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INVERTEBRATE ZOOLOGY
ISSN 1812-9250 
ISSN 1814-0815
(online)

 

KMK

 

 

Volume 7, Number 2

Published online 30/12/2010

Two new species of Pileolaria (Polychaeta: Spirorbidae) from the Southern Hemisphere with a brief review of related species

A.V. Rzhavsky

A.N. Severtsov Institute of Ecology and Evolution, RAS, Leninskij Prospekt 33, Moscow, Russia 119071

 ABSRACT: Two new polychaete species of family Spirorbidae are described, both similar to those species of Pileolaria that have the distal part of the brood-chamber smooth and domed or bilobed. Pileolaria connexa sp.n. from Kerguelen Island (and probably Palmer Archipelago), unlike most species of the genus, commonly retains the primary operculum (plate and talon) distal to the brood chamber, and has sickle chaetae with unusually long distal serrated parts of the blades. Pileolaria invultuosa sp.n. from Bouvet Island and Adelie Land (and perhaps Enderby Land and Signy Island) sheds the primary operculum before the brood chamber is fully developed and has distal serrated parts of sickle chaetae blades similar in length to proximal thick parts of the blades. Both new species are similar, but unusual amongst this group, in having a shallow calcified cap restricted to the distal part of the brood chamber. The primary opercula of both species differ from each other (and from those of most Pileolaria species) in the shape and position of the distal plates talons.

KEY WORDS: Spirorbidae, Pileolaria, Antarctic, Subantarctic.

(in English with Russian Summary)

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A description of Anoplostoma nhatrangensis sp.n. from mangrove habitats of Nha Trang, Central Vietnam, with a review of the genus Anoplostoma Bütschli, 1874 (Nematoda: Enoplida)

Alexei V. Tchesunov1, Nguyen Vu Thanh2

1 Department of Invertebrate Zoology, Faculty of Biology, Moscow State University, Moscow 119991, Russia.

2 Institute of Ecology and Biological Resources (IEBR), Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Rd., 10000 Hanoi, Vietnam.

ABSTRACT: Anoplostoma nhatrangensis sp.n. is described from a degrading mangrove habitat in the Nha Trang area, Central Vietnam. The new species is characterized by relatively long outer labial setae (81–120% c.b.d.); relatively long tail with longer posterior cylindrical portion (c 5.71–6.92, c’ 8.96–11.8, distal tail part 63–90%); males without preanal bursal papillae and only a minute postanal bursal papilla besides the posterior bursal spine. Anoplostoma nhatrangensis sp.n. is most similar to the A. heterurum differing in certain morphometric values: a bit more stout body (a 33–45 versus 56), and relatively longer tail (c 5.9–6.6 versus 11 and c’ 10–12 versus 6.5) with greater posterior slender cylindrical portion (82–90 versus 75%). A short taxonomic review of the Anoplostoma species is proposed. The genus contains twenty nominal species: fourteen of them are considered as valid; A. brevispiculum is considered as a species incertae sedis because its characters do not fit the generic diagnosis, A. demani as a species inquirenda because of incomplete data of the original description and A. macrospiculum as a junior synonym of A. sunderbanae. Tables of simplified images of male heads and tails as well as list of important morphometric values are proposed as a tool for quicker identification of Anoplostoma species.

KEY WORDS: Anoplostoma, free-living nematodes, mangroves, taxonomy, Vietnam.

(in English with Russian Summary)

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Micronephthys (Polychaeta: Nephtyidae) of Northern Europe and Arctic

N.Yu. Dnestrovskaya, I.A. Jirkov

Moscow State University, Biological Faculty, Department of Hydrobiology; Leninskie Gory, 1, bldg. 12, Moscow 119991, Russia

ABSTRACT: Three species of Micronephthys inhabit Northern European and Arctic waters: Micronephthys minuta (Theel, 1879), M. neotena (Noyes, 1980), and M. hartmannschroederae Jirkov et Dnestrovskaya, 2001. All species are re-described, original illustrations and distribution maps accompany all descriptions. Micronephthys minuta and M. neotena are a mainly Arctic and boreal species, respectively, very abundant in brackish waters. Micronephthys hartmannschroederae should be very abundant sporadically in boreal European waters. The existing literature on biology and distribution of these species is reviewed. The taxonomic characters used to separate genera within Nephtyidae are analysed, proving that the family needs to be fully reviewed.

KEY WORDS: Polychaeta, Nephtyidae, Micronephthys, Northern Europe, Arctic.

(in English with Russian Summary)

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The first record of parasitic nematode Clavinema mariae (Dracunculoidea: Philometridae) in gadiform fishes (Osteichthyes: Gadiformes)

S.G. Sokolov1, S.E. Frolova2, E.V. Frolov2

1 A.N. Severtsov Ecology and Evolution Institute, Leninskiy pr. 33, Moscow 119071, Russia.

2 Sakhalin Research Institute of Fisheries and Oceanography, Komsomolskaya str. 196, Yuzhno-Sakhalinsk 693023, Russia.

ABSTRACT: Nematode Clavinema mariae has been found in Pacific saffron cod Eleginus gracilis, caught in Izmenchivoye lagoon (Sakhalin). This is the first report of this parasite from gadiform fishes. The new data on location of dorsal oesophageal gland in this species has been obtained. Diagnosis of the genus Clavinema has been adjusted.

