Podocnemis fajumensis Andrews (1903)

PØrez-García, AdAEn, 2021, New shell information and new generic attributions for the Egyptian podocnemidid turtles “ Podocnemis ” fajumensis (Oligocene) and “ Podocnemis ” aegyptiaca (Miocene), Fossil Record 24 (2), pp. 247-262 : 249-250

Podocnemis fajumensis Andrews (1903) , Fourteau (1920) Podocnemis blanckenhorni Reinach (1903b)

Podocnemis blanckenhorni var. ovata Reinach (1903b) Erymnochelys fajumensis Broin (1977)

aff. Erymnochelys fajumensis Lapparent de Broin (2000) Neochelys fajumensis Gaffney et al. (2011)

“ Neochelys ” fajumensis PØrez-García and de Lapparent de Broin (2015), Ferreira et al. (2018), Lapparent de Broin et al. (2020)

“ Podocnemis ” fajumensis PØrez-García et al. (2017), PØrez-García (2019)

Type material

Andrews (1903) figured, by a schematic drawing (see Fig. 3d , as well as fig. 2C in plate 8 of Andrews, 1903), the anterior lobe of an individual that he identified as the type specimen. It is currently lost. Therefore, a neotype is designated here, also corresponding to an anterior plastral lobe: AMNH 5086 ( Fig. 1a–b ; see also fig. 86B in Gaffney et al., 2011, corresponding to a partial drawing of its ventral view).

Other specimens attributed to this taxon

AMNH 5087, carapace and partial plastron ( Fig. 2a–f ; previously cited by Gaffney et al., 2011, but so far not figured); SMNS 11233/1, partial carapace ( Fig. 2g –h ); SMNS 11233/2, partial carapace ( Fig. 3a–c ); SMNS 12647, plastron ( Fig. 3e–g ); SMNS 12646, plastron ( Fig. 3h–i ); NHMUK R3435, anterior plastral lobe ( Fig. 4a–b ; previously cited by Gaffney et al., 2011, but so far not figured); CGM C8509, anterior plastral lobe (see Fig. 4c–d , corresponding to a plaster cast of the specimen, NHMUK R8441); AMNH 5093, articulated epiplastra and entoplastron ( Fig. 4e–f ; fig. 86D in Gaffney et al., 2011, corresponding to a drawing of the external view); SMNS 11233/6, anterior plastral lobe ( Fig. 4g – h ); NHMUK R3103, partial anterior plastral lobe ( Fig. 4i– j ; previously cited by Gaffney et al., 2011, but so far not figured); SMNS 11233/5, right hypoplastron ( Fig. 4k–l ); SMNS 11233/3, articulated left hypoplastron and xiphiplastron ( Fig. 4m –n ); specimen without number, and currently lost, corresponding to the anterior plastral lobe identified by von Reinach (1903b) as the type specimen of Podocnemis blanckenhorni (see figs. 1 and 2 in the plate 9 of von Reinach (1903b), corresponding to the drawings of the dorsal and ventral views of the specimen); specimen without number, and currently lost, corresponding to the anterior plastral lobe identified by von Reinach (1903b) as the type specimen of Podocnemis blanckenhorni var. ovata (see figs. 3 and 4 in the plate 9 of von Reinach (1903b), corresponding to the drawings of the dorsal and ventral views of the specimen); DPC 3146, skull (see figs. 44–45 in Gaffney et al., 2011); DPC 99–245, skull (see fig. 46 in Gaffney et al., 2011). Furthermore, Gaffney et al. (2011) cited other specimens as attributable to this species, but they remain unpublished (their attribution to this taxon should be confirmed by their study and figuration). They correspond to complete and partial shells ( CGM 8790, DPC 2149, DPC 2491, DPC 4605, DPC 6209, DPC 7747, DPC 9483, DPC 10434, DPC 10686, YPM 6202-6203), complete and partial skulls ( DPC 1697, DPC 3882, DPC 12143, DPC 15310), and complete and partial lower jaws ( DPC 1699, DPC 2003, DPC 2223, DPC 2230, DPC 2602, DPC 2747, DPC 2754, DPC 2779, DPC 2858, DPC 3249, DPC 3261, DPC 3308, DPC 3442, DPC 3862, DPC 3973, DPC 4291, DPC 4400, DPC 4413, DPC 4495, DPC 5068, DPC 5193, DPC 5520, DPC 5749, DPC 5786, DPC 5892, DPC 6205, DPC 6413, DPC 6522,

250 A. PØrez-García: New shell information and new generic attributions for Egyptian podocnemidid turtles

DPC 6558, DPC 7331, DPC 7545-7546, DPC 7673, DPC 9352A, DPC 9795, DPC 10226, DPC 10382, DPC 10607, DPC 11192, DPC 11403, DPC 12116).

