Mogharemys, Gaffney & Meylan & Wood & Simons & De Almeida Campos, 2011

Gaffney, Eugene S., Meylan, Peter A., Wood, Roger C., Simons, Elwyn & De Almeida Campos, Diogenes, 2011, Evolution Of The Side-Necked Turtles: The Family Podocnemididae, Bulletin of the American Museum of Natural History 2011 (350), pp. 1-237 : 46-48

Mogharemys , new genus

TYPE SPECIES: Sternothaerus blanckenhorni Dacque´, 1912.

INCLUDED SPECIES: Mogharemys blanckenhorni .

DISTRIBUTION: Miocene of Egypt.

DIAGNOSIS: A podocnemidid of the Tribe Stereogenyini known only from the skull,

uniquely possessing a median maxillary ridge on palatine smaller than lateral maxillary ridge; secondary palate and midline palatal cleft absent, medially expanded triturating surfaces not meeting on midline; orbits facing more anteriorly than laterally as in Bairdemys venezuelensis ; eustachian tube confluent with fenestra postotica; parietal-pterygoid contact in septum orbitotemporale as in Tribe Stereogenyini and in contrast to Erymnochelys , Peltocephalus , and Podocnemis ; dorsal process of palatine reaches ventral process of frontal as in Tribe Stereogenyini and in contrast to all other podocnemidids; posteri- or pocket of fossa orbitalis as found in Tribe Stereogenyini absent; fossa precolumellaris absent as in all Tribe Stereogenyini and in contrast to Erymnochelys , Peltocephalus , and Podocnemis ; foramina nervi hypoglossi combined into one recessed opening posteriorly as in Tribe Stereogenyini .

DISCUSSION: This new genus is based on a skull in the British Museum, BMNH R.8440 (figs. 48–51) that was described but not named, by Williams (1954), who did not realize that the skull was the holotype of ‘‘ Sternothaerus’ ’ blanckenhorni Dacque´, 1912. Williams listed characters showing BMNH R.8440 to be distinct from all other podocnemidid skulls, but refrained from naming it because he thought it was probably the skull of the shell-based taxon ‘‘ Podocnemis’’ aegyptica Andrews, 1900, which Williams stated (1954: 5) ‘‘is on shell characters barely, if at all, distinguishable from Erymnochelys madagascariensis .’’ Williams hypothesized that the Moghara skull, BMNH R.8440, was ‘‘a structural intermediate between the Recent genera, Peltocephalus or Erymnochelys , and the Oligocene Dacquemys ’’ (Williams, 1954: 6). Williams also suggested that BMNH R.8440 could be the skull of the other Moghara shell, Podocnemis bramlyi , but did not decide in favor of either hypothesis.

Williams discussed ‘‘Sternothaerus’ ’ blanckenhorni , the only other Moghara skull known at that time. He felt the sole figure of the specimen, a dorsal view (Dacque´, 1912: fig. 12) neither supported nor contradicted the assignment to Pelusios (5 Sternothaerus ). However, Williams was misled by the written description of Dacqué (1912: 321), that ‘‘ Sternothaerus ’’ blanckenhorni was characterized by a strongly developed secondary palate, which does not occur in BMNH R.8440. No other figures of ‘‘ Sternothaerus ’’ blanckenhorni , showing the ventral view, for example, have appeared or were available to Williams, although the cast, MB.R.2860, was in the Berlin Museum at this time. Williams was aware that the Egyptian Tertiary had podocnemidids, such as Stereogenys , with well-developed secondary palates and concluded that ‘‘ Sternothaerus ’’ blanckenhorni could be one of these, but, in any case, a secondary palate is not present in BMNH R.8440. BMNH R.8440 has an expanded triturating surface compared with the living podocnemidids, which was apparently all that Dacqué meant, but it was not expanded to the extent seen in Stereogenys .

A recent examination by E.S.G. of the cast of ‘‘ Sternothaerus ’’ blanckenhorni Dacque´, 1912, MB.R.2860, in the Berlin Museum shows that the original of the cast is actually BMNH R.8440. In ventral view the comparisons are exact, even though some of the cast does not preserve surface details. The actual specimen, BMNH R.8440, has lost the prefrontals and some chips from the edges of the skull, so the dorsal view is now significantly different from the 1912 figure. When Dacqué examined the specimen it was in the collection of the Geological Survey of Egypt (Dacque´, 1912: 321); exactly how it came to be at the BMNH is unknown. The reconstruction of the skull produced here (fig. 48) combines both the original specimen and the missing snout features from the cast.

Mogharemys blanckenhorni Dacqué (1912) , new combination

Sternothaerus blanckenhorni Dacque´, 1912 Pelusios blanckenhorni Williams, 1954

TYPE SPECIMEN: BMNH R.8440, the holotype of ‘‘ Sternothaerus ’’ blanckenhorni Dacque´, 1912, is a partial skull in two pieces, not in contact. Dacqué did not specifically designate a type, and the only specimen he figured was the cast of this skull. However, it is apparent that he considered the skull the type specimen, and we affirm that. Dacqué (1912: 321) mentions shell fragments associated with the skull. What seem to be these specimens was examined by one of us (R.C.W.) and found to be too fragmentary to support Dacqué’s original identifications. They were not figured.

TYPE LOCALITY: ‘‘Wadi Moghara’’ label (see Miller, 1999).

HORIZON: Unnamed formation, Miocene. ‘‘untermiocänen Eisensandstein von Moghara: die Knochenplatten aus derselben Stufe in Wadi Faregh’’ (Dacque´, 1912: 321).

DIAGNOSIS: As for genus.

ETYMOLOGY: For the locality, Wadi Moghara, Egypt, and emys, Greek for ‘‘freshwater tortoise.’’

REFERRED MATERIAL: MB.R.2860, a cast of BMNH R.8440, made before damage resulting in the loss of the snout occurred, figured in Dacqué (1912: fig. 12).

PREVIOUS WORK: See below.

DISCUSSION: The species name blanckenhorni , has been used by two different authors for two different species with two different type specimens. Both specimens are podocnemidids from the same area, the Fayum of Egypt, but from slightly different ages and different localities. Professor M. Blanckenhorn was a German geologist who worked in Egypt for many years ( Blanckenhorn, 1900, 1903, 1921) and was particularly active in collecting in the Moghara area ( Andrews, 1906), and apparently popular.

The older blanckenhorni was named by von Reinach in 1903 (1903a) and consisted of the anterior half of a plastron, at that time housed in the Munich Museum, and which was probably destroyed in World War II ( Crumly, 1984). Named ‘‘ Podocnemis ’’ blanckenhorni by Reinach (1903a: 460), Reinach also named it in Reinach (1903b: 27; the present authors do not know which publication was first, so we use the lettering from Kuhn, 1964). Andrews (1906: 292) suggested that ‘‘ Podocnemis ’’ blanckenhorni was a junior synonym of ‘‘Podocnemis’ ’ fajumensis Andrews, 1903 , and we have accepted that.

In 1912, Dacqué used the species name for ‘‘ Sternothaerus ’’ blanckenhorni , the specimen named here Mogharemys blanckenhorni (Dacque´). It was Kuhn (1964) who confused blanckenhorni Reinach, 1903a and 1903b, with blanckenhorni Dacque´, 1912, and put them into synonymy. Lapparent de Broin (2000a) clearly differentiated the two species.

All of this may be moot, as the commonest shell in the Moghara unit according to Andrews (1900: 2), belongs to ‘‘ Podocnemis ’’ aegyptica Andrews, 1900 (fig. 87). Perhaps someday a skull-shell association may allow a new assessment of the taxonomy of BMNH R.8440.