martin, Emroy Powell, Aubie Rhoden, and Dale Wyatt. Washing and sorting of some of the matrix was done by John Beaudua. I would also like to thank colleagues of mine who aided me with various identifications and discussions during the course of this project: Dr. R. H. Tcdford and Mssrs, B. Taylor and H. Galiano of the American Museum of Natural History; Dr. R. M. Hunt of the Nebraska State Museum; Dr. L. D. Martin of the University of Kansas Museum of Natural History, and Mr. Waldrop. Figures 1 A-B, 1 1 - 1 ; and 4 were drawn by Mr. Ray EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 3 Gooris. Ms. Deb Bennett assisted with stippling and layout. A special note of gratitude is extended to the officials of Florida Rock Products, Inc., for permission to collect on their properties. Geology The following information was provided by Mr. John S. Waldrop. Site Stratigraphy.— The general stratigraphic section in the pit area is 20 to 30 feet of exposed Suwannee Limestone unconformably overlain by a conglomeratic sequence that is also 20 to 30 feet thick and capped by a reddish clay deposit or residuum that ranges from to 7 feet in thickness, excluding sinkhole fillings. The conglomer- atic sequence begins with a basal bed of reworked Suwannee Lime- stone boulders grading into an unstratified, poorly sorted, yellowish- white limestone conglomerate. The contact between the underlying Suwannee Limestone and the bounder bed is an undulating erosional surface. Three periods of activity, here referred to as Zones, are shown at the fossil site itself, as the main bone quarry rests on a second boulder bed consisting of boulders 3 to 4 feet in diameter and is overlain by a third boulder bed. The three conglomeratic zones are alternating, irregularly developed, unstratified beds with cobble-sized particles dominant in one area and pebble-sized particles dominant in another. There does not seem to be a pattern to the dispersion of these particles in the sequence, as they appear to alternate randomly within the plane of the bed. The thickness of the zones of the sequence is highly variable. Zone 1, the lowest bed, was the most nearly uniform bed, ranging in thickness from 8 to 10 feet. Zone 2, the middle bed, was observed to vary between 2 and 6 feet; and Zone 3, the upper bed, varied between' 3 and 15 feet in the pit area. At the fossil site. Zone 1 is S feet thick, Zone 2 is 4 to 5 feet thick, and Zone 3 is 15 feet thick. The vertebrate fossils occur in the finer matrix of the unstratified, poorly sorted, yellowish-white limestone conglomerate in Zone 2. This finer matrix consists of a white to yellowish-white argillaceous calcarenite with blebs and stringers of almost pure green clay with white clay surrounding many of the larger particles. During quarry operations in March, 1975, a small lens of clay was encountered in the lower part of the quarry. This lens was about 2 feet thick and extended laterally for about 4 feet. The conglomeratic particles are reworked Suwannee Limestone, some of which are virtually un- weathered (although strongly recrystallized as is the Suwannee Limestone in this area) and some of which are weathered to a limestone saprolite. The white clay is probably derived from this saprolite as it generally occurs within crevices in and surrounds these saprolitic particles for 1 to 6 inches. The conglomeratic fraction ranges from pebble-sized to boulder-sized particles with the pebble and cobble sized particles being most numerous. The 4 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY more strongly recrystallized particles are well rounded but some are angular or subangular and nearly all are roughly spheroidal in shape, although many show concavities due to erosion. The bone is overall, very well permineralized and preserved, although often badly broken by expansion and contraction of the clay inside- and around the bone. A few bones are badly weathered and crumbly, however, and some- were not collectable. Generally, the bone in' the white elav either shows the least permmerahzation or greatest post-depositional weathering. Numerous well perminer- alized angular bone and tooth fragments occur throughout the site. There was little- evidence of association of postcranial elements in the site and no cranial-postcranial association. In several instances associated groups of camel teeth were found in their natural sequence but without any trace of the jawbone. In other instances, the jawbones had been completely shattered but were in association with the teeth. This shattering appears to have occurred due to the expansion and contraction of the clay within the- cavities in the jaws. This phenomenon would explain the extreme rarity of complete mandibles and the- absence of the resistant skulls. The main fossil quarry is located in Zone 2 althexigh some bone fragments, possibly due to stratigraphic leakage, were found m Zone 1, and a few bone fragments, possibly reworked, occur m Zone 3. Neither Zone 1 nor Zeme 3 were found to be rich enough to warrant quarry operations. The apparent absence or extreme scar- city of bone from the remainder of the