A new genus and species of damselfish †Chiarachromis salazzarii gen. et sp. nov. (Pomacentridae) from the Eocene (49 Ma) Pesciara deposits of the Bolca locality, Italy, is described. †Chiarachromis gen. nov. is characterized by a unique combination of vertebral (11+14=25) and unpaired fin-ray counts (D X, 11; A II, 7; C 7, I,7-6,I, 6), long pelvic fins, and the possession of three supraneurals. With exceptional preservation of the fin shape and the body form, this damselfish raises questions about the role of body shape, especially fin height, in the early evolution of reef fishes, and offers new insights into the rapid development of modern, predator-prey interactions in the early evolution of reef fishes.

A new species of fossil surgeonfish, †Caprovesposus daniltshenkoi sp. nov., is described based upon two specimens from the terminal Maikopian (upper Lower to lower Middle Miocene; not less than 15 mya) in the northwestern Caucasus. The specimens were excavated from brownish gray clays in the bank of the Pshekha River in the Krasnodar Region of Apsheronsk District, Russia. Both specimens are in the acronurus presettlement stage of development and are placed within the formerly monotypic genus †Caprovesposus based upon their possession of vertically elongated, needle-like scales on the body. They differ from the Oligocene †Caprovesposus parvus Daniltshenko, 1960 in (1) lacking serrations on the frontal, mesethmoid, preopercle, and basipterygium; and (2) having the vertically elongated, needle-like scales only on the anterior and middle portions of the body, rather than on the entire body. Three additional, previously collected specimens from the Caucasus and Crimea are referred to the new species.

Otolith finds in situ are important for connecting the independent data sets of articulated fish skeletons and isolated otoliths in the fossil record. Here we describe an otolith in situ retrieved from a skeleton of the stromateid Pinichthys shirvanensis Bannikov, 2021, which was collected from the Tarkhanian (Langhian, Middle Miocene) from the prolific Pshekha River locality in the Krasnodar Region of the northern Caucasus, Russia. It represents the first find of an otolith in situ made in a fossil stromateoid skeleton. The extracted otolith is compared to fossil otolith-based species allocated to the genus Pampus. One of these species is being reallocated in the process to Pinichthys: Pinichthys steurbauti (Schwarzhans, 1994) from the late Oligocene to early Middle Miocene in the North Sea Basin.

V.V. Bogachev (1933) described the scombrid fish Auxis caucasica based on an incomplete skeleton from the Sarmatian (Middle Miocene) of the North Caucasus (Stavropol Region). Subsequently, this species was assigned to the mackerel genus Scomber. New findings in the Sarmatian of the North Caucasus (Krasnodar Region, Pshekha River) revealed a significant reduction in the number of vertebrae in S. caucasicus (Bogatshov) (up to 28), which is extremely unusual for Scombridae, with at least 31 vertebrae. A new genus Mioscomber is established to accommodate the Sarmatian species of scombrids. The scombrids from the Sarmatian of the former Yugoslavia, originally described as Auxis vrabcensis Kramberger, 1882, A. thynnoides Kramberger, 1882 and Scomber sujedanus Steindachner, 1860, are assigned to the same genus—these also have a reduction in the number of vertebrae. The generic character of Mioscomber gen. nov. assumes correction of the diagnosis of the family Scombridae, from “Vertebrae 31–66” to “Vertebrae 28–66”.

The fossil puffer fish genus †Archaeotetraodon Tyler & Bannikov, 1994 is unique among the Tetraodontidae in having the upright central spinule of the dermal scale plates bifid rather than singular and undivided. Six species of this genus have previously been described variously from the Oligocene and Miocene of Russia, Italy, Algeria, and Ukraine. Described herein is a seventh species of this genus, †Archaeotetraodon bemisae sp. nov., based upon two specimens from the Pshekha River, Krasnodar Region, North Caucasus, Russia. These Maikopian specimens are no less than 15 mya, in the basal-most Middle Miocene. The new species is distinguished from the other six species in the genus by the following combination of characters: thick, sturdy, and smooth bifid spinules; frontal width broad over the orbit; 18 vertebrae; slender ventral postcleithrum; a moderately long rayless pterygiophore; height/length ratio of the posteriormost abdominal centrum being 0.78–0.79; 10 dorsal-fin rays; 9 anal-fin rays; and 14 pectoral-fin rays.

