Some observations on the taxonomy and systematics of the pentastomid genus Armillifer (Sambon, 1922) in south east Asian and Australian snakes

Summary The taxonomic status of three of the previously described Armillifer spp. is unequivocal but there is some confusion regarding A. moniliformis. By using three diagnostic criteria, namely, hook dimensions, annulus number and the form of the terminal segment, we have shown that A. moniliformis australis from Australasian pythons, previously considered as a race of A. moniliformis by Heymons (1932), is, in fact, a distinct species. These criteria also distinguish another species A. arborealis sp. nov. from Australasian tree snakes. The genus Ligamifer, which embraces the single species Ligamifer mazzai, is shown to be invalid. A reinterpretation of the morphology of the terminal segment firmly places the species within the genus Armillifer. The species is renamed Armillifer mazzai to preserve the nomenclatural homogeneity of the taxon. The latter now comprises seven species. There is a distinct possibility that some of the new species could utilize man as an accidental intermediate host. ac]19800813     

A review of the taxonomy and systematics of the pentastomid genus Raillietiella Sambon, 1910 with a description of a new species

Systematic Parasitology - Four previously established Raillietiella spp. are redescribed. Two of these, R. kochi and R. shipleyi from African monitor lizards, cannot be reliably separated, R....     

A new blunt-hooked pentastomid belonging to the genus Raillietiella Sambon, 1910, from two species of agamid lizards in Namibia

The pentastomid Raillietiella namibiensis n. sp., from the lungs of the agamid lizards Agama aculeata aculeata and A. planiceps planiceps taken at Windhoek, Namibia, is described. The type-series comprised 14 mature female and 9 mature males specimens, all with bluntly-rounded tips to the posterior hooks. The flared, rounded base of the male copulatory spicule was furnished with a knobbly extension projecting towards the mid-ventral line, a feature known only in two other species: Raillietiella mabuiae from Mabuya sulcata in Namibia and an as yet unnamed raillietiellid from M. homalocephala from Kenya. Significant differences in annulus number, and in the dimensions of the hooks and copulatory spicules, separate the latter species from R. namibiensis. However, the holotype female of R. mabuiae was immature and therefore of little diagnostic value, whereas the single paratype male possesses an identical spicule to R. namibiensis n. sp., but a larger hook with a much longer barb. The latter difference was sufficiently great (148 vs 108 m, range 95–115, in R. namibiensis) to justify the recognition of a new species.     

The phylogeny of squamate reptiles (lizards, snakes, and amphisbaenians) inferred from nine nuclear protein-coding genes

Squamate reptiles number approximately 8000 living species and are a major component of the world's terrestrial vertebrate diversity. However, the established relationships of the higher-level groups have been questioned in recent molecular analyses. Here we expand the molecular data to include DNA sequences, totaling 6192 base pairs (bp), from nine nuclear protein-coding genes (C-mos, RAG1, RAG2, R35, HOXA13, JUN, alpha-enolase, amelogenin and MAFB) for 19 taxa representing all major lineages. Our phylogenetic analyses yield a largely resolved phylogeny that challenges previous morphological analyses and requires a new classification. The limbless dibamids are the most basal squamates. Of the remaining taxa (Bifurcata), the gekkonids form a basal lineage. The Unidentata, squamates that are neither dibamids nor gekkonids, are divided into the Scinciformata (scincids, xantusiids, and cordylids) and the Episquamata (remaining taxa). Episquamata includes Laterata (Teiformata, Lacertiformata, and Amphisbaenia, with the latter two joined in Lacertibaenia) and Toxicofera (iguanians, anguimorphs and snakes). Our results reject several previous hypotheses that identified either the varanids, or a burrowing lineage such as amphisbaenians or dibamids, as the closest relative of snakes. Our study also rejects the monophyly of both Scleroglossa and Autarchoglossa, because Iguania, a species-rich lineage (ca. 1440 sp.), is in a highly nested position rather than being basal among Squamata. Thus iguanians should not be viewed as representing a primitive state of squamate evolution but rather a specialized and successful clade combining lingual prehension, dependence on visual cues, and ambush foraging mode, and which feeds mainly on prey avoided by other squamates. Molecular time estimates show that the Triassic and Jurassic (from 250 to 150 Myr) were important times for squamate evolution and diversification.     

