Latonia cf. ragei, Hossini, 1993

Latonia cf. ragei

Figures 7 View Fig , 8 View Fig , 9 View Fig , 10 View Fig , 11 View Fig , 12 View Fig

Material. Spilia 1: one frontoparietal ( UU SP1 1022), four maxillae ( UU SP1 1018, UU SP1 1024, UU SP1 1044, and UU SP1 1046), two atlantes ( UU SP1 1028), three trunk vertebrae [ UU SP1 1021 (two elements) and UU SP1 1027], one urostyle ( UU SP1 1134), and five ilia ( UU SP1 1017, UU SP1 1026, UU SP1 1110, UU SP1 1133, and UU SP1 1141); Spilia 3: one frontoparietal ( UU SP3 624), two maxillae ( UU SP3 639 and UU SP3 672), four angulars ( UU SP3 629– UU SP3 631, and UU SP3 680), one trunk vertebra ( UU SP3 628), one sacral vertebra ( UU SP3 637), one scapula ( UU SP3 632), two humeri ( UU SP3 636 and UU SP3 641), and seven ilia ( UU SP3

621– UU SP3 623, UU SP3 625– UU SP3 627, and UU SP3 638); Spilia 4: five maxillae ( UU SP4 523, UU SP3 524, UU SP4 693, and UU SP4 737), four angulars ( UU SP4 715 and UU SP4 728), one atlas ( UU SP4 525), one trunk vertebra ( UU SP4 712), four sacral vertebrae [ UU SP4 529 and UU SP4 530 (three elements)], two urostyles ( UU SP4 520 and UU SP4 521), two ribs ( UU SP4 714), four humeri [ UU SP4 517, UU SP4 518, and UU SP4 519 (two elements)], and seven ilia ( UU SP4 513, UU SP4 526, UU SP4 528, UU SP4 531, UU SP4 532, and UU SP4 716).

Description.

UU SP1 1022 is a rather large element that most likely represents the anteromedial part of the frontoparietal

( Fig. 7a, b View Fig ). Te ventral surface is smooth, whereas the dorsal one is almost completely covered by a dense dermal sculpturing composed by tubercles, which fuses to form longitudinal ridges anteriorly. Te bone sections exposed along the broken margins clearly show that the ornamentation was secondarily connected to the frontoparietal table and not directly ossified on it. UU SP3 624 is a fragment of a moderately large frontoparietal, of which only the left anterolateral portion is preserved

( Fig. 9a, b View Fig ). Te ventral surface shows part of the incrassatio frontoparietalis, which is long and reaches the anterior end. Te lateral margin of the incrassatio is marked by a low and wavy ridge. Lateral to the incrassatio, there is a narrow pars contacta, the lateral portion of which bends ventrally. Anteriorly, the pars contacta develops an anterior horn, provided with a strongly striated ventral surface for the contact with the sphenethmoid. Te dorsal surface of the fragment of frontoparietal bears a well-developed dermal sculpturing. Te only unsculptured part is the anterior horn. Te sculpturing is made up by a moderately dense accumulation of small tubercles. Anteriorly, the tubercles are joined together to form longitudinal ridges. Laterally, the tectum supraorbitale is present, but poorly developed, at least in the preserved portion of the bone.

Several fragments of maxillae are represented in the Spilia localities ( Figs. 7c–f View Fig , 9c–e View Fig , 11 View Fig ). Te large UU SP3 639 ( Fig. 9c–e View Fig ) and the moderately large UU SP1 1018