conglomeratic secmence has not been satisfactorily explained. It should be pointed out, however, that due to the vertical and unstable nature of much of the pit wall, continuous direct observation could not be made in the inte-re-st of safety. Field observation resulted in no apparent reason for the concentration of bone in this one small area. Slumping and heavy vegetative growth have also hampered research into this problem and the ejuestion is as yet unresolved. Although no well defined bedding planes were observed by close examination during excavation of the main bone quarry, the overall appearance of the conglomeratic se (1 ue-nce at a distance of one-halt mile suggests that the three boulder be-ds are essentially horizontally bedded. Even though the- zones thicken and thin and, as a result, the contacts between the basal boulder be-ds and the- upper part of the underlying conglomeratic zones are wavy and undulating, no sharply dipping beds or angular disconformities were observed. Sinkhole development was not apparent within any of the zones. The hemzontality of the beds was much more apparent at a distance, however, than close up, and no appearance of bedding was observed within any of the zones. The upper surface of the- conglomeratic sequence is very irreg- ular and undulating, but it has not been determined whether this EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 5 was a naturally undulating erosional surface or was influenced by karst activity or perhaps by a combination of the two. The above mentioned horizontally of the beds would sugest that the dominant effect was one of erosion. The conglomeratic sequence is unconformably overlain by an orangeish-red and gray mottled clay or sandy clay representing what is thought to be a residuum and soil profile, but is possibly a sedi- mentary deposit. This clay rests upon either the pebble or cobble conglomeratic material of Zone 3, depending upon the size particle that is dominant in that particular area. The unconformable nature of the contact between this upper clay and the upper part of the conglomeratic sequence, without the development of a weathering profile, might be one reason for considering the clay a sedimentary deposit or redeposited residuum. The absence of a weathering profile is puzzling as the geologic history of the area indicates a long period of subaerial exposure, a period of at least post-Hemphil- lian (Early Pliocene). Where the section along the pit wall has not been obscured or disturbed by mining activity, vegetative growth, or slumping, sinkholes are seen to be developed down into and through the conglomeratic sequence. These sinkholes are filled with a red or gray sandy clay or clay alone. The sinkholes near the main quarry that were studied in detail are filled with a blocky, orangeish-red and gray mottled clay or sandy clay. The overall ap- pearance is a reddish color but with much gray locally. As this clay seems to be the same as the surface veneer, the formation of, or at least collapse of, these sinkholes must have been subsequent to the time of deposition of the conglomeratic sequence. The depth of the observed sinkholes ranges from 1 to more than 50 feet. Mode of Formation and Significance of Deposit.— The site would seem to be one of proximal deposition with little transport as evi- denced by the associated, but loose, teeth. Reworked Suwannee Limestone invertebrates are common in the site. These consist of casts of mollusks, echinoids and echinoid spines, and tubes or burrows of invertebrates. Younger invertebrates are totally absent. This is surprising due to the abundance of early to middle 'Miocene mollusks in deposits along the Suwannee River about 15 miles north- east of the site (Brooks, 1966). A similar yellowish elav about 10 miles north of the site contains numerous silicified specimens of Ostrea normalis associated with and stratigraphically below a mid- dle Miocene land vertebrate fauna. Except for some as vet uni- dentified frog and snake remains, the vertebrate fauna from SR-1A is strictly terrestrial. There is a definite absence of freshwater fishes alligators, and freshwater turtles as well as the marine sharks and rays that are common in many other Miocene vertebrate faunas of Honda. The erosion and pitting on some bone and many of the teeth suggests that the bone lay in the open for a period' of time before being covered. 