Some ascaridoid nematodes of fishes: Paranisakis and Mawsonascaris n. g.

As a result of examination of type-material and other specimens representing species previously assigned to Paranisakis Baylis, 1923, it is proposed that this genus be reduced to one species, namely P. squatinae Baylis, 1923. The other species are distributed as follows: pastinacae Rudolphi, 1819, australis Johnston & Mawson, 1943 and laymani Mozgovoy, 1950 are assigned to a new genus Mawsonascaris. The main features differentiating Mawsonascaris from Paranisakis are: dentigerous ridges on the lips (absent in Paranisakis), digitiform extensions of the labial pulp (absent in Paranisakis), excretory pore posterior to the nerve-ring (anterior to the nerve-ring in Paranisakis) and long filiform spicules (short and stout in Paranisakis). The following new host records are reported: Rhinobatos cemiculus for P. squatinae; and Aptychotrema banksii, Rhinobatos batillum, Rhynchobatus dijddensis and Taeniura lymma for M. australis. Specimens were not available from teleosts. It is considered that the proposal of Yamaguti (1961) to raise the subgenus Ortoanisakis Mozgovoy, 1951 to full generic status be upheld provisionally, Ortoanisakis containing species from teleosts, formerly in Paranisakis, but described as having no dentigerous ridges and no gubernaculum. These include O. lophii (Yamaguti, 1935), O. halieutaeae (Yamaguti 1941), O. muraenesocis (Yamaguti, 1935), O. lophii hoplobrotulae (Yamaguti, 1941) and O. sciaenae Khan & Begum, 1971. The remaining species formerly in Paranisakis are relegated to the status of species inquirendae.     

Gongylonema aegypti n. sp. (Nematoda: Thelaziidae) from Egyptian rodents

Summary A new species of spiruroid nematode,Gongylonema aegypti, is described from two rodents,Mus musculus andGerbillus gerbillus, from Egypt.G. aegypti is distinguished from closely related species by the size of the spicules and gubernaculum, the absence of cuticular bosses in males, and the size of the egg. SEM studies suggest that the generic diagnosis ofGongylonema should be amended to include the presence of a dorsal pore on the cephalic plate and the presence around the buccal cavity of three triangular teeth (not lips) and two sclerotized plates or interlabia. ac]19850414     

Dujardinascaris spp. (Nematoda: Ascaridoidea) in Old World crocodilians

Five new species of the genus Dujardinascaris Baylis, 1947 are described from Old World crocodilians: D. petterae n. sp. in Osteolaemus tetraspis from the Congo, Central Africa; D. blairi n. sp in Crocodylus johnstoni from Northern Australia; D. harrisae n. sp., D. angusae n. sp., and D. westonae n. sp. in C. porosus from Papua New Guinea. The species are differentiated by the relative length of the spicules, the shape of the gubernaculum and the form of the male tail. Females of the species cannot be readily distinguished morphologically.     

Dujardinascaris mormyropsis n. sp. (Nematoda: Anisakidae) from the osteoglossiform fish Mormyrops anguilloides (Linnaeus) (Mormyridae) in Central Africa

A new nematode species, Dujardinascaris mormyropsis n. sp. (Anisakidae), is described from specimens found in the stomach and intestine of the cornish jack Mormyrops anguilloides (Linnaeus) (Osteoglossiformes; Mormyridae) in the Sangha River (Congo River basin) in Dzanga-Sangha Protected Areas, Central African Republic. Based on light and scanning electron microscopical examination, the new species differs from the only other congeneric species parasitising fishes in Africa, D. malapteruri (Baylis, 1923), mainly in the presence of dentigerous ridges on lips, absence of lateral caudal alae in the cloacal region, in the anteriorly curved, non-bifid distal tip of the gubernaculum and larger eggs (60–90 × 52–78 vs 45 × 30 μm); males of D. mormyropsis are characterised by the presence of a ventral precloacal cuticular ornamentation not observed in other Dujardinascaris spp. Dujardinascaris mormyropsis and D. malapteruri also differ in the order of their fish hosts (Osteoglossiformes vs Siluriformes). Specimens previously reported as Dujardinascaris graberi Troncy, 1969, a junior synonym of D. malapteruri, from Mormyrops engystoma Boulenger in Chad belong to the new species D. mormyropsis.     

