Gregory Kolbasov

Lomonosov Moscow State University | MSU · N. A. Pertsov White Sea Biological Research Station

For the first time, ultrastructural studies have been conducted on the sensory apparatus of male Tantulocarida (Crustacea). Comparative morphological analysis with specialized sensory structures of Thecostraca, known as lattice organs, has allowed for conclusions about possible homologies and further clarification of the phylogenetic position of Ta...

Ultrastructural studies on the sensory apparatus of male Tantulocarida (Crustacea) have been conducted for the first time. Comparative morphological analysis with the specialized sensory structures of Thecostraca, known as lattice organs, has allowed for conclusions about possible homologies and further clarification of the phylogenetic position of...

Despite discovery more than 100 years ago and documented global occurrence from shallow waters to the deep sea, the life cycle of the enigmatic crustacean y-larvae isincompletely understood and adult forms remain unknown. To date, only 2 of the 17 formally described species, all based on larval stages, have been investigated using an integrative ta...

Resolution of recalcitrant nodes in the Tree of Life has been substantially eased recently by increased worldwide sampling and advancements in sequencing technology. It has become routine to use molecular data to characterise and taxonomically allocate tens to hundreds of taxa based on the DNA occurring in a few drops of water. Despite this, the ad...

Petrarca is an ascothoracidan endoparasite in scleratinian dendrophyllid corals. Petrarca can stimulate coral growth, forming a gall chamber to house itself inside the coral skeleton. The diversity, molecular phylogeny and feeding ecology of Petrarca are understudied. This is the first study of Petrarca to be based on light and scanning electron mi...

The enigmatic “y-larvae” (Pancrustacea: Facetotecta) still have an incompletely understood lifecycle, and their adult forms remain unknown despite their discovery more than 100 years ago and their documented global occurrence from shallow waters to the deep-sea. Only two of the 17 formally described species, all based on larval stages, have been in...

Although the naupliar and cypridiform stages of the enigmatic y-larvae of Facetotecta have been found in the marine plankton worldwide, they still represent the last significant group of crustaceans for which the adult forms are still unknown. From a number of y-cyprids representing different taxa from different locations, we employ scanning electr...

The invasion of novel habitats is recognized as a major promotor of adaptive trait evolution in animals. We tested whether similar ecological niches entail independent and adaptive evolution of key phenotypic structures related to larval host invasion in distantly related taxa. We use disparately related clades of coral barnacles as our model syste...

A new facetotectan species, described herein as Hansenocaris spiridonovi Kolbasov, Savchenko et Høeg sp.n. and based on its cypridiform stage, was found in the plankton off Azores Islands. We employed scanning electron microscopy to document the fine-scale external morphology of this species. We discuss the findings of facetotectan larvae showing c...

A new ectoparasitic ascothoracidan species has been discovered off northern Tasman Sea at a depth of 520 m. Single female, described herein as Waginella ebonita Kolbasov and Newman sp. nov. in the family Synagogidae Gruvel, 1905, was collected on the column of crinoid Metacrinus sp. This is the first study of a new form of Waginella to be based on...

William Anderson Newman passed away on December 26th 2020 at his home in La Jolla, California, aged 93. Bill spent much of his academic life at Scripps Institution of Oceanography, and also had a long and enduring association with the California Academy of Sciences. A marine biologist with deep interests in palaeontology and geology, Bill made spec...

We present a comprehensive revision and synthesis of the higher-level classification of the barnacles (Crustacea: Thecostraca) to the genus level and including both extant and fossils forms. We provide estimates of the number of species in each group. Our classification scheme has been updated based on insights from recent phylogenetic studies and...

From a number of partial moult series obtained by laboratory culture of plankton-caught specimens, we described all naupliar instars of the facetotectan species, Hansenocaris itoi. It reveals seven naupliar instars, instead of the five that were previously supposed for the Facetotecta. This number of naupliar instars is unique not only for Facetote...

We examined the diversity and host use of sponge-associated barnacles of Thailand (Andaman Sea and the Gulf of Thailand) using a combined morphological and molecular approach. Eight barnacle species (including two new species) were collected from 12 host sponges. Host-specific barnacle species includes Acasta lappa sp. nov., which exclusively inhab...