6 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY The sediments, especially the cobbles and boulders, suggest considerable current energy, if transported by water. The poorly sorted sediments indicate rapid transport and deposition. The total absence of any marine or freshwater animals of similar age in association with the fauna suggests a means of transport other than water, although it is conceivable that the aqueous environment could have been present without these forms becoming entombed within the sediments. In a paper on the geological history of the Suwannee River, Brooks (1966) makes several statements that might suggest an answer to this seeming paradox. In speaking of the structures of an area approximately 15 miles to the northeast of SB-1A, Brooks discusses the stratigraphic displacement in the narrow belt between the karst plain and the high flatland physiographic entities. He also suggests the possibility that this displacement, which is commonly 60 & or more feet, is due to faulting. The SB-1A Locality lies very near the boundary between the karst plain, which the site is located upon, and the high flatlands just to the north and northeast of the site. Displacement of 60 or more feet in the vicinity of SB-1A with its attendant mass wasting and colluvial transport, could provide the conditions necessary for the rapid transport and deposition of poorly sorted sediments that contain particles ranging from clay to boulder size. This would also explain the extreme varibility in the dispersion of particle sizes and the unstratified nature of the sediments. The appearance in the fauna of only terrestrial vertebrates is also ex- plained as is the absence of marine or freshwater forms. If younger marine sediments were deposited in this area they have since been eroded, except perhaps for the upper clay veneer. It should be born in mind that definite proof for this hypothesis is lacking at present although it best explains this otherwise puzzling catastrophe of nature. Younger sediments occur at similar elevations to the north and northeast. A similar widespread catastrophe of a similar age is also present in south-central Florida, again in the same geologic setting. If this hypothesis can be proven, then it indicates that uplift and erosion of the Ocala Arch continued into the late Early Miocene and is perhaps the best direct evidence for uplift and erosion of the Ocala Arch. SYSTEMATIC ACCOUNTS Order CARNIVORA Bowdich, 1821 Family AMPHICYONIDAE Trouessart, 1885 Genus Mammacyon Loomis, 1936 Mammacyon cf. obtusidens Loomis, 1936 Figs. 1A-G Discussion.— Familial rank follows Hunt (1972). The M 1 (TRO 390) of a large carnivore in the SB-1A Local Fauna is immediately EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 7 referable to either Mammacyon or Temnocyon on the characteristic prominence of three cusps, the paracone, metacone, and the cen- trally located protocone, and the anteroposterior expansion of the tooth at the protocone. The latter characteristic gives the tooth a rough "figure 8" outline in occlusal view. The very large size of Fig. 1.— A-G. Mammacyon cf. obtusidcns. A. M\ TRO 390, labial view; B. M\ TRO 390, occlusal view; C. Lower canine, TRO 388, labial view d' Medial phalanx, TRO 387, lateral view; E. Medial phalanx, TRO 387, dorsal view; F. Proximal phalanx, TRO 386, lateral view; G. Proximal phalanx, TRO 386, dorsal view. H-I. Paroligobunis frazieri n. sp., UF 23928, holotype. H. Occlusal view of dentition; I. Labial view of ramus. 8 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY the protocone and the wide expansion of the tooth at the protocone and a heavy lingual cingulum are more like Mammacyon obtusidens and the referral is made on that basis. The size of the \f (17.7 x 24.4, length x width) is elose to that of Mammacyon obtusidens although the relative expansion of the protocone area (expressed as a ratio of labial length /labial width across the protocone. Hunt, 1971) is greater than in M. obtusidens (1.1 vs. 1.32-1.36). This greater expansion of the tooth in this area may be no more than an extreme of individual variation or may later prove to be a species distinction. The uncertainty on this point prevents certain referral of this specimen to M. obtusidens: 1 A right lower canine (TRO 388, Fig. 1C), presumably of Mammacyon cf. obtusidens because of its size, has a long, flat wear facet from its tip to the base of the crown. The advanced wear of this tooth contrasts with the slight wear on the M 1 and indicates the presence of more than one individual in the deposit. A proximal and a medial phalanx from SB-1A (TRO 386; 387; Figs. 1D-G) are attributed to Mammacyon cf. obtusidens. In size and proportions they are similar to those of Daphoenodon superbus as described by Peterson ( 1910). Mammacyon obtusidens occurs in Arikareean beds (Monroe Creek and possibly Harrison formations) of South Dakota and Nebraska with a single specimen recorded from the Upper John Day beds ( Hunt, 1971). This referral indicates a Monroe Creek or possibly Harrison age equivalence for the SB-1A Local Fauna. Subfamily CANINAE Gill, 1872 ?Mesocyon Scott, 1890 Discussion.— A medium-sized canid is represented in the fauna by a single, badly damaged P 1 (TRO 391) which is missing the protocone. This tooth is questionably referred to Mesocyon because it lacks a large parastyle, as do the P's of Mesocyon, and because Mesocyon is the only canid of this size which occurs in the Arikare- ean, the age indicated by the other faunal members. Tomaretus and Cynodesmus are of this size range but have a large parastyle on P 1 and occur in Hemingford and later times. Phlaocyon sp. Matthew, 1899 Figs. 2A-B Discussion.