60 research outputs found
Phylogenetic position of gastrostomobdellid leeches (Hirudinida, Arhynchobdellida, Erpobdelliformes) and a new family for the genus Orobdella
The leech family Gastrostomobdellidae is characterized by its possession of an agnathous and euthylaematous pharynx, a ventral gastropore and a gastroporal duct. In this study, the phylogenetic position of two gastrostomobdellid genera, Gastrostomobdella and Orobdella, was investigated using partial nucleic 18S, 28S rDNA and mitochondrial 12S rDNA
sequences. Our phylogenetic analyses showed that both Gastrostomobdella and Orobdella are nested within Erpobdelliformes, but Gastrostomobdellidae is not a monophyletic taxon. Orobdella is a sister taxon of the other Erpobdelliformes taxa. The phylogenetic position of
Gastrostomobdella within the clade of Gastrostomobdella, Erpobdellidae and Salifidae still remains uncertain. According to the reconstruction of the ancestral state of the pharynx in Erpobdelliformes, a euthylaematous pharynx is considered to be plesiomorphic in this taxon. Examination of Gastrostomobdella and Orobdella specimens indicates that the morphology of the gastroporal duct of Orobdella is quite different from that of Gastrostomobdella. A new family, Orobdellidae fam. nov., was therefore erected for the genus Orobdella. Orobdellidae is characterized by its possession of a generally tubular gastroporal duct, lying on the female orga
Taxonomic revision and re-description of Ateuchosaurus pellopleurus (Hallowell, 1861) (Reptilia, Squamata, Scincidae) with resurrection of A. okinavensis (Thompson, 1912)
The scincid lizard Ateuchosaurus pellopleurus (Hallowell, 1861) has been recognized as a single species widely distributed in the Osumi, Tokara, Amami, and Okinawa Groups of the Ryukyu Archipelago, southern Japan. However, a recent molecular phylogenetic study suggested that this skink should be divided into two species: one distributed in the Osumi to Amami Groups, and another distributed in the Okinawa Group. For A. pellopleurus, two extant syntypes collected from an island of the Amami Group were confirmed. Therefore, we identified the species in the Osumi to Amami Groups as A. pellopleurus sensu stricto by designating one of the syntypes as the lectotype for this species. For the species in the Okinawa Group, we resurrected A. okinavensis (Thompson, 1912), of which the type locality is on Okinawajima Island in the Okinawa Group. Ateuchosaurus pellopleurus and A. okinavensis can be differentiated by the following characteristics: usually separated frontonasal and frontal, 8–14 subdigital scales on the fourth toe (mode = 11), and usually two or three pairs of dorsal median scale rows with black stripes in A. pellopleurus; usually fused frontonasal and frontal, 10–16 subdigital scales on the fourth toe (mode = 13), and usually no stripe on the dorsal scales or a pair of dorsal median scale rows with black stripes in A. okinavensis
Phylogenetic Relationships of Eublepharid Geckos (Reptilia: Squamata): A Molecular Approach
Phylogenetic analyses were carried out for representatives of all eublepharid genera and afew other gekkonoid taxa using sequence data for 879 base pairs of mitochondrial 12S and 16S ribosomalRNA genes. Neighbor-joining (NJ) distance analysis of the data suggested independent great divergencesof Coleonyx and Aeluroscalabotes, and monophyly of the remainder within Eublepharidae (bootstrap proportion[BP]=76%). Of the latter, the two African genera, Hemitheconyx and Holodactylus, were almost certainlymonophyletic altogether (BP=99%), whereas their sister-group relationship with Eublepharis received a weaker,but still substantial support (BP=68%). Within Goniurosaurus kuroiwae, G. k. splendens first diverged fromthe remainder (BP=100%), followed by G. k. kuroiwae from the northern part of Okinawajima (BP=100%): G.k. kuroiwae from the southern part of Okinawajima and G. k. orientalis, differing from each other at onlyseven bases, diverged finally (BP=99%). Parsimony analysis yielded results consistent with those of NJanalysis with respect to the monophyly of the two African genera and relationships within G. kuroiwae, butretained the other relationships within Eublepharidae unresolved. Our results, while showing no seriousdiscrepancies with the relationships among eublepharid genera hypothesized from morphological data, casta serious doubt to the currently accepted population systematics within G. kuroiwae. Furthermore, results ofboth analyses suggested a closer affinity of Diplodactylinae (as represented by Rhacodactylus trachyrhynchus)with Eublepharidae, rather than with Gekkoninae. Our study lends a robust support to the Laurasian origin ofthe family Eublepharidae
Phylogenetic Relationships of the Family Agamidae (Reptilia: Iguania) Inferred from Mitochondrial DNA Sequences
Phylogenetic Relationships of the Flying Lizards, Genus Draco (Reptilia, Agamidae)