This paper describes a new species of sponge-inhabiting barnacle, Neoacasta liui sp. nov., collected in Fukuoka, Kyushu, Japan. In the present study we used both the morphological examination and DNA barcode (cytochrome c oxidase I gene) to distinguish this new species from acastine species including its congeners from Neoacasta Kolbasov, 1993. Neo...

More than 40 specimens of a new endoparasitic ascothoracidan species, described herein as Sessilogoga captiva Kolbasov & Grygier sp. nov. in the family Synagogidae Gruvel, 1905, were found at 35 m depth near Green Island off southeastern Taiwan infecting a colony of the antipatharian Antipathes sp. aff. A. atlantica Gray, 1857. Its sole known conge...

Symbiotic relations and range of host usage are prominent in coral reefs and crucial to the stability of such systems. In order to explain how symbiotic relations are established and evolve, we used sponge-associated barnacles to ask three questions. (1) Does larval settlement on sponge hosts require novel adaptations facilitating symbiosis? (2) Ho...

Symbiotic relations and range of host usage are prominent in coral reefs and crucial to the stability of such systems. In order to explain how symbiotic relations are established and evolve, we used sponge-associated barnacles to ask three questions. (1) Does larval settlement on sponge hosts require novel adaptations facilitating symbiosis? (2) Ho...

A new ascothoracidan species has been discovered off Taiwan in the north part of the west Pacific at SCUBA depths. Twelve specimens including both sexes of the new species, described herein as Synagoga arabesquesp. nov. , were collected from colonies of the antipatharian Myriopathes cf. japonica Brook, 1889. Three previously described species of Sy...

The Tantulocarida is a small taxon of microscopic parasitic crustaceans that has a sophisticated life-cycle. The unique larval stage is called a tantulus, which is adapted to both free-swimming in sediments and attached parasitic mode of life. The anatomy of free-swimming tantulus larvae was studied using confocal laser scanning microscopy (CLSM) f...

Sponges are common in coral reefs and provide secondary habitats and shelter to a very diverse associated biota. To examine the symbiotic relationships between crustacean associates and their sponge hosts, the most important step is to collect live crustaceans and sponges for subsequent taxonomic identification as well as for larval rearing and exp...

The ability to survive freezing has repeatedly evolved across multiple phyla. This suggests that the mechanisms of freeze tolerance must be readily evolvable from basal physiological traits. While several biochemical correlates to freeze tolerance have been described, the mechanism that confers freeze tolerance is still not well understood. To unde...

Two new ascothoracidan species in the family Ascothoracidae Grygier, 1987, Ascothorax rybakovi sp. nov. and Cardiosaccus pedri gen. et sp. nov., are described from the Kuril-Kamchatka Trench at abyssal depths of 5150–5700 m. They are among the deepest known ascothoracidans. They live as mesoparasites in permanent cysts within the bursae of the brit...

The morphology of Tantulocarida, a group of minutely sized ectoparasitic Crustacea, is described here using for the first time transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). This enabled a detailed analysis of their internal anatomy to a level of detail not possible with previous light microscopic investigatio...

A new ascothoracidan species has been discovered in the Macaronesia region of the eastern Atlantic Ocean at SCUBA depths. Ten specimens including both sexes of the new species, described herein as Synagoga grygieri sp. nov., were collected from colonies of the antipatharian Antipathella wollastoni (Gray, 1857). Two previously described species of S...

A new deep water acrothoracican species, Weltneria acanthostoma sp. nov., has been discovered from the area of the Blue Ridge Seamount, South China Sea, at a depth of 534 m. A single female was found in a burrow in the scleractinian Madrepora oculata. This specimen is assigned to the genus Weltneria due to the possession of six pairs of cirri and t...

Within the family Archaeobalanidae, the sponge-inhabiting barnacles include species from the subfamilies Acastinae and Bryozobiinae as well as from the genus Membranobalanus in the subfamily Archaeobalaninae. Members of these groups are obligatory symbionts of poriferans, but the Acastinae can also be found in association with alcyonaceans and anti...

The morphology of archaeobalanid barnacles of the genera Conopea and Acasta inhabiting cnidarians of the orders Alcy-onacea and Antipatharia was surveyed. Based on morphological characteristics, it became evident that the species of the nominal genus Conopea fell into three natural groups affiliated to three archaeobalanid genera, Conopea s.s., Aca...