— The P', TRO 392, from SB-1A is smaller than the P* on the holotype of P. leucosteus (AMNH 8768) and has a rela- tively smaller hypocone. A small, accessory cusp is present on the ~ Dr. R. M. Hunt is currently studying the taxonomy and relationships of Temnocyon and Mammacyon. He has generously allowed me to draw upon his work in progress hut a more complete discussion of these genera must await his paper. EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 9 3mr -i Fig. 2.— A-B. Phlaocyon sp., right F, TRO 392. A. Occlusal view; B. Lingual view. C-D. Protosciurus sp., right ramus with lower incisor and !>,, TRO 401. C. Occlusal view of P,; D. Labial view of ramus. anterior cingulum of the SB-1A P 4 which is absent on that of Phlaocyon leucosteus. Phlaocyon marslandensis (McGrew, 1941) is even larger than P. leucosteus but shares the features of P* with P. leucosteus which contrast with the P 4 from SB-1A. The P 4 of Phlaocyon found at SB-1A could be within the limits of variation for P. leucosteus. On the other hand, the species of Phlaocyon from SB-1A may be new but certain identification is not possible with the material at hand. 10 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Measurements of the P' from SB-1A and that of P. leucosteus are compared in Table 1. Table 1. -Comparative measurements (mm) of P 1 of Phlaoctjon sp. from SR-1A and of Phlaocyon leucosteus (AMNH 8768, holotype). Family MUSTELIDAE Swainson, 1835 Gexus Paroligobunis Peterson, 1906 Paroligobunis frazieri, new species Fig. 1H-I Etymology.— Named for Michael Frazier, whose skill in prep- aration saved this specimen and in honor of his work in Florida paleontology. Holotype.— UF 23928, right ramus with C,, P 2 -M i; Pi and M 2 alveoli. Diagnosis.— Ramus more slender than in P. simplicidens or P. petersoni. Premolars less crowded than in either species. Paroligo- bunis frazieri is larger than P. petersoni but slightly smaller than P. simplicidens. Description and Comparisons.— The shortened M, with a strong labial convexity is characteristic of Oligobunis and Paroligobunis and serves to separate these genera from other mustelids of this size range. The ramus from SB-1A is further referrable to Paroligobunis (using CM 1553, holotype of P. simplicidens) and not Oligobunis (using AMNH 6903, holotype of O. crassivultcs) on dental features. Paroligobunis, and the SB'-1A ramus, has a smaller M, than Oligo- bunis; a larger P, (P, of Oligobunis is reduced to a simple, insignifi- cant peg); no diastemata between the premolars (small diastemata are present between P,-P, and P,-P, of Oligobunis) ; and in not having an entoconid on M, as does Oligobunis. Paroligobunis simplicidens (Peterson, 1910) and P. petersoni (Loomis, 1932) are the only species of this genus currently recog- nized as valid. Paroligobunis frazieri differs from P. simplicidens in being slightly smaller ( see Table 2 ) ; in having a more slender ramus (in depth and width); the premolars of P. frazieri are less massive than those of P. simplicidens: P 2 and P. ; are less crowded (P 2 in P. simplicidens has been crowded in the tooth series to the point that it is rotated, labially, about 30°); P, and P :! of Paroligobunis frazieri EARLY MIOCENE FAUNA — NO RTHCENTRAL FLORIDA 11 are not broadly widened, posteriorly, as are those of P. simplicidens; and P, and P, of P. frazicri have a more distinct posterior cingulurn than do these premolars in P. .simplicidens. The apparent less crowd- ing of the premolars in P. frazicri may be an artifact of the recon- structed mandible but it appears to be natural. The rotation of P 2 in P. simplicidens places this tooth parallel to the sagittal section of the animal. In P. frazicri, P, is in line with the tooth row. Paroligobunis petersoni, according to Loomis (1932), is much smaller than either P. simplicidens and hence also of P. frazicri Paroligobunis petersoni also has a massive mandible in agreement with P. simplicidens and in contrast to the light ramus of P. frazicri. Discussion.— Paroligobunis simplicidens occurs in the Harrison Formation (late Arikareean) of Nebraska (Peterson, 1910) Paroligobunis petersoni was discovered in beds of "Upper Harri- son" age (=Hemingfordian, Schnltz and Falkenbach, 1968) near Van Tassel, Wyoming. These two species are probably more close y related to each other than either is to P. frazicri as a massive mandible, present in both species, is very likely a derived character in this genus. Oligobunis and Paroligobunis are undoubtedly closely related Oligobunis is known from the Thomas Farm Local Fauna (Late Hemmgfordian) of Florida (Oligobunis fioridanus). The relation- ship between O. fioridanus and P. frazicri is not readily apparent but is probably no closer than for other species in each genus. Table 2.-Comparative measurements (mm) of Paroligobunis frazicri, new species, and P. simplicidens. Character Length, P 1 -M 2 C, (length) (width) P 2 (length) (width) P, (length) ( width ) P* (length) ( width ) Mi (length) (width) Depth of mandible ( below Mi ) Width of mandible ino T o n (at MO io ' U \2 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Order CARNIVORA Gen. et sp. indet. Fig. 3A-B Discussion.