Rutilus robustus Kovalchuk, 2014

Kovalchuk, O. М., 2014, New Extinct Carp Fish Species (Teleostei, Cyprinidae) From The Late Neogene Of Southeastern Europe, Vestnik Zoologii 48 (5), pp. 411-418 : 413-414

Rutilus robustus Kovalchuk , sp. n.

T y p e s p e c i m e n. The holotype ( fig. 2 ) is a complete right pharyngeal bone with one preserved tooth ( Prz 10–1/12). It is deposited in the Geological and Paleontological Museum of the Transnistrian State University ( Republic of Moldova).

T y p e l o c a l i t y. Priozernoe (46°48.13' N, 29°55.39' E), Slobozia District, Trans-Dniester Region, Republic of Moldova.

G e o l o g i c a l a g e. Early Pliocene, late Ruscinian, MN 15.

A d d i t i o n a l m a t e r i a l. Fragment of the right pharyngeal bone ( NMNH – P 41 /2342), Odesa Pontian Lectostratotype (46°28.18’ N, 30°42.37’ E), Odesa Region, Ukraine .

D i a g n o s i s. New fossil Rutilus species is characterized by the massive high ceratobranchiale, long anterior non-dentiferous process, and also thick bulkheads between the septum on cavernous surface.

3 4

Рис. 2. Глоточные кости: 1 — Rutilus robustus sp. n., голотип (Prz 10–1/12, Приозёрное); 2 — Rutilus robustus sp. n., фрагмент ceratobranchiale (NMNH–P 41/2342, лектостратотип понта); 3 — Rutilus frisii , subfossil (NMNH–P 53/4108, Виноградный Сад); 4 — Rutilus frisii , современный. CS — кавернозная поверхность; DS — озубленная поверхность.

D e s c r i p t i o n a n d c o m p a r i s o n. Pharyngeal bone is broad and massive. Anterior, laterally bent non-dentiferous process is relatively long; its length exceeds the height of the front pharyngeal tooth. Ventral edge is straight to the front angle, whose value is about 95°. Ventral edge forms a flattened ledge at the anterior angle. Curved posterior edge of ceratobranchiale rises to the clear-expressed posterior angle (140°). The length of pharyngeal bone from Priozernoe is 62.0 mm, restored L crbh of the item from Odesa Pontian Lectostratotype ~ 50 mm. Dorsal non-dentiferous branch bends anterodorsally and medially from the posterior angle. Dentiferous surface is a little bit shorter than the posterior non-dentiferous process (LDS ~ 32.7–34.1 mm), which is almost three times longer than the anterior one. Dentition consists of approximately 5 teeth, one of which is preserved. Wide cavernous surface has three large and one small septum (cavities) with the thick bulkheads between them. Pharyngeal tooth is massive and laterally compressed, has broad flattened pedicle with clear contraction at the neck. Arched tooth back gradually rises to top without the hook. Elongated grinding surface is smooth and convex, slightly canted to a rounded tooth belly. Height of the tooth is 7.3 mm, width of the crown — 10.2 mm. Porus canalis at the basis of pharyngeal teeth is clearly visible. Recovered fish body length is near 60 cm.

Measurements of the holotype, additional material and its comparison with related bones of the close species are shown at the table 1, pictures — at the figure 2 . Rutilus robustus sp. n. as compared to all other known Rutilus species is clearly bigger. A new fossil taxon is characterized by the massive ceratobranchiale with a large anterior angle of the ventral edge, longer dentiferous surface, larger diameter of the porus canalis, and also thickened bulkheads between the septum on the cavernous surface. A general morphological similarity to the remnants of this species to Rutilus frisii (Nordmann, 1840) may indicate the presence of close phylogenetic relationship among them.

E t y m o l o g y. The specific name is a Latin derivation and reflects the diagnostic criteria — robustness and large size of the pharyngeal bone.

D i s t r i b u t i o n. Late Miocene of Southern Ukraine and Early Pliocene of the Republic of Moldova.

Figures

Fig. 2. Pharyngeal bones: 1 — Rutilus robustus sp. n., holotype (Prz 10–1/12, Priozernoe); 2 — Rutilus robustus sp. n., fragment of ceratobranchiale (NMNH–P 41/2342, Odesa Pontian Lectostratotype); 3 — Rutilus frisii, subfossil (NMNH–P 53/4108, Vinohradnyi Sad); 4 — Rutilus frisii, recent. CS — cavernous surface; DS — dentiferous surface.