The molecular evolutionary tree of lizards,snakes, and amphisbaenians

Squamate reptiles (lizards, snakes, amphisbaenians) number approximately 8200 living species and are a major component of the world's terrestrial vertebrate diversity. Recent molecular phylogenies based on protein-coding nuclear genes have challenged the classical, morphology-based concept of squamate relationships, requiring new classifications, and drawing new evolutionary and biogeographic hypotheses. Even the key and long-held concept of a dichotomy between iguanians (～1470 sp.) and scleroglossans (all other squamates) has been refuted because molecular trees place iguanians in a highly nested position. Together with snakes and anguimorphs, iguanians form a clade – Toxicofera – characterized by the presence of toxin secreting oral glands and demonstrating a single early origin of venom in squamates. Consequently, neither the varanid lizards nor burrowing lineages such as amphisbaenians or dibamid lizards are the closest relative of snakes. The squamate timetree shows that most major groups diversified in the Jurassic and Cretaceous, 200–66 million years (Myr) ago. In contrast, five of the six families of amphisbaenians arose during the early Cenozoic, ～60–40 Myr ago, and oceanic dispersal on floating islands apparently played a significant role in their distribution on both sides of the Atlantic Ocean. Among snakes, molecular data support the basic division between the small fossorial scolecophidians (～370 sp.) and the alethinophidians (all other snakes, ～2700 sp.). They show that the alethinophidians were primitively macrostomatan and that this condition was secondarily lost by burrowing lineages. The diversification of alethinophidians resulted from a mid-Cretaceous vicariant event, the separation of South America from Africa, giving rise to Amerophidia (aniliids and tropidophiids) and Afrophidia (all other alethinophidians). Finally, molecular phylogenies have made it possible to draw a detailed evolutionary history of venom among advanced snakes (Caenophidia), a key functional innovation underlying their radiation (～2500 sp.). To cite this article: N. Vidal, S.B. Hedges, C. R. Biologies 332 (2009).     

Prevalence and intensity of pentastomid infection in two species of snakes from northeastern Brazil.

This study aimed to evaluate the infection rates of snakes by pentastomids in the semi-arid region of Brazil. Fifteen snakes (four Micrurus ibiboboca (Merrem, 1820) and eleven Philodryas nattereri Steindachner, 1870) were collected between January and April of 2005, in the municipality of Crato (07 degrees 14' S and 39 degrees 24' W), State of Ceará, Brazil. Laboratorial analysis of the respiratory tracts of the sampled snakes indicated differences in host infection rates: four individuals of P. nattereri (36.4%) were infected by Cephalobaena tetrapoda Heymons, 1922 (mean infection intensity 1.5 +/- 0.28, 1-2) and three specimens (27.3%) by Raillietiella furcocerca (Diesing, 1863) (2.3 +/- 1.32, 1-5). Only one individual of M. ibiboboca (25%) was infected by a non-identified species of Raillietiella sp. These are the first data on pentastomid infection in snakes in Northeastern Brazil and both snake species comprise new host records for the pentastomids. The results also indicate that the generalist parasites C. tetrapoda and R. furcocerca share their definitive hosts.     

A molecular revision of the taxonomic status of mermithid parasites of black flies from Quebec (Canada)

The four currently recognized mermithid (Nematoda) species parasitizing black flies (Diptera: Simuliidae) from Northeast America were distinguished using discriminatory PCR primers aimed at COI and 18S rDNA. Isomermis wisconsinensis, Gastromermis viridis and Mesomermis camdenensis were easily differentiated using either genomic target, even for juvenile mermithids damaged beyond morphological recognition. However, specimens from Mesomermis flumenalis being identical in external morphology and producing a unique-sized PCR product were classified by sequence data into four clearly distinguished molecular variants. This quartet was made of two winter and two summer ‘physiological variants’, including one which also belonged to, but diverged early from the rest of the Mesomermis genus. Combining the multiplex PCR and sequencing approaches allowed for the characterization of a multiple parasitism which simultaneously implicated I. wisconsinensis and two M. flumenalis variants. With another instance where parasites were identified by morphology only, this is the first report of black fly parasitism by multiple mermithid species. A phylogenetic tree built by combining our sequences to previous GenBank entries likely indicates a monophyletic origin for the mermithid family, but also suggests that differentiation between parasite genera sometimes occurred before the evolutionary emergence of the actual host group.     

