Alexandre F. Bannikov

VOLHYNIAN (EARLY SARMATIAN SENSU LATO) FISHES FROM TSUREVSKY, NORTH CAUCASUS, RUSSIA

Abstract A new fish fauna is described from the late Middle Miocene (Volhynian; early Sarmatian sensu lato) of Tsurevsky, North Caucasus, Russia. Ten taxa belonging to nine families are described, of which two may be new (Micromesistius sp., Bothus sp.), but not formally described awaiting better-preserved material. The predominant faunal element is Sardinella sardinites, including more than 42% of all investigated specimens. The paleoecological analysis reveals a semienclosed marine environment not far from the coast, characterized by shallow depths and a soft bottom. The sedimentological features of the deposits and the preservation of the specimens suggest that periodic oxygen minima affected the bottom waters, causing repeated hypoxic events, probably related to the decay of organic matter previously accumulated in the basin. Paleoenvironmental considerations of fish faunas from several Paratethyan localities suggest that marine waters characterized by a little shift in chemical composition (high alkalinity) filled up the entire basin during the Sarmatian.

A remarkable clupeomorph fish (Pisces, Teleostei) from a new Upper Cretaceous marine locality in Lebanon

A new clupeomorph fish,Sorbinichthys elusivo n. g., n. sp. is described from a new Upper Cretaceous (Middle ? Cenomanian) marine locality at Nammoura (Lebanon). The characteristic features of the new genus, such as dorsally expanded posttemporal, subrhomboid spiny dorsal scutes, a very wide and deep gap between second and third hypurals, second ray of dorsal and pectoral fins greatly elongated and filamentous, and anterior procurrent caudal fin rays deeply extended between vertebral spines are unusual for clupeomorphs and warrant the establishment of the new family Sorbinichthyidae. The new fish displays several clupeomorph and clupeiform characters, but its placement within the clupeiforms is problematic. The new family is referred to the Clupeomorpha incertae ordinis.KurzfassungEin neuer clupeomorpher Fisch,Sorbinichthys elusivo n. g., n. sp. wird beschrieben. Er stammt von einer ebenfalls neuen Lokalität, Nammoura, die in die marine Oberkreide (? Mittleres Cenomanium) des Libanons eingestuft wird. Die neue Gattung zeichnet sich durch eine Reihe von Merkmalen aus, die für clupeomorphe Fische außergewöhnlich sind: ein dorsal ausgedehntes Posttemporale, subrhomboide, ctenoide dorsale Schildschuppen („scutes“), einen sehr breiten und tiefen Einschnitt zwischen dem zweiten und dritten Hypurale, einen stark verlängerten und filamentösen zweiten Flossenstrahl in der Dorsalis und Pectoralis, sowie vordere Schwanzflossen-Randstrahlen, die tief zwischen die Processus spinosi der Wirbelkörper ragen. Daher wird es für sinnvoll erachtet eine neue Familie, Sorbinichthyidae, zu begründen. Die neue Gattung zeigt verschiedene Merkmale der Clupeomorpha und Clupeiformes. Eine Eingliederung in die Clupeiformes erscheint daher problematisch, und die neue Familie wird als Clupeomorpha incertae ordinis eingestuft.

Bellwoodilabrus landinii n. gen., n. sp., a new genus and species of labrid fish (Teleostei, Perciformes) from the Eocene of Monte Bolca

ABSTRACT A labrid fish, Bellwoodilabrus landinii n. gen., n. sp., is described based on a single specimen collected from the Eocene locality of Monte Bolca, northern Italy. Bellwoodilabrus landinii n. gen., n. sp. is characterized by a prominent frontal relief, broad ethimoid-frontal depression, strongly developed supraoccipital crest, bar-like nasal, jaw teeth arranged in a single row, posterior preopercular margin apparently entire, rounded and molariform lower pharyngeal teeth, six branchiostegal rays, 24 (9+15) vertebrae, moderately reduced neural spine of the first vertebra, parhypurapophysis absent, XI + 9 dorsal fin elements, III + 9 anal fin elements and 12 pectoral-fin rays. The comparative analysis of morphological and meristic features reveals that Bellwoodilabrus landinii n. gen., n. sp. possesses a combination of plesiomorphic and derived features, which is unique within the Labridae. Bellwoodilabrus landinii n. gen., n. sp. represents the third valid species of the family Labridae described up to now from Monte Bolca. The morphofunctional analysis of the cranial and appendicular skeleton suggests that Bellwoodilabrus landinii n. gen., n. sp. was a benthic invertebrate feeder that inhabited the deep and calm settings along the northern coasts of the central Tethys. The evolutionary significance of the Eocene labrids from Monte Bolca is also discussed.

