Historical biogeography of Hexabathynella , a cosmopolitan genus of groundwater Syncarida (Crustacea, Bathynellacea, Parabathynellidae)

Hexabathynella is the only cosmopolitan genus of the order Bathynellacea (Crustacea). The known species number 18, found in Europe (9), Africa (1), South America (2), North America (3) and Australia and New Zealand (3). Phylogenetic analysis suggests that the least derived species are those from South America and the most derived those from the Iberian Peninsula, North America and Australia. The five species with the most plesiomorphic characters occur in salt or brackish water, which supports a marine origin for the genus. Phylogenetic and biogeographical analyses suggest that the distribution of the genus can be explained by dispersion and a double vicariant biogeographical model based on plate tectonics and the evolution of the Tethys during the Mesozoic and Cenozoic.  © 2003 The Linnean Society of London . Biological Journal of the Linnean Society , 2003, 78 , 457–466.     

A statistical approach to the evaluation of characters to estimate evolutionary relationships among the species of the aquatic subterranean genus, Iberobathynella (Crustacea, Syncarida)

The 13 known species of the genus Iberobathynella were studied. Twenty-six characters with usually two or three states were revealed to have low within-species variability but show clear differences among some species. These characters were hypothesized to have states convex on the branching pattern of the phylogenetic lines that gave rise to these 13 species (i.e. be uniquely derived). Each pair of these hypotheses was tested for logical compatibility; then, for each character, a new character was created by choosing equiprobably one of the possible permutations of the 13 species to rename the species in each state. Characters created in this random way would have convex states only by chance, not by evolution. This random character was tested with each of the remaining 25 for logical compatibility as hypotheses of convexity. For each character, one thousand such random characters were created and tested. Sixteen observed characters were compatible with more other observed characters than 90% of their randomly generated counterparts, and so were considered plausibly non-random. They were used to speculate on branching patterns of the phylogenetic lines among the 13 species.     

Psammaspides williamsi gen.n., sp.n., ein Vertreter einer neuen Familie mesopsammaler Anaspidacea (Crustacea, Syncarida)

A new species of the order Anaspidacea, Psammaspides williamsi gen.n., sp.n., is described from Australia. It belongs to a family of its own, Psammaspididae fam.n. This family seems to bridge the gap between the Stygocarididae and the Anaspidacea. The new species was found in gravel along a stream in northern New South Wales extending the range of distribution of the Anaspidacea far beyond its known limits to the north. It is the first fully interstitial species within the Anaspidacea.

Zusammenfassung

Eine neue Art der Ordnung Anaspidacea, Psammaspides williamsi gen.n., sp.n. wird aus Australien beschrieben. Sie gehört zu einer neuen Familie, den Psammaspididae. Diese Familie scheint zwischen den Stygocarididae und den Anaspidacea zu vermitteln. Die neue Art wurde im Schotter eines Baches im nördlichen New South Wales entdeckt und dehnt das Verbreitungsareal der Anaspidacea weit über seine bisher bekannten Grenzen nach Norden aus. Es ist die erste echt mesopsammale Art innerhalb der Anaspidacea.     

Habrobathynella nagarjunai n. sp., the second representative of Bathynellacea (Crustacea, Syncarida) from groundwaters of South India

A new species of the genus Habrobathynella Schminke, 1973, i.e. H. nagarjunai n.sp., is described from the groundwater of the Nagarjuna University campus near Guntur town, South India. One of the principal criteria in the original definition of Habrobathynella is amended to accommodate the new species. H. nagarjunai n.sp. differs from its three congeners, i.e. H. milloti (Delamare & Paulian, 1954), H. jeanneli (Delamare & Paulian, 1954) from Madagascar, and H. schminkei Reddy, 2002 from India, in several essential morphological details: the sympodite of uropod bears 8–10 similar spines; the apophysis on segment 4 of the antennule is short; of the two setae on the exopodite of uropod, one is apical and the other subapical in position; the basal segment of maxilla has three unequal setae; the male thoracopod VIII is relatively elongate. H. nagarjunai n. sp. is the second representative of the groundwater (eustygobiont) Bathynellacea in South Asia. Furthermore, a key to the identification of Habrobathynella spp. is given.     

