Vladimir A. Gusakov

• PhD (Biol.)
• Senior Researcher at Russian Academy of Sciences

This monograph summarizes results of meiobenthos studies for the semicentennial period (1940-1990) of the Rybinsk Reservoir existence. All the known published materials are generalized and the data of our investigations are presented. Species composition and quantitative parameters of the basic groups of meiobenthos in the profundal and inshore zon...

This chapter of the collective monograph considers the current state of research on the meio- and macrozoobenthos in fresh waterbodies of Vietnam. It also presents data of our investigations of taxonomic structure and quantitative characteristics of the communities in central and southern provinces of the country (in 2008, 2010) and discusses probl...

This paper presents an annotated list of nematode taxa found in the course of investigations of meiobenthic communities in various freshwater bodies in central and southern Vietnam. Data on the structure and abundance of populations, ecology, and global and local distribution are given along with taxonomic and other comments. The occurrence and lev...

Two new nematode species, Mesodorylaimus rivalis sp. n. and Allodiplogaster media sp. n., from the highly mineralized rivers of the El'ton Lake basin (Russia) are described and illustrated from numerous mature females and males. Mesodorylaimus rivalis sp. n. is similar to M. vulvapapillatus Bagaturia & Eliava, 1966, but differs from it in the longe...

A non-native oligochaete, Bratislavia dadayi (Michaelsen 1905), is recorded from a water body of the cooling system of the Khmelnitsky Nuclear Power Plant (Ukraine). This is the first registration of this species in the central part of the European continent, far from sea and river navigable waterways. The only previous record of B. dadayi in Europ...

This work is the third installment in a series of publications devoted to the diversity, distribution and ecology of major groups of hydrobionts discovered during the study of meiobenthic communities in inland waters of central and southern Vietnam. Here, a checklist of cladoceran crustaceans (Cladocera) found for the period 2010–2022 is presented,...

The article presents the results of long-term studies (2008–2014 and 2017–2019, 2023) of macrozoobenthos communities and the trophic conditions for their development in six saline rivers of the Lake Elton basin, characterized by important stopovers sites of migrating waterfowl in Europe. The aim of the work was to study the salinity tolerance of ma...

Дан обзор исследований макрозообентоса и мейобентоса средних и малых рек бассейна Нижней Волги. Изучение макрозообентоса в этом регионе в основном было направлено на определение таксономического разнообразия, количественных показателей и закономерностей формирования донных сообществ под влиянием природных и антропогенных факторов. Начиная с конца X...

This article provides an overview of studies of macrozoobenthos and meiobenthos of medium and small rivers of the Lower Volga basin. The study of macrozoobenthos in this region is mainly aimed at determining the taxonomic diversity, quantitative indicators, and patterns of formation of bottom communities under the influence of natural and anthropog...

In previous papers, it was shown that the Far East is a territory where moving south, Boreal fauna is fluently changed to Tropical fauna. Kotov (2016) proposed to place all taxa from the northern portion of Far East in several faunistic complexes according to the area of their differentiation in the past, i.e. in Pleistocene refugia. But many daphn...

This work continues a series of publications on the diversity of the main groups of invertebrates found through the investigation of meiobenthic communities in various inland waterbodies in central and southern Vietnam. Here, a checklist of oligochaetes and aeolosomatids (the annelid worms) discovered for the period 2010–2021 is presented, as well...

Two new nematode species of the genus Daptonema, D. brzeskii sp. n. and D. rivale sp. n., are described and illustrated based on the material collected from Mekong River Delta, Vietnam. Daptonema brzeskii sp. n. is close to D. lutosum Gagarin, 2021, D. dihystera Gagarin, Nguyen Vu Thanh, 2005 and D. hyalocella Aryuthaka, Kito, 2012 in the presence...

Illustrated descriptions of two new free-living nematode species, Amphimonhystrella tropica sp. n. and Oncholaimus mekongis sp. n., found in the Mekong River delta (Vietnam) are given. A. tropica is similar to A. major Gagarin, Nguyen Dinh Tu, 2021 and A. paramonovi (Phan Ke Long, Nguyen Dinh Tu, Gagarin, 2020) in body size. It differs from the fir...