— An isolated metatarsal II (TRO 402) of an uni- dentified carnivore is illustrated in Fig. 3A-B. The features of the articular surfaces are obscured by an apparent osteopathology which renders taxonomic referral inconclusive. The size of the metatarsal is between that expected for Phlaocyon or Mesocyon the two carnivores in the fauna which are nearest in size, and the size one would expect for an animal like Leptocyon or Nothocyon. The carnivore which possesed this metatarsal was digitigrade and the metatarsals were not closely appressed. The distal articu- lation is rounded with only a posterior keel and has much the appearance of a felid distal articulation. ■ o 5mm FlG 3 _ A -B. Carnivora gen. et sp. indet., right metatarsal II, pathologic, TRO 402. A. Dorsal view; B. Lateral view. C-D. Protosciurus sp., left tibia, TRO 400. C. Anterior view; D. Lateral view. EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 13 Order PERISSODACTYLA Owen, 1848 Family EQUIDAE Gray, 1S21 Subfamily ANCHITHERIINAE Osborn, 1910 Gen. et sp. indet. Discussion.— An anchitherine horse about the size of Parahippus leonensis is represented in the SB-1A Local Fauna by a single lateral metapodial (TRO 393). The scarcity of horse material from this deposit, and the evident rarity of horses in the vicinity during deposition, is an intriguing problem for which there is no satis- factory answer. In this respect SB-1A stands in sharp contrast to the Hemmgfordian faunas in Florida, especially Thomas Farm, in which horses are abundantly represented. Order ARTIODACTYLA Owen, 1848 Suborder TYLOPODA Illiger, 1811 Family CAMELIDAE Gray, 1821 Gexus Nothokemas White, 1947 Nothokemas waldropi, new species Fig. 4 Etymology.— Named for John S. Waldrop, who collected this material, in respect for his diligent stratigraphic paleontology. Holotype.—UF 23927, left ramus with C, P,-\L Diagnosis.— About 1/2 the size of N. floridanus and A T . hidal- gensis, the only previously recognized species of Nothokemas: Description and Comparisons.— Lower Dentition: The lower incisors are spatulate, thin, and form a closely set, fan-shaped group in which I, and I, each slightly overlaps the incisor in front. The lower canine tooth is long and strongly recurved. The first lower premolar is not present in this genus and its McSof a beCn 1 USCd aS part ° f a § eneric description by Patton (lyoJj. As can be seen on a radiograph of the holotype of N. waldropi on file at the Timberlane Research Organization the P, is truly absent and not merely suppressed. A long diastema separates C, from P 2 . The dorsal border of the diastema drops quickly between C, and P 2 apparently as a result of the missing P,. P, is a simple, linear tooth. The central cusp is prominent. P. and P, are relatively thinner than these teeth in N. floridanus and N niaaLgensis. P, is elongate and slender. A lingual stylid is present which arises just posteriorly to the protoconid and which may extend to the rear margin of P, or less than half that distance depending upon the individual. i & i P4 is typically eamelid in appearance with its widest part at the nypocomd giving the characteristic wedge-shape to the tooth. 14 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY FlG 4-Nothokcmas waldropi n. sp. A. Right F-M 3 with partial maxilla TRO 389 labial view; B. TRO 389, occlusal view; C. UF 2392/ holotype, left ramus with C h R-M, occlusal view of dentition; D. UF 23927, holotype, labial view. The lower molars have the discontinuous and overlapping crests which are typical of oxydactyline camels in which the posterior crest unites 'first with the anterior crescent, and not the anterior crest, during wear. Intercolumnar styles are generally absent, but slight styles are present on molars of some individuals and are presumed to be only another example of individual variation in this species. Internal ribs are faintly discernible on the crests. A small extension of the posterior crest (entoconid) which is present on the M, of two individuals (TRO 357, 360) is suggestive of the "double-enamel loop" of Floridatragulus (Patton, 1969). The posterior terminus of the posterior crest of M 3 in N. waldropi is apparently also individually variable. Upper dentition: I 1 - are unknown; I 3 is large, curved, and labially-lingually flattened. Small blades are present on the anterior and posterior margins. The diastema between I- and P was small, approximately 2 mm in length. C 1 is curved, caniniform, and larger than I 3 or P. P 1 is a simple, short-bladcd tooth as is also seen in Oxijdactylus. P 1 is double-rooted but the roots are fully fused. P- is an elongate, tricuspid tooth which has a simple linear enamel pattern. The protocone is located anterior to the center of the tooth and is the most prominent cusp. Other than the P- ot Floridatragulus, the P- of Nothokcmas waldropi is the longest, rela- tive to P\ among all the genera examined. The length of P- approximates that of P '. P 3 like P-, appears to be elongated antero-posteriorly. This effect'is produced in part by the small size of the internal cingulum. EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 15 This eingulum docs, however, have two distinct cuspules which arc located above