Contents of Proceedings of the Zoological Institute

The present article is dedicated to the 90th anniversary of the foundation of the Department of Ichthyology and Hydrobiology in Saint-Petersburg State University, as well as to the formation of ichthyological school by talented scientist and bestow teacher Professor Nikolai Lvovich Gerbilcky. The results of fundamental works which were fulfilled during much time when using the principle of ecological histophysiological analysis laid by N.L. Gerbilsky are shown in this article. Also the results of the analysis of species adaptations connecting with the reproduction of fishes and with survival of its progeny when using this new method were presented. The basic principles of the biotechnology of fish reproduction in industrial conditions were created because of these results. The sphere of the principles of morphological-physiological analysis were expended and continued by following leaders of the Department and Laboratories – the schoolers and the followers of N.L. Gerbilsky. The mechanisms of hormonal regulation of fish’s gametogenesis were studied and the patterns of phase changes in the regulation and ecological – physiological staging of fish’s gametogenesis were opened by B.N. Kazansky. Fundamental investigations of osmotic and ionic regulation in different species of acipenserids and salmonids from the perspective of ecological morphological physiology when using present experimental methods leaded up to the creation of new direction in the study of fish osmoregulation and its adaptation to water with different salinity by L.S. Krayushkina and her pupils and colleagues. The mechanisms of regulation of the gametogenesis and the functions of sex gonads, the differentiation of fish sex and the influence of extremal factors on the process of gameto- and gonad genesis in different fishes were investigated by G.M. Persov and his Laboratory of Experimental Ichthyology. The use and the development of the principle of Gerbilsky’s method outside the Department by his pupils were presented: in the creation of the theory of functional basis of fish migrations, in the studies of endocrine regulation of reproductive cycle in acipenserids and salmonids by I.A. Barannikova and colleagues of her Laboratory. Structural and functional peculiarities of hypothalamic-hypophysial neurosecreting system of fishes were studied by A.L. Polenov. The continuation of traditional ruse to the analysis of different fish adaptations were demonstrated in the investigations of the ichthyologists at present time.

The article describes the history and present state of the collection of fish of Middle Asia which is currently kept at the Department of Ichthyology and Hydrobiology and Department of Vertebrate Zoology of Saint Petersburg State University. The collecting of fish specimens in the Zoological Cabinet of the University started in the 60s of the XIX century. This was the time of the beginning of the active study of biological diversity and development of natural resources of Middle Asia (Turkestan) as well as military expansion of the Russian Empire into the region. Extensive ichthyological material was collected by A.P. Fedchenko in the Turkestan Expedition (1868–1871), M.N. Bogdanov and V.D. Alenitsyn in the Khiva Campaign (1873) and the Aral-Caspian Expedition (1874), A.M. Nikolsky in the Balkhash Expedition (1884) as well as I.S. Polyakov, D.D. Pedashenko, A.A. Kushakevich, P.Y. Schmidt, K.M. Deryugin and others. Professor K.F. Kessler described 12 new fish species based on study of the material brought from Turkestan. Today, the collection of Middle Asian fish includes 45 lots with 109 specimens in good condition. The taxonomic diversity of fish is represented by 5 families, 19 genera, and 28 freshwater and migratory species. Main part of the collection (89%) is stored at the Department of Ichthyology and Hydrobiology of Saint Petersburg State University, and other part is stored at the Department of Vertebrate Zoology.

This review presents data on the role of cortisol (F) at the final stages of the reproductive cycle in migratory sturgeons (Acipenseridae) of the Volga-Caspian region: Russian sturgeon (Acipenser gueldenstaedtii Brandt et Ratzeburg, 1833), stellate sturgeon (Acipenser stellatus Pallas, 1771) and beluga (Huso huso (Linnaeus, 1758) obtained using a special variant of enzyme-linked immunosorbent assay (ELISA), which allowed us to compare the indicators of different years. The dynamics of F level in blood serum (BS) and the state of the interrenal gland (IG) in sturgeons were studied during feeding in the sea and at the beginning of the anadromous migration, as well as at the reproduction in the conditions of hatcheries. Higher levels of F in BS and high functional activity of IG are characteristic of sturgeon migrants when entering the river compared with data for fish during feeding in the sea. Reservation of sturgeon breeders at the hatchery led to decrease of the F serum level; and hormonal stimulation of maturation caused an increase in this indicator. Data on the F content in oocytes and abdominal (coelomic) fluid during maturation of female sturgeon are also presented. The F “profiles” were evaluated in sturgeon breeders under stress impacts that are unavoidable at the conditions of hatchery enterprises, as well as under experimentally simulated stress impacts. Peculiarities of the interaction of the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-interrenal axes in sturgeons during reservation at hatcheries and during hormonal stimulation of fish maturation are discussed. Particular attention is paid to the compilation of data contained in the works performed in the late 90s – early 2000s under the guidance of Dr. Sc., prof. I.A. Barannikova (1926–2017), to whose memory the review is dedicated.

The ovarian condition was studied in juveniles of six species of the Pacific salmon of different ages, taken for research at four hatcheries, as well as captured in lakes and rivers in the Sakhalin Province and Kamchatka Territory. The formation of the older generation of germ cells, consisting of previellogenic oocytes, in females of the Pacific salmon ends at the age of 0+, in pink salmon, with a mass of about 0.2–0.3 g, in other species, with a mass of about 1–2 g. In all species, the replenishment of this generation ceases during the habitat of juvenile fish in fresh water. After the formation of the older generation of germ cells is completed and its number reaches a certain level characteristic of each fish species, two oogenesis processes, that are not externally related to each other, continue to be carried out in the ovaries. The first process is the growth of the older generation oocytes, which develop relatively synchronously, varying 1.5–2 times in diameter. The second process is the mitotic reproduction of the gonies, their entry into meiosis, and subsequent resorption at the stage of pachytene and early diplotene. The mitotic activity of the gonies is minimal in females of the pink salmon, and, in fact, it is not detected in the fish caught in the coast. In females of other species, a decrease in both mitotic activity and initiation of new meiotic cycles does not occur during the entire period of their habitat in fresh water.