Two new nematode species of the genus Daptonema, D. brzeskii sp. n. and D. rivale sp. n., are described and illustrated based on the material collected from Mekong River Delta, Vietnam. Daptonema brzeskii sp. n. is close to D. lutosum Gagarin, 2021, D. dihystera Gagarin, Nguyen Vu Thanh, 2005 and D. hyalocella Aryuthaka, Kito, 2012 in the presence...

Illustrated descriptions of two new nematode species, Amphimonhystrella tropica sp. n. and Oncholaimus mekongis sp. n., found in the mouth of the Mekong River (Vietnam) are given. А. tropica is close to A. major Gagarin, Nguyen Dinh Tu, 2021 and A. paramonovi Phan Ke Long, Nguyen Dinh Tu, Gagarin by body size. It differs from first species in phary...

Alien freshwater mollusks belonging to the genus Physella (Gastropoda: Physidae) were for the first time discovered in the basin of the Dong Nai River (Vietnam). The mollusks were described as Physella acuta (Draparnaud, 1805) on the basis of the analysis of morphological traits and the nucleotide sequence of a fragment of the mitochondrial gene en...

Invasive freshwater molluscs of the genus Physella (Gastropoda: Physidae) were discovered in the basin of the Dong Nai River, Vietnam for the first time. Based on the analysis of morphological features and the nucleotide sequence of the fragment of the COI mitochondrial gene, these molluscs were identified as belonging to the species Physella acuta...

The paper provides illustrated descriptions of two new nematode species of the order Monhysterida Filipjev, 1929 found in the Mekong River Delta in Vietnam. Geomonhystera longisoma sp. nov. is morphologically similar to G. longispiculata Prado-Vera, Ferris, Subbotin, 2018 and G. chiautzingoensis Prado-Vera, Ferris, Subbotin, 2018. However, the new...

A new nematode species in the order Mononchida, Miconchus prokini sp. nov., found in Lake El'gygytgyn (Chukotka, Russia) is described and illustrated. The new species is the largest member of the genus known to date. It is morphologically close to Miconchus rex in the big body size, vulva position in females, the number of precloacal supplements in...

Two new nematode species of the genus Eudorylaimus Andrássy, 1959 found in Lake El'gygytgyn (Chukotka, Russia)-E. chukotkanus sp. n. and E. mylnikovi sp. n.-are described and illustrations are provided. E. chukotkanus sp. n. is close to E. similis (de Man, 1876) and E. imitatoris Gagarin, 1982. It differs from both species by a longer body and odon...

The paper presents an illustrated description of two nematode species of order Monhysterida, found in the Mekong River delta, Vietnam. Sphaerotheristus rivalis sp. nov. is morphologically similar to S. macrostoma Timm, 1968, S. bengalensis Timm, 1968 and S. pseudodentatus Timm, 1968, however it has a longer body and specific structure of spicules....

A new oligochaete of the family Naididae, subfamily Naidinae, Bratislavia gusevi sp. n., was found in a forest stream in Vietnam. The worm is characterized by small size, asexual reproduction by fragmentation, and dorsal bundles of chaetae beginning from segment II. Each dorsal bundle bears one to two hairs and one to two simple-pointed or bifid, r...

A new species of the Aeolosomatidae, Aeolosoma vietnamicum sp. n., found in freshwater bodies of Vietnam, is illustrated and described. The new species differs from its congeners in the presence of specific sigmoid chaetae in the dorsal and ventral bundles of all segments, beginning from II. These chaetae are characterized by tips with two apical t...

Saline rivers are highly productive ecosystems in arid regions. The meiobenthic community (bottom meiofauna) and its dominant representatives are one of the least studied components of these aquatic ecosystems. Ostracods Cyprideis torosa and Heterocypris salina are major consumers among the species of bottom meiofauna in saline rivers flowing into...

The food spectrum and trophic and length–weight characteristics of an invasive species, South American suckermouth armored catfishes Pterygoplichthys spp. (Loricariidae), from lotic and lentic inland waters of Vietnam have been studied. It is found that the diet of suckermouth armored catfishes consists of plant and animal food, as well as organic...