This paper describes a new species, Bryozobia rossi sp. n., collected by scuba diving in both Taiwan and Japan. B. rossi sp. n., a member of the subfamily Bryozobiinae (Ross and Newman 1996), has atria and open end portals and a single irregular basal whorl of portals at the same level as basal hemiportals; this morphology varies from all previousl...

A new ascothoracidan species, Gorgonolaureus bicornutus sp. nov., has been discovered off south-eastern Taiwan at a depth of 227 m. Five females were found in permanent cysts on the branches of a plexaurid octocoralian alcyonacean (former "gorgonian"), Echinogorgia sp. These specimens are assigned to the genus Gorgonolaureus on account of their hav...

Acrothoracican barnacles of the genus Berndtia are exclusive coral borers and the type species is Berndtia purpurea Utinomi, 1950a, reported in the corals Lepastrea purpurea and Psammocora profundacella in Wakayama, Japan. We confirmed the type is only from the coral Lepastrea purpurea and is distributed from Japan, Taiwan to Hong Kong. In contrast...

Complete 18S rDNA sequences of two species of the Tantulocarida Arcticotantulus pertzovi (Basipodellidae) and Microdajus tchesunovi (Microdajidae) were obtained and used for estimating the relationship of the class with other Crustacea. This constitutes the first use of tantulocaridan gene sequences, and we conclude that the Tantulocarida are very...

We list five acrothoracican barnacles of the order Lithoglyptida currently found in Taiwanese waters, including two new records, Trypetesa habei Utinomi, 1962 and Berndtia purpurea Utinomi, 1950 and a new undescribed species of the genus Lithoglyptes. We also investigate the morphology and molecular genetics of Balanodytes taiwanus Utinomi, from it...

The morphology of the cypris larvae of four genera of pedunculate lepadomorph barnacles of the family Poecilasmatidae (Megalasma, Octolasmis, Poecilasma and Temnaspis) was studied with SEM, focusing on the carapace with lattice organs, thoracopods and abdomen with furcal rami. The morphology of adult poecilasmatid barnacles presents few if any conv...

Free-swimming definitive males of two species of Tantulocarida (Crustacea), Arcticotantulus pertzovi (Basipodellidae) and Microdajus tchesunovi (Microdajidae), were reared for the first time. Their morphology and ultrastructure were studied using scanning electron and light microscopy. A detailed analysis of the morphological characters of all curr...

Cirripedes of the superorder Acrothoracica are normally found as epizoic borings on marine calcareous substrates. Armatoglyptes taiwanus (Utinomi, 1950) is a lithoglyptid acrothoracican barnacle reported from different parts of the Indo-Pacific. Recent studies have demonstrated phylogenetic breaks between the Indian and Pacific Oceans populations i...

A new species of Tantulocarida, Microdajus tchesunovi sp. n., was found on tanaid host, Typhlotanais sp. of the family Nototanaidae, collected from silty sediment in the Kandalaksha Bay in the White Sea. Several tantulus larvae, developing males at different stages of metamorphosis, and early stages of parthenogenetic females were found attached to...

We use a previously published phylogenetic analysis of the Thecostraca to trace character evolution in the major lineages of the taxon. The phylogeny was based on both molecular (6,244 sites from 18S rna, 28S rna and H3 genes) and 41 larval morphological characters with broad taxon sampling across the Facetotecta (7 spp.), Ascothoracida (5 spp.), a...

A single tantulus larva was found at the abyssal depth of the Indian Ocean attached to a harpacticoid host of the family Cletodidae. It represents a new genus and species of Tantulocarida, family Basipodellidae. Its ultrastructure was studied with SEM. This genus can be easily distinguished from the other genera of Basipodellidae by the pore patter...

Until now morphological and molecular datasets have failed to agree on phylogenetic relationships within the Crustacea Thecostraca (=Facetotecta, Ascothoracida, and Cirripedia). Three recent phylogenetic studies using 18S ribosomal DNA sequences from selected Cirripedia (Thoracica, Rhizocephala, and Acrothoracica) and Ascothoracida revealed Acrotho...

The material on Arcticotantulus pertzovi, a parasite of the harpacticoids Bradya typica and Pseudobradya acuta, was collected in the White Sea (the White Sea Biological Station, Moscow State University) in 2004–2006. The morphology of the tantulus larva, the “parthenogenetic female,” and the male was studied using SEM. The data obtained add signifi...