the medial root near the protocone. The overall appearance is like the P 3 of Oxydactylus longipes. P 4 is simple, camelid-like in shape and pattern and nndiagnostic except by its small size. Only a very slight eingulum is present on the posterior part of the crescent on a few individuals while totally absent in others. The upper molars are characteristically oxydactyline in their low crown height, prominent ribs and styles (particularly the meso- style), and the non-linear overlap of the anterior crest (paracone) by the posterior crest (metacone). The external ribs are only slightly less prominent than the mesostyle (as in all oxydactyline genera except Miolabis). Intercolumnar styles are almost totally lacking although occasionally found on M 3 . These styles are more frequently distributed among other genera of camels with the oxydactyline molar pattern although subject to some degree of individual variation in Miolabis and Oxydactylus. The anterior crescent may bifurcate posteriori)', again determined by individual variation, reminiscent of the bifurcation seen in xiphodonts and in some individuals of Pocbrothcrium. Dental measurements of Nothokemas waldroui are given in Table 3. Table 3.— Measurements (mm) of the teeth of Nothokcma.s waldropi 16 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Discussion.— The genus Nothokemas was first recognized by White (1947) who placed it in a new family, the Nothokcmadidae, inccrtae sedis, within the Hypertraguloidea. Patton (1969) rein- terpreted the hypertraguloid features of Nothokemas as plesio- morphic for artiodactyls and transferred Nothokemas to the Family Camelidae, Subfamily Aepycamelinae Webb, 1965. The Aepycame- linae is probably a paraphyletic group and at present contains such genera as Oxydactylus, Acpycamelus, Paratylopus, and Miolabis '(Webb, 1965; Simpson, 1945). Nothokemas is undoubtedly similar to Oxydactylus and could logically be placed within the Aepycamelinae, but, because or the questionably validity of that subfamily, I have chosen instead to refer to Nothokemas as an "Oxydacty Jus-like camelid m reference to the characteristic molar pattern shared by these two genera. Other Oxi/dacti/lus-MVe camelids are Miolabis, Gentilicamelus, and Floridatragulus, but decidedly not Paratylopus. Paratylopus is a slightly advanced poebrothere. Acpycamelus is probably closely related to Oxi/dactiilus but has modified the Oxydactylus molar pat- tern through hvpsodontv, a derived condition possibly indicative of relationship with Procamclus and later camels. The inclusion of Floridatragulus in this group appears at first to be inappropriate m view of the striking features of this genus which have led to its placement in the monotypic Subfamily Floridatragulinae Magho, 1966. Many of the characters of Floridatragulus, however, are prim- itive ruminant characters as recognized by Patton (1969) and are of no use in phvlogenetic grouping. The most unusual features are the greatly elongated muzzle and the double enamel loop or divided hypoconid on M 3 . The elongated muzzle is certainly autapomorphic but the double enamel loop may not be. The resemblance of the small posterior extension of the posterior crest as seen on some individuals of Nothokemas ualdropi to the lingual half of the double enamel loop of Floridatragulus suggests an hypothesis for the origin of this characteristic feature of Floridatragulus. A further extension of the posterior crest (the entoconid) of M, onto the talonid would produce a typical double enamel loop. A similar decree of variation in the posterior limit of the posterior crest of M, is seen in some individuals of Miolabis (F:AM 6S9S5, 6S9S8) from Trinity River, Texas ( Barstovian), and supports the contention that the double enamel loop of Floridatragulus is not as exceptional as White (1940, 1947) and Patton (1967b, 1969) believed. These enamel loops on the talonid of M, would then not be homologous with those of hvpertragulids in which both crests of the talonid of M 3 probably arose from two small crests which run anteriorly from the single cusp on the talonid, the hypoconulid, as can be seen m Archaeomcryx and other early artiodactyls. Nothokemas was previously known from the Hemingfordian of EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 17 Florida and Texas (Patton, 1969). The occurrence of Nothokcmas in the SB-1A fauna is the earliest occurrence of this characteristic Gulf Coast genus. Order RODENTIA Bowdich, 1821 Suborder SCIUROMORPHA Brandt, 1855 Family SCIURIDAE Gray, 1S21 Tribe SCIURIM Burmeister, 1854 Genus Protosciurus Black, 1963 Protosciurus sp. Figs. 2C-D, 3C-D Discussion.