The comparative ultrastructural analysis of steroid-secretory cells (SC) in gonads of youngs lamprey Lampetra fluviatilis (Linnaeus 1758), Siberian sturgeon Acipenser baerii Brandt 1869, sterlet A. ruthenus Linnaeus, 1758, rainbow trout Oncorhynchus mykiss (Walbaum 1792) and pink salmon Oncorhynchus gorbuscha (Walbaum 1792) at similar stages of gametogenesis was carried out. The SC localization and size, the diameters of mitochondria, tubules of agranular reticulum, lipid inclusions and also the relative volume density of these structures were determined and calculated. It is concluded that localization of SC in gonads and their activity changes are closely related to the processes of sex differentiation and the growth of oocytes. Thus, in females of all studied species there was a change in SC localization in the direction of stroma→theca→granulosa of previtellogenic oocytes with a simultaneous increase of their secretory activity (increase in SC size, size and volume density of mitochondria and of agranular endoplasmic reticulum tubules). In males, during gametogenesis, the SC localization also changed in the direction of epithelium→stroma testicular with an increase of their secretory activity. In this case, the largest and most active SC were found in the stroma of pink salmon testicular during the natural sex inversion. At the same time, however, were revealed differences in SC ultrastructural organization, appeared to be of species-specific nature. The highest average diameter of the agranular endoplasmic reticulum tubules was observed in sturgeon SC and they are characterized by a large number of lipid inclusions in early stages of gametogenesis. This should be taken into account when comparatively analysing of quantitative data in fish of different systematic groups.

Until the early 1930s the Svir River freshwater population of Atlantic salmon (Salmo salar Linnaeus, 1758) was the largest in the Ladoga Lake basin. A catastrophic decrease in the salmon abundance took place due to loss of spawning grounds after the dam construction in the riverbed and a long-time timber rafting in the main tributaries. Over-fishery in the 1950s and a poaching also contributed to this negative trend. The Svirsky hatchery was put in action in 1933 to support the salmon population. In course of 30-year monitoring the size characteristics of smolts, lake-living individuals and spawners were determined, as well as the state of gonads in males and females at different stages of the life cycle were evaluated. The “autumnal” form was described. It was found that all salmon spawners caught near the dam of the hydroelectric power station over the last decades were of hatchery origin and belonged to the same age classes as in the previous period. The present-day scale of hatchery propagation is too small for conservation of the Svir River salmon population. The population will be lost soon, if an artificial reproduction will not expanded and effective actions of fishery control inspection will not restored.

The participation of the hypothalamo-hypophysial neurosecretory system (HHNS) in fish reproduction was shown by histomorphological and electronic microscopical studies with the use of quantitative morphometry. The activation of HHNS at the beginning of spawning and the following decrease of its functional activity was revealed in all studied one-time spawning fish species independently of the spawning season (based on spring-, autumn- and winter-spawning genera: Acipenser, Oncorhynchus, and Lota respectively). The diphasic reaction of HHNS corresponding to stages of “an alarm and resistance to stress”, is considered to be the reflection of its participation in protective-adaptive reactions of an organism to a physiological stress. In monocyclic species, right after spawning, there becomes the blockade of neurohormone releasing function from neurohypophysis corresponding to supernatural inhibition of system at disstress. At the beginning of spawning nonapeptide neurohormones (NpNh) of HHNS initiate spawning behavior and the appearance of “mating attire” by exposure to the central nervous system, pituitary gland and complex visceral organs. Then they promote ovulation and spermiation by stimulating the contraction of the smooth muscles of gonad. By the end of reproduction, they participate in the implementation of the body’s adaptations, aimed at overcoming physiological stress-spawning. Maintaining the body’s metabolic equilibrium is ensured by the pronounced anti-gonadotropic NpNh effect by inhibiting the gonadoliberin secretion and stimulating at the same time its antagonist – adrenocorticotropin secretion, as well as their direct effect on endocrine and generative gonad’s functions. This effect is crucial for the normalization of the physiological body state after spawning, as it allows to radically affect the nature of metabolic processes, by “switching” them from generative to plastic metabolism. A constructive working scheme of neuroendocrine regulation fish reproduction – its initiation (stimulating neurohormonal effect) and completion (inhibitory effect) by the self-regulation principle is presented. The important HHNS functional role in the integration of fish reproduction and the intended mechanisms for its participation in spawning migrations are discussed.

The paper deals with the main historical moments of the Caspian sturgeon population dynamics and the formation of their stocks. The participation of researchers of the Department of Ichthyology and Hydrobiology of Saint-Petersburg State University in creating the concept of sturgeon conservation in the Caspian Sea and the specialized institute of sturgeon farming in Astrakhan was highly appreciated. The materials on the contribution of the Department’s researchers to the study of the physiological state of sturgeon producers, improving their quality, survival and safety in the conditions of artificial breeding of these species are presented. The data on the reduction of the sturgeon abundance reared and released into the Caspian Sea by the Caspian littoral states are presented. A description of the current state of the sturgeon of the Caspian basin is given. The data on changes in stocks, the structure of the spawning part of the population and reproduction of the beluga, Russian sturgeon and stellate sturgeon in the Volga-Caspian basin under the conditions of the prohibition of their commercial fishing are analyzed. It was shown that during the years of the ban, the abundance and stocks of sturgeon and biological indicators of breeding migrants to spawn in the Volga continued to decrease and the proportion of females among them, which is associated with the illegal catch of sturgeon, comparable in scale to the commercial fishery before the ban was introduced. Reduced natural (up to its complete cessation in the Beluga) and artificial reproduction of sturgeons are stated. Only observing the moratorium on sturgeon fishing in all the Caspian littoral states, strengthening the protection of fish at feeding grounds and spawning migrations can preserve and restore their unique Caspian populations.