To date, soft-tissue remains of extinct incirrate octopods have been described exclusively from Upper Cretaceous deposits. Here, three specimens of an incirrate octopodid with well-preserved soft tissue imprints are described for the first time from Paleogene strata. This material originates from the upper Ypresian (lower Eocene) fish-bearing levels of the Bolca Konservat-Lagerstätte in the Pesciara of Bolca in north-eastern Italy. Previously, these specimens had tentatively been interpreted as teuthids. Based on a detailed study of their anatomical structure, a new genus and species of octopodid, Bolcaoctopus pesciaraensis, belonging to the extant family Octopodidae, are here erected. Bolcaoctopus gen. nov. may be distinguished from the Late Cretaceous genus Styletoctopus by the presence of long and thin arms and an elongated body shape with a narrowed apical end and covered by longitudinal wrinkles. Although finds of fossil octopuses in the Bolca Konservat-Lagerstätte remain extremely rare, it is worth noting that Cenozoic marine vertebrate localities constitute an important potential source of additional finds of coleoid cephalopods, the study of which may shed light on a poorly understood period in the evolutionary history of these molluscs.

The stratigraphic scale of the Eastern Paratethys is revised based on a study of the Neogene stratotype and reference sections, their biotic characteristics, and paleomagnetic and sedimentological data. New data on the correlation of its regional subdivisions with the Central Paratethys and Mediterranean stratotypes are presented. The section “Regional Stage Scale of the Eastern Paratethys” considers the history of identification and a brief description of the horizons of the regional scale, which later became regional stages, as well as their historical stratotypes and lectostratotypes, and division into Beds and Substages. The section “History of Separate Biota Groups” provides reviews on the most important groups of fauna, phytoplankton, and terrestrial vegetation, as well as on magnetostratigraphy, the possibility of correlation and dating of sections based on these data, and comparison with the Central Paratethys and stratotypes of the Mediterranean. In conclusion, the main results of the revision of the stratigraphic scheme of the Neogene of the Eastern Paratethys are given.

A new species of Chinese perch (Perciformes, Sinipercidae), dagger Coreoperca chosun, sp. nov., is described based on four specimens (mostly fragmentary and disarticulated) found in the freshwater Lower Miocene Geumgwangdong Formation in the vicinity of Pohang City, South Korea (N35 degrees 57'30.5, E129 degrees 26'57.3). Such characters of this fossil sinipercid as the serrated ventral margin of the preopercle, the third dorsal-fin spine being shorter than the fourth and fifth spines, the third to fifth neural spines inserted shallowly rather than deeply between the proximal dorsal-fin pterygiophores, the relatively strong supraneurals and relatively large scales indicate its attribution to the genus Coreoperca. However, its unique combination of characters dearly distinguishes dagger C. chosun, sp. nov. from both the extinct and extant members of the genus Coreoperca. This is the first fossil record of the family Sinipercidae in the Korean Peninsula, one of the earliest representatives of Coreoperca known to date, and the first described Neogene freshwater fish from South Korea.

Data on the principal Cenozoic localities of marine bony fishes (represented by skeletal remains, not otoliths) from the territory of the development of the Tethys and Paratethys are presented. The historical development of many supra-generic taxa of the higher Teleostei (spiny-rayed) in the Cenozoic basins of the Tethys and Paratethys has been traced. The available paleontological data do not confirm the appearance of most lineages of "crown Acanthomorpha" (and even "crown Percomorpha") already at the end of the Cretaceous, as indicated by the time-calibrated molecular phylogeny.

A new species of horse mackerel fish (Carangidae), Archaeus solus sp. nov., was described based on the imprint of a complete skeleton from the Lower Oligocene (Pshekha Formation) of Gorny Luch locality. This is the third known species of the Eocene–Oligocene genus Archaeus Agassiz, 1844, and the first discovery of Carangidae in the Oligocene of the North Caucasus. The new species differs from A . glarisianus Agassiz, 1844 from the Rupelian of Switzerland and A. oblongus Daniltshenko, 1968 from the basal Eocene of Turkmenistan by a larger number of rays in both the spiny and soft dorsal fin.

A fossil mackerel Scomber collettei sp. nov. (Percomorpha, Scombroidei, Scombridae) is described from the Tarkhanian (lowermost Middle Miocene) of the northwestern Caucasus (Krasnodar Region, Pshekha River) based on several skeletons. This is the first discovery of a fossil representative of the genus Scomber in the Tarkhanian regional stage. The new species differs from the more ancient, late Oligocene to early Miocene mackerels from the Eastern Paratethys—S. cubanicus and S. gnarus—in having a different ratio of the abdominal and caudal vertebrae (14 + 17 vs. 15 + 16), and wider separated dorsal fins. S. collettei sp. nov. is also characterized by its unusually large teeth and lachrymal.

