Eugene S. Gaffney

EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE

Abstract Although pleurodires have been considered significantly less diverse than their sister group, the cryptodires, current discoveries show that pleurodires had a more complex and extensive evolutionary history than had been realized. Previously unknown radiations, particularly in the near-shore marine realm, are revealed by taxa with diverse cranial morphology, indicating many different feeding and sensory strategies. The pleurodire group that is changed the most by the new discoveries is its largest group, the hyperfamily Pelomedusoides. The hyperfamily Pelomedusoides now consists of the families Pelomedusidae, Podocnemididae, Bothremydidae, Araripemydidae, and Euraxemydidae, new family. The families Bothremydidae, Araripemydidae, and Euraxemydidae, new family, are documented with descriptions of skulls, lower jaws, and shells. The relationships of the family Podocnemididae to its sister taxa Hamadachelys and Brasilemys are recognized by placing them in the epifamily Podocnemidinura. The epifamily Podocnemidinura is the sister group to the family Bothremydidae, and together they form the superfamily Podocnemidoidea. The family Araripemydidae consists of one taxon, Araripemys barretoi, from the Aptian-Albian of Brazil. Description of new cranial material suggests that it is the sister group to all other Pelomedusoides or the sister group to the Pelomedusidae, but these relationships are only weakly supported. There is strong support for a multichotomy of Araripemys, Pelomedusidae, and remaining Pelomedusoides. Araripemys is characterized by very thin triturating surfaces and by a shell that lacks mesoplastra and has the first costals reaching the shell margin. The new family Euraxemydidae consists of two new genera: Euraxemys essweini, n. gen. et sp., from the Albian Santana Formation of Brazil, and Dirqadim schaefferi, n. gen. et sp., from the Cenomanian Kem Kem beds of Morocco. Members of the Euraxemydidae are united by the unique possession of a medial process of the quadrate partially covering the prootic and narrowly contacting a ventral process of the exoccipital, in contrast to all other pleurodires, which have either complete exposure or complete covering of the prootic ventrally. Furthermore, members have a ventral process of the exoccipital that is exposed at the lateral margin of the basioccipital in an elongate foot. The Euraxemydidae is hypothesized as the sister group to the superfamily Podocnemidoidea. The family Bothremydidae and the epifamily Podocnemidinura (consisting of the family Podocnemididae, Hamadachelys, and Brasilemys) are united as the superfamily Podocnemidoidea based on the possession of a quadrate-basioccipital contact, the complete or nearly complete ventral covering of the prootic, and the extension of the pectoral scales onto the entoplastron. The family Bothremydidae is a large and diverse group extending from the Albian to the Eocene in North and South America, Europe, Africa, and India. Its monophyly is supported by the presence of a wide exoccipital-quadrate contact, a eustachian tube separated from the incisura columellae auris usually by bone to form a bony canal for the stapes, absence of a fossa precolumellaris, a supraoccipital-quadrate contact (except in the tribe Taphrosphyini), and a posterior enlargement of the fossa orbitalis. Although there is a diversity of triturating surfaces within the family, primitively bothremydids have a posteriorly wide triturating surface with a significant palatine contribution in the upper jaw. The family Bothremydidae consists of four newly recognized, monophyletic groups: the tribes Kurmademydini, Cearachelyini, Bothremydini, and Taphrosphyini. The tribe Kurmademydini consists of two taxa: Kurmademys kallamedensis, from the Maastrichtian Kallamedu Formation of India, and Sankuchemys sethnai, from the Maastrichtian Intertrappean beds of India. The tribe Kurmademydini is characterized by extensive temporal and cheek emargination, a large fossa precolumellaris, and a small, anterior exposure of the prootic on the ventral surface. The tribe Kurmademydini is the sister group to the subfamily Bothremydinae (consisting of the tribes Cearachelyini, Bothremydini, and Taphrosphyini). Members of the subfamily Bothremydinae all possess a foramen stapedio-temporale that faces anteriorly. The tribe Cearachelyini consists of Cearachelys placidoi, from the Albian Santana Formation of Brazil, and Galianemys emringeri and Galianemys whitei, both from the Cenomanian Kem Kem beds of Morocco. The tribe Cearachelyini is characterized by a jugal retracted from the orbital margin and a fenestra postotica formed into a short slit. The tribe Cearachelyini is the sister group to the infrafamily Bothremydodda (consisting of the tribes Bothremydini and Taphrosphyini). The infrafamily Bothremydodda is characterized by a quadrate shelf formed below the cavum tympani, a foramen stapedio-temporale and foramen