Saline rivers of Elton Lake Region (N49° 13', E46° 40') are highly productive systems. The flow of energy and nutrients can go beyond the hydroecosystem into the surrounding landscape, which is facilitated by the high diversity and quantitative development of the fauna. For the first time, field and experimental studies of planktonic and bottom com...

Проведены исследования спектра питания, трофических и размерно-массовых характеристик видов-вселенцев – южноамериканских кольчужных сомов Pterygoplichthys spp. (Loricariidae) в водоемах и водотоках Вьетнама. Установлено, что спектр питания кольчужных сомов представлен растительной и животной пищей, а также органическим детритом. По преимущественном...

The paper provides the first results of a study of the qualitative and quantitative structure of the community of bottom meiofauna (meiobenthos) in shallow, hypereutrophic Lake Nero (Volga River basin, Yaroslavl region, Russia). In the samples, collected in early September 2017, 106 representatives from 16 systematic groups of aquatic organisms wer...

This paper presents the first data on the flora of silica-scaled chrysophytes (orders Synurales and Paraphysomonadales) in the delta of the Mekong River (Vietnam). A total of 15 taxa have been identified: nine from the genus Mallomonas, one from Synura, and five from Paraphysomonas. Six taxa are reported for the first time from Vietnam. At most sit...

Приведены первые данные о флоре золотистых водорослей из порядков Synurales, Paraphysomonadales. Выявлено 15 таксонов, из них 9 рода Mallomonas, 1 – рода Synura, 5 родa Paraphysomonas. Шесть таксонов впервые отмечены во Вьетнаме. Распределение найденных таксонов по станциям было неравномерным, чаще всего присутствовало по одному-два вида. Наибольше...

We present the results of a comprehensive study of five saline rivers in the arid region of Lake Elton, including hydrobiological surveys of plankton and benthic communities. The DIABLO method was used for a statistical analysis of the associative links between the species structures of the macrozoobenthos, meiobenthos, and zooplankton communities....

The physicochemical characteristics of bottom sediments in inland water bodies in the Central and Southern Vietnam are presented for the first time, including particle-size distribution, organic matter content, bulk density, and natural moisture content. The main types of sediments in rivers, lakes, reservoirs, abandoned quarries, and ponds were de...

As established by numerous research the community of bottom meiofauna (meiobenthos) plays an important role in the diversity, quantitative characteristics and trophic relationships of the hydrofauna, as well as in the general flow of matter and energy of both marine and freshwater ecosystems. At the same time, to date it remains poorly studied in m...

As established by numerous research the community of bottom meiofauna (meiobenthos) plays an important role in the diversity, quantitative characteristics and trophic relationships of the hydrofauna, as well as in the general flow of matter and energy of both marine and freshwater ecosystems. At the same time, to date it remains poorly studied in m...

Data on the content of plant pigments in the bottom sediments (BSs) of the water bodies of Central and South Vietnam are given for the first time. The average concentration of chlorophyll a and phaeopig-ments (Chl + Ph) in total reaches up to 3.9 μg/g dry matter in rivers, 5.6 in ponds, 13.8 in sand quarries, 56.8 in reservoirs, and 245 in lakes. M...

Hydrological, hydrochemical, and hydrobiological data for five saline rivers of the arid Lake Elton region were analyzed. We found that interactions between plankton and benthic communities, in particular, between macrozoobenthos, meiobenthos and zooplankton, created mixed ecological groups of species. Abundances of plankton and bottom communities...

The modern distribution of South American armored catfishes (Loricariidae) is studied in three provinces in Central Vietnam. In the investigated area, representatives of the genus Pterygoplichthys occur, and at present they have moved into all main river basins. During the last 2–5 years, alien species have entered into many water bodies isolated f...

Illustrated descriptions of two new species of free-living nematodes found in sediments of small water bodies of Vietnam are presented. Laimydorus propinquus sp. n. is morphologically similar to L. papillatus Ahmad, Ahmad, 2002, but it is distinguished from it by a relatively longer and thicker body, a longer tail in females, a more anterior positi...

The peculiarities of Nile tilapia feeding and growth in the lakes of Vietnam were studied. It is found out that Nile tilapia mainly feeds near the bottom, gulping detritus with vegetative debris and benthic organisms. At the same time, some individuals were observed to feed on animals selectively, evidencing for presence of intraspecific trophic di...