— A partial right ramus with the incisor and P 4 (TRO 401 and a tibia (TRO 400) of a squirrel are the only indication of small mammals in the SB-1A fauna. The P 4 of the squirrel from SB-1A, unlike the P 4 s of most genera of squirrels, does not have a laterally compressed trigonid or rad- ically enlarged hypoeonid and retains a basically unmodified tree squirrel tooth pattern as is seen in Protosciurus. The following description of the P 4 from SB-1A, using the terminology of Black (1963), is also applicable, except where noted, to the P 4 s of P mengi and PProtosciurus jcjfersoni (referral of Black, 1965). The P 4 of Protosciurus condoni has been figured by Black (1963) but it is damaged and little can be said about it. The P 4 s of the other species of Protosciurus are unknown. The trigonid of P 4 is composed of a clearly defined protoconid and metaconid which are well separated vet connected bv a metal- ophid anterior to which is a trigonid basin and a small, knob-shaped anterior cingulum. the Pparaconid. The protoconid and metaconid are not well separated on the P 4 of ?P. jcffcrsoni and an elongate anteroconid is present on the protoconid which may be equivalent to the knob on the anterior cingulum of P. mengi and the Proto- sciurus horn SB-1A. The metaconid on the P 4 from SB-1A is strongly cone-shaped (as are the protoconid and hypoeonid), whereas in P. mengi the metaconid is less clearly separable from the anterior run of P 4 . The protoconid is placed slightly posteriorly to the metaconid. The protoconid and metaconid are not appressed 3 and are approximately of the same size. The hypoeonid is slightly larger and creates a postero-labial swelling on 'the otherwise square to rectangular occlusal outline. In all other genera of squirrels, the hn/P C F, T the , holo J- v P e nf P - cond °™ (UOMNH F-5171) is badly damaged (!%' ) 1 "° tOCOn ; d ai \ d ™*aconid appeared to be closely appressed to Black (Ubo). On a referred specimen in the American Museum of Natural History Protosaurus cf. condoni (F:AM 99254). the metaconid and protoconid of S appear to be relatively closely placed due to the much larger size of the 18 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY relatively great size of the hypoconid, combined with the laterally compressed trigonid, produces a more triangularly shaped F 4 . lne rim of the talonid is continuous between the hypoconid and a distinct entoconid. A mesoconid is present on a faint ectolophid. The mesostylid is represented by a slight rise on the posterior ot the metaconid. . , , The ramus also has features of Protosciurus as given by Black (1963) in his diagnosis of the genus: The massateric fossa ends anteriorly beneath M x ; the diastema is short; the diastemal depres- sion is deep; and the mental foramen is positioned well below the depression of the diastema. Without including PP. jeffersoni, four species of Protosciurus have been described (Black, 1963). Listed in decreasing order of size these are: Protosciurus concloni, P. tccuyensis, P. mengi, and P. rachelae. The P 4 of Protosciurus sp. from SB-1A is slightly smaller than that of P. mengi and differs in having a more distinct meta- conid. The P 4 from SB-1A measures 2.1 x 1.7 mm versus 2.5 x 2.2-2.5 for P. mengi (Black, 1963). The ramus from SB-1A has a small muscle scar anterior to the massateric fossa as does P. tccuyensis but unlike P. condom (un- known in P. mengi and P. rachelae). The massateric fossa on the SB-1A ramus is deeper than on the species of Protosciurus for which this fossa is known ( all except P. rachelae ) . A complete tibia (TRO 390) from the SB-1A locality is referred to Protosciurus sp. on the basis of its size and sciuromorph features. The significance of this specimen lies in its greater resemblance to tibiae of arboreal squirrels (Sciurus, Tamiasciurus) than to those of crround squirrels (Tamias, Citellus, Spermophilus). Specimen TRO 390 is slender, relatively straight, the tibial crest terminates in the proximal one-fourth of the total length, and the distal articular grooves (especiallv the medial) are not well defined as in tree squirrels and in contrast to the sturdy, curved tibiae of ground squirrels in which the tibial crest reaches approximately one-third the length and the articular grooves are more sharply defined. These similarities support the conclusion of Black (1963), based on dental characters, that Protosciurus was a tree squirrel. Protosciurus occurs from the Chadronian (PProtosciurus jeffer- soni; Black, 1965) or Orellan to the Prc-Harrison Arikareean ( Black, 1963). This occurrence of Protosciurus at SB-1A would appear to be one of its latest occurrences. Age of the Fauna The SB-1A Local Fauna contains genera which are found in Arikareean and Hemingfordian deposits outside of Florida and could conceivably be referred to either age. Phlaocyon (Matthew, 1901- Galbreath, 1953) and Nothokcmas (Patton, 1969) are the most EARLY MIOCENE FAUNA — NORTHCENTRAL FLORIDA 19 apparent Hemingfordian forms. Paroligobunis is both an Arikareean (P. simplicidens) and Hemingfordian (P. petersoni) genus. Paroligo- bunis frazieri, however, is more like P. simplicidens in its features. Mammacyon is primarily an Arikareean genus; Mammacyon obtu- sidens occurs in the middle Arikareean (Monroe Creek Formation). Protosciurus has never been found later than the Middle Arikareean ( Black, 1963 ) . As a choice must be made on the reliability of the indicators, I think it more probable that the widespread and better known forms, Mammacyon and Protosciurus, are better age indica- tors and that the presence of Phlaocyon and