nervi trigemini that are very close together on the anterior face of the otic chamber, and a condylus occipitalis and occipital neck that are formed only by the exoccipitals. The tribe Bothremydini consists of Foxemys mechinorum, from the Campanian-Maastrichtian of France; Polysternon provinciale, from the Campanian of Europe; Zolhafah bella, from the Maastrichtian Dakla Formation of Egypt; Rosasia soutoi, from the Campanian-Maastrichtian of Portugal; Araiochelys hirayamai, n. gen. et sp., from the Danian phosphates of Ouled Abdoun Basin, Morocco; Bothremys cooki, from the Maastrichtian Navesink Formation of New Jersey; Bothremys maghrebiana, n. sp., from the Danian phosphates of Ouled Abdoun Basin, Morocco; Bothremys kellyi, n. sp., from the Ypresian phosphates of Ouled Abdoun Basin, Morocco; Bothremys arabicus, from the Santonian of Jordan; Chedighaii hutchisoni, n. gen. et sp., from the Campanian Kirtland Formation of New Mexico; and Chedighaii barberi, n. gen., from the Campanian of Arkansas, Alabama, Kansas, and New Jersey. The tribe Bothremydini is the sister group to the tribe Taphrosphyini. The tribe Taphrosphyini is characterized by the presence of a jugal-quadrate contact, the absence of a maxilla-quadratojugal contact, and the absence of a supraoccipital-quadrate contact. Members of the tribe Taphrosphyini have a considerable variety of triturating surfaces but they lack the wide, triangular surfaces typical of the other bothremydids. The tribe Taphrosphyini consists of Taphrosphys sulcatus, from the Danian Hornerstown Formation of New Jersey; Taphrosphys congolensis, from the Paleocene of Cabinda, west Africa; Taphrosphys ippolitoi, n. sp., from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Labrostochelys galkini, n. gen. et sp., from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Phosphatochelys tedfordi, from the Ypresian phosphates of the Ouled Abdoun Basin Morocco; Ummulisani rutgersensis, n. gen. et sp., from the Ypresian phosphates of the Ouled Abdoun Basin, Morocco; Rhothonemys brinkmani, n. gen. et sp., from the Paleogene phosphates of the Ouled Abdoun Basin, Morocco; Azabbaremys moragjonesi, from the Paleocene Teberemt Formation of Mali; Nigeremys gigantea, from the Maastrichtian of Niger; and Arenila krebsi, from the Maastrichtian Dakla Formation of Egypt. Among the Bothremydidae, the Taphrosphyini is the most diverse morphologically. The triturating surfaces show a wide range of variation. The long, narrow skull of Labrostochelys differs significantly from the very short skull of Phosphatochelys. Other genera, such as Azabbaremys and Arenila, have large and massive skulls, but without broadly expanded triturating surfaces, while Ummulisani has very narrow and deep labial ridges. The nasal regions of Taphrosphyini also show wide diversity. Rhothonemys has nasal openings and cavities more than twice the size of the orbits, but the nasal openings in Labrostochelys are smaller than the relatively small orbits. This diversity of Taphrosphyini skull morphology is mostly evident in the Paleogene of North Africa. A phylogenetic analysis of the core dataset of 41 taxa, 122 cranial characters, and 52 postcranial characters relies on comparative descriptions of these taxa. The analysis using PAUP results in one most parsimonious cladogram of 382 steps with a consistency index of 0.6. A Bremer decay analysis shows that the family Bothremydidae is strongly supported at five steps: the tribes Kurmademydini and Cearachelyini have an index of 2, and the tribe Taphrosphyini has an index of 3. The tribe Bothremydini becomes unresolved at one step and is the most weakly supported of these groups. The addition of selected shell-only taxa with low missing data values to the core dataset results in one equally parsimonious cladogram that is resolved as: (Proterochersis (Platychelyidae (Dortoka (Chelidae (Pelomedusidae + Araripemys) (Euraxemydidae (Teneremys (Podocnemididae + Hamadachelys + Brasilemys (Bothremydidae)))))))). A partitioned dataset consisting only of cranial characters (excluding all shell-only taxa) results in one equally parsimonious cladogram identical to the most parsimonious cladogram resulting from the whole dataset; however, a partitioned dataset consisting only of postcranial characters (excluding all skull-only taxa) resulted in 2704 trees, the consensus of which lacks resolution for nearly all Pelomedusoides, but which does resolve more basal pleurodires. When the skull morphology of the Bothremydidae is placed in the context of all other turtles, it becomes apparent that this family has the greatest range of skull forms of any turtle family yet known. In fact, the skull morphologies of many turtle families seem remarkably uniform in comparison (e.g., Testudinidae, Kinosternidae, Pelomedusidae, Trionychidae, Carettochelyidae). There are other turtle families with bizarre skull morphologies (e.g., Nanhsiungchelyidae; Meiolaniidae) but these are not taxonomically diverse, at least as they are now known. In