We describe the external morphology of the two cypridiform larval instars (first and second ascothoracid-larvae, or “a-cyprids”) of the ascothoracidan genus Dendrogaster. Ascothoracid-larvae of five species were studied with light and scanning electron microscopy, including both ascothoracid-larval instars in Dendrogaster orientalis Wagin. The firs...

The relationship between sponge hosts and barnacles are investigated, and the dependence of the morphology of the barnacles on the skeletons of the sponges is shown. The evolutionary development of this group is analysed. Five genera: Archiacasta, Neoacasta, Euacasta, Acasta and Pectinoacasta, are distinguished from the original genus Acasta on the...

We used SEM to investigate the morphology of the cypris larvae from a range of species of the Cirripedia Acrothoracica, representing all three families and including the first detailed account of cyprids in the highly specialized Cryptophialidae. Special attention was given to the head shield (carapace), the lattice organs, the antennules, the thor...

A y-cypris larva, representing a new species of Facetotecta from Indonesia, was found in the gut of the cardinalfi sh Pterapogon kauderni. Its external morphology was examined using scanning electron microscopy (SEM). Features such as the anterior papilliform protrusions, the short head shield and the lack of pointed posterioventral extensions of t...

The external ultrastructure of adult stages in eleven crustacean species of the genus Dendrogaster parasitic in the sea-star coelom was studied. In females, the cuticular structures are weakly developed. They are characterized by the absence of setae, pores, and papillae on the cuticle of mantle branches. The rounded, plaque-like projections with a...

The morphology of the females and males of the ancient acrothoracican burrowing barnacle family, the Lithoglpytidae Aurivillius, 1892, was surveyed. It became evident that by resurrecting a previously described family-group taxon and proposing a new family-group taxon, the Lithoglyptidae could readily be divided into three subfamilies, the Lithogly...

A single female, belonging to a new species of the genus Gorgonolaureus Utinomi 1962, was found in paramuriceid gorgonians in a habitat similar to that of G. vietnamianus Grygier. Despite this fact, the new species Gorgonolaureus helenae is closer to G. decurvatus Grygier from western Australia. Both species have several common characteristics, suc...

The new species Cryptophialus gantsevichi is characterized by a long opercular neck and opercular bar with 4 projections. This species is similar to C. variabilis, C. cornophorus, C. longicoolatus, and C. lanceolatus by the shape of the opercular neck and structure of opercular bars. C. longicollatus and C. variabilis have a smaller number of the o...

Lattice organs are peculiar chemoreceptors found only in the Crustacea Thecostraca (Facetotecta, Ascothoracida, Cirripedia). In these taxa, five pairs occur in the head shield (carapace) of the terminal larval instar (y-cyprid, ascothoracid larva, cyprid), which is the settlement stage. Lattice organs represent an autapomorphy for the Thecostraca b...

From a number of partial moult series obtained by laboratory culture of plankton-caught specimens, and based on drawings from whole-mounted material, we describe all the larval instars, including the y-cypris, of a new species of Facetotecta. The mid-length constriction of the antentrulary aesthetasc and the shape of the head shield separate the y-...

From a number of partial moult series obtained by laboratory culture of plankton-caught specimens, and based on drawings from whole-mounted material, we describe all the larval instars, including the y-cypris, of a new species of Facetotecta. The mid-length constriction of the antennulary aesthetasc and the shape of the head shield separate the y-c...

The external morphology of the dwarf males of Lithoglyptes mitis, Lithoglyptes bicornis, Kochlorine hamata, Kochlorine sp., Cryptophialus hoegi, Cryptophialus sp., and Trypetesa lampas was examined under SEM. New data on the cuticular structures are compared with existing information on acrothoracican and thoracican males. The structure of the male...

The new species Kochlorine grebelnii sp. n. from the Cape Verde Islands has a long, curved hook-like process on the middle of the opercular bars. It is similar to that in K. hamata Noll, but differs in having the longer hook-like process of the opercular bars with one-ended top. The morphology of K. grebelnii cypris larva is characteristic of the r...

Scanning and transmission electron microscopy (SEM and TEM) were used to study lattice organs in facetotectan y-cyprids from the White Sea and from Norwegian and Bahamian waters. The larvae represent at least four and possibly five different species of Facetotecta. Y-cyprids have five pairs of lattice organs in the head shield (carapace) organized...