Some features of response to hyperosmotic environment (artificial sea water with a salinity of 12.5–12.7 ‰ (403–409 mosm/l) were studied in the osmoregulatory system of freshwater sturgeon species from the Volga river, starlet Acipenser ruthenus Linnaeus, 1758. Morphofunctional changes were traced in certain elements of the organ complex responsible for the osmoregulatory process. 72 hours after the immature sterlet individuals (age 2+) were transferred from fresh water to the hyperosmotic medium, blood serum osmolarity becomes iso-osmotic respective to the external environment. The interrenal gland responds to saline exposure by increasing cortisol concentration in the blood serum. A high cortisol level (75.13 ± 12.96 vs. 19.29 ± 6.36 ng/ml in the control group) persists throughout the entire experimental period (7 days), which indicates that fishes are under stress. The cortisol excretion into the bloodstream is not followed by an increased activity of the transport enzyme, Na+/K+ ATPase, in homogenate of the gills and an increased Na+ concentration in chloride cells, was identified by A-gold technique. The ultrastructure of chloride cells, being the main site for the removal and sorption of monovalent ions (Na+, K+, Cl-) in fishes, does not display the characteristic of an active excretion in sterlet. Thus, cortisol does not provide a stimulating effect on increasing Na+/K+ ATPase activity, an enzyme needed to transport excess ions from the body. The thyroid gland responds by increasing the thyroxin (T4) concentration during 3–6 hours of saline exposure. In the next 114 hours, the concentration of this hormone decreases to its initial level (in the control group). The thyroxin dynamics in serum does not correlate with the dynamics of serum osmolarity. So it seems possible to conclude that no functional relationship exists between the effector “organ” (the set of numerous chloride cells of the gills epithelium) and the endocrine glands (interrenal and thyroid) controlled by the hormones of tropic pituitary cells. In sterlet dwelling in hyperosmotic medium the kidney keeps a higher Na+/K+ ATPase activity, as compared with the gills. High Na+ concentration in the urine (163.2 ± 5.3 meq/l), close to its concentration in the hyperosmotic environment, high Na+ proportion (87.1 ± 0.1%) in the total concentration of major urinary cations, low level of water sorption (50.8 ± 4.0%) in the renal tubules, high diuresis (0.58 ± 0.09, ml/hr/100 g body weight) determine high level of Na+ excretion in the urine (100.95 ± 13.21 meq/ml/hr /100 g body weight). The important role of the kidney in removing Na+ excess under hyperosmotic environment underlies the osmoconformity strategy in sterlet.

Temporary “extraembryonic” systems are important for the development of representatives of many Metazoan taxa and are characterized by significant diversity. The yolk syncytial layer (YSL), a component of embryonic and larval teleost yolk complex, is a provisory structure performing morphogenetic, nutritional and immune functions. Despite the crucial role of YSL in the early ontogeny of bony fishes, the data concerning YSL structure and morphological diversity is scant. Here, we describe YSL organization in the postembryonic development of the green terror cichlid, Andinoacara rivulatus, studied by the analysis of serial histological sections. YSL cytoplasm contains numerous yolk inclusions decreasing in size from basal to apical surface of YSL. The mode of yolk engulfment is one of the most variable YSL characteristics in the species studied. The yolk syncytial nuclei (YSN) have especially complex shape, and large nucleoli are well distinguished. The yolk mass consists of homogenous globules. It contains the oil globules, many of which are in contact with the basal surface of YSL. The YSL thickness is very uneven due to its interaction with oil globules. Significant part of the apical YSL surface is associated with the blood vessels and pigment cells. During the period of mixed feeding the yolk complex locates anterior to the liver. Thus, the yolk complex of green terror cichlid has a well-differentiated structure. Our results contribute to the knowledge of the morphology of fish temporary systems and allow clarifying their common and species-specific features.

A comparison was performed of the morphological variability of the spotted lumpsucker Eumicrotremus pacificus Schmidt, 1904, E. spinosus (Fabricius, 1776), whose synonymy recently included E. eggvinii Koefoed, 1956, and E. gyrinops sensu Stevenson et al., 2017, recently established as the senior synonym for E. phrynoides Gilbert et Burke, 1912 and Lethotremus muticus Gilbert, 1896. Based on a number of morphological differences between E. spinosus and E. eggvinii, corresponding to differences between young and spawning males E. pacificus, it was suggested that individuals E . eggvinii may be nesting males of E. spinosus. It was established that the range of variability of a number of morphological characters of E. gyrinops exceeds that of E. pacificus, which suggests its complex nature. Notable differences in the ratio of the size of the anterior and posterior nostrils, the size of the chin tubes of the seismosensory system and the shape of bone plaques between E. phrynoides and E. gyrinops indicate the validity of E. phrynoides. The absence of an external skeleton in both males and females of L. muticus, unlike other species of the genus Eumicrotremus, allows us to conclude that L. muticus is also a valid species.

The goal of this work is to revise the endemic South Ocean species Zanclorhynchus spinifer, one of the most numerous demersal fish species inhabiting waters off subantarctic islands. Despite its high abundance and significant role in trophic chains, the species remained poorly described. Morphological parameters were studied for the first time on a significant amount of material; individual variability was clarified for a number of parameters. Such variability, according to some characteristics, is beyond the range of values previously used in the description of the species, and the occurring break of the infraorbital canal was previously considered to be characteristic in the family Congiopodidae only for the sister genus Alertichthys. The two new subscpecies Zanclorhynchus spinifer armatus subsp. nov and Z. spinifer macquariensis subsp. nov. are described in this paper in addition to the nominative subspecies and the previously described subspecies from the seamounts of the Pacific Ocean sector of the Southern Ocean Z. spinifer heracleus. Type series were collected in the Indian sector of Southern Ocean off the Prince Edward Islands and the Crozet Islands from the depth 170–310 metres, and off the Macquarie Island from the depth 21–84 meters. New subscpecies well differs from other two subcpecies Z. spinifer spinifer and Z. spinifer heracleus with arming of the head and first dorsal fin, scales and body proportions. A key to the species and subspecies of the genus Zanclorhynchus is presented.

