Catalogue of the type specimens of Pogonophora (Annelida; seu Polychaeta: Siboglinidae) from research collections of the Zoological Institute, Russian Academy of Sciences

The Catalogue includes the images of mainly dorsal, but also ventral and lateral views of the pogonophorans, including their tubes; survey drawings of species main morphological features composed of views of holotype and other specimens as well; views of deposit units (pots and mounts); label and collection data; maps showing type localities; references to original descriptions for primary and secondary types of 75 species of the pogonophorans of the subclasses Frenulata Webb, 1969 [24] and Monilifera Ivanov, 1991 [15] (Annelida; or family Siboglinidae Caullery, 1914 [3] comprised all pogonophoran high level taxa). For some type specimens additional details, among them cuticular structures of the body and details of the tubes, are given as well.Pogonophorans are sedentary marine worms that lack an intestine. They live in tubes made from protein and chitin, which they secrete. Pogonophorans occur in all oceans and many of the marginal seas at depths from 22 to more than 8000 m. They generally prefer cold waters. About 80 % of the species occur at depths between 200 and 4000 m. Pogonophorans live primarily on soft silty bottoms, especially in reducing sediments, burrowing deeply (subclass Frenulata). Some prefer to live in decaying organic matter, or sediments rich in methane and sulfide (subclass Monilifera), others in warmer hydrothermal vent conditions or cold seeps (subclass Vestimentifera Land et Nørrevang, 1977 [17]). There are currently about 170 species of Pogonophora, 90 % of which belong to the subclass Frenulata.Pogonophorans get their energy primarily from chemoautotrophic methane- or sulfur-oxidizing bacteria, living endosymbiotically in a specialized organ called the trophosome. They also get some nourishment from dissolved organic matter in the sediment pore water. The morphological body plan of Pogonophora is very peculiar because of an original multilevel regionation of the body, which firstly originates on the base of elongation of some segments (but not of fusion of segments like in many sedentary polychaetes), following by the irregular growth of different parts of the trunk accompanied with metamerism of different epidermal organs. The pinnules, separate cells in the epithelium of the tentacles in Frenulata with internal blood capillaries, are unique stuctures demonstrating extremely deep specialization of the pogonophoran circulatory system for respiration and transport of some matters (methane, hydrogen sulfide) dissolved in water to endosymbiothic chemoautotrophic bacteria. The absence of the gut in pogonophoran adults (and in early embryonic stages in some species) is a striking example of specialization of nonparasitic animals. In addition, the heart and the chitin-protein tube are also synapomorphic peculiarities of Pogonophora.The collection of Pogonophora of the Zoological Institute RAS has been gathered by trouble of dozen of researchers for many decades, first of all by efforts of prominent Russian zoologist, first-rate specialist in pogonophores and their actual discoverer academician Artemij Vasilevich Ivanov (1906–1992), creator and long-term head of Laboratory of evolutionary morphology of the Zoological Institute RAS. That is the very name which is associated with the detailed comparative anatomical description of Pogonophora and the erection of it to a separate phylum — one of the most striking event in zoology of XX century.First pogonophorans got known to science in 1914 owing to findings of the Netherlands “Siboga” expedition in the seas of the Malayan Archipelago. First pogonophoran material in the collection of the Zoological Institute RAS came from P.V. Ushakov in 1932 from the Sea of Okhotsk. In 1949 A.V. Ivanov found a third representative of Pogonophora from the Arctic (Laptev Sea). Then the number of known species and volume of materials in the collection of the Zoological Institute began to grow rapidly, due mainly to the investigations of the soviet expeditions onboard the research vessel “Vityaz” (1949–1960) in the western part of the Pacific Ocean. In that period of time prof. L.A. Zenkevitch and prof. V.G. Bogorov (P.P. Shirshov’s Institute of Oceanology RAS) considerably contributed to the quick supplement of the pogonophoran collection.Later on the pogonophoran materials came in less quantity but regularly from various parts of the World Ocean. Great contribution to this process was made by the colleagues from Institute of Oceanology RAS and Zoological Institute RAS Z.A. Filatova, G.M. Belyaev, A.V. Neelov, I.S. Smirnov, V.V. Potin, V.N. Romanov, etc. The most part of the material corresponds to coastal seas and regions off the coasts of continents and large islands, also deep-water trenches and basins throughout the World Ocean are well represented. The floors of the open ocean are less rich in pogonophorans. The materials came mostly from the Pacific Ocean, mainly from its north-western and north-eastern parts, due to great number of expedition which took place in these regions in various years. In general, pogonophoran biodiversity depends considerably of how some region of the World Ocean is well studied or not. For example, there had only two species of Pogonophora been known from the whole Antarctic Ocean for a long time, until regular investigation of Antarctic benthos allowed increasing their number in 7 times recently [20–23].At present the collection of pogonophorans of the Zoological Institute RAS (both the collection of types with systematic part and undetermined materials) is the largest in the world and unique by its representativeness. The collection involved now 95 of 171 species of worldwide fauna of Pogonophora and about 3500 deposit units. The collection is well structured and consists of three parts.The systematic (determined) part contains more than 3000 deposit units, undetermined part contains more than 200 units. The completely digitized collection of types now comprises of 155 deposit units containing 329 typical specimens, mainly holotypes and paratypes, but also several syntypes, which were collected on 63 hydrobiological stations throughout the World Ocean. These specimens belong to 75 pogonophoran species that is about 44 % of the whole species volume of Pogonophora. Deposit units are represented by pots and mounts. Pots fill two cabinets (cabinet 1, shelfs 1,2,3,5 in upper part and shelfs 1,2 in lower part, cabinet 2, shelf 2 in lower part — collection of types and systematic collection; cabinet 1, shelfs 4,5 in upper part — undetermined collection). Histological mounts are stored separately.All main taxonomic units of Pogonophora, subclasses Frenulata, Vestimentifera and Monilifera are represented in the collection. Frenulates are represented mostly complete — the both orders, all five families and 16 of 20 genera. Vestimentiferans are represented only by two species from two genera. Moniliferans are two species from both the known genera. The collection continues to grow due to materials of Russian and foreign expeditions and complex investigation projects, mainly in the Arctic Ocean, both its open part and coastal seas, mainly in Russian Arctic.Maintenance of the general collection, mounting and identification of the material have been performed by the preparators and researchers A.V. Ivanov, M.A. Gureeva, R.V. Selivanova, O.V. Bubko, R.V. Smirnov. General collection comprises the primary types (holotypes) of 30 species of pogonophorans (synonyms included) represented in a great part by the Frenulata species, as well as the secondary types (paratypes and syntypes) of 57 species. Some species are represented by both categories of types. Primary and secondary types belong chiefly to the species described by A.V. Ivanov [6–16], R.V. Smirnov [18–23], M.A. Gureeva [4,5,16], O.V. Bubko [1,2], and some other specialists [25].Digitizing of research collections of the Zoological Institute is performed within the framework of RFBR №15-29-02457 (competition of oriented basic research on important interdisciplinary themes 2015) «The collections of the Zoological Institute as an important tool and information basis of fundamental biological research» (project leader Dr. N.B. Ananjeva). Special thanks are due to A.N. Shumeev for his assistance in imaging of views of the pogonophorans.