PERCIDAE Cuvier, 1816

Kovalchuk, O. M., 2015, A New Extinct Species Of Pikeperch Sander Svetovidovi (Teleostei, Percidae) From The Late Miocene Of Southern Ukraine, Vestnik Zoologii 49 (4), pp. 317-324 : 320-321

Family PERCIDAE Cuvier, 1816

Sander Oken, 1817 (= Stizostedion Rafinesque, 1820 )

Sander svetovidovi Kovalchuk , sp. n.

2011 Sander cf. lucioperca — Kovalchuk, p. 134, fig. 2 (6).

T y p e s p e c i m e n. The holotype ( fig. 3, A–D) is a near-complete right quadrate bone (quadratum) , NMNH-P 41 /4527. It is deposited in the Department of Vertebrate Paleozoology and Paleontological Museum , National Museum of Natural History , National Academy of Sciences of Ukraine (Kyiv) .

T y p e l o c a l i t y. Egorovka 2, Odesa Region, Southern Ukraine .

G e o l o g i c a l a g e. Late Miocene, Maeotian, MN 12.

A d d i t i o n a l m a t e r i a l. Fragment of the left quadrate bone (NMNHU-P 29/1716), Popovo 3, Zaporizhya Region, Southern Ukraine.

D i a g n o s i s. The new Sander species is characterized by the large articular angle between the axis and the plane of the quadrate bone, middle-sized oval lateral condyle (condylus lateralis) and also presence of additional double crista on the anterior inferior edge of quadratum.

D e s c r i p t i o n. Quadrate bone is flat and triangular ( fig. 3, A–D). Its lower top forms the joint in a double oblique arthrodial block. The angle between the articular axis of the bone and the plane is 75°. The superior edge of the quadratum is somewhat thickened. There is a clearly visible double crest on the posterior edge of the quadrate bone. It is begun from the articular block and terminated by the elongated spicular process (processus praeopercularis). The inferior anterior angle has thickened edge with an additional low crista. Front notch at the neck of quadrate bone (incisura colli anterior) is small and rounded. There is no invagination at the condylus lateralis. Lateral condyle is oval and middle-sized, with rounded edges. It is separated from the rear edge of the quadrate bone by the clear shallow groove. Measurements of the type species and some other extinct and recent percid fishes are presented at the table 1. The length of the articular surface facet is 9.7 mm, width of the articular surface — 4.1 mm; width of processus praeopercularis — 6.0 mm; diameter of condylus lateralis — 4.5 mm. Recovered fish body length is near 52–60 cm.

C o m p a r i s o n. A new species, as compared with Sander lucioperca , is characterized by the larger tilt angle of the quadrate bone ( fig. 3, C–D, G–H), fits into the limits of variability of the Leobergia zaissanica (68–80°; fig. 3, K–L) and less than in the Perca fluviatilis (90°; fig. 3, O–P). There is an additional crest on posterior edge of the quadratum in all studied specimens, and distinct only in the genus Sander (including a new species). New species and Sander lucioperca are comparable in the presence of expanded anterior inferior angle. Additional double crest is clearly visible in the Sander svetovidovi sp. n. ( fig. 3, C), less developed in the extant Sander lucioperca ( fig. 3, G), and absent in representatives of the genera Perca ( fig. 3, K) and Leobergia ( fig. 3, O). Most of the studied specimens are characterized by the weak incisura colli anterior (except Sander lucioperca ). There is a specific invagination at the lateral condyle of Sander lucioperca ( fig. 3, E) and Leobergia zaissanica ( fig. 3, I), however it is absent in the Sander svetovidovi sp. n. ( fig. 3, A). Representatives of the new species (as compared to other studied percids) are characterized by an intermediate position under the development of condylus lateralis between the Sander lucioperca (on the one hand), and also Perca and Leobergia (on the other). Lateral condyle is rounded in majority of Percidae . However, it is triangular in the Sander lucioperca ( fig. 3, E–F) and oval in the new species ( fig. 3, A–B). Besides, condylus lateralis is separated from the plane of the quadrate bone only in the Sander svetovidovi sp. n. Described remnants of the new species are comparable in size to those in the extant Sander lucioperca , somewhat bigger than those in the Leobergia zaissanica and twice bigger than quadratum of the extant Perca fluviatilis (table 1).

E t y m o l o g y. In honour of the Russian ichthyologist A. N. Svetovidov for his contributions to the knowledge of recent and fossil percid fishes.

D i s t r i b u t i o n. Late Miocene of Southern Ukraine, late Sarmatian — Maeotian, MN 11-12.