These are the first and so far only records of a sailfin velifer fish from the Lower Oligocene of the Unterfeld (“Frauenweiler”) clay pit at Rauenberg (S Germany), and only the fourth fossil skeletal finds of this group worldwide. The new genus and species † Oechsleria unterfeldensis is described in detail, diagnosed, and compared to other fossil and extant representatives of the Veliferidae. It appears to be a comparatively small-sized fish, which differs from the other representatives of this family, apart from body proportions, by having a lower number of vertebrae and dorsal-fin rays, the absence of massive spines in the dorsal and anal fins, four anal-fin pterygiophores in front of the anteriormost haemal spine, and a different morphology and size of various skeletal elements. Amongst others, the following character states are of relevance: a supraoccipital that is laterally sculptured by strong surface ridges; a weak ascending process of the premaxilla that is shorter than in the other veliferid taxa; compound (fused) anteriormost dorsal- and anal-fin pterygiophores, together with spineless dorsal and anal fins with unornamented rays (no spinules), of which the majority are bilaterally paired and both halves are fused only proximally but separate and segmented distally; a short coracoid that does not reach the ventral body margin; a broad and anterodorsally directed pelvic bone that bears a well-developed postpelvic process, and probably also the presence of a short pointed neural spine (in contrast to a distally blunt one and/or a low crest) on the second preural centrum. All in all, the new fossil records remarkably increase the known biodiversity of the Veliferidae. They also expand the known palaeogeographic range of this family as far as to the Western Paratethys. With reference to the occurrence and life habits as deduced from the extant forms, they seem to be another Indo-Pacific (respectively Palaeo-Mediterranean, when referring to the fossil forms) element of the Grube Unterfeld fish fauna with a preference for deeper waters and affinities to temperate to tropical climates.

The middle Miocene (upper Serravallian, lower Volhynian) deposits at Karpov Yar near Naslavcea, northern Moldova, are among the few settings in which fossil fish are preserved with otoliths in situ. Here, we describe the new gobiid † Moldavigobius helenae gen. et sp. nov. from this locality. The taxon is characterized by small size (up to 34.2 mm SL), a compact body (body depth 17–21% SL), a fan-shaped caudal fin, large ctenoid scales (< 30 scales in the longitudinal row) and nearly square otoliths (sagittae) with a slender, shoe sole-shaped sulcus. It has 27 vertebrae, six spines in the first dorsal fin, one spine and 11 soft rays in both the second dorsal and the anal fin, 15–17 pectoral-fin rays, and 17 (9/8) segmented caudal-fin rays. The meristic characters of † Moldavigobius gen. nov., together with its sagitta shape, suggest a relationship with Lesueurigobius Whitley, 1950, but its fan-shaped caudal fin and the unique sulcus contour of the otoliths preclude its attribution to that genus. In addition, we re-assign an otolith-based species previously described as Knipowitschia suavis Schwarzhans, 2014 as a second member of † Moldavigobius gen. nov. Accordingly, † Moldavigobius gen. nov. was represented by at least two species in the Serravallian of the Eastern Paratethys († M. helenae gen. et sp. nov., † M. suavis nov. comb.). Moreover, † M. suavis is also known from the Serravallian ichthyofauna of the SE Mediterranean. † Moldavigobius gen. nov. thus demonstrates the key role of fossil skeletal material with otoliths in elucidating the ancient diversity of the Gobioidei.

Otoliths found in situ in fossil fish specimens offer the rare opportunity to relate taxa based on articulated skeletons and isolated otoliths. Here, we describe for the first time otoliths found in situ in two moderately well-preserved articulated skeletons belonging to the extinct lotine fish genus Palaeomolva, and, more particularly, to the species P. tarchanica Daniltshenko, 1947 recently discovered from the middle Miocene (Tarkhanian) of the NW Caucasus in Russia. The otolith-based species Brosme heinrichi Gaemers, 1976 known from a single large specimen from the middle Miocene of the North Sea Basin is now referred as a junior synonym of Palaeomolva tarchanica. The affinities of the known species of Palaeomolva are also briefly discussed.

Studies of otoliths suggest that Gobioidei, which are among the most species-rich groups of modern-day vertebrates, were prominent elements of late middle Miocene (early Sarmatian sensu lato) fish faunas in Europe and Western Asia. However, few complete skeletons have come to light. Here, we report an assemblage of six marine gobiid species, based on skeletons preserved with otoliths in situ, from the lower Volhynian (lower Sarmatian s.l.) of Karpov Yar, Naslavcea, northern Moldova (Eastern Paratethys). Previously only one of these species had been reported from the Central Paratethys, based on its otoliths alone. Five new species representing four new genera are described: † Katyagobius prikryli gen. et sp. nov., Pseudolesueurigobius manfredi gen. et sp. nov., † Sarmatigobius compactus gen. et sp. nov., † Yarigobius decoratus gen. et sp. nov., and † Y. naslavcensis gen. et sp. nov. All six species share the following set of characters, suggesting that they represent a monophyletic clade: 27–29 vertebrae (of which 10 are abdominal); spines of first dorsal fin distally filamentous; second dorsal fin with spine and 14–16 soft rays; anal fin with spine and 13–15 soft rays; caudal fin longish-to-lanceolate; otoliths (sagittae) with rounded, trapezoid-to-squarish shape. Their skeletal features suggest that they are closely related to Lesueurigobius Whitley, 1950, but the otoliths preserved in situ do not support such a classification. The new fossils most likely represent a stem lineage of the European Aphia lineage, and indicate that the diversity of gobiid lineages 12 million years ago differed clearly from that observed today.

