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

 

KMK

 

 

Volume 3, Number 2

 

Redescription of Limnoithona tetraspina Zhang et Li, 1976 (Copepoda, Cyclopoida) with a discussion of character states shared with the Oithonidae and older cyclopoids

Bernardo Barroso do Abiahy, Carlos Eduardo Falavigna da Rocha, Frank D. Ferrari

1 Avenida Manuel Hipolito do Rego 1270/ap. 09, 11.600-000 Sao Sebastiao, SP, Brasil

2 Universidade de São Paulo, Instituto de Biociências, Departamento de Zoologia, Rua do Matão, travessa 14, No. 321, 05508-900 São Paulo, Brazil

3 Department of Invertebrate Zoology, MRC-534, National Museum of Natural History, Smithsonian Institution, 4210 Silver Hill Rd., Suitland, MD 20746 U.S.A.

Abstract: Limnoithona tetraspina Zhang et Li, 1976 is redescribed, and the morpho-logy of the cephalosome, rostral area, oral appendages, legs 1–6 and urosome of adult males and females is illustrated. Morphological features separating L. tetraspina from its only congener, L. sinensis, include: a more pronounced rostrum; 1 seta more on the proximal lobe of the basis of the maxillule; 1 seta more on the endopod of the maxillule; middle endopodal segment of swimming legs 2–4 with 1 seta more; proximal and distal seta of the middle endopodal segment of swimming leg 4 with a flange; exopod of leg 5 with a proximal lateral seta; male cephalosome ventrally with pores with cilia. A rounded projection between labrum and rostrum is a shared derived state for both species of Limnoithona. Derived morphological features of the remaining species of Oithonidae, which are not shared with L. tetraspina and L. sinensis, include: elongation of the mandibular basis; fusion of the proximal endopodal segment of the mandible of females to the basis; 2 setae of the fused proximal endopodal segment of the mandible extend ventral to labrum; 3 setae on the proximal complex of three endopodal segments of the maxilliped. The two species of Limnoithona do not belong to the Oithonidae. They appear to be closely related to species of Cyclopettidae, but at this time it would not be meaningful to assign them to a known family of the Cyclopoida or to propose a new family for them. The following morphological attributes which are shared with different related cyclopoids also are discussed: shape of female cephalosome; pores with cilia on male cephalosome; setation of basis and proximal segment of the endopod of the mandible; brush-like setae on the exopod of the mandible; setation of the maxillule including brush-like seta on the exopod; hyaline flange on setae of the endopod of swimming leg 4; lateral location of copulatory pores and leg 6 of females, and of leg 5 in both genders; configuration of leg 5.

(in English with Russian Summary)

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New benthopelagic aetideids (Crustacea: Copepoda: Calanoida) from deep Antarctic waters

Elena L. Markhaseva1, Knud Schulz2

1Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia.

2DZMB-Senckenberg, Biozentrum Grindel & Zoologisches Museum, Martin-Luther-King-Platz 3, Hamburg D-20146, Germany.

Abstract: Three new and one rare benthopelagic aetideid species of Bradyetes and Pseudeuchaeta are described from female specimens collected during the German expeditions ANDEEP I–III in 2002 and 2005 from bathy- and abyssopelagic depths above the sea bed. Pseudeuchaeta acuticornis sp.n. is distinguished from congeners by 5 setae on the second endopodal segment of mandible, presence of lateral spine on the first exopodal segment of P1 and 3 setae on the maxillule coxal endite. P. acuticornis is the second representative of the genus found in high Antarctic waters. Bradyetes weddellanus sp.n. differs from the other species of the genus by, among other states, a very small sensory appendage on the syncoxa of maxilliped, a short lateral spine of P1 exopod segment 2, one additional seta on the distal segment of antennule. Bradyetes curvicornis sp.n. is distinguished from congeners by the number of setae on the second endopodal segment of mandible and maxillulary endopod and a very long sensory appendage on the syncoxa of maxilliped. Within Bradyetes both new species are distinctly larger than their congeners. Furthermore, present collections yielded female specimens of Bradyetes cf. inermis from the South Atlantic and in the Southern Ocean; these are the first records for Bradyetes from the southern hemisphere.

(in English with Russian Summary)

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The nervous system ontogeny in cestodes and amphilinids

N.M. Biserova1, J.V. Korneva2

1Department of Invertebrate Zoology, Faculty of Biology, Moscow State University, Leninskie Gory, Moscow 119992, Russia

2Institute for Biology of Inland Waters RAS, Borok, Nekouz, Yaroslavl distr. 152742, Russia.