Modern Turtle Origins: The Oldest Known Cryptodire

The discovery of a turtle in the Early Jurassic(185 million years before present) Kayenta Formation of northeastern Arizona provides significant evidence about the origin of modern turtles. This new taxon possesses many of the primitive features expected in the hypothetical common ancestor of pleurodires and cryptodires, the two groups of modern turtles. It is identified as the oldest known cryptodire because of the presence of a distinctive cryptodiran jaw mechanism consisting of a trochlea over the otic chamber that redirects the line of action of the adductor muscle. Aquatic habits appear to have developed very early in turtle evolution. Kayentachelys extends the known record of cryptodires back at least 45 million years and documents a very early stage in the evolution of modern turtles.

Domo de Zaza, an Early Miocene Vertebrate Locality in South-Central Cuba, with Notes on the Tectonic Evolution of Puerto Rico and the Mona Passage1

Abstract This report summarizes the results of paleontological and geological investigations carried out during the 1990s at Domo de Zaza, a late Early Miocene vertebrate locality in south-central Cuba. Paleontologically, the most important result of fieldwork at Zaza was the first discovery of terrestrial mammals of Tertiary age in Cuba. Three terrestrial mammal taxa are now known from this locality—a megalonychid sloth (Imagocnus zazae), an isolobodontine capromyid rodent (Zazamys veronicae), and a platyrrhine primate (Paralouatta marianae, new species). In addition to these finds, a number of selachian, chelonian, crocodylian, cetacean, and sirenian remains have been recovered. Domo de Zaza is a low hill transected by a large artificial channel, the Canal de Zaza, whose walls provide an extensive exposure of Miocene sediments attributable to the Lagunitas Formation (Fm). This formation is laterally and vertically complex, showing evidence of at least four different depositional regimes. However, the sedimentary sequence indicates that all depositional phases took place within a broader episode of transgression. Estimated Burdigalian age (16.1–21.5 Ma) for Lagunitas Fm is based on the presence of marine invertebrate taxa corresponding to the late Early Miocene Miogypsina–Soritiidae zone. The overall transgressive aspect of Lagunitas suggests rising sea level, possibly in correlation with a global onlap event. Within Burdigalian time, the most likely correlate is the eustatic rise centered on 17.5–18.5 Ma. Most of the vertebrate fossils were recovered from lagoonal and alluvial beds; those from lagoonal beds are exceptionally well preserved. The terrestrial facies displays evidence of paleosol formation, subaerial erosion, and plant life in the form of grass and palm pollen. Other evidence indicates that most of the present-day highlands of Cuba, including the Cordillera del Escambray near Zaza, have been continuously subaerial since the latter part of the Late Eocene. Although no land vertebrate fossils of this age are known from Cuba, recent discoveries elsewhere in the Greater Antilles indicate that land vertebrates could have colonized landmasses in the Caribbean Basin as early as 33–36 Ma. Recently, marine geological data have been interpreted as showing that (1) the Mona Passage began to form in the Early Oligocene, and (2) the Puerto Rico/Virgin Island block was entirely transgressed by shallow marine environments during the period between the Late Oligocene and the Early Pliocene. However, the seismic reflection profile evidence for an Early Oligocene opening of the Passage is ambiguous. Even if the separation of Puerto Rico and eastern Hispaniola occurred relatively early, it remains more probable than not that this happened in the medial Oligocene or even somewhat later (i.e., ≤30 Ma). On the other hand, the evidence is not at all ambiguous concerning the hypothesized mid-Cenozoic inundation of Puerto Rico: it did not happen. When available land and marine indicators are adequately compared, apparent contradictions in datasets can be evaluated and resolved. When examined in this way, the preponderance of evidence supports the contention that Puerto Rico has been an emergent landmass and has supported terrestrial environments continuously since the latest Eocene.