The present work is dedicated to a modern complex morphological study on a representative sample (42 fish specimens from the stock collection of the Zoological Institute RAS and 3 specimens-holotypes from the collection of the Zoological Museum of the National Museum of Natural History NAS of Ukraine) Kerguelen icefish of the genus Channichthys Richardson, 1844 (Channichthyidae) with a special structure of the gill apparatus – double-rowed gill rakers: charcoal icefish Channichthys panticapaei Shandikov, 1995, big-eyed icefish Ch. bospori Shandikov, 1995, and pygmy icefish Ch. irinae Shandikov, 1995. All this species of icefish, with their common similarity, are united by the special structure of the gill apparatus - the presence of two well-developed rows of gill rakers on the gill arches, especially on the first gill arch, which is a key defining sign that is clearly distinguishes them from all other species of the genus Channichthys. Until now, there is no unambiguous universally accepted opinion of specialists about the taxonomic status of these icefish. They are distinguished either in one species, or in three species, or are identified as Channichthys sp. In the course of this work, a redescription of Ch. panticapaei with the confirmation of the validity of this species, based on complex data of external morphology, the study of the seismic sensor system and especially the structure of the gill apparatus, highlighting the most important diagnostic features of the species, as well as the replace of the species Ch. bospori and Ch. irinae, to the synonymy of Ch. panticapaei.

A new species of free-living nematode Monhystera tibetica sp. nov. from a thermal spring in the Garuda Valley at an altitude of 4249 m in Western Tibet is described. The general morphology corresponds to the generic diagnosis. The cephalic setae are very short. In the lower part of the stoma there is a small denticle. The amphid of males is situated over the level of the denticle. The distance from the edge of the head to the denticle is about 6 μm. The amphid of females is situated above the denticle. The esophagus is dilated at the base, pseudobulbus width is 22 μm. Males have numerous precloacal supplements. From the geographically close species of M. curvicaudata Tsalolikhin, 1915 the new species is distinguished by body size, amphid position, position of the vulva and the presence of the stomal denticle. From M. wangi Wu et Hoeppli, 1929 the new species differs by the amphid position and the presence of the stromal denticle. From M. shibrui Eyualem et Coomans, 1996 the new species differs in body size and length of spicules. The taxonomic status of the species with one and two denticles is discussed. The replacement of the name Tridentulus with Tridentula is no longer relevant. The validity of the name Tridentulus Eyualem et Coomans, 1995 is maintained.

A new species of Eucyclops (Cyclopiformes: Copepoda: Crustacea) is described from a bog-lake on the top of a hill near Titary fisherman village in the top of The River Lena delta, Eastern Siberia, Russia. Eucyclops delongi sp. nov. belongs to the speratus group of species and can be clearly separated from other related species by a combination of characters that include smooth hyaline membrane on 3 distal segments of antennule, missing of long hairs on antenna basipodite posterior surface (on the top), presence of several long setules on the distal side of the caudal rami (saw), homogeneous hair row on both sides of inner coxal spine in 4th swimming legs, relatively short caudal rami (length/width ratio less than five), clearly seen difference in caudal saw denticles on lateral edge, very long innermost caudal seta subequal to ramus length, inner spine of distal segment of endopodite 4th swimming leg 1.1 times as long as segment itself. Male of new species can also be separated from other species by a combination of the following characters: antenna basipodite on posterior surface without groups of long hairs (on the top), coxal spine of 4th swimming legs homogenously covered with long hairs, rudimental 5th legs with relatively short inner spine similar in length to segment itself, rudimental 6th legs with 3 appendages including strong inner spine reaching the middle of the next segment, outer seta as long as spine, middle seta is shorter than spine. This species is suggested to be an endemic of Arctic zone in Eastern Siberia (Beringia), which is well known as a Pleistocene refuge during glaciation in North-East Asia.

Ricamela lata gen. et sp. nov. is described from the state of Bahia in Brazil based on a single female from L. Melichar’s collection in the Moravian Museum, Brno, Czech Republic. The new genus belongs to the subfamily Pharsalinae Gnezdilov of the family Ricaniidae Amyot et Serville and represents the third genus of this group. The systematic position of the American Ricaniidae are discussed. A key to genera of Pharsalinae is given.

Duroides globosus Melichar, 1906, type species of the genus Duroides Melichar, 1906, known after a single female from Brazil, is redescribed and placed in the tribe Parahiraciini Cheng et Yang, 1991 according to well developed bilobed hind wings, with deep cubital cleft. This is the first record of the tribe Parahiraciini from the New World treated before mostly as Oriental endemic.

Based on the study of archival materials and literary sources, the scientific biography of W.A. Lindholm (1874–1935), an outstanding Russian zoologist of the first half of the XX century, has been reconstructed. Most published works of W.A. Lindholm are devoted to studies of continental molluscs and reptiles. The life course of W.A. Lindholm is described and his contribution to the development of Russian malacology of the last century is characterized as well as his scientific connections with contemporary German zoologists. Deprived of university education, W.A. Lindholm managed to progress from amauterish faunal studies to writing significant works on taxo­nomy, biogeography and zoological nomenclature. It is shown that the greatest contribution of W.A. Lindholm to malacology was his works on the endemic malacofauna of Lake Baikal, terrestrial gastropods of the Caucasus and Central Asia, as well as fossil Pliocene molluscs of Western Siberia. In all these fields W.A. Lindholm performed pioneering studies that have retained their value to this day. The most important stages of the scientific career of W.A. Lindholm and the circumstances allowed him to acquire the status of a professional scientist (an employee of the Zoological Museum of the Imperial Academy of Sciences) are described. The available archival documents allow us to reconstruct not only the scientific, but also the “private” biography of W.A. Lindholm, which is of interest for studying the situation of scientists in Russia during the First World War, as well as in the post-revolutionary period. A number of biographical documents from the W.A. Lindholm’s archive, stored in the St. Petersburg branch of the Archive of the Russian Academy of Sciences, are given as an Appendix to this article.