ABSTRACT: The nervous system (NS) development in all stages of Triaenophorus nodulosus (Pallas, 1781) (Cestoda: Pseudophyllidea), and also juvenile and adult Amphilina foliacea Rud., 1819 (Amphilinida) were studied. The first experimental data concerning the relationship between larval and adult nervous systems in Cestoda have been obtained. Significant differences in the ontogeny of the CNS in amphilinids and cestodes have been observed. We have shown that the oncosphere stage of Cestodes lacked an integrated nervous system because a neuropile and synapses between neurons were absent. Paired neurons (2–4) form contact only with myofibrills of the larval hooks and the body-wall muscle cells. The main processes of development, differentiation and integration in the CNS take place during the first parasitic procercoid stage when the cerebral ganglion, median commissure and main cords are usually formed. The pioneer neurons transit from oncosphere and indicate a way for developing nerves. Undifferentiated cells and developing neurites gather (congregate) around growth axons of the pioneer neurons. Cytodifferentiation of the uni- and bipolar neurons differs from that of the multipolar neurons. The PNS is formed at the next plerocercoid stage, in which also the CNS and sensory organs expand. The nervous system never stops growing in adult cestodes. Growth and formation of main cords and compartments innervating the reproductive organs occur from the stem cells from the neck region.

According to the data by Rohde (1994) and Xylander (2000), lycophora larva of amphilinides has well developed neuropile and many different sensory structures. We showed that young worm has two symmetrical cerebral ganglia of equal size and the connecting median commissure running between the frontal organ and uterus. Adult CNS has an asymmetrical position of the cerebral ganglion, many ganglionar knots in MCs and several well-developed caudal ganglia. In contrast to adult cestodes, the nervous system of adult amphilinids lacks undifferentiated nerve cells. The CNS of amphilinids is more concentrated and has metamerism features. The amphilinids’ CNS has several types of glial cells which produce myeline-like envelopes of the cerebral ganglia and main cords.

In contrast to amphilinds, the cells of the excretory system in adult T. nodulosus can exert glial function and form unique envelopes of the cerebral ganglia and main cords in early stages of ontogeny. We have shown that in the procercoid stage, CNS develops ahead of the development of the excretory system.

(in Russian with English Summary)

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Phylogenetic relationships within Schminkepinellidae fam. n., a new monophyletic group of marine cyclopinids (Cyclopoida: Copepoda), description of two new genera and four new species

Pedro Martinez Arbizu

DZMB — Forschungsinstitut Senckenberg, Südstrand 44, 26382 Wilhelmshaven, Germany.

ABSTRACT: The new family Schminkepinellidae fam.n. includes five genera: three known ones: Muceddina Jaume et Boxshall, 1996, Barathicola Humes, 1999, and Cyclopinella, Sars 1913, and 2 new genera: Einslepinella gen.n. and Schminkepinella gen.n. The new monophyletic group is characterised by the absence of a coxal endite on the maxillule, and by the spinal condition of the distal inner element on the middle endopodal segment of leg 4. A phylogenetic analysis shows Muceddina to be the relatively most primitive taxon, followed in sequence by Barathricola, Cyclopinella, Einslepinella gen.n. and Schminkepi-nella gen.n. It is argued, that at least, species belonging to Einslepinella gen.n. may be loosely associated with invertebrates.

(in English with Russian Summary)

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A comparative study of two sympatric subspecies of trematodes, Bunodera luciopercae luciopercae (Müller, 1776) and B. l. acerinae Roitman et Sokolov, 1999 (Trematoda: Bunoderidae)

S.G. Sokolov1, D.G. Tseitlin1, K.I. Afanasyev2, T.V. Malinina2, G.A. Rubtsova2

1 Institute of parasitology RAS, Leninskij pr., 33, Moscow 119071, Russia.

2 Vavilov’s institute of general genetic RAS, Goobkina st. , 3, Moscow 117809, Russia.

ABSTRACT: Two subspecies of trematodes, Bunodera luciopercae luciopercae (Müller, 1776) and B. l. acerinae Roitman et Sokolov, 1999 differ in morphological and genetical characters and hostality. Findings confirm Roitman and Sokolov’s (1999) point of view about necessity for taxonomic division of B. luciopercae s. lato.

(in Russian with English Summary)

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