A COMPUTER ASSISTED ANALYSIS OF THE RELATIONSHIPS OF THE HIGHER CATEGORIES OF TURTLES

Abstract— A character matrix of 39 characters for 14 supregeneric categories of living and extinct turtles was examined using PAUP 2.41 and 3.0L. The Branch and Bound algorithm found a single most parsimonious cladogram of 55 steps, consistency index of 0.709, retention index of 0.848 and a rescaled consistency index of 0.601. The cladogram is identical to that proposed by Gaffney and Meylan (1988). The Pleurodira and Cryptodira are each shown to be monophyletic and are supported by synapomorphies involving complex structures of the basicranium and adductor musculature. These synapomorphies are judged to be relatively well‐tested homologies. A paraphyletic Cryptodira occurs in 18% of 38 equally parsimonious trees 57 steps in length, but these trees are based on characters, such as absence of pterygoid teeth, that are susceptible to homoplasy in amniotes. We re‐iterate the notion that it is better to choose fewer, well‐analysed characters than large numbers of poorly analysed characters.

Chubutemys, a New Eucryptodiran Turtle from the Early Cretaceous of Argentina, and the Relationships of the Meiolaniidae

Abstract Chubutemys copelloi is the oldest nonmarine cryptodire from South America represented by a skull. The skull and associated postcranial fragments are from the Aptian Cerro Costano Member of the Cerro Barcino Formation of Chubut, Argentina. Chubutemys has a processus trochlearis oticum, showing that it is a cryptodire, and an enclosed canalis caroticus internus extending to the posterior margin of the pterygoid, showing that it is a eucryptodire. The skull of Chubutemys is similar to that of other primitive eucryptodires, particularly Dracochelys, but also to Hangaiemys, Judithemys, Sinemys, and Ordosemys. Chubutemys differs from all these, however, in possessing a solidly roofed skull, formed by long, wide parietals, rather than a posterior emargination. Chubutemys also differs from these taxa in having no cheek emargination. A phylogenetic analysis using PAUP* analyzed 104 parsimony-informative characters resolving into one most parsimonious cladogram of 224 steps, a consistency index of 0.55, an...