A list of malacological publications of W.A. Lindholm, issued between 1901 and 1936, is represented alongside with an annotated catalogue of molluscan taxa described by him. A list of molluscan taxa named in honour of Wasily Lindholm is also given.

The molluscan fauna of Lake Baikal is currently known to comprise about 150 species of gastropods, of which approximately 70% are endemics. Baikal gastropods include 8 families: Baicaliidae, Benedictiidae, Bithyniidae (Caenogastropoda), Valvatidae (Heterobranchia), Acroloxidae, Planorbidae, Lymnaeidae and Physidae (Panpulmonata). By studying the samples collected during a three-year expedition supervised by A.A. Korotneff, professor of the Kiev University, W.A. Lindholm described 55 new species, varieties (= subspecies) and forms (= morphs) that belonged to all families of gastropods (except Physidae) living in Baikal and in the connected shallow water bodies (sors). Lindholm was the first to note a wide spectrum of conchological variability of Baikal gastropods and their heterogeneous geographic distribution in the lake. Using collection of naturalist Petr Mikhno, Lindholm described two new species from Lake Hövsgöl (= Khubsugul) in Mongolia that has the hydrological connection to Lake Baikal via the Selenga River. Despite more than a century of studying the gastropod fauna in lakes Baikal and Hövsgöl, some species and subspecies described by Lindholm are rare, with only a few specimens subsequently being reported, and some have never been found again. The present study is a brief review of 46 species, subspecies and morphs of gastropods described by Lindholm. The review includes photographs of type specimens, main synonyms and references, detailed information on the type localities, diagnoses, and information on distribution in Baikal including depth zones and substrate types. All type specimens (except those of one species) are well preserved and are currently stored in the collection of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg).

This paper presents notes on the herpetological biography of W.A. Lindholm (1874–1935), a Russian-Soviet zoologist known mostly by his contributions to malacology and herpetology. His 15 herpetological publications, which are annotated in this paper, include naturalistic observations of amphibians and reptiles, commentaries on the catalogue of reptiles and amphibians from the collection of the Museum Wiesbaden, descriptions of new taxa of lizards, snakes, and turtles, revision of the classification of Recent turtles and studies on the nomenclature of some amphibians and reptiles. This paper also contains a list of 21 reptilian taxa introduced by Lindholm and a list of four reptilian taxa named in honour of him.

This paper considers some aspects of the history of the Zoological Museum and the Zoological Institute of the Academy of Sciences of the USSR, which appeared on its base in 1931, during two decades following the outbreak of the First World War. It deals with the scientific, social and political consequences caused for the Zoological Museum by the First World War, two Revolutions of 1917 and subsequent Civil War. The paper describes establishment of the Museum’s Council, which ruled from 1917 to 1930, and an attempt to evacuate collections in 1917, as well as conditions under which the Museum zoologists had to work in the period of the wars and revolutions. The first years of the restoration of normal work of the Zoological Museum after the Civil War are considered, as well as the effects of the flood, which damaged the Ichthyological, Herpetological and Osteological departments of the Museum in 1924. The renaming of the Museum into the Institute during the reform of the Academy of Sciences in 1929–1934 is discussed as well as layoffs and repressions during this reform. The paper considers changes in the Exhibition Department, made on demand of the authorities. The information is given about the Faunistic Conference of 1932, which was hosted by the Zoological Institute of the Academy of Sciences of the USSR under the slogan for “the Party’s” and “Bolshevik’s faunistic studies”.

The current paper describes material from Medvezhyi Klyk Cave Late Pleistocene–Holocene deposits that represented mostly by isolated teeth. The morphology and size variation of the first lower teeth (n = 542) were studied. There are Alexandromysfortis, A. cf. maximowiczii, A. cf. oeconomus, A. cf. mongolicus determined in the material. We could not determine the taxa due to uncertainty in a spatial variation of the species ranges during Late Pleistocene and Holocene, a broad variety of the m1 anteroconid shape among medium-sized species of voles, and supposed presence “archaic” and “deviant” morphotypes of m1. Geometric morphometrics methods were shown the broad variety of the m1 anteroconid shape without strict species-relation, i.e., each tooth shows proper anteroconid shape, which can repeat within limits in populations in and among species.

The pigment of tooth enamel is an important odontological character for character for assessing Soricidae taxonomy and phylogeny. This paper describes the original observations of ‘pigment patterns’ (PPt) and ‘visible pigment’ (VPg) in fossil beremendiin shrews in light of the “differential pigmentation” found using UV detection and EDX analysis. The term “differential pigmentation” was used to describe the irregular pigmentation on the teeth of extinct Nesiotites (Neomyini). Our analysis of fossil and recent specimens reveals different reasons for differential pigmentation formation. The first reason is related to fossilization, namely, the chemical alterations of the buried specimen. The second reason is related to a developmental disorder, namely, the enamel organ disorder, which locally stops forming the twin enamel layer. Our original results and published data from EDX analysis of the enamel elemental content and SEM-image analysis of the enamel microstructure again raise the question of a relationship between ferruginous pigmentation and enamel microstructure. Further studies of the enamel structure and pigment chemical composition of red-toothed shrews compared to white-toothed shrews are required.