New genus of primitive ocean sunfish with separate premaxillae from the Eocene of southwest Russia (Molidae, Tetraodontiformes)

The upperjaws of a fossil fish from the late Eocene of Russia (Kumsky Horizon, North Caucasus) are referred to the Molidae because of their uniquely derived features of highly striated external bone surfaces and laterally elongate trituration teeth, as well as overall morphological similarity to the upper jaws of molids. However, the Eocene upper jaws differ from those of all other fossil (previously known only from the Miocene and Pliocene) and extant molids by having the premaxillae separate and articulated medially by interdigitating processes (versus fused in the midline). The separation of the premaxillae in the new genus and species, Eomola bimaxillaria, is a retention of the plesiomorphic condition found in triodontids and tetraodontids.

Otoliths in situ from Sarmatian (Middle Miocene) fishes of the Paratethys. Part I: Atherina suchovi Switchenska, 1973

Several well-preserved otoliths were extracted from four slabs containing fish specimens of Atherina suchovi. Atherina suchovi is one of the five Atherina species recorded from the Middle Miocene of the Central and Eastern Paratethys established on articulated skeletal remains. This corresponds to two otolith-based species so far identified from the same time interval in the Paratethys—Atherina austriaca and Atherina gidjakensis. Our correlation of isolated otoliths and otolith in situ documents in this case that A. suchovi is not synonymous to any of the otolith-based species, although it appears to be closely related to A. gidjakensis. A list is presented and briefly discussed showing Sarmatian skeleton-based fish records from the Central and Eastern Paratethys with an overview of known and currently studied fishes with otoliths in situ.

A new family of gymnodont fish (Tetraodontiformes) from the earliest Eocene of the Peri-Tethys (Kabardino-Balkaria, northern Caucasus, Russia)

The environmental changes that occurred during the Paleocene–Eocene transition are crucial for the interpretation of the patterns and processes of diversification of vertebrate clades. A prominent increase of the number of vertebrate families occurred between the late Paleocene and early Eocene, resulting in the appearance of many in the earliest representatives of extant lineages, including a number of marine fish groups. Tetraodontiforms are a monophyletic group of derived teleost fishes encompassing a variety of bizarre morphologies. Even though the earliest members of this order appeared in the Late Cretaceous, most of the crown lineages date back to the Eocene. One of the crown tetraodontiform groups that appeared in the fossil record during the Eocene are the gymnodonts (pufferfishes, porcupinefishes, ocean sunfishes and their allies), which include a variety of species characterized by highly modified teeth incorporated into beak-like jaws and scales usually modified into prickly spines. Herein, we describe †Balkaria histiopterygia gen. et sp. nov., a gymnodont fish characterized by a strikingly peculiar morphology. The single available specimen in part and counterpart documented herein was recovered from the sapropelitic deposits that originated in the northern Peri-Tethys during the transition between the Paleocene and Eocene. Today, these deposits are exposed near the village of Gerpegezh, Republic of Kabardino-Balkaria, Russia. The skeletal structure reveals an extreme mosaicism of primitive and derived characters that result in a very bizarre and unexpected morphology. †Balkaria histiopterygia gen. et sp. nov. is unique among the extant and other fossil gymnodont fishes by, among many other features, the huge size of its spiny-dorsal fin and the position of these spines on the top of the head. †Balkaria histiopterygia gen. et sp. nov. is the earliest unequivocal gymnodont fish, representing the sole member of the new family †Balkariidae. More particularly, †Balkaria histiopterygia gen. et sp. nov. is shown herein to be the oldest and arguably the most informative fossil of the gymnodont suborder Tetraodontoidei. The phylogenetic placement of this new taxon has been assessed based on both morphology alone and on a combination of morphological and molecular data that strongly supports the close relationship of †Balkaria gen. nov. to the herein restricted Tetraodontoidei. However, its position within Tetraodontoidei is unstable depending on the type of method of phylogenetic inference. Significantly younger ages, during the Late Cretaceous, are estimated for the diversification of Tetraodontiformes than in previous tip-dating analyses (Jurassic and Early Cretaceous) using the fossilized birth-death process; these new age estimates are in better agreement with the tetraodontiform fossil record. http://zoobank.org/urn:lsid:zoobank.org:pub:41764800-B0D8-4CA4-A111-5F4C4A281C37