Evolution of the Side-Necked Turtles: The Family Podocnemididae

Abstract The family Podocnemididae consists of 20 genera and 30 species considered here as valid and diagnosable by cranial characters. Three of these genera and eight species persist into the Recent fauna, barely reflecting the evolutionary diversity and distribution of the group. The family extends from the Late Cretaceous to the Recent and occurs in North and South America, Europe, Asia, and Africa. A phylogenetic analysis utilizes 31 podocnemidid taxa (30 named and one unnamed; a total of 37 taxa analyzed includes outgroups) in the Podocnemididae that are analyzed using PAUP. The resulting consensus of nine equally parsimonious cladograms is the basis for a new classification of the family. The family Podocnemididae is reconfirmed as monophyletic, using the unique possession of a cavum pterygoidei formed by the basisphenoid, pterygoid, prootic, and quadrate, underlain by the pterygoid and basisphenoid, among other characters. Much of our resolution agrees with that of França and Langer (2006), which can be modified and restated as follows: (Bauruemys (vilavilensis (Podocnemis (Peltocephalus, Erymnochelys)))). The two clades proposed by Broin (1991) and Lapparent de Broin (2000b, 2001, 2003a, 2003b), designated by her as the “subfamily Podocnemidinae” and the “subfamily Erymnochelinae,” are inconsistent with our analysis. In our analysis the “Podocnemidinae” (sensu Broin, 1991) is paraphyletic, and the “Erymnochelinae” (sensu Broin, 1991) could be made monophyletic, with the important addition of Peltocephalus (placed in the “Podocnemidinae” by Broin). We add a number of new taxa to the basal Podocnemididae and to the broad-jawed subtribe Stereogenyina. Within the family Podocnemididae Cope, 1868, the sister taxon to all other podocnemidids and recognized as the subfamily Bauruemydinae, new, is Bauruemys elegans (Suárez, 1969a), known from associated skulls and shells. All other podocnemidids, the redefined subfamily Podocnemidinae Cope, 1868, are united by a slight to absent temporal emargination, a completely closed foramen jugulare posterius, and saddle-shaped cervical centra (modified as a separate state in Erymnochelys). A basal group of Cretaceous-Paleocene podocnemidids that are the sister group to all remaining podocnemidids, here termed the infrafamily Peiropemydodda, consisting of two taxa from the late Cretaceous of Brazil, Peiropemys mezzalirai, n. gen. et sp., and Pricemys caiera, n. gen. et sp., and Lapparentemys vilavilensis (Broin, 1971), n. gen., from the Paleocene of Bolivia. The resolution of the basal members of the family is: (Bauruemys (Pricemys (Lapparentemys, Peiropemys)) (Infrafamily Podocnemidodda)). The remaining podocnemidids form the infrafamily Podocnemidodda Cope, 1868, new rank, and is characterized by the possession of a cheek emargination that does not reach above the level of the orbit, the medial expansion of the triturating surfaces with a median maxillary ridge present, and the presence of accessory ridges on the triturating surfaces. This group contains the living podocnemidids and a series of extinct forms, including the marine broad-jawed taxa. Within the Podocnemidodda, the genus Podocnemis is the sister group to all the remaining taxa, which is the magnatribe Erymnochelydand. When only the living fauna is considered our results show Podocnemis as the sister taxon to Erymnochelys plus Peltocephalus, in common with Williams (1954c), França and Langer (2006), Meylan et al. (2009), and Cadena et al. (2010). With the fossil taxa present, the Erymnochelydand is united only by the small to absent cheek emargination. However, some of the fossil taxa (i.e., Caninemys, Dacquemys), are not known for a number of characters, and, if the analysis is reduced to include only the living species, Erymnochelys and Peltocephalus are united by a greater number of characters: cavum pterygoidei with enlarged anterior opening, so that the foramen cavernosum enters the roof of the cavum pterygoidei, orbits facing anterolaterally, jugal-quadrate contact present, cheek emargination slight to absent, horizontal occipital shelf absent, premaxillae reach apertura narium interna (also in some Podocnemis), supraoccipital roof exposure slight or absent, chorda tympani enclosed in processus retroarticularis, neural series extends to costal six, and axillary musk duct not in bridge. When one considers just the Recent