A new genus, Euryburnia gen. nov. (type species: Megamelus magnifrons Crawford, 1914) is erected to accommodate the group of Nearctic species of the family Delphacidae erroneously placed by Hamilton (2002) in the genus Eurybregma Scott, 1875. The new genus differs from Eurybregma by narrower metope without intermediate carinae on eumetope (only median carina is developed). According to male genitalia structure the new genus is close to the genera Unkanodes Fennah, 1956 and Chilodelphax Vilbaste, 1968, but distinguished by angular (not rounded) latero-ventral lobes of pygofer and by pygofer phragme without teeth and processes. From the genus Eurybregma the new genus differs by the presence of latero-ventral lobes of male pygofer. According to presence of unique, well developed beak-shaped basal lobes of dorso-lateral plates of ovipositor (first valvifers) the new genus is distinguished within all Delphacidae. New combinations proposed: Euryburnia magnifrons (Crawford, 1914), comb. nov. (=Megamelus magnifrons Crowford, 1914), Euryburnia montana (Beamer, 1952), comb. nov., (=Eurysa montana Beamer, 1952), Euryburnia obesa (Beamer, 1952), comb. nov. (=Eurysaobesa Beamer, 1952), Euryburnia eurytion (Hamilton, 2002), comb. nov. (=Eurybregma eurytion Hamilton, 2002).

Cixidia confinis (Zetterstedt, 1828) is recorded from the north of Saint Petersburg and from the Kurgalsky Reserve and near Volkovitsy village in Leningrad Province after the series of larvae collected since late April to late May 2019 with the adults appeared later in the laboratory. Until the present C. confinis was known from Russia only after few specimens. The photos of alive adults and larvae of C. confinis are provided for the first time.

A sample of 136 isolated theropod teeth from nine vertebrate localities within the Lower Cretaceous (Barremian-Aptian) Ilek Formation in West Siberia, Russia, can be separated into five dental morphotypes referred to five оr six theropod taxa based on morphological characters. The Morphotype A includes small to large lateral teeth with relatively large distal denticles and smaller mesial denticles. Some of these teeth can be attributed to the Dromaeosauridae, while other teeth may belong to a basal member of the Tyrannosauroidea. The distinctly smaller lateral teeth referred to the Morphotype B are similar with Morphotype A in most respects but differ in the lack of mesial denticles and mesial carina, or having a lingually displaced mesial carina. These teeth may belong to juvenile individuals of the same dromaeosaurid taxon. The teeth belonging to Morphotype C also lack mesial denticles and differ from Morphotype B by a flattened area on the lingual side, which is also often present on the labial side. These teeth may belong to either Troodontidae or Microraptorinae, or to both groups. The mesial and lateral teeth of Morphotype E are characterized by unserrated mesial and distal carinae. These teeth most likely belong to a distinct taxon of Troodontidae with unserrated dentition. The teeth of the Morphotype D include mesial teeth with the mesial carina displaced lingually at various extent and denticles present on both carinae. The teeth with moderately displaced lingual carina can be referred to the same dromaeosaurid taxon, which lateral teeth represented by Morphotype A. The teeth with more displaced mesial carina and deeply U-shaped basal crown section belong to an indeterminate Tyrannosauroidea.

The paper provides data on the current location of the type specimens of Lacerta viridis media Lantz et Cyrén, 1920 as on December 1, 2018. In the collections of ZISP, NHM and NMG 17 syntypes were identified during our study, ten of which appeared to be lost. According to catalogue records, other type specimens of this taxon likely were also stored in NMG, but this cannot be established for sure due to the loss of part of the collection. It is possible that part of the type specimens is stored in the Göteborgs Naturhistoriska Museum, as the majority of the Cyrén’s collections is kept there. The herpetological collection of NM KhNU has two specimens of L. media, coming from the collection of the Caucasian Museum. Most probably these lizards were received from Tiflis for study by A.M. Nikolsky, who lived and worked in Kharkov from 1903 to 1942. However, these specimens cannot be attributed to the type series of this species as their localities data are absent from the list of Lantz and Cyrén. The designation of the lectotype by Šmíd et al. (2014) is considered invalid, as it does not correspond to ICZN rules. To ensure the stability of the nomenclature we designate herein the specimen ZISP 12387 as the lectotype of L. viridis media. The history of the taxon description is given. It is demonstrated that O. Cyrén (1933) was first who upgraded the status of this taxon to a species level, using a binomen.

We studied age structure, growth and distribution of European flounder Platichthys flesus at the sea in Chupa Inlet (Kandalaksha Bay, the White Sea). Immature and mature fishes fed at shallows of Chupa Inlet and adjacent open sea area in June-August. Size-age and sex composition of fishes in catches are presented in the paper. Individuals of 17–27 cm length and 4–5 year age constituted the majority of catches (45%). On the whole, males numerically predominated over females in the samples. Analysis of sexual differences of growth has shown that females grew faster than males. The most intensive growth took place in July–August, according to the increments on the otoliths. Growth rate of the flounder from Chupa Inlet appeared to be similar to the growth rate of the flounder from other open shore sites of Kandalaksha Bay. We have compared also peculiarities of growth and age structure of flounder populations from Kandalaksha Bay to those from other bays of the White Sea. Significant differences of the growth rate were found between flounders from Kandalaksha, Onega, Dvina and Mezen' Bays. Both males and females from Onega Bay grew faster than other. Growth rate of fish decreased towards the north (Kandalaksha Bay) and the north-east (Mezen' Bay). The most slow-growing flounder inhabited shallows of Mezen' Bay. Statistical analysis has shown that age structure of flounder populations varied in different bays of the White Sea, and observed regional variations were characteristic for both males and females. Flounder population in Onega Bay was characterized by the dominance of the younger individuals compared to populations in other bays. The greatest mean age of flounder was registered in populations from the north-west (Kandalaksha Bay) and the north-east (Mezen' Bay) parts of the White Sea. Males and females in populations from Onega and Dvina Bays differed significantly in the mean age, and as a rule females were older. No age differences between sexes were found in flounder population of Mezen' Bay. We suppose that temperature conditions were among the main factors influencing regional differences in growth rate and age structure of the flounder populations in the White Sea.