A reappraisal of the Eocene priacanthid fish Pristigenys substriata (Blainville, 1818) from Monte Bolca, Italy

Abstract. Priacanthids are a small family of percomorph fishes comprising fewer than 20 extant species currently assigned to four genera. One of these, Pristigenys, was established by Louis Agassiz (1835) to include the Eocene species Pristigenys substriata from Monte Bolca, and is usually regarded as a subjective senior synonym of Pseudopriacanthus. Consequently, Pristigenys currently comprises five extant species plus the fossil Pristigenys substriata. The osteology of the type species of this genus, however, is poorly known, and this makes it difficult to provide an adequate comprehensive definition of the taxonomy of the whole family. Pristigenys substriata is redescribed in detail based on five well-preserved articulated skeletons. Pristigenys substriata can be easily distinguished from other priacanthids based on its unique combination of characters. Morphological analysis of the fossil specimens reveals that there is substantial evidence to justify recognition of both Pristigenys and Pseudopriacanthus as valid genera, with extant species previously assigned to Pristigenys now referred to Pseudopriacanthus. Within the Priacanthidae, Pristigenys and Pseudopriacanthus form sister taxa and this pair can be considered as the sister-group to all remaining extant priacanthid genera (Cookeolus + [Heteropriacanthus + Priacanthus]).

A long-bodied centriscoid fish from the basal Eocene of Kabardino-Balkaria, northern Caucasus, Russia

The Paleocene–Eocene transition is of crucial interest for interpreting the Cenozoic evolutionary radiation of vertebrates. A substantial increase of the number of vertebrate families occurred between the Late Paleocene and Early Eocene, with the appearance of most of the representatives of extant lineages. Basal Eocene marine fish diversity is currently poorly known, exclusively restricted to two assemblages from Denmark and Turkmenistan, respectively. Exceptionally well-preserved articulated skeletal remains of fishes have recently been discovered from a basal Eocene sapropelitic layer exposed along the Kheu River in the Republic of Kabardino-Balkaria, northern Caucasus, Russia. Here, we report on Gerpegezhus paviai gen. et sp. nov., a new peculiar syngnathoid fish from this new Ciscaucasian locality. The morphological structure of the single available specimen suggests that it is the first long-bodied member of the superfamily Centriscoidea, representing the sole member of the new family Gerpegezhidae, which forms a sister pair with the extant family Centriscidae.

The new family Caucasichthyidae (Pisces, Perciformes) from the Eocene of the North Caucasus

Caucasichthys kumaensis gen. et sp. nov., a representative of a new monotypic perciform family Caucasichthyidae, from the Middle Eocene (Bartonian, Kuma Horizon) of the North Caucasus (Gorny Luch locality) is described. The new family is characterized by elongated body, strong preopercular spine in adults, absence of supraneurals, large pelvic fins, long caudal peduncle, and anal fin longer at the base than soft dorsal fin. Scales vary from cycloid to spinoid on different parts of the body. Caucasichthys shares a number of apomorphic features with members of certain percoid families, most notably the Priacanthidae. However, because of its unique combination of features, the new family cannot be properly placed within any existing perciform suborder and it is placed incertae sedis among the Perciformes.

A new genus and species of early Sarmatian porgies (Perciformes, Sparidae) from the Krasnodar Region

A new genus and species of porgies (Perciformes, Sparidae), Pshekharus yesinorum gen. et sp. nov., from the Lower Sarmatian locality of bony fishes on the Pshekha River (northern Caucasus) is described. The dentition of the new taxon distinctly differs from that of the majority of 11 sparid genera known from the modern Mediterranean. Pshekharus gen. nov. is tentatively considered to be related to the subfamily Pagellinae.