( Fig. 7c–e View Fig ), UU SP1 1024, and UU SP4 523 ( Fig. 11a, b View Fig ) are the largest ones, whereas the others are slightly smaller. Medially, the maxillae display a mediolaterally short lamina horizontalis, which is rather high in medial view. Ventrally to the lamina, a high number of closely-spaced tooth positions is present. When preserved, the teeth are clearly pleurodont and cylindrical. When the posterior end is preserved [e.g., UU SP4 523 ( Fig. 11a, b View Fig ) and UU SP4 693 ( Fig. 11d View Fig )], the tooth row extends slightly posteriorly to the lamina horizontalis. A well-developed processus pterygoideus is preserved only in few specimens (e.g., UU SP1 1044, UU SP3 639, and UU SP4 693), but it was probably present at least in other specimens where the posterior end is not missing also judging from the visible medially-directed curvature of the posterior end of the lamina horizontalis. Te posterior depression is present, but not marked by ridges. Te margo orbitalis is strongly concave. Te lateral surface of the maxillae is smooth. Only UU SP4 523 ( Fig. 11b View Fig ) displays very few and small rugosities towards the posterodorsal corner (i.e., the processus zygomaticomaxillaris). It has to be noted that the other largest specimens, UU SP1 1018, UU SP1 1024, and UU SP3 639, show no sculpturing.

Te angulars from Spilia 3 ( Fig. 9f, g View Fig ) and Spilia 4 are medium to moderately large sized. None of them is completely preserved. Tey carry both a processus coronoideus and a processus paracoronoideus. Te former is distinctly dorsally directed and, when completely preserved, not extended posteriorly. Te lateral surface is characterized by a depressed area marked ventrally by a sharp crista mandibulae externa.

Te atlantes from the Spilia localities are not complete and they preserve different portions of this element. UU SP4 525 preserves only the dorsal portion of the neural arch ( Fig. 12a, b View Fig ). It is moderately large and displays a long and robust posterior point. Te dorsal surface is smooth, but the remnants of a poorly preserved, low longitudinal ridge are recognisable in the middle. Te other atlantes preserved only the centrum and are smaller. Tey bear two anterior cotyles, which are somehow reniform in anterior view, dorsally inclined and distinctly separated medially by a spatium interglenoidale. Posteriorly, a subcircular cotyle is present. A distinct, variably developed longitudinal ridge stands out on the ventral surface of the centrum.

Te trunk vertebrae from the Spilia localities are of medium size ( Fig. 10j View Fig ). Only the opisthocoelous centrum is preserved. It is subcylindrical, with circular anterior condyle and posterior cotyle. Te anterior condyle is followed by a poorly distinct neck. In lateral view, the centrum is distinctly ventrally concave.

Te sacral vertebrae from Spilia are also medium-sized and preserving the centrum alone ( Figs. 10a, b View Fig , 12c View Fig ). Tey have an anterior condyle, which is elliptical, and two posterior condyles, which are elliptical as well and well separated. Te ventral surface of the sacrals is not distinctly concave in lateral view as it is in the trunk vertebrae.

Te urostyles from Spilia are medium to moderately large sized and rather well preserved ( Figs. 8a View Fig , 12d, e View Fig ). Anteriorly, they bear two wide and roughly suboval cotyles, which are slightly mediolaterally extended and clearly separated medially. Posteriorly, the urostyle has a moderately high crista dorsalis, which is not closed dorsally for its whole length in UU SP4 521 and closed only by the anterior margin in UU SP4 520 ( Fig. 12d, e View Fig ). Two transverse processes are present by the anterior end of the crista. Teir distal ends are missing, but a narrowing is clearly visible. Only the right process in UU SP4 521 and the left one in UU SP4 520 ( Fig. 12d, e View Fig ) extend slightly posteriorly to form a short lamina, but this ends not far from the process itself. Te canalis coccygeus is wide and ogival in anterior view.

Te ribs from Spilia are medium sized and moderately robust. Tey are constricted at mid-length and present a distinct process on the dorsal surface.

Te single scapula (UU SP3 632) from Spilia 3 is large and fragmentary, preserving the pars suprascapularis alone ( Fig. 10c View Fig ). Te latter is very wide. A very well-developed crista anterior is present.

Te humeri from Spilia ( Fig. 12f–h View Fig ) reach a rather large size (but a very small one is also present: UU SP3 636) and preserve only their distal half. Te shaft is moderately robust and straight. Te spherical eminentia capitata is shifted laterally. Te fossa cubitalis ventralis is present, but moderately shallow (somehow slightly deeper in the very small UU SP3 636). Te epicondylus ulnaris is large, whereas the radialis one is small. Cristae medialis and lateralis follow the same proportions, with the former distinctly more developed than the other. Te olecranon scar is well distinct and elongated.