Squamation of the European flounder Platichthys flesus is formed by the common cycloid scales and the bony plates. The number of the bony plates and their localization on the body vary considerably in the flounders from different parts of their range. Study of the variability of bony plates coverage in the European flounder are of importance for understanding structural diversity and for use of this character for morphological differentiation of the local populations. We compared the bony plates on the eye side of the body in the flounders from Chupa Inlet (Kandalaksha Bay) and from the delta of the North Dvina River (Dvina Bay). The localization and the number of the bony plates near the bases of dorsal, anal, pectoral fins and above/below of the lateral line were analyzed. Our results clearly showed that the compared samples can be characterized by certain phenotypes, differing by number and location of the bony plates on the eye side of the fish body. The individuals of one phenotype were found in Chupa Inlet only. Small amount of the bony plates on the body and the presence of relatively wide aggregation of the bony plates near the pectoral fin are the traits of this phenotype. Three phenotypes were distinguished among fishes from the North Dvina delta. The absence of the bone plates on the most part of the body is typical for the prevalent phenotype. Individuals of the second phenotype were similar to the flounder from Chupa Inlet. Large amount of the bony plates covering the whole eye side of the body is characteristic for the third phenotype. The obtained results complement the existing data on the variability of squamation of the White Sea flounders, and indicate the importance of this character in the study of the differences between local populations in this region.

The taxonomic position of the genus Notosimus Fennah, the family Acanaloniidae Amyot et Serville, 1843 is discussed and confirmed by the characters of ovipositor structure described and illustrated for the first time. Notosimus angustipennis (Melichar, 1906) is newly recorded from Cordoba Province in Central Argentina. The photos of holotype of N. angustipennis and the drawings of hind wing of this species as well as Acanalonia conica (Say, 1830) and A. pumila (Van Duzee, 1908) are given.

The publication presents results of the reproductive biology study of the Lissotriton lantzi (Wolterstorff, 1914) from the Abrau Peninsula (Krasnodar Territory, Russia). Ten females and ten males of this species were caught before breeding began. Animals were kept in plastic containers with water at a temperature of 11.5–23.0°C, one pair of newts in each container. Every day the reproductive behavior was recorded and laid eggs were selected. Males showed reproductive behavior (mating dance and position of spermatophore) within 1–36 days after the start of the research. Position of first eggs was observed in different females from 6 to 16 of April at a water temperature of 13.0–16.5°C. All ten females bred in April and May, only five females laid eggs in June and three females in July. The total duration of the oviposition period in different females was 41–99 days. Last eggs were found from May 26 to July 18 at a temperature of 17.5 to 23.0°C. Fertility of females in the breeding period was 67–832 eggs. The eggs of newts had a length of 3.1–4.0 mm and width of 1.9–2.8 mm. The duration of egg incubation at a temperature 14.5–20.5°C was from 13 to 24 days. Pre-larvae length after the hatching was equal to 6.5–9.8 mm. The larvae started to eat during 0–5 days after hatching. The length of larvae at the beginning of exogenous feeding was 8.2–11.3 mm. It is noted that most of the studied females (9 out of 10) had higher fertility than previously noted for this species (283–832 against 70–220 eggs).

The life cycle of nematode Paramononchus alimovi Tsalolichin on two deepwater stations (St. 2 and St. 18) in Lake Krivoe and the contribution of the long-term climate variability to the dynamics of the quantitative development of this species were investigated. As a result of the research, it was shown that the life cycle of this species in Lake Krivoe is 2–3 months. The temperature conditions of this species existence are stable and close to the temperature optimum for this species. Climatic factors indirectly influence the quantitative development of this species in Lake Krivoe. To analyze the influence of climate on the dynamics of quantitative development of P. alimovi, we calculated the correlation coefficients of the relationship between the average seasonal (May-September) nematode abundance and biomass and indices of the North-Atlantic Oscillation (NAO), arctic oscillation (AO). We found a significant effect of the North Atlantic Oscillation on the quantitative development of nematodes at St.2 for the period July-September (NAO_JAS) with a lag of 2 years, for the period December – March (NAO_DJFM) with a lag of 1 year. For St. 18 a reliable relationship of quantitative development of nematodes with the index for the period March-May (NAO_MAM) without lag is shown. Correlations of climatic indices with benthic biomass with a lag of 1 year and without lag are characteristic of many northern lakes. The maximum income of nutrients should be observed after complete thawing of soils and should be confined to autumn floods. Thus, years with positive index anomalies provide favorable opportunities for the development of phytoplankton in the next year, which is indirectly reflected in the zoobenthos through the trophic chain. Correlation of the NAO index with the values of quantitative development of nematodes in current year is related to the weather preceding the ice disappearance on the lake. Explanation of the obtained two-year lag is associated with another component of the ecosystem – macrozoobenthos. The main component of macrozoobenthos in the depths of the Lake Krivoe is amphipod Monoporeia affinis. This species has 2-year cycle and competes for resources with P. alimovi.

A new species of rock lizards of the genus Darevskia Arribas, 1997 – Darevskia aghasyani sp. nov. is described from Urts Ridge in Southern Armenia. This species is characterized by a combination of the following characters: small size L – 49–54 mm, L. cd – 107, Sq – 52–56, Ventr – 26–27, G – 24, P. g. – 32–34, P. fm. – 18–20; it is painted in brownish-beige tones from above; the belly is whitish in both sexes, males in the anal area have yellow with ochre femoral pores; bluish spots appear on the edge of the outer ventral shields at the middle of trunk through one shield; on the sides of the trunk (chest area) there are two blue spots in males and one in females; rostral is separated from frontonasal by nasal shields and it does not touch the nostril; upper postocular is twice wider than upper temporal shield; posterior temporal shields are not pronounced, or slightly pronounced; in front of central temporal (Massetericum), there is one enlarged temporal shield; along the throat from ear to ear fold there are 32-34 scales; two large preanal shields present in front of the anal shield. A comparison of Darevskia aghasyani sp. nov. with other species of the genus from Armenia and representatives of “raddei” complex from neighboring regions of Turkey and Iran (Darevskia dahli (Darevsky, 1957), D. unisexualis (Darevsky, 1966), D. raddei (Boettger, 1892), D. raddei vanensis (Eiselt et al., 1993), D. nairensis (Darevsky, 1967), and D. defilippii (Camerano, 1877)) is given. Conservation status of taxa assessed as CR B2ac(iv) "CRITICALLY ENDANGERED".

