Chersina langebaanwegi Delfino, Cohen & Macaluso, sp. nov.

Chersina langebaanwegi Delfino, Cohen & Macaluso sp. nov. (Figs 1–10) 1973 Chersina sp. - Hendey, p. 13. 1974 Chersina sp. - Hendey, p. 35. 1981 Chersina sp. - Hendey, p. 31. 1986 Chersina sp. - Meylan and Auffenberg, p. 288. 1997 Chersina sp. - Broadley, p. 111. 2000 Chersina sp. - Lapparent de Broin, p. 64. 2007 Chersina sp. - Daniels et al., p. 916. 2021 Chersina sp. - Georgalis et al., p. 49. 2023 Chersina angulata (Duméril in Schweigger. 1812) - Bhat et al., p. 2. Derivation of name: The species name,meaning ‘of Langebaanweg’, derives from the site where it was collected, and is currently the only site at which it has been identified. Worth noting is that turtles represent the most common vertebrate taxon at Langebaanweg, and that this species is by far the most common taxon in the turtle assemblage. This species is dedicated to Prof. Margaretha D. Hofmeyr (1950–2020) for her commitment to the study of African extant tortoises and for having promoted the study of the fossil tortoises from Langebaanweg. Zoobank LSID: urn:lsid:zoobank.org:pub:A8B93307-034E - 4D7F -96BC -B17F8F32B122. Holotype: SAM-PQL-20734: nearly complete female shell (Figs 1–3). Paratypes: SAM-PQL-20925: partial male shell with a nearly complete plastron, several peripherals and pygal (Fig. 4); SAM-PQL-21109: partially preserved shell of a male spe - cimen missing most of the costals and all the neurals (Fig. 5); SAM-PQL-21174: highly fragmentary, incomplete shell whose best -preserved elements are the nuchal, fifth neural, pygal, and, above all, both epiplastra (Fig. 6); SAM-PQL-21749: crushed but nearly complete shell with partially articulated elements, including well -preserved and well -exposed nuchal, pygal, epiplastra, and xiphiplastra (Fig. 7); SAM-PQL-22076: a com - plete male plastron (Fig. 8); SAM-PQL-35023d: partially pre - served shell of a very large specimen represented mostly by an epiplastra, entoplastron, left hyoplastron, three neurals, pygal with the surrounding fragmentary peripherals, and three peri - pherals (Fig. 9). Referred specimens: SAM-PQL-12740a: right epiplastron; SAM-PQL-12750c: left epiplastron; SAM-PQL-12754a: two epiplastra sutured to the entoplastron; SAM-PQL-12754b: left epiplastron; SAM-PQL-12754c: left epiplastron; SAM-PQL-24826b: right epiplastron; SAM-PQL-24827a: left epiplastron; SAM-PQL-24862a: right and left epiplastrons; SAM-PQL-24862b: right epiplastron; SAM-PQL-52640: right epiplastron; SAM-PQL-73745: right epiplastron; SAM-PQL-73747: nuchal; SAM-PQL-73749: right epiplastron; SAM-PQL-73750, left epiplastron; SAM-PQL-73751: nu - chal; SAM-PQL-73754: nuchal; SAM-PQL-73757: nuchal; SAM-PQL-73761: right epiplastron; SAM-PQL-73763: right epiplastron; SAM-PQL-73765: nuchal; SAM-PQL-73769: entoplastron; SAM-PQL-73777: nuchal; SAM-PQL-73781: left epiplastron; SAM-PQL-73789: right epiplastron; SAM-PQL-73792: left epiplastron; SAM-PQL-73795: entoplastron; SAM-PQL-73799: left epiplastron; SAM-PQL-73803: left epiplastron; SAM-PQL-73807: pygal; SAM-PQL-73808: nuchal; SAM-PQL-73809: pygal; SAM-PQL-73811: right epiplastron; SAM-PQL-73819: entoplastron; SAM-PQL-73825: right epiplastron; SAM-PQL-73828: right epiplastron; SAM-PQL-73829: entoplastron; SAM-PQL-73831: nuchal; SAM-PQL-73832: pygal; SAM-PQL-73834: right epiplastron; SAM-PQL-73836: left epiplastron; SAM-PQL-73837: left epiplastron; SAM-PQL-73845: left epiplastron; SAM-PQL-73860: right epiplastron; SAM-PQL-73862: entoplastron; SAM-PQL-73863: pygal; SAM-PQL-73876: entoplastron; SAM-PQL-73877: right epiplastron; SAM-PQL-73878: right epiplastron. Type locality and age: ‘E’ Quarry, Langebaanweg (18°9’ E, 32°58’ S), approximately 110 km NNW of Cape Town, South Africa. Upper Varswater Formation; Early Pliocene, about 5.1 Mya (Roberts et al. 2011). The fossil vertebrates of this locality have been studied since the late 1950s (Singer and Hooijer 1958, Simpson 1971, Hendey 1973, 1974a, b, 1976) and have been still actively in - vestigated in recent years (among others see Groenewald et al. 2020, Valenciano and Govender 2020a, b, Govender 2021, Nacarino -Meneses and Chinsamy 2022, Rabe et al. 2022, Valenciano et al. 2022, Doughty et al. 2023, Govender and Marx 2023, Jannello and Chinsamy 2023, Jiangzuo et al. 2023, Matthews and Steininger 2023; and literature therein). Differential diagnosis: Member of testudinid genus Chersina be - cause of the following combination of characters: wide vertebral scutes almost equal to the vertebral scutes; single trapezoidal suprapygal, notched pygal, and distinct gular protrusion covered by fused gulars scutes. Differing from Chersina angulata regarding the following characters (see Supporting information for the comparison with C. angulata): the shell is distinctly domed and not relatively low and elongated as in C. angulata (Fig. 1E, F; Supporting in - formation, Fig. S1); the nuchal is not as significantly arched (in anterior view) as that of C. angulata (Fig. 1G; Supporting in - formation, Fig. S2) and does not develop a ventral transversal ridge with medial notch and a dorsal shelf as in C. angulata (Fig. 6B; Supporting information, Fig. S3A, B); the cervical is, on the dorsal surface, much broader and proportionally longer than that of C. angulata (Fig. 2A, B; Supporting information, Fig. S3C, D); the first neural is hexagonal and not rectangular as in C. angulata (Figure 1A, B; Supporting information, Fig. S4); most of the neurals host the ribheads (Figs 3A, 9B; Supporting infor - mation, Fig. S5) and not regularly the costals as in C. angulata; the sixth marginal scute does not contact the third pleural scute as in C. angulata (Fig. 1E, F; Supporting information, Fig. S6); the anterior protrusion of the plastron (the gular protrusion of the epiplastra) is comparatively more developed than in C. angulata (especially in males; Figs 4A, B, 5C, D, 6D, E, 8A, B, 9C, D, 10; Supporting information, Fig. S7); the dorsal surface of the epiplastral lips is nearly flat or very slightly convex and not vari - ably concave as in C. angulata (Fig. 10; Supporting information, Fig. S8); the epiplastral lips in most of the cases end posteriorly with a nearly straight or moderately convex profile (in most cases not producing any significant pocket) and not with a very strong convexity as in C. angulata (which regularly has a very deep gular pocket) (Figs 3B, 5D, 6D, 8B, 9D, 10A, D; Supporting informa - tion, Fig. S9); the entoplastron is wider than long instead of being longer than wide, or circular, as in C. angulata (Figs 1D, 3B, 4A, B, 5C, D, 8A, B, 9C, D; Supporting information, Fig. S10). Description: If not otherwise stated, the following descrip - tion is mostly based on the holotype SAM -PQL -20734 (Figs 1–3) as it is the only nearly complete and mounted shell so far available. There are no cranial, axial, or appendicular elements associated with the holotype and the referred specimens. Carapace The nearly complete female shell SAM -PQL -20734 (holotype) indicates that the carapace of this species was highly domed (length 23.6 cm, width 15.7, height 14.7 mm), with a nearly smooth dorsal profile both in lateral and anterior/posterior views. The posterior border is relatively curved inwards and not significantly flared. Very weak bosses are visible in lateral view (Fig. 1C, D) that correspond to five vertebral scutes. In dorsal view, the anterior edge of the shell (Fig. 2A, B) has a modest notch laterally delimited by the small protrusion of the first peripherals (corresponding to the sulcus between the first and second marginal) and, moreover, the central area of the carapace, corresponding to the bridge, is somewhat swollen if compared to the areas anterior and posterior to it. The anterior opening is kidney shaped because the anterior lobe of the plastron is ele - vated in the dorsal direction (Fig. 3A; see description of the plas - tron). The posterior opening is rather broad (Fig. 2C, D) and markedly much broader than in extant Chersina angulata. The carapace has no hinge and moreover there is no hinge between the carapace and plastron [as also indicated, among other, by the partial plastron SAM -PQL -20925 (Fig. 4) that is still sutured with some bridge peripherals] or within the plastron (see also SAM -PQL -22076— Fig. 8). Bony plates: The nuchal is a hexagonal element, about 1/3 broader than long (65 mm wide and 47 mm long in the holo - type SAM -PQL -20734), with borders that can be nearly straight (SAM -PQL -21174) or weakly concave (SAM - PQL -20734, SAM -PQL -21174) (the character has been scored as straight because of the weak concavity). The anterior edge can be straight (SAM -PQL -21174) or shallowly concave with, at least in some cases (SAM -PQL -20734), a small, acute notch at the centre. In anterior view, the anterior edge is only modestly arched (but not deeply arched as in C. angulata). On the ven - tral surface, the transversal ridge marking the line of maximum thickness of the element (slightly posterior to the end of the ventral fold of the scutes) is straight and medially notched as in C. angulata that develops a sort of dorsal shelf (Supporting information, Fig. S3A, B). There are eight neural elements and the neural formula is: 6,8,4,8,4,6A,4,6A. The first neural of SAM -PQL -20734 is anteroposteriorly elongated and hexagonal with anterolateral sides approximately equal to the posterolateral ones. Neurals from two to seven are wider than long (in absence of the proper state, the third has been scored as square but it is in fact rect - angular). The eighth is longer than wide and, at least on the better -preserved right side, it seems to be hexagonal (with a short anterolateral side). On the visceral surface of the neurals from two to five there is clear evidence for the emergence of very thin costal processes from the neural and not from the corres - ponding costals. In addition, the sixth neural may show the same condition as indicated by a small irregularity located close to the posterior border (an