A new species of free-living nematodes of the family Dorylaimidae, Dorylaimus proximus sp. n., found in small freshwater bodies of Vietnam is described and illustrated. The species is morphologically similar to D. fodori Andrassy, 1988 and D. bengalensis Sen et al., 2013. From the former it differs by a relatively thicker body, relatively longer an...

Illustrated descriptions of two nematode species from the genus Aquatides Heyns, 1968, A. heynsi sp. n. and A. thornei (Schneider, 1937) found in freshwater bodies of Vietnam are given. A. heynsi sp. n. is similar to A. intermedius (de Man, 1880) and A. thornei (Schneider, 1937). It differs from the former species in a shorter odontostyle and compa...

Illustrated description of two free-living nematodes Paractinolaimus cattienus sp. n., Labronemella papillata (Khan, Ahmad et Jairajpuri, 1995) comb. n. found in freshwater bodies of Vietnam is given. P. cattienus sp.n. differs from near species P. acuprus Khan, Ahmad, Jairajpuri, 1994 by the relatively thinner body, shorter tail, shorter Odontosty...

Приводится иллюстрированное описание двух видов свободноживущих нематод, Paractinolaimus cattienus sp. n. and Labronemella papillata (Khan, Ahmad et Jairajpuri, 1995) comb. n., обнаруженных в пресных водоемах Вьетнама. P. cattienus sp. n. отличается от близкого вида, P. acuptus Khan, Ahmad, Jairajpuri, 1994 относительно более тонким телом, более ко...

Illustrated descriptions are given of two new species of free-living nematodes of the genus Dorylaimoides found in small fresh waterbodies of Vietnam. D. curvicaudatus sp. n. is morphologically similar to D. singaporensis Ahmad, Mushtaq, 2004 and D. elongatus Husain, Khan, 1968, but it has a shorter tail, longer basal widening of pharynx, different...

Two new species of free-living nematodes of the genus Laimydorus (L. gigas sp. nov. and L. tenuis sp. nov.), found in the sediments of small freshwater bodies in Vietnam, are described and illustrated. Laimydorus gigas sp. nov. is similar to L. distinctus Dey, Baqri, 1986 and L. elephas Andrassy, 1988. From the former species it differs in the long...

A new species of free-living nematode, Daptonema salinae sp. n., found in the sediments of highly mineralized rivers of Lake El'ton basin (Russia), is described and illustrated. D. salinae sp. n. is similar in the structure of the spicular apparatus to D. aquaedulcis (Gagarin, 1987) and D. vicinus (Riemann, 1966). From both the species it differs i...

Two new nematode species of the order Dorylaimida found in small freshwater bodies of Vietnam are described and illustrated. Enchodelus minor sp. n. is close to E, parvus Loof, 1971, but differs from it in the shorter body, longer oesophagus and tail, longer prerectum and absence of saccate bodies at tail. Mesodorylaimus vietnamicus sp. n. is close...

This chapter of the collective monograph gives the basic hydrochemical and some other characteristics of various inland waterbodies of Vietnam investigated in 2008-2010. [In Russian]

The new nematode species Monhystera longivaginata sp. n. and the rare species Mononchulus nodicaudatus (Daday, 1901) collected in waterbodies of Vietnam are described. M. longivaginata sp. n. is morphologically similar to M. paludicola de Man, 1881, but differs from it in a longer and slenderer tail in females, ocelli situated closer to the anterio...

A new genus and two new species are described and illustrated from Vietnam. Neotripyla gen. n. has distinctive morphological characters of both Tripylidae and Tobrilidae. The presence of three lips, a narrow stoma with no sclerotized walls, and the arrangement of outer labial and cephalic setae are characteristic of nematodes of the family Tripylid...

The zooplankton from six small rivers in the basin of Lake Elton with the water mineralization of 9–41 g/l was studied in August of 2008–2009. A total of 36 species from eight taxonomical groups were identified; they mainly belonged to halophilous and halobiontic complexes of organisms. In the lake basin, 11 species were recorded for the first time...