genera, none of the published molecular results reproduce the Gaffney and Meylan (1988) and Lapparent de Broin (2000b) resolution of (Erymnochelys (Podocnemis, Peltocephalus)); rather these publications show a preference for the (Peltocephalus (Podocnemis, Erymnochelys)) arrangement, while we, in agreement with França and Langer (2006) and the earlier version of the present data set, Meylan et al. (2009), place our marbles with the third alternative, (Podocnemis (Peltocephalus, Erymnochelys)). This latter hypothesis has a number of characters favoring its resolution, even when fossils are excluded. One of the more compelling ones is the large cavum pterygoidei with an enlarged anterior opening and the foramen cavernosum containing the lateral head vein, entering the roof of the cavum pterygoidei. Within the magnatribe Erymnochelydand are the following taxa: Caninemys, Dacquemys, unnamed genus UCMP 42008, Albertwoodemys, Turkanemys, Peltocephalus, Erymnochelys, Neochelys, Papoulemys, and the members of the tribe Stereogenyini (see below). The resolution of Caninemys within the Erymnochelydand is not strongly supported; in only one step it becomes a multichotomy with Podocnemis and the infrafamily Peiropemydodda. Neochelys, Papoulemys (possibly a synonym of Neochelys), and Dacquemys, however, are strongly supported as part of the magnatribe Erymnochelydand, as proposed earlier (Broin, 1991; Lapparent de Broin, 2000b, 2001, 2003a, 2003b). A new shell-based taxon, Albertwoodemys testudinum, n. gen. et sp., and an unnamed skull and shell, UCMP 42008, are united by a high-domed shell with thick lateral ridges along the plastron and the absence/fusion of the pectoral scales. The skull of UCMP 42008 agrees with that in Dacquemys in having large parietals and a supraoccipital covering the posterior margin. Lacking a skull, Albertwoodemys is not entered into the data set, but the skull-shell specimen of the closely related UCMP 42008 is in the analysis. New skull material identifiable as Neochelys has been discovered associated with shells of “Podocnemis” fajumensis Andrews, 1903, resulting in the new combination Neochelys fajumensis (Andrews, 1903). Neochelys has the Erymnochelydand synapomorphy of a large cavum pterygoidei with an enlarged anterior opening and the foramen cavernosum entering the roof of the cavum pterygoidei, as in Peltocephalus and Erymnochelys. The European Neochelys species are Eocene and the African Fayum species is Early Oligocene, extending both spatial and temporal ranges of the genus. The tribe Stereogenyini has a dorsal process of the palatine that reaches the frontal in the septum orbitotemporale, the fossa precolumellaris is absent, and both foramina nervi hypoglossi are combined and recessed in a short canal that opens on the occipital surface. Within the tribe Stereogenyini, Mogharemys blanckenhorni Dacqué (1912), n. gen., is the sister taxon to the well-defined subtribe Stereogenyina. Two groups are recognized within the subtribe Stereogenyina. The infratribe Bairdemydita contains Bairdemys Gaffney and Wood, Latentemys plowdeni, n. gen. et sp., Cordichelys antiqua (Andrews, 1903), n. gen. The infratribe Stereogenyita contains Brontochelys gaffneyi (Wood, 1970), n. gen., Lemurchelys diasphax, n. gen. et sp., Shweboemys Swinton, 1939, and Stereogenys Andrews, 1901. The subtribe Stereogenyina is strongly supported by a secondary palate with a median cleft, unique among turtles, as well as other characters. While the other Podocnemididae were apparently freshwater species, there is evidence that many or all of the subtribe Stereogenyina were marine or near-shore marine. Compared with a group such as the Bothremydidae, we see in the evolution of the Podocnemididae, a relatively conservative series of South American paraphyletic taxa with an unusually persistent cranial as well as shell morphology, beginning in the Late Cretaceous with Bauruemys, Peiropemys, and Pricemys, and continuing with the Paleocene Lapparentemys, culminating in the Recent Podocnemis. A monophyletic Tertiary group with more geographic, taxonomic, and morphologic diversity, the magnatribe Erymnochelydand, contains African, European, Asian, and South American taxa, as well as a radiation of marine, broad-jawed species in the mid-Tertiary. The living remnants of the Erymnochelydand are the South American Peltocephalus and the African Erymnochelys, close relatives despite their current geographic separation.