What lies beneath: molecular phylogenetics and ancestral state reconstruction of the ancient subterranean Australian Parabathynellidae (Syncarida, Crustacea)

The crustacean family Parabathynellidae is an ancient and significant faunal component of subterranean ecosystems. Molecular data were generated in order to examine phylogenetic relationships amongst Australian genera and assess the species diversity of this group within Australia. We also used the resultant phylogenetic framework, in combination with an ancestral state reconstruction (ASR) analysis, to explore the evolution of two key morphological characters (number of segments of the first and second antennae), previously used to define genera, and assess the oligomerization principle (i.e. serial appendage reduction over time), which is commonly invoked in crustacean systematics. The ASR approach also allowed an assessment of whether there has been convergent evolution of appendage numbers during the evolution of Australian parabathynellids. Sequence data from the mtDNA COI and nDNA 18S rRNA genes were obtained from 32 parabathynellid species (100% of described genera and ~25% of described species) from key groundwater regions across Australia. Phylogenetic analyses revealed that species of each known genus, defined by traditional morphological methods, were monophyletic, suggesting that the commonly used generic characters are robust for defining distinct evolutionary lineages. Additionally, ancestral state reconstruction analysis provided evidence for multiple cases of convergent evolution for the two morphological characters evaluated, suggesting that caution needs to be shown when using these characters for elucidating phylogenetic relationships, particularly when there are few morphological characters available for reconstructing relationships. The ancestral state analysis contradicted the conventional view of parabathynellid evolution, which assumes that more simplified taxa (i.e. those with fewer-segmented appendages and setae) are derived and more complex taxa are primitive.     

Historical biogeography of Iberobathynella (Crustacea, Syncarida, Bathynellacea), an aquatic subterranean genus of Parabathynellids, endemic to the Iberian Peninsula

• 1 The origin and distribution of the species of freshwater interstitial (stygobiont) syncarids of the Iberobathynella genus (Crustacea, Parabathynellidae), endemic to the Iberian Peninsula, are considered in the context of evolutionary biogeography.
• 2 We established the most likely phylogenetic relationships between the 14 known species of the Iberobathynella genus on the basis of morphological characters. We assumed a common marine ancestor and estimated the possible phylogenetic ages of the 14 inland species from the number of cladogram nodes.
• 3 The land ages at the sites where the species are found help to tell us when the landmasses emerged definitively: most species are found in areas that have undergone one or more marine transgressions/regressions since the Triassic and which could therefore have been colonized by the common ancestors.
• 4 We assessed the Boutin–Coineau two‐step model of colonization and evolution in an attempt to elucidate the evolutionary history of Iberobathynella and to offer a plausible palaeogeographical scenario. We looked for concordance between the possible chronology of Iberobathynella taxa colonization and their phylogenetic relationships, but found none of significance. Hence, we cannot reject the possibility that evolutionary clade divergence within the genus was independent of sea‐level changes in the Senonian (88.5–65 mya) and Eocene (56.5–35.4 mya) epochs. We can therefore neither confirm nor rule out a correlation.

     

A new species of blackflies--Simulium (Argentisimulium) dolini sp. n. (Diptera, Simuliidae)

Female, male and larva of the new species of black flies, Simulium (Argentisimulium) dolini sp. n. are described. By its morphology the species occupies an "intermediate position" between S. nolleri and S. palustre. In the USSR the species was found in wooded and forest-steppe zones of West Ukraine.     

Basipodella harpacticola n.gen., n. sp. (Crustacea,Copepoda)

Several stages of the copepodBasipodella harpacticola n. gen., n. sp., which lives as a parasite on harpacticoid copepods, are described on the basis of four individuals obtained from the Peruvian deep-sea. The taxonomic position of the new species is discussed.     

Branchipus cortesi n. sp.: a new anostracan from western Spain (Crustacea,Branchiopoda)

Branchipus cortesi, n. sp. (Anostraca, Branchipodidae) is characterized by the broadly enlarged distal segments of male antenna 2, and a combination of morphological features concerning thoracic limbs, abdominal segments and egg morphology. The species occurs in temporary fresh water bodies in flatlands with temperate Mediterranean climate; it is distributed in the south-western part of Spain. Our study includes a morphological analysis using optical and scanning electronic microscopes. Questions about ecology and distribution of the new species are also discussed.     

A new species of Ampelisca (Crustacea, Amphipoda) from NW Iberian Peninsula: Ampelisca troncosoi sp. nov.