The new species Crocodorylaimus minor sp. n. is described, and Aporcella maitai (Yeates, 1967) comb. n. is redescribed. C. minor sp. n. resembles C. dadayi (Thorne et Schwanger, 1936), but differs from it in a shorter body, shorter odontostyle, absence of vulvar papillae, slenderer tail in females, and shorter spicules. Aporcelaimellus maitai Yeate...

Two new species of free living nematodes from freshwater bodies of Vietnam are described and illustrated. Paractinolaimoides camranhius sp. n. differs from P. unicus Khan, Ahmad et Jairajpuri 1994 in the narrower labial region, shorter odontophore, shorter tail in females, longer prerectum in females and shorter spicules. Neoactinolaimus tenuis sp....

A new species of Mesodorylaimus Andrássy, 1959 is described and illustrated from Vietnam. Mesodorylaimus dolichurus sp. nov. is similar to M. flagellifer Andrássy, 2002 and M. derni Loof, 1969 and differs from both by longer odontostyle, longer tail in females, longer spicules and larger number of precloacal supplements in males. [In English]

The meiobenthos of six tributaries of the hypergaline Lake El’ton (the Volgograd region) in the low-flow period (August) has been researched for the first time. New species have been found for science, Russia, and the region. Widespread halophilic and halobiontic organisms formed the basis of the community, which was characterized by the relatively...

A new species of free-living nematode (Calodorylaimus salinus sp. nov.), found in sediment of the highly mineralised rivers of the Elton lake basin (Russia), is described and illustrated. This species is close to C. mongolicus Andrássy, 1988, but differs from the latter in having a wider labial region, a stouter tail in females and a greater number...

A new species of free-living nematode, Oncholaimus rivalis sp. n. found in sediments of highly mineralized rivers of Lake El’ton basin (Russia), is described and illustrated. Oncholaimus rivalis sp. n. is close to O. bajulus Paramonov, 1937, but differs from it in the comparatively shorter pharynx (498 µm), longer buccal cavity (37 µm), shorter bod...

This paper describes the results of investigations of tardigrades as a part of meiobenthos in different waterbodies (rivers, lakes, reservoirs) of the Upper Volga basin. To the present time 21 species of freshwater Tardigrada have been found in the region. In the investigated waterbodies the most widespread and numerous species were Pseudobiotus me...

The first data on the composition and quantitative development of meiobenthos in the small tropical Cái River (Central Vietnam) at the end of the “small rainy season” (early June) have been obtained. In the community composition, 101 taxa out of 15 systematic groups have been documented. Specimens which are new for science (Acari), new for the faun...

The copepod Apocyclops dengizicus (Lepeschkin, 1900), a denizen of the saline waterbodies of the desert and semidesert regions of the world, was found in one of the tributaries of the hyperhaline Lake Elton (Volgograd oblast). This finding marks the northernmost locality where this species has been recorded in Russia. An analysis of the latest publ...

[In Russian]

The mesofauna of five small rivers of the El'ton Lake basin with a mineralization ~9-30 g/L is investigated in August 2008. The 24 species, mainly belonging to halophilic and halobiontic complexes of organisms, out of 8 taxonomic groups are identified. For the first time 10 species (Nais elinguis, Keratella tropica, Synchaeta pectinata, Euchlanis p...

The male and females of Paramonchus arcticus Mulvey. 1978. found in the freshwater lake of Vladimir Province. Russia, are described and illustrated. The male being described for the first time has 2431 μm long body, 70 μm long spicules, 18μm long gubernaculum and 12 preanal, regularly spaced, tuboid, ventromedian supplements. A key for the identifi...

For the first time the community of meiobenthos in the river Oka (the second-largest inflow of the Volga) is investigated. Data about a species composition, abundance and biomass of the community in channel (flowing) zone and in quiet (without stream) areas are given. Data of the previous researches, concerning some groups of bottom meiofauna of th...

[In Russian]

Females and males of the rare free-living nematode species, Ischiodorylaimus cognatus Andrassy 1983, found in Yukhor Lake (Vladimir oblast) are described and illustrated. This species was recorded on the territory of Russia for the first time. Descriptions of females and a previously unknown male of Eumonhystera tuporis Gagarin 1991 from Sankhar La...