Diagnosis

Member of the lineage of Podocnemididae Erymnochelyini considering the medial contact of the extragulars, posteriorly to the reduced gular that they frame. It is defined by the following characters recognized as exclusive within this clade: thickening in the visceral plastral area, close to the hypoxiphiplastral sutures; broad dorsal expansion of the plastral scutes; anteriorly directed and well-developed medial protrusion in the prefrontals–frontals suture. It shows the following unique combination of characters: absence of carapacial medial keel; six neurals; medial contact of the sixth to eighth pairs of costals; heptagonal first vertebral, with short latero-anterior margins, and wider than the nuchal; subequal width of the second and third vertebrals, with substraight lateral margins, their maximum width being located at the interpleural sulci level; first pair of marginals overlapping on half of the nuchal lateral margins; anal length along the lateral xiphiplastral margin less than 2 times that of the femorals; absence of premaxillary beak; snout length greater than half the orbit length; interorbital width less than the orbital length; suborbital height less than that of the orbit; high cheek emargination, exceeding the ventral orbital margin; convex interparietal anterior margin, located on the frontals.

Figures

Figure 1. AMNH 5086, neotype of the podocnemidid turtle Shetwemys fajumensis comb. nov. (Erymnochelyini), from the lower Oligocene (Rupelian) of the Fayum Depression (Fayum Governorate, northern Egypt), in ventral (a) and dorsal (b) views.

Figure 2. Shell remains of the podocnemidid turtle Shetwemys fajumensis comb. nov.(Erymnochelyini), from the lower Oligocene (Rupelian) of the Fayum Depression (Fayum Governorate, northern Egypt). (a–f) AMNH 5087, carapace and partial plastron, in dorsal (a), ventral (b), anterior (c), posterior (d), left lateral (e), and right lateral (f) views. (g–h) SMNS 11233/1, partial carapace, in dorsal (g) and ventral (h) views.

Figure 3. Shell remains of the podocnemidid turtle Shetwemys fajumensis comb. nov.(Erymnochelyini), from the lower Oligocene (Rupelian) of the Fayum Depression (Fayum Governorate, northern Egypt). (a–c) SMNS 11233/2, partial carapace, in dorsal (a), ventral (b), and left lateral (c) views. (d) Ventral view of the anterior lobe the holotype of the species, currently lost, based on the fig. 2C in plate 8 of Andrews (1903). (e–g) SMNS 12647, plastron, in ventral (e), dorsal (f), and left lateral (g) views. (g’) corresponds to an enlarged photograph of the posterior plastral lobe, in left lateral view, in which the thickness in the regions close to the hypo-xiphiplastral suture (in blue), between the pelvic scars (in green), and at the level of the anal notch (in red), have been represented by arrows (h–i), SMNS 12646, plastron, in ventral (h) and dorsal (i) views.

Figure 4. Plastral remains of the podocnemidid turtle Shetwemys fajumensis comb. nov. (Erymnochelyini), from the lower Oligocene (Rupelian) of the Fayum Depression (Fayum Governorate, northern Egypt). (a–b) NHMUK R3435, anterior plastral lobe, in ventral (a) and dorsal (b) views. (c–d) NHMUK R8441, plaster cast of the specimen CGM C8509, anterior plastral lobe, in ventral (c) and dorsal (d) views. (e–f) AMNH 5093, articulated epiplastra and entoplastron, in ventral (e) and dorsal (f) views. (g–h) SMNS 11233/6, anterior plastral lobe, in ventral (g) and dorsal (h) views. (i–j) NHMUK R3103, partial anterior plastral lobe, in ventral (i) and dorsal (j) views. (k–l) SMNS 11233/5, right hypoplastron, in ventral (k) and dorsal (l) views. (m–n) SMNS 11233/3, articulated left hypoplastron and xiphiplastron, in dorsal (m) and ventral (n) views, and detail of the outer ornamental pattern (o).