Until now morphological and molecular datasets have failed to agree on phylogenetic relationships within the Crustacea Thecostraca (=Facetotecta, Ascothoracida, and Cirripedia). Three recent phylogenetic studies using 18S ribosomal DNA sequences from selected Cirripedia (Thoracica, Rhizocephala, and Acrothoracica) and Ascothoracida revealed Acrotho...

The external morphology of females and a dwarf male of T. lampas were studied. The mantle sack exhibits the structures common to all acrothoracicans, such as: single teeth with associated simple setae on the apertural lips; feeble multifid scales on the apertural lips and ventral part of the opercular region; small mantle teeth and minute multifid...

The chromosome set in Crustacea larvae of the subclass Facetotecta collected in the White Sea, nearby the White Sea Biological station was investigated. The diploid set of the investigated species contains 28 chromosomes. The occurrence of 29 chromosomes in some individuals may indicate the presence of an unpaired sex chromosome. The presence of te...

The new acrothoracican species, Weltneria bekae, is described from Papua (New Guinea). The new species is similar to those of Weltneria (W. spinosa, W. hirsuta, W. reticulata, W. aapta and W. zibrowii) having carinal projections of the opercular bars, being armed with conspicuous teeth. Weltneria bekae differs from W. spinosa in having straight pro...

The external morphology of female and male Lithoglyptes bicornis was examined under SEM. The structure of the mantle, the thorax and, especially, the trophi were thoroughly examined. The data on the mantle and the thorax structures were compared with the previous data on the acrothoracican ultrastructure. The data on the structure and the character...

Calcareous plates were found in the shallow-water species Lithoglyptes mitis and L. habei. Their morphology is similar to the same plates on deep-water lithoglyptids. The plates are located in the area of the attachment disk and are covered with a thin membrane-like cuticle with tiny cuticular papillae-like structures. These structures probably sec...

Three species of the genus Heteralepas Pilsbry, H. microstoma Gruvel, H. meteorensis Carriol, and H. alboplaculus, were found in surveying materials from the Canary Islands and the Azores. Their morphology was described in detail and compared with earlier descriptions by other specialists. The new species is similar to H. adiposa and H. cygnus, but...

A new species of the genus Cryptophialus, was found in a gastropod (Purpura persica) shell from the Aden Gulf. The short neck, four projections of opercular bars, and mandibles with two main teeth are characteristic of this new species. All its characteristics indicate its close relation to C. coronatus Tomlinson, 1960. However, the new species dif...

A new species of burrowing barnacles Lithoglyptides echinoideus was found in the hydrocoral Distichopora sp. offshore Island Nauru (around 00°30′ S, 166°55′ E) at a depth of 19-20 m. This species possesses four terminal cirri and caudal appendages like other species of the genus Lithoglyptes. Its opecular bars bear conspicuous conical opercular pro...

A new species of the Lithoglyptes from the Seychelles is described. The external morphology of the mantle sac and the body were examined under SEM. The position of a new species within Lithoglyptes and the ultrastructural characters of different species of this genus are discussed.

A new lithoglyptid species, Lithoglyptes egorovi, was found in a shell of Morula cavernosa gastropod from the Maldives region (3°48′N; 73°05′E) at a depth of 1.8 m. The new species possesses four terminal cirri and caudal appendages like other species of the genus Lithoglyptes. Besides, its opercular lips bear the conspicuous rounded opercular proj...

In this study eight different species of barnacles were found within nine species of sponges from the Red Sea. This brings to 11 the number of sponge-symbiotic barnacles reported from the Red Sea, two of these are new Acasta species (not described herein) and one (A. tzetlini Kolbasov) is a new record for this sea. This number is much higher than t...

A new species of Paralepas from near Madagascar is described and its affinities are indicated. A generalized complemental male and a male cyprid larva were found attached below the aperture in two specimens. This is the first male reported for this group of barnacles, and its morphological characters are investigated.

Scanning electron microscopy was used to provide a full morphological description of cypris morphology in the acrothoracican species Lithoglyptes mitis and L. habei (Lithoglyptidae). Special attention was given to lattice organs, antennules, thorax, thoracopods, abdomen, and furcal rami. Cypris larvae of the Acrothoracica share some putative plesio...

Untill the present time the genus Pagurolepas was considered as a monotypical. Descriptions of three new species P. utinomii, P. zhadani and P. elongata are given. The subspecies P. c. atlantica is referred to the rank of species. The latter differs from P. conchicola by the position of scutal umbo, mandible form and smaller length of caudal append...