The morphology and genetic characterization of Iheringascaris goai n. sp. (Nematoda: Raphidascarididae) from the intestine of the silver whiting and spotted catfish off the central west coast of India

In this study a new species of nematode, Iheringascaris goai n. sp., is reported from two fish hosts, including silver whiting, Sillago sihama, and spotted catfish, Arius maculatus, caught off the Central West Coast of India at Goa. The new species can be differentiated morphologically from I. inquies, the most closely related species collected from cohabiting marine fish. The distinguishing characteristics are distinct cuticular striations, a unilateral excretory system, the presence of dentigerous ridges on the inner margin of the lips and the ratio of oesophagus to body length. In males, the ratio of spicules to body length is higher and the number of pre-anal papillae is less in comparison to those in I. inquies. In addition, the tail curves ventrad in males, while in females, the vulva is post-equatorial. The sequence alignment of 18S rDNA and cytochrome c oxidase subunit I with sequences of known species selected from the same superfamily shows a significant difference. The morphological and molecular differences reported here can, therefore, be used to assign the specimen to a new species.     

An SEM study of Phocascaris cystophorae Berland, 1964 (Nematoda: Anisakidae), a parasite of the hooded seal Cystophora cristata

Scanning electron microscopy was used to study the surface morphological characteristics (excretory pore, interlabia knobs, lips and adjacent structures, caudal papillae and papilla-like structures) of the nematode Phocascaris cystophorae, a parasite from the stomach of the hooded seal Cystophora cristata. A comparative morphological analysis was made between species of Phocascaris and Contracaecum osculatum (sensu lato), which are all parasitic in phocid seals.     

Crocodilian phylogeny inferred from twelve mitochondrial protein-coding genes, with new complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae

We report complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae, whose gene orders match those of other crocodilians. Phylogenetic analyses based on the sequences of 12 mitochondrial protein-coding genes support monophyly of two crocodilian taxonomic families, Alligatoridae (genera Alligator, Caiman, and Paleosuchus) and Crocodylidae (genera Crocodylus, Gavialis, Mecistops, Osteolaemus, and Tomistoma). Our results are consistent with monophyly of all crocodilian genera. Within Alligatoridae, genus Alligator is the sister taxon of a clade comprising Caiman and Paleosuchus. Within Crocodylidae, the basal phylogenetic split separates a clade comprising Gavialis and Tomistoma from a clade comprising Crocodylus, Mecistops, and Osteolaemus. Mecistops and Osteolaemus form the sister taxon to Crocodylus. Within Crocodylus, we sampled five Indopacific species, whose phylogenetic ordering is ((C. mindorensis, C. novaeguineae), (C. porosus, (C. siamensis, C. palustris))). The African species C. niloticus and New World species C. acutus form the sister taxon to the Indopacific species, although our sampling lacks three other New World species and an Australian species of Crocodylus.     