A new species of Ampelisca (Crustacea, Amphipoda) is described from samples collected in shallow subtidal fine and very fine sand in the inlet of Baiona (Galicia, NW Iberian Peninsula). Ampelisca troncosoi sp. nov. is closely related to A. brachyceras and A. heterodactyla by having a rostrum between antenna 1 pair and one lateral angle at each side of the head. The new species may be distinguished by the following combination of characters: a distally rounded rostrum between the antenna 1 pair, one laterodorsal pair of corneal lenses, antenna 1 longer than antenna 2 peduncle, antenna 2 never reaching half of the body length, epimeral plates with rounded posterodistal angle, a prominent rounded urosomal carina and two rows of minute spines on the outer rami of the uropod 3.     

Lamprops donghaensis sp. n. (Crustacea,Cumacea, Lampropidae), a new species from Korean waters

A new species of Cumacea belonging to the genus Lamprops Sars was collected from the East Sea of Korea. This new species resembles Lamprops comatus Zimmer, Lamprops carinatus Hart, Lamprops flavus Harada, Lamprops pumilio Zimmer, Lamprops tomalesi Gladfelter, and Lamprops obfuscatus (Gladfelter) in lacking lateral oblique ridges on the carapace and lateral setae on the telson. The new species, however, is distinguished from its congeners by having a dorsal concave groove and a lateral rounded depressed area on pereonite 2. The new species is fully illustrated and compared with related species. A key to the world Lamprops species lacking lateral ridges on the carapace is also provided.     

Janiridae (Crustacea, Asellota) from the Southern Hemisphere: laniropsis varians sp. n. and redescriptions of five little-known species

Ianiropsis varians sp. n. is described, and it is shown that dorsal pigment patterns of this species vary widely within a single population. The janirid species Austrofilius furcatus Hodgson, 1910, A. serratus Vanhöffen, 1914, Neojaera antarctica (Pfeffer, 1887). Notasellus chilensis (Menzies, 1962), and N. sarsii Pfeffer, 1887 are redescribed. Additionally, sexual dimorphisms of maxilliped, pereopods, and pleopod 3 observed in some janirid species are discussed.     

A new species of Leucothoid Amphipod, Anamixis bananarama, sp. n., from Shallow Coral Reefs in French Polynesia (Crustacea, Amphipoda, Leucothoidae)

Both leucomorph and anamorph developmental stages of Anamixis bananaramasp. n., are illustrated and described from shallow back reef environments of Moorea, French Polynesia. Distinguished by vestigial first gnathopods that persist in post-transformational adult males, this is the second species in the genus to exhibit this unusual character. In other features such as coxae and second gnathopods Anamixis bananaramasp. n. resembles other Pacific Plate endemics of Anamixis known from the region. Specific host association is not documented but suspected to be small calcareous asconoid sponges associated with coral rubble.     

Serratotantulus chertoprudae gen. et sp. n. (Crustacea, Tantulocarida, Basipodellidae): A new tantulocaridan from the abyssal depths of the Indian Ocean

A single tantulus larva was found at the abyssal depth of the Indian Ocean attached to a harpacticoid host of the family Cletodidae. It represents a new genus and species of Tantulocarida, family Basipodellidae. Its ultrastructure was studied with SEM. This genus can be easily distinguished from the other genera of Basipodellidae by the pore pattern, bilobed oral disk with strong longitudinal ridges and the posterior projection of the cephalic shield. A morphological analysis of two related families Basipodellidae and Deothertridae shows that they represent polyphyletic taxa and need further revision.     

Amphiascus discrepans sp.n., a new benthic copepod (Crustacea) from lquique (Chile)

A new diosaccid copepod, Amphiascus discrepans sp.n., is described from the eulittoral zone of Playa Blanca, near Iquique (Chile). It differs from all presently known Amphiascus species in the characteristic structure of the female furca.     

Chirocephalus ponticus n.sp. (Crustacea: Anostraca) and its affinities to the other Turkish species of the genus

Chirocephalus ponticus n.sp. (Crustacea: Anostraca) from Turkey is described. The new species is characterized by the form of the second antenna and the frontal appendages of the male. This species seems to be related to C. turkestanicus Daday. Furthermore, analysis of limb structure reveals differences between the three Chirocephalus species previously known from Turkey: C. paphlagonicus, C. vornatscheriand C. diaphanus. New localities for these species are reported. This revised version was published online in August 2006 with corrections to the Cover Date.