The paper summarizes known published materials of meiobenthos studies in the Gorky Reservoir (Volga River, Russia). The data of own investigations in the River part of the water body are given. The peculiarities of the community's distribution in different parts of the water area are discussed. [In Russian]

First data obtained in 2003 during combined ecological studies of 7 soft-water karst lakes are presented. The lakes are situated on the territory of the Klyazminsky-Lukhsky complex nature reserve (Vladimir Oblast). The lakes studied are: Yukhor, Kschara, Sankhar, Bolshiye (Big) Garavy, Maliye (Small) Garavy, and Svetlen'koye. The lakes Yukhor, Ksch...

Zoobenthos and littoral macroinvertebrate communities were investigated in three small lakes in Darwin Reserve (Vologda region, Russia) during summer 1990-1996. Lake Hotavets is eutrophic, polyhumic with water pH 6.5-8.5, two other lakes are acidified (pH 4.4-4.8). Lake Dubrovskoye is mcsotrophic, polyhumic and Lake Motykino is oligotrophic, oligoh...

Zooplankton of the central part of three small lakes in Darwin Reserve (Vologda region, Russia) was investigated in summer 1990-1996. Hotavets is an eutrophic, polyhumic lake with water pH 6.5-8.5, two other lakes are acidified (pH 4.4—4.8). Lake Dubrovskoye is mesotrophic, polyhumic and lake Motykino is oligotrophic, oligohumic. Based on study of...

Aporcelaimellus sarpophilus sp. n. from Lachost River (Yaroslavl Prov., Central Russia) is described and illustrated. It differs from A. cylindricus Ahmad, 1995 in the thicker body, longer odontostyle and spicules and larger number of supplements in males; from A. simus (Andrássy, 1958), it differs in the thicker body, distinctive shape of the lip...

Data on the abundance, horizontal distribution, and the seasonal dynamics of the dominant species and the entire group Cyclopoida in the meiobenthos of the open littoral and profundal of the Rybinsk Reservoir are presented. The probability that the passive and active migrations of cyclops in the reservoir are controlled by the natural (transsedimen...

Thirteen females of a new free-living nematode species, Tridentulus brzeskii sp. nov. were found during a hydrobiological investigation on Latka River (Central Russia, Yaroslavl' district). The new species differs from the only valid species of the genus Tridentulus, T. floreanae (Eyualem et Coomans, 1995) by the longer body, wider oral aperture, s...

For the first time for the small different lakes in marshy territory of the Mologa-Scheksna watershed (the Upper Volga basin) the data on a qualitative composition and quantitative development of the meiobenthic community in a central part, littoral zone and saturated with water mosses on floating mats and shores are given. The species composition...

Descriptions and illustrations are given for two new nematode species from the Sheksna river (the Volga river tributary) by Cherepovets city. Peritobrilus tumidus sp. n. is similar to P. arcticus (Gagarin, 1991), but the former species has biocrystals in muscle cells, subterminal seta at the tail tip, as well as segmented and shorter head setae. To...

Eleven individuals of the marine harpacticoid Paraleptastacus spinicauda (T. Scott, A. Scott, 1895), different in sex and age, were found in the Oka river (a right tributary of the Volga river) near Kasimov town. The species were previously described in the Black, Northern, Baltic Seas and in the Atlantic Ocean. The species is a typical interstitia...

Stenocypris akatovae sp.n. is described from the reservoircooler of the Tchernobyl NPS. It is similar to S. derupta Vavra and S. pankratovae Akat., but differs from these species by the body size, the armature of furcal rami and the absence of maxillular spines. Stenocypris sp. was found in Moshkovich bay of the Ivankovo reservoir (Tver distr., Rus...

Stenocypris akatovae sp.n. is described from the reservoircooler of the Tchernobyl NPS. It is similar to S. derupta Vavra and S. pankraiovae Akat., but differs from these species by the body size, the armature of furcal rami and the absence of maxillular spines. Stenocypris sp. was found in Moshkovich bay of the Ivankovo reservoir (Tver distr., Rus...

Specimens of a rare benthic species T. wesenbergi from the Gorky reservoir (Volga River) are described and figured. These specimens differ from the type specimens from Denmark by longer cephalic setae and shorter tail. [In Russian]