Molecular phylogenetics of squamata: the position of snakes, amphisbaenians, and dibamids, and the root of the squamate tree

Squamate reptiles (snakes, lizards, and amphisbaenians) serve as model systems for evolutionary studies of a variety of morphological and behavioral traits, and phylogeny is crucial to many generalizations derived from such studies. Specifically, the traditional dichotomy between Iguania (anoles, iguanas, chameleons, etc.) and Scleroglossa (skinks, geckos, snakes, etc.) has been correlated with major evolutionary shifts within Squamata. We present a molecular phylogenetic study of 69 squamate species using approximately 4600 (2876 parsimony-informative) base pairs (bp) of DNA sequence data from the nuclear genes RAG-1(approximately 2750 bp) and c-mos(approximately 360 bp) and the mitochondrial ND2 region (approximately 1500 bp), sampling all major clades and most major subclades. Under our hypothesis, species previously placed in Iguania, Anguimorpha, and almost all recognized squamate families form strongly supported monophyletic groups. However, species previously placed in Scleroglossa, Varanoidea, and several other higher taxa do not form monophyletic groups. Iguania, the traditional sister group of Scleroglossa, is actually highly nested within Scleroglossa. This unconventional rooting does not seem to be due to long-branch attraction, base composition biases among taxa, or convergence caused by similar selective forces acting on nonsister taxa. Studies of functional tongue morphology and feeding mode have contrasted the similar states found in Sphenodon(the nearest outgroup to squamates) and Iguania with those of Scleroglossa, but our findings suggest that similar states in Sphenodonand Iguania result from homoplasy. Snakes, amphisbaenians, and dibamid lizards, limbless forms whose phylogenetic positions historically have been impossible to place with confidence, are not grouped together and appear to have evolved this condition independently. Amphisbaenians are the sister group of lacertids, and dibamid lizards diverged early in squamate evolutionary history. Snakes are grouped with iguanians, lacertiforms, and anguimorphs, but are not nested within anguimorphs.     

Some North American parasites ofAclerda (Hymenoptera,Encyrtidae)

Résumé L'auteur décrit, dans cette note, deux espèces nord-américaines d'Encyrtides, parasites de cochenilles du genreAclerda: Mayridia ferrierei, obtenue deAclerda xalapenseae Mcconnell, etAenasioidea ferrierei, obtenue deA. andropogonis Mcconnell. Chez les deux espèces d'Encyrtides, les males sont ailés, tandis que les femelles possèdent des ailes plus ou moins réduites.      

A reassessment of the pentastomid genusLeiperia Sambon, 1922, with a description of a new species from both the Indopacific crocodileCrocodylus porosus and Johnston's crocodileC. johnsoni in Australia

The two pentastomid species currently included in the genusLeiperia Sambon, 1922 (family Sebekidae Fain, 1961) are re-assessed. Measurements of chitinous structures, notably the hooks, fulcra and oral cadre of three adult females of the otherwise well-characterised speciesL. cincinnalis Sambon, 1922, from the bronchi of the Nile crocodileCrocodylus niloticus, exhibit a degree of variation that is usual in pentastomid morphometrics. Similar measurements of six nymphs from the aorta and heart of two other crocodiles, although equally variable, do not differentiate these from infective nymphs removed from cysts within the body cavity of a South African fish (Pelamatachromis robustus) intermediate host. Adult females of another species,L. australiensis n. sp., from the bronchi of the Indopacific crocodileCrocodylus porosus from Northern Australia are described. Females (N=3) are smaller and more slender than their African counterparts, and their chitinous structures, although equally variable, are correspondingly smaller. A mature male, from the lung of Johnston's crocodileC. johnsoni, is also allocated to this species because the ranges and diet of the two crocodilian hosts overlap. Also, this zone of syntopy is sufficient to maintain populations of two other species belonging to the family Sebekidae (Sebekia spp.) in both hosts. This male is the first of the genusLeiperia to be fully described, and its copulatory spicules are quite distinctive. Three other immature specimens ofL. australiensis from the lung, or near to the lung, of the definitive host are also described. In the light of these findings the literature is re-appraised, and it is evident that at least two moreLeiperia spp. exist in South America, and that presently these are known only as nymphs. The existing South American species,L. gracilis Heymons & Vitzthum, 1935 (=Pentastoma gracile Diesing, 1835) was established only on the basis of immature or nymphal forms, almost certainly encompassing several genera. Despite claims to the contrary in the literature, this ‘species’ should be regarded as aspecies inquirenda. Aspects of the life-cycle ofLeiperia spp., from the infective stage in fish and the subsequent instars, are also discussed.     

A revision of the taxonomy of the Redshank Tringa totanus

A quantitative study of over 1000 skins of Redshank from Iceland to India and China forms the basis of a complete revision of the taxonomy of the species throughout its present geographical range. Problems of dimorphism and hybridization are also discussed.