KEY WORDS: Clavinema mariae, Dracunculoidea, Eleginus gracilis, Philometridae.

(in Russian with English Summary)

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Fine structure of nervous system in plerocercoid Ligula intestinalis (Cestoda: Diphyllobothriidea)

N.M. Biserova, I.I. Gordeev

Department of Invertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia.

ABSTRACT: The fine structure of the nervous system in plerocercoid Ligula intestinalis (Diphyllobothriidae) has been studied. The ultrastructure of the cerebral ganglion, the main nerve cords and peripheral nervous system has been described. The cerebral ganglion has complicated microanatomy. It consists of symmetric pair frontal and lateral lobes connected by the massive median commissure, and ventral azygos lobe, located in the center and on the ventral surface of the commissure. Two crossed ventral nerves are originated from the unpaired median (ventral) lobe. It was found, that the neurons in the lateral lobes and the commissure have asymmetrical position (localization neurons in the lateral lobes and the commissure has dorso-ventral polarity): large neurons (20–40 µm) are concentrated on the dorsal surface of the cerebral ganglion. We found four types of neurons with different fine structure and size, peripheral neurosecretory cells and undifferentiated cells. Three types of synaptic contacts have revealed in neuropiles. Giant axon occurred as part of the main cord. On the surface membrane of the giant axon are numerous incoming synapses. The peripheral nervous system consists of numerous compact bunches of nerve processes taking place along the longitudinal and dorso-ventral muscle fibers. Also three types of sensory organs were found in the tegument: one type a ciliate and two types unciliate receptors. Comparative analysis of nervous system organization in representatives of the two orders Diphyllobothriidea and Bothriocephalidea showed that the cerebral ganglion L. intestinalis possesses bilateral symmetry, characterized by the presence of the ventral lobe, ventral nerves and the dorso-ventral polarity in the arrangement of neurons and exiting nerves. On the contrary, the cerebral ganglion of Triaenophorus nodulosus (Bothriocephalidea) has a double-beam symmetry: it has symmetrical lobes in ganglion with symmetrical dorsal and ventral nerves, lack of lobe in the median commissure, and send symmetrical dorso-ventral rootlets in the bothria. Our data confirm the belonging of the studied species to different groups and support the idea of separation Pseudophyllidea sensu lato into two new orders Diphyllobothriidea and Bothriocephallidea.

KEY WORDS: platyhelmintes, tapeworms, nervous system, ultrastructure, symmetry, polarity, neuron, synapse, Cestoda, Diphyllobothriidea, Ligula intestinalis.

(in Russian with English Summary)

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Cladocera (Crustacea: Branchiopoda) in Indian hot water springs

S. Padhye1, A.A. Kotov2

1 Laboratory for Zooplankton Studies, Dept. of Zoology, University of Pune, Pune-411007, India.

2 A.N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, Moscow 119071, Russia.

ABSTRACT: We found two species of Cladocera (Crustacea: Branchiopoda), namely Latonopsis cf. australis Sars, 1888 (family Sididae) and Alona cambouei Guerne et Richard, 1893 (family Chydoridae), in the Unhere hot water springs near Pali, State of Maharashtra, India at temperatures of 34.5–36.7 °C. Our finding is the first record of cladocerans with exact species determination in hotsprings of the Oriental zone.

KEY WORDS: Anomopoda, fauna, India, abiotic factors, temperature.

(in English with Russian Summary)

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Structure and differentiation of the tissues of cysticercoids. 3. Differentiation of the endocyst of typical diplocyst of Aploparaksis bulbocirrus (Cestoda: Aploparaksidae)

V.P. Nikishin

Institute of the Biological Problems of the North, Portovaya Str. 18, 685000 Magadan, Russia. 

Abstract: Fine structure of endocyst of the developing and young cysticercoid Aploparaksis bulbocirrus Deblock et Rausch, 1968, referring as “typical diplocyst” has been studied. It was shown that a cavity for invaginated scolex and neck, was formed de novo. During cystogenesis tegument, muscle elements, excretory system, inner boundary of endocyst and secretory cells, were differentiated. Muscular cells form both muscles and fibrous layers located between distal cytoplasm of tegument and cellular layer. Fibroblasts and nervous elements were not identified. Full formation of endocyst’s wall including formation of glycocalix layer, modification of microvilli and distal cytoplasm of tegument took place after invagination of scolex and neck into its cavity. The results confirm our consideration about endocyst as a defensive structure adapted to mechanical and chemical actions in the initial part of digestive tract of their definitive host.

Key words: cysticercoid, typical diplocyst, ultrastructure, development, first invagination, scolexogenesis, endocyst.

(in Russian with English Summary)

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