Cearachelys, a New Side-Necked Turtle (Pelomedusoides: Bothremydidae) from the Early Cretaceous of Brazil

Abstract The early Cretaceous Santana Formation exposed on the Chapada do Araripe in Ceará State, northeastern Brazil, has yielded remains of a side-necked turtle, Cearachelys placidoi, new genus and species. Cearachelys is based on two skeletons, each consisting of articulated shell, associated skull, and postcrania in varying degrees of completeness. Cearachelys is a pelomedusoid pleurodire belonging to the family Bothremydidae Baur, 1891, based on these bothremydid characters: (1) precolumellar fossa absent, (2) occipital condyle consisting only of exoccipitals, (3) foramen stapedio-temporale anteriorly facing, and (4) exoccipital contacts quadrate. Within the Bothremydidae, Cearachelys is best resolved as the sister group of Bothremys, Rosasia, Foxemys, Zolhafah, and Polysternon. Cearachelys differs from the other two pleurodires in the Santana Formation in the bothremydid characters listed above and in having a quadrate-basioccipital contact, a prootic completely covered in ventral view, and a high lingual ridge on the lower jaw.

Kurmademys, a New Side-Necked Turtle (Pelomedusoides: Bothremydidae) from the Late Cretaceous of India

Abstract The Maastrichtian Kallamedu Formation of southern India near the village of Kallamedu, Tamil Nadu, has yielded skulls and postcrania of a new genus of side-necked turtle. Kurmademys kallamedensis, new genus and species, is based primarily on a single well-preserved skull. Kurmademys is a pelomedusoid pleurodire belonging to the family Bothremydidae Baur, 1891, with these bothremydid characters: (1) exoccipital-quadrate contact, (2) incisura columellae auris closed by bone, and (3) eustachian tube and stapes separated by bone. Kurmademys is unique among known bothremydids in having extensive temporal emargination, a small postorbital, a large precollumellar fossa, and a foramen posterius canalis carotici interni formed completely by the basisphenoid.

Side-Necked Turtle Lower Jaws (Podocnemididae, Bothremydidae) from the Late Cretaceous Maevarano Formation of Madagascar

Abstract Two lower jaws from the upper part (early Maastrichtian) of the late Cretaceous Maevarano Formation in the Mahajanga Basin, northwestern Madagascar, are identified as belonging to side-necked turtles (Pleurodira). A nearly complete lower jaw is identified as cf. Erymnochelys because of its close resemblance to the living Malagasy Erymnochelys madagascariensis. Both uniquely possess the combination of a posteriorly directed processus retroarticularis and a nearly identical triturating surface that is narrow anteriorly with a horizontal labial ridge and a dorsally rising lingual ridge. A second specimen, consisting of an incomplete symphyseal region, is questionably identified as Bothremydidae on the basis of a thick wedge-shaped symphysis with partial or complete pits on the rami. The cf. Erymnochelys specimen is the oldest record of Erymnochelys or a taxon very similar to it, and it indicates the persistence of a Mesozoic element in the extant Malagasy turtle fauna. The possible bothremydid jaw suggests a more cosmopolitan element now extinct.

Bairdemys, a New Side-Necked Turtle (Pelomedusoides: Podocnemididae) from the Miocene of the Caribbean

Abstract A new genus, Bairdemys, is erected for two species of side-necked turtles. Bairdemys venezuelensis (Wood and Díaz de Gamero, 1971) from the late Miocene Urumaco Formation of Venezuela is represented by four skulls and a number of shells. Bairdemys hartsteini from the Miocene of Puerto Rico is known from a skull. Bairdemys is a member of the Podocnemididae because it possesses a cavum pterygoideus, and is related to the Shweboemys Group because it has a well-developed secondary palate. It differs from all other Podocnemididae in having large ventral convexities on the secondary palate, the eustachian tube separated by bone from the fenestra postotica, and the frontal and prefrontal strongly convex dorsally.