Bidirectional closure of the rostral neuropore in the human embryo

The length of each neuropore was measured in 23 human embryos of stages 10-12 (about 22-26 days), and the closure of the lips of the rostral neuropore was studied in 24 embryos of stage 11 (about 24 days), with particular reference to the terminal lip. Graphic reconstructions were prepared from two particularly suitable examples, and mitotic figures were plotted for one of these. The lengths of the rostral and caudal neuropores are basically similar, but the rostral opening closes 1 day earlier and more abruptly (within a few hours) than the caudal (which takes a day). Closure of the rostral neuropore in the human embryo is bidirectional, proceeding simultaneously from 1) midbrain and diencephalon 2 and 2) the telencephalic region adjacent to the chiasmatic plate. Species differences are emphasized. Closure at the terminal lip of the neuropore is by fusion of right and left neural folds, as occurs elsewhere during primary neurulation. The rostral end of the neural plate in the median plane is, in the human embryo, at the rostral limit of the chiasmatic plate. Histological differences, however, exist between closure at the terminal lip and that at the dorsal lip: the surface epithelium plays a more significant role at the terminal lip, and the seam is more visible and presumably stronger. In future anencephaly it has been found that fusion at the terminal lip may occur, although that at the dorsal lip is deficient.     

Spalacina yanchevi n. g., n. sp. (Nematoda: Heligmonellidae) from the lesser mole rat Spalax leucodon (Rodentia: Spalacidae)

Spalacina n. g. (Heligmonellidae, Nippostrongylinae) is erected for S. yanchevi n. sp. (type-species) [syns Heligmonina nevoi of Genov & Janchev (1982) and Genov (1984)] from Spalax leucodon (Spalacidae) and two other species from spalacid rodents previously considered as members of Heligmonina Baylis, 1928: S. spalacis (Sharpilo, 1973) n. comb. and S. nevoi (Wertheim & Durette-Desset, 1975) n. comb. The new genus belongs to the subfamily Nippostrongylinae and is closely related to the genus Heligmonina from which it can be distinguished by a greater angle of rotation of the synlophe, the absence of a gradient on the ventral ridges and a weakly developed right dorsal ridge. The zoogeographical distribution of Spalacina spp. is associated with that of Palaearctic spalacids. S. yanchevi differs from S. spalacis and S. nevoi in the number and size of the ridges, the distance between the extremities of the rays 6 and 8, the degree of reduction of the dorsal ray and the length of the spicules.     

Molecular identification of crocodile species using novel primers for forensic analysis

All crocodilians are under varying degrees of threat due to over exploitation and these species have been listed in Appendix I or II of CITES. The lack of molecular techniques for the identification of confiscated samples makes it difficult to enforce the law. Conclusive forensic identification of species requires a complete gene sequence which is difficult in case of degraded samples. We have developed two novel sets of primers to amplify two partial cytochrome b gene sequences of six crocodile species i.e. Crocodylus palustris, Crocodylus porosus, Crocodylus siamensis, Crocodylus niloticus, Gavialis gangeticus and Caiman crocodilus. These partial sequences were edited to give a complete cyt b gene sequence, which can be used as an effective tool for forensic authentication of crocodile species. A phylogeny of crocodile species was reconstructed using these sequences. The described primers hold great promise in forensic identification of crocodile species, which can aid in the effective enforcement of law and conservation of these ancient species.     

Ascaridia sprenti, a new species of nematode in Australian parrots

A new species of Ascaridia from Australian parrots is described. The type host is Psephotus haematogaster. The special features of the new species differentiating it from other species reported from parrots are lips with single cutting ridge without cup-like structures, small interlabia present, non-alate spicules and caudal papillae arranged in two distinct rows on each side, anterior row of four, posterior row of five or six.     

Cross-species amplification of microsatellites in crocodilians: assessment and applications for the future

Microsatellite DNA loci have emerged as the dominant genetic tool for addressing questions associated with genetic diversity in many wildlife species, including crocodilians. Despite their usefulness, their isolation and development can be costly, as well as labour intensive, limiting their wider use in many crocodilian species. In this study, we investigate the cross-species amplification success of 82 existing microsatellites previously isolated for the saltwater crocodile (Crocodylus porosus) in 18 non-target crocodilian species; Alligator sinensis, Caiman crocodylus, Caiman latirostris, Caiman yacare, Melanosuchus niger, Paleosuchus palpebrosus, Crocodylus acutus, Mecistops cataphractus, Crocodylus intermedius, Crocodylus johnstoni, Crocodylus mindorensis, Crocodylus moreletii, Crocodylus niloticus, Crocodylus novaeguineae, Crocodylus palustis, Crocodylus rhombifer, Crocodylus siamensis, and Osteolaemus tetraspis. Our results show a high level of microsatellites cross-amplification making available polymorphic markers for a range of crocodilian species previously lacking informative genetic markers.     