A morphologically bizarre fish larva is described based on a single specimen from Eocene (Bartonian) locality of Gornyi Luch, Krasnodar Region, Northern Caucasus, SW Russia. The fossil larva described here was collected form the Kuma Horizon and inhabited an open marine setting with bottom waters characterized by poorly oxygenated conditions, where it was associated with abundant pelagic fish taxa. This fossil fish larva exhibits a peculiar morphology, being characterized by remarkably expanded and thickened bones that form an armour-like protective covering, a strong and greatly elongate pelvic-fin spine and a unique head spination that comprises a conical and posterodorsally directed supraoccipital spine, a rostral spine formed by the nasals, and enormous spines on the preopercle and opercle. Moreover, this fish larva has an advanced insertion of the dorsal fin and 17 principal rays in the caudal fin thereby revealing its affinity to percomorph fishes. The hypertrophied bony plates encasing the head and forming a bony armour are shared with the so-called tholichthys larval stage of chaetodontid butterflyfishes, as well as with the larval stages of some other percomorphs. Comparison with selected percomorph larval morphotypes (e.g. families Chaetodontidae, Malacanthidae, Ostracoberycidae and Scatophagidae) suggests that the Eocene larva described herein exhibits a unique combination of characters that would support an attribution to a new, previously undescribed taxon.

The first well-preserved soft-body imprint of a fossil squid was discovered from the Lower Oligocene of the Krasnodar region, Russia. The squid is perfectly preserved, with many details of its body available for study, such as imprints of eyes and head, a pair of statoliths, jaws, and stomach contents. Statoliths of this squid are the first finds of in situ statoliths in fossil non-belemnoid coleoids, and their shape is characteristic of the genus Loligo (family Loliginidae). Although some Mesozoic coleoids were previously classified as teuthids, these finds remain controversial and the squid described herein is the first unquestionable representative of fossil Teuthida known to date. It should be noted that the squid is preserved not due to phosphatization, which is typical for fossil coleoids, but by pyritization and carbonization. Numerous fish remains in the stomach contents of the squid indicate its piscivorous diet. A small cutlassfish Anenchelum angustum, which was buried together with the squid and whose bones are located near the squid's jaws, sheds light on the circumstances of the death of this animal. Most likely, the squid suffocated in the anoxic bottom waters, where it drowned along with its last prey (distraction sinking).

The stromateid fish Pinichthys shirvanensis sp. nov. (Perciformes, Stromateoidei), the latest species of the Oligocene–Miocene genus Pinichthys Bannikov, 1985, is described from the Tarkhanian (lowermost Middle Miocene) of the northwestern Caucasus (Krasnodar Region, Pshekha River) based on complete and incomplete skeletons. The new species differs from P. pulcher Bannikov, 1988 and P. fractus Bannikov, 1985 in having fewer soft rays in the anal fin and spines in the dorsal fin, a wider hypural diastema, and a greater number of abdominal vertebrae. Tricuspid teeth in the oral jaws, which are characteristic of Stromateidae, are documented in Pinichthys for the first time.

The Miocene fossil fish dagger Pentaceros sakhalinicus Gretchina, 1975, (Perciformes, Pentacerotidae) is redescribed based on the holotype and numerous additional materials collected on Sakhalin Island (western Pacific, Russian Far East) at the end of the 20th century. The general appearance and body proportions, as well as the presence of multiple (more than three) anal-fin spines, make the Miocene taxon similar to members of the family Pentacerotidae, whereas generalized morphological characters such as the presence of three supraneurals and the absence of rugosity of the superficial head bones differentiate this species greatly from any known pentacerotid genus. Thus, the new genus dagger Portentosoceros is erected for this fish, which was considered the only known fossil member of the family. Due to the fact that this fish lacks the main synapomorphic characters of the Pentacerotidae, dagger Portentosoceros gen. nov. is left incertae sedis within the Percoidei, though probably related to Recent armorheads. The observed variability in the number of anal-fin spines (from four to six) in dagger Portentosoceros sakhalinicus is extremely unusual.