Phylogenetic relationships among 12 species of the genus Draco were inferred from 779 base pairs of mitochondrial 12S and 16S rRNA genes and allozymes for 20 presumptive loci. Results indicated the presence of at least four distinct lineages within the genus. The first lineage consists of D. volans and D. cornutus, whereas the second only of D. lineatus, which exhibits a great genetic divergence between two subspecies. The third is monotypic with D. dussumieri, the only species distributed in southern India. The fourth included all the remaining species. The third and fourth lineages are supposed to exclusively share a common ancestor. It is likely that the common ancestor of whole Draco originally diverged into three groups, the ancestors of the first, second, and third and fourth lineages, by vicariance. In the fourth lineage, D. blanfordii, D. haematopogon, D. melanopogon, D. obscurus and D. taeniopterus are likely to be exclusively close to each other. The resultant phylogenetic tree contradicts the dichotomous relationships previously hypothesized on the basis of morphological characters
Evolution of Asian and African Lygosomine Skinks of the Mabuya Group (Reptilia: Scincidae): A Molecular Perspective
Phylogenetic relationships among Asian and African lygosomine skinks of the Mabuya group were inferred from 825 base pairs of DNA sequences of mitochondrial 12S and 16S rRNA genes. Results indicated the presence of two distinct lineages within this group, of which one consisted of Lamprolepis and Lygosoma, and the other of Apterygodon, Dasia, and Asian and African Mabuya. Within the latter, African species of Mabuya first diverged from the remainder, leaving the Asian congeners together with the Apterygodon-Dasia clade. Our results, while suggesting the non-monophyly of the genus Mabuya, do not support the currently prevailing phylogeographical hypothesis which assumes the independent origins of Lamprolepis and Lygosoma from the Asian Mabuya-like stock. On the other hand, our results suggest that morphological and karyological similarities between the Apterygodon-Dasia clade and Lamprolepis are attributable to symplesiomorphy, while their ecological similarity to convergence. Morphological and karyological character states unique to Apterygodon are supposed to have evolved from those exhibited by Dasia
On a Small Collection of Lizards and Snakes from Cameroon, West Africa
A small number of lizards and snakes, obtained by the Kyoto University expeditions to the southwestern part of Cameroon, West Africa, are examined. The collection consists of three species of lizards and 10 species of snakes. External characteristics of the specimens are presented, together with results of brief ecological observations
The Amphibians and Reptiles Collected by the Hokkaido University Expedition to Nepal Himalaya
A small number of amphibians and reptiles collected by the Hokkaido University Expedition to Nepal Himalaya are examined. The collection includes seven species: Bufo melanostictus, B. himalayanus, Agama tuberculata, Calotes versicolor, Japalura tricarinata, Boiga cyanea and Trimeresurus albolabris. Of these, the record of Bufo himalayanus is the first for Kathmandu valley and that of Boiga cyanea is the second for Nepal
Geographic variation in the two smooth skinks, Scincella boettgeri and S-formosensis (Squamata : Scincidae), in the subtropical East Asian islands
Scincella boettgeri and S. formosensis are two small lygosomine skinks endemic to the southern Ryukyus and Taiwan, respectively. Taxonomic separation of these two species depends on only a few external characters that are seemingly more or less variable within each species. To investigate the geographic pattern of their morphological variations, multivariate analyses were performed for 23 meristic and 16 morphometric characters in 680 specimens of S. boettgeri from 12 islands of the Miyako and Yaeyama Groups and 193 specimens of S. formosensis from ten localities in Taiwan. The canonical discriminant analysis (CDA) for samples representing local populations using meristic data completely separated the southern Ryukyu and Taiwanese assemblages, supporting their assignments to different taxa. On the other hand, the analyses using morphometric data remained their variations partially overlapping each other. Of the samples of S. boettgeri examined, the Haterumajima sample markedly varied from the others, whereas the Kaohsiung sample was somewhat divergent among the S. formosensis samples. Neighbor-joining phenograms derived from Mahalanobis distances among the samples showed branching patterns apparently inconsistent with the topographical (for S. formosensis) or putative geohistorical relationships of their localities (for S. boettgeri). This suggests that in these species external quantitative characters often rapidly vary under the influence of localized environments rather than of the passage of time after geographical isolations
Aphaniotis nasuta (de Jong, 1930), a Junior Synonym of A. ornata (Van Lidth de Jeude, 1893) (Squamata: Agamidae)
Volume: 19Start Page: 11End Page: 1
- …