湾鳄(Crocodylus porosus)线粒体基因组全序列结构分析与鳄类系统发生

该文测序了湾鳄的线粒体基因组全序列,全长为16,917bp。湾鳄mtDNA结构与其他脊椎动物相似,由22个tRNA,2个rRNA和13个蛋白质编码基因及1个非编码的控制区(D-loop)所组成。除NADH6和tRNAGln、tRNAAla、tRNAAsn、tRNACys、tRNATyr、tRNASer(UCN)、tRNAGlu、tRNAPro在L-链上编码之外,其余基因均在H-链编码。基因排列顺序与已测序的鳄类一致,这显示了鳄类线粒体基因排列顺序上的保守性。但鳄类线粒体基因排列顺序与脊椎动物的典型排列方式相比,有较大的差异,尤其是tRNAPhe基因的重排、tRNASer-tRNAHis-tRNALeu基因族的排列方式等。湾鳄mtDNA和已测序的鳄类一样,缺失轻链复制起始点(OLR)。基于17种鳄mtDNA控制区保守区,采用PAUP4.0最大简约法(Maximumparsimony,MP)构建MP树,邻接法(Neighbor-joiningmethod,NJ)构建NJ树,结果显示:食鱼鳄(Gavialisgangeticus)和假食鱼鳄(Tomistomaschlegelii)聚为一支后再与鳄科(Crocodylidae)的其他物种形成姐妹群,这与基于食鱼鳄和假食鱼鳄的线粒体全序列的分析结果一致,支持将食鱼鳄并入鳄科的观点。结果还支持非洲窄吻鳄(Crocodyluscataphractus)与鳄属(Crocodylus)构成姐妹群,可以单独划分为属的观点。     

Ticks from a Morelet's crocodile in Belize.

Parasitism of crocodilians by ticks has rarely been reported, and to our knowledge only seven published accounts exist. On 3 July 1999, we collected four ticks from a subadult Morelet's crocodile (Crocodylus moreletii) captured in northern Belize. These were identified as Amblyomma dissimile (one female), and Amblyomma sp. (two nymphs, one larva). The crocodile was captured on land approximately 100 m from water, and all four ticks were attached to loose skin on the lateral surface of the tail. Crocodilians are most susceptible to terrestrial ectoparasites, including ticks, during overland movements. However, most such movements occur in response to drought, when tick questing activity is suppressed, which likely accounts for the small numbers of tick specimens recorded from crocodilians and the absence of any noticeable impact of parasitism on host fitness.     

Some studies on Tylenchorhynchinae: proposal ofDivittus n.g. (Nematoda: Tylenchida)

Summary A new genusDivittus is proposed in the subfamily Tylenchorhynchinae Eliava, 1964 with only three incisures in the non-areolated lateral fields and the body cuticle without longitudinal ridges or lamellae. It is also proposed to restrictTrilineellus Lewis & Golden, 1981 to its type species only, i.e.,T. clathrocutis which has three incisures in the lateral fields and longitudinal ridges or lamellae on the body, andTylenchorhynchus to species which have four incisures in the lateral fields but no ridges or lammellae.T. divittatus Siddiqi, 1961,T. triglyphus Seinhorst, 1963 andT. sculptus Seinhorst, 1963 which were transferred toTrilineellus by Lewis & Golden (1981) are now included inDivittus with the following species ofTylenchorhynchus which have three incisures in the lateral fields:T. obscurisulcatus Andrássy, 1959,T. chonai Sethi & Swarup, 1968,T. madrasensis Gupta & Uma, 1981 andT. pruni Gupta & Uma, 1981. The synonymy ofT. chonai withT. triglyphus proposed by Tarjan (1973) is not accepted.Divittus labiatus n.sp. from soil around roots of sugarcane from north-eastern Nigeria is described. It is characterized by having the lip region continuous with the body, the spear 14–16 m long, the basal oesophageal bulb with a small overlap over the intestine and the tail with a large post-anal intestinal sac and 20 to 30 annules. A key to species ofDivittus is provided. ac]19830105     

Evolutionary history of Cuban crocodiles Crocodylus rhombifer and Crocodylus acutus inferred from multilocus markers

Among crocodilians, Crocodylus rhombifer is one of the world's most endangered species with the smallest natural distribution. In Cuba, this endemic species coexists with the American crocodile (Crocodylus acutus). Hybridization between these two species is well known in captivity and might occur in the wild, but has never been demonstrated genetically. Here, we combined molecular data with environmental, geographic, and fossil data to infer the evolutionary history of Crocodylus in the Cuban Archipelago, and to evaluate genealogical support for species boundaries. We analyzed seven microsatellite loci plus DNA sequence data from nuclear (RAG-1) and mitochondrial (cytochrome b and cytochrome oxidase I) genes from 89 wild-caught individuals in Cuba, Grand Cayman Island, Jamaica, and Central America, and two samples from zoo collections. Microsatellites showed evidence of introgression, suggesting potential hybridization among Cuban groups. In Cuba, C. acutus contained one mitochondrial DNA (mtDNA) haplotype, whereas C. rhombifer contained two haplotypes. MtDNA data showed that C. acutus is paraphyletic with respect to C. rhombifer, revealing 1% sequence divergence between species within Cuba vs. 8% divergence between Cuban forms and mainland C. acutus. We suggest that hybridization has been a historical as well as a current phenomenon between C. acutus and C. rhombifer. These findings suggest that long-term conservation of crocodiles in Cuba will require identification of genetically pure and hybrid individuals, and a decrease in anthropogenic activities. We also recommend more extensive morphological and genetic analyses of Cuban population to establish clear boundaries of the hybrid zone between C. acutus and C. rhombifer.     

Hirschmanniella pomponiensis n. sp. (Nemata: Pratylenchidae), Parasitic on Bulrush,Scirpus robustus Pursh

A new species of Hirschmanniella was found in bulrush roots; LM and SEM morphological studies revealed that it is distinct from other species in the genus. Therefore, it is designated Hirschmanniella pomponiensis n. sp. Six lips are fused to form a hexagonal labial plate, six inner sensilla encircle the stoma opening, and four cephalic sensilla open in the corners of subdorsal and subventral lips. Cephalic lip region consists of six or seven annuli. The female has incomplete areolation in the lateral field, the intestine overlaps the rectum, the tail tip is pointed and without annulation.     

Deurithitrema gingae n.g., n.sp. (Digenea: Plagiorchioidea) from the kidneys of a salt-water crocodile (Crocodylus porosus Schneider) from Australia

Summary The name Deurithitrema gingae n. g., n. sp. is proposed for worms from the kidneys of one Crocodylus porosus from Darwin, Northern Territory, Australia. The following combination of characters distinguishes the new genus from all others: prepharynx very short; oesophagus absent; caeca reaching to posterior end of body; testes tandem in middle third of body, contiguous or amost so; cirrus-sac large, over-reaches ventral sucker, contains bipartite seminal vesicle, prostatic regions and ejaculatory duct with spines around its opening into genital atrium; genital pore immediately in front of ventral sucker; uterus coiled to posterior end of body; vitellaria lateral from ventral sucker to slightly behind testes; excretory vesicle small, receiving a single ventro-lateral duct from each side behind end of uterine loops. Deurithitrema belongs to the superfamily Plagiorchioidea Dollfus, 1930. It superficially resembles a number of genera, but its relationships within the superfamily are obscure.