Te ilia from Spilia ( Figs. 8b–e View Fig , 10d–i View Fig ) are medium-sized, with only UU SP3 622 ( Fig. 10f View Fig ), UU SP3 623, UU SP4 513, UU SP4 531, and UU SP4 716 being smaller and UU SP1 1017 ( Fig. 8b, c View Fig ), UU SP1 1133, and UU SP3 638

( Fig. 10h, i View Fig ) being larger. None of them is completely preserved. Tey have a dorsal crest, which is well preserved only in UU SP3 638 ( Fig. 10h, i View Fig ) and UU SP4 528. In these specimens, the crest is visibly straight (i.e., not medially bending). In the smallest specimens, the posterior end of the dorsal crest merges with a laminar dorsal prominence, not clearly presenting a developed dorsal protuberance in this position. Larger specimens, on the other hand, display a slightly more evident protuberance. Te latter is elongated and presents a gently-curving dorsal margin. UU SP3 638 ( Fig. 10h, i View Fig ) and UU SP4 528 clearly shows that the dorsal prominence is not exceeded by the crista dorsalis in height. A distinct tubercular fossa (fossula tuberis superioris sensu Roček, 1994) is not clearly visible in any of the specimens, but few small foramina are present where it should be located. Te acetabulum is large and very deep, with a very strongly developed anterior margin. Anterior to the acetabulum, a distinct preacetabular fossa is present in UU SP3 622 ( Fig. 10f View Fig ), UU SP3 623, UU SP3 625 ( Fig. 10g View Fig ), UU SP3 627, UU SP4 513, UU SP4 526, and UU SP4 531, but clearly not in UU SP1 1141 ( Fig. 8e View Fig ) and UU SP4 528. A shallow supraacetabular fossa is visible dorsally in UU SP1 1141 ( Fig. 8e View Fig ), UU SP3 622, and UU SP4 513 and very poorly in UU SP3 638 ( Fig. 10h, i View Fig ), UU SP4 531, and UU SP4 532, but the same area is not preserved in the other specimens. Te base of the dorsal acetabular expansion is preserved only in UU SP3 627, UU SP3 638 ( Fig. 10h, i View Fig ), UU SP4 513, UU SP4 526, and UU SP4 531, which show apparently that the angle between the latter and the dorsal prominence is very wide (> 90°). Te ventral acetabular expansion is regularly missing. On the medial side, a wide and deep interiliac groove (sensu Bailon, 1999) is present, but due to breakage an interiliac tubercle is clearly visible only in UU SP1 1141 ( Fig. 8e View Fig ) and UU SP3 627.

Remarks. Latonia is well represented in the Spilia localities. Among the diagnostic features reported for this genus by e.g., Roček (1994, 2013) and Syromyatnikova et. al. (2019b), we can mention the double processes on the angular and the secondary sculpturing on dermal bones as particularly significant. Compared to the five currently recognized extant and extinct species of the genus (Biton et al., 2013, 2016; Roček, 1994, 2013; Syromyatnikova & Roček, 2019; Syromyatnikova et al., 2019b), the Spilia Latonia differs from Latonia nigriventer (Mendelssohn & Steinitz, 1943) because of the highly sculptured frontoparietal, from Latonia seyfriedi Meyer, 1843 (including Latonia gigantea [Lartet, 1851]; Syromyatnikova et al., 2019b) in the smooth maxilla, from Latonia vertaizoni (Friant, 1944) in the well-developed coronoid process, and from Latonia caucasica Syromyatnikova & Roček, 2019 , in the tooth row slightly extending posteriorly. A certain similarity in the significant features reported by Syromyatnikova and Roček (2019) is present between the Latonia from Spilia and Latonia ragei , at least as far as the elements known for both are concerned. Tus, we tentatively refer these fossils to the latter species. Te light rugosities present on the lateral surface of a single maxilla, UU SP4 523, which is otherwise undistinguishable from the other maxillae, are a peculiar feature, worth being highlighted here. However, the taxonomic significance of these rugosities, which do not represent clearly a dermal sculpturing, cannot be clearly evaluated here in the context of Latonia species with smooth maxillae.