Benthic habitats of Tikhaya Bight (Hooker Island, Franz Josef Land, High Arctic) were studied by using SCUBA equipment (diving quantitative method) and Van Veen grabs. Three main communities have been described. A Gammarus setosus-macroalgae community, probably seasonal, developed above 5 meters depth, had a relatively low diversity with biomass 7.6±0.9 g/m² and abundance 135±40 ind/m²; a mixed bivalves-amphipods-bryozoan community (Serripes groenlandicus, Mya truncata, Haploops laevis, Alcyonidium disciforme) occured in muddy bottoms with some interspersed boulders between 7 and 30 m depth; it included 101 taxons, had a relatively high biomass 152.3±114.2 g/m² and abundance 1600±940 ind/m². A bivalve-dominated community with Musculus niger and Yoldia hyperborean inhabited depth of 67–72 m, included 38 taxons and was characterized by high density of abundance and biomass – 670±295 ind/m² and 356.1±57.1 g/m², respectively. Comparison with the previous data obtained 20 years ago at the depth 7–30 m, showed that, possibly, the retreat of the glacier under the influence of increasing temperature in the environment and increased runoff of melt water, washes away clay deposits which led to siltation of the bottom in the bay and caused degradation of kelp, which was partially replaced by invertebrate communities inherent in silted soils.

Issus christiani sp. nov. is described from Mostaganem Province of Northwestern Algeria. The new species belongs to “yellowish green” group of Issus species and it is closely related to I. vaucheri Gnezdilov, 2017 according to the structure of male genitalia, but differs by shorter fore wings (length – 4.0 mm) and shorter ventral aedeagal hooks (0.25 times as long as aedeagus). Thus including the new species currently the genus Issus Fabricius, 1803 is documented from the Mediterranean Africa with five species. Key to African species of Issus is given.

Genera Ischyrocnemis and Terozoa (both initially monotypic) have been synonymized by H. Townes (1971) and preliminary placed in the subfamily Metopiinae. The results of molecular analyses (Quicke et al., 2009) did not clarify their systematic position. In this work Terozoa Förster, 1869 gen. resurr. (=Parablastus M. Constantineanu, 1973, syn. nov.) is restored from synonyms and placed into the subfamily Tryphoninae. Terozoa includes three species: type of the genus, Terozoa quadridens Perkins, 1962 (= Parablastus bituberculatus M. Constantineanu, 1973, syn. nov.) and two more species described earlier in Parablastus – T. iberica (Kasparyan, 1999) comb. n. and T. anatolica (Gürbüz et Kolarov, 2005) comb. n. The genus Terozoa and species T. quadridens are new records for Russia (North Caucasus, Essentuki). A key to species is provided. Four new Western Palearctic species are in Ischyrocnemis: I. femorator sp. nov. (with two subspecies: Caucasian I.f. femorator subsp. nov. and I. f. turanicus subsp. nov. from Central Asia), I. kotenkoi sp. nov. from the Transcaucasia, I. nigrans sp. nov. from steppes of Eastern Ukraine, Volga region and Kazakhstan, and I. verae sp. nov. from Kopet-Dag. A key to five species of the genus is given. Ischyrocnemis is treated provisionally in Metopiinae after H. Townes (1971), G. Broad and M. Shaw (2005). The characters common for Ischyrocnemis and Metopiinae are discussed: Ischyrocnemis approaches to Metopiinae in having the face and clypeus completely fused and clypeal fovea entirely lacking, that is unusual for most of Ichneumonidae but is typical for many Metopiinae (Acerataspis, Colpotrochia, Periope, Hypsicera, Triclistus, etc.); epipleura very wide (in metopiine present in Colpotrochia, Periope, Hypsicera, Seticornuta, Triclistus, etc.). Unusual for Metopiinae 1st metasomal segment of Ischyrocnemis (without glymmae with spiracles beyond the middle, and strongly narrowed in front of spiracles) found in Periope and in many ways is similar to some other Metopiinae (in genera Apolophus, Colpotrochia).

This article is dedicated to the oldest member of Zoological Institute of the Russian Academy of Sciences and her biography. She devoted her life to the service of science and preservation of collection of osteology department in theriology laboratory. With her own hands she boiled, cleaned and prepared countless exhibit items for storing, expert examination and displaying in the museum. Skillfully reuniting bone fragments found by paleontologists, she assembled numerous skeletal elements and even whole skulls of fossil animals. She was making plaster models from the most precious pieces, so they could be used as emergency copies or sent to the scientists from other institutes and museums in different cities and countries. Many researchers based their scientific articles and monographs on the samples made by G.Kh. Nuraeva. In March 1971 together with the members of the Laboratory of mammals she took part in preparations for the First conference on mammoths and mammoth fauna and in organizing of the exhibition. She also helped in ciphering, packaging and shipping the exhibits for the International hunting exhibit in Budapest (Hungary) in Autumn 1971 and preparing exhibits for “World of a mammoth” exhibition in Japan in 1981 and 1987. She restored a skull and the horns of an Irish elk Megaloceros giganteus, a skeleton of a southern mammoth Archidiscodon meridionalis, the skulls of fossilized bears Ursus deningeri, Ursus spelaeus kudarensis, elements of a skeleton of hoofed animals such as wild ox Bos primigenius and Stenon zebra Equus stenonis, not counting others valuable parts. She took a big part in writing a monograph «Baby mammoths Mammuthus primigenius». G.Kh. Nuraeva was a hard-working person and loved her job. Thanks to that she made an invaluable contribution to increasing of the Zoological Institute collection. Everyone who got to work beside her noted her nimble fingers and her big heart. We will always remember her with fondness and gratitude.