Nothoketnas in the SB-1A Local Fauna represent Arikareean occurrences of these genera. Summary A small Arikareean fauna, the third known from Florida, is described. The fauna consists of Mammaci/on cf. obtusidens Phla- ocyon sp., PMesocyon, Paroligobunis frazieri n. sp., an indeterminate carnivore, an indeterminate anchitherine horse, Nothoketnas wal- dropi n. sp., and Protosciurus sp. All the included taxa, with the exception of the higher taxa which represent indeterminate species are new additions to the faunal record of Florida. Mammacyon Protosciurus, and Paroligobunis are present in Arikareean faunas of the classic Great Plains sequence and allies the SB-1A Local Fauna with this North American Land Mammal Age. Mammacyon and Protosciurus may be eonspecific with known forms but the small amount of material referable to these genera prevents a full taxo- nomic treatment at the species level. The presence of Phlaocyon in 11 tt r a 1S cvidentl y an early occurrence of this more typ- ically Hemingfordian genus, and in some respects this specimen is more primitive than the later species. The new species of Nothoke- mas _rrom SB-1A extends the temporal range of this characteristic en It Coast Hemingfordian camel back into the Arikareean. The bli-LA fauna as a whole is similar to the better-known Arikareean faunas of western North America with the added dimension of regional differentiation as exhibited in new species of Paroligobunis and the endemic Gulf Coast genus Nothokemas. Further distinc- tions among the rarer taxa, which are now conservatively attributed to individual or populational variation, may become apparent as the fossil record of Florida becomes better known. The fauna is from unsorted terrestrial outwash sediments over- lying the Suwannee Limestone (Middle Oligocene) which may have been associated with faulting caused by the uplift of the Ocala Arch in northcentral Florida. LITERATURE CITED ,tA fc 'L™Lt Sow? m-m 1 American Tertiary Sciuridae ' Ml 20 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY Black C C. 1965. Fossil rodents from Montana. Part 2. Rodents from the Early Oligocene Pipestone Springs Loeal Fauna. Ann. Carnegie Mus., 38 (2): 1-48. Brooks H. K. 1966. Geological history of the Suwanee River. In. Geology of the Miocene and Pliocene series in the north Florida-south Georgia area, N. K. Olsen (ed.), Atlantic Coastal Plain Geol Assoc, and South- eastern Geol. Soc. Guidebook, Seventh Annual Field Conf., pp. o,-45. Galbreath, E. C. 1953. A contribution to the Tertiary geology and paleon- tology of northeastern Colorado. Vertebrata, Univ. Kansas Publ., Art. 4: 1-120. . Hunt, R. M. 1971. North American Amphicyonids (Mammalia; Carmvora ) . Unpubl. Ph.D. Diss., Columbia Univ., New York. Hunt R M 1972. Miocene amphicyonids (Mammalia, Carnivora) from the Agate Springs Quarries, Sioux County, Nebraska. Amer. Mus. Nat. Hist. Novit, 2506: 39 pp. Loomis, F. B. 1932. The small carnivores of the Miocene. Am. Jour. Sci., 24: 316-329. Matthew W. D. 1901. Fossil mammals of the Tertiary of northeastern Colorado. Mem. Amer. Mus. Nat. Hist., Vol. I, Part VII: 353-447, 4 pi. McGrew, P. O. 1941. A new procyonid from the Miocene of Nebraska. Publ. Field Mus. Nat. Hist.. Geol. Ser., 8: 33-36. Olsex, S. J. 1965. Vertebrate fossil localities in Florida. Florida Geol. Surv., Spec. Publ. 12: 28 pp. Olsen, S. J. 1968. Miocene vertebrates and north Florida shorelines. Paleo- geogr., Paleoclimatok, Paleoecol., 5: 127-134. Pattox, T. H. 1967a. Oligocene and Miocene vertebrates from central Florida. In: Miocene-Pliocene Problems of Peninsular Florida, H. K. Brooks, E. C. Pirkle, R. C. Fountain (eds. ), Guidebook, Southeastern Geol. Soc. Thirteenth Field Trip. pp. 3-10. Pattox, T. H. 1967b. Revision of the selenodont artiodactyls from Thomas Farm. Quart. Jour. Florida Acad. Sci., 29 (3): 179-190. Pattox, T. II. 1969. Miocene and Pliocene artiodactyls, Texas Gulf Coastal Plain. Bull. Florida State Mus., 14 (2): 115-226. Pattox, T. H., and B. E. Taylor. 1971. The Synthetoceratinae (Mammalia, Tylopoda, Protoceratidae ) . Bull. Amer. Mus. Nat., 145 (2): 123-218. Petersox, O. A. 1910. Description of new carnivores from the Miocene of western Nebraska. Mem. Carnegie Mus., 4 (5): 205-278. Schultz, C. B., and C. H. Falkexbach. 1968. The phylogenv of the oreo- donts, Parts 1 and 2. Bull. Amer. Mus. Nat. Hist., 139: 1-498. Simpsox, G. G 1930. Tertiarv land mammals from Florida. Bull. Amer. Mus. Nat. Hist., 59 (3): 149-211. Simpsox, G G. 1945. The principles of classification and a classification of mammals. Bull. Amer. Mus. Nat. Hist., 85: 350 pp. Szalay, F. S. 1969. Mixodectidae, Microsyopidae, and the insectivore-primate transition. Bull. Amer. Mus. Nat. Hist., 140 (4): 195-330. 40 pi. Webb, S. D. 1965. The osteology of Camclops. Bull. Los Angeles Countv Mus., Sci., No. 1: 1-54. White, T. E. 1940. New Miocene vertebrates from Florida. Proc. New England Zool. Club, 18: 31-38. White, T. E. 1942. The lower Miocene fauna of Florida. Bull. Mus. Comp. Zool., 92: 1-49. White, T. E. 1947. Additions to the Miocene fauna of North Florida. Bull. Mus. Comp. Zool., 99 (4): 497-515.