摘要:

The cnidoms ofLaomedea flexuosa, Gonothyraea loveni, Obelia geniculata, O. longissimaandO. dichotomawere studied by light and scanning electron microscopy to find out whether the nematocysts could be used as taxonomic characters. Three b‐rhabdoid heteroneme nematocysts (microbasic b‐mastigophore) and three isorhizous haploneme nematocysts (atrichous isorhiza) were distinguished. A small b‐rhabdoid nematocyst with spindle‐shaped capsule occurred in all the species examined. In the polyp and planula ofG. loveni, and the planula ofL. flexuosait was the only nematocyst present. Specific forL. flexuosawas a b‐rhabdoid with curved capsule. In the polyp and newly‐liberated medusa ofO. longissimaanother b‐rhabdoid appeared with bean‐shaped capsule and markedly long spines at the distal tube. The polyp and newly‐liberated medusa ofO. dichotomawere characterized by two different isorhizas. A special type of isorhiza occurred in the polyp ofO. geniculata. The curved capsules of the different isorhizas varied somewhat in shape and size. Differences in nematocyst structure and occurrence are presumed to provide characters for taxonomy. Thus,O. dichotomaandO. Iongissimaare regarded as separate species due to their distinctly different nematocysts, in conjunction with other morphological and ecolo

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00536.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A historical review of the systematics ofParacanthonchus caecus(Bastian, 1865) and a comparison of specimens from different localities show that this “species” in fact comprises four distinct species.Paracanthonchus caecusMicoletzky, 1924 necP. caecus(Bastian, 1865) is designated as the valid type species of the genusParacanthonchus. P. heterodontus(Schulz, 1932) andP. thaumasius(Schulz, 1932) are re‐established.P. caecmsensu Gerlach 1965 is considered as a distinct species:P. gerlachisp.n.P. canadensissp.n. is described and is very close toP. caecusMicoletzky, 1924. The subspeciesP. caecus opthalmophorus(Steiner, 1921), different from the typicalcaecusby the presence of ocelli, is considered as a different species; we therefore proposeP.ophthalmophorus(Steiner, 1921) stat.n. The genusParacanthonchusis rede

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00537.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Psammodrilus aedificatorsp.n. is described from an arctic subtidal sandy habitat at 2–3 m depth. The new species represents a link between the two generaPsammodrilusandPsammodriloides, but it has a distinct warty collar shared only withPsammodrilus balanoglossoides. This unique structure was investigated by transmission electron microscopy. Each wart consists of one large cell with microvilli arranged in a hexagonal pattern. The collar epidermis is devoid of cilia. The head consists of prostomium and peristomium, the thorax consists of 7(8) segments, both tagmata totally ciliated. Each of the six pairs of cirri have an aciculum. The abdomen consists of 20 segments and is ciliated except for the dorsal sulcus.Psammodrilus aedifcatorsp.n. is sessile and forms a “house” of agglutinated sand grains. Only females (8 mm) and a few juveniles (4 mm) were found in July‐August. Mature eggs are extremely large (310 μm), evidently an adaptation to arctic conditions. Throughout the year the interstitial fauna at the type locality was rich, both in species and individuals. Some of the associated fauna included coelenterates, many turbellarians, nemerteans, chaetonotid gastrotrichs, archiannelids and polychaetes and, less abundantly, a few gnathostomulids, macrodasyid gastrotrichs, nematodes, eutardigrades, halacarids, harpacticoid copepods and o

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00538.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Microcerberus tabaisp.n. from the Gulf of Elat is described in detail. The relationship of the Microcerberida to the Anthuridea is discussed: the Microcerberidea have none of the synapomorphies of the Anthuridea.

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00539.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Morphological and ethological criteria were used in studying the taxonomic relations between different forms within the genusAraniella. Criteria for a diagnosis of all species and subspecies of the genus are given.A. opisthographa(Kulczyǹski, 1905),A. cucurbitina(Clerck, 1757),A. proxima(Kulczyǹski, 1885) andA. maderiana(Kulczyǹski, 1905) form one group of sibling species in the narrowest sense,A. alpica(L. Koch, 1869) andA. inconspicua(Simon, 1874) a second distinct one.A. displicata(Hentz, 1847) seems to occupy a relatively isolated position.A. cossoni(Simon, 1885) is regarded as a synonym forA. cucurbitina. It is impossible to make a statement about the status ofA. silesiaca(Fickert, 1876) andA. croatica(Kulczyǹski, 1905) because of the lack of sufficient material.A. silesiacais not a synonym forAraneus crispulusTullgren, 1952, a species which does not belong to the genusAranie

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00540.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Apistogramma inconspicuasp.n. is described from the Rio Candclaria in the Rio Guaporé drainage in Bolivia, and recorded also from Cáceres on the Rio Paraguay in Brazil. The new species is closely related to the Paraguayan speciesA. commbrae(Regan) and an undescribed species in the Guaporé drainage system. These species share a specialized feature in the colour pattern, viz. an expanded vertical bar on the caudal peduncle which it confluent with the caudal spot. The now presumably complete record of ParaguayanApistogrammaspecies allows an analytical key to be given. Of the additional species,A. borellii(Regan) andA. trifasciata(Eigenmann&Kennedy) represent two distinct lineages.Apistogramma pleurotaenia(Regan) is probably a La Plata basin species, although no localities are known, and its relationship remain obscure. The assemblage of ParaguayanApistogrammaspecies reflects the heterogeneity of the Paraguayan cichlid fauna as a who

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00541.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Sexual dimorphism in the skull of the feral American mink is discussed, based on 15 measurements of 53 adults from southern Norway. The differences in means are highly significant. Variation is found to be greatest in males. Sexual dimorphism is thought to be an adaptation for different reproductive roles of the sexes in a polygynous mating system with lack of male parental care.

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1982.tb00542.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY