Not as clear as expected: what genetic data tell about Southern Hemisphere corellids (Ascidiacea: Phlebobranchia)

ABSTRACT

The morphology of corellids (Ascidiacea) has led to numerous misidentifications and wrong taxonomic decisions over the last century. Paradoxically, the morphology has also enabled new species to be identified and ancient entities to be re-established in the Southern Hemisphere. There are many examples of the integration of morphological and molecular data leading to the same taxonomic conclusions, and therefore we aimed to analyse DNA sequences of the gene cytochrome oxidase subunit I of currently accepted species within Corellidae occurring in the Southern Hemisphere. Haplotype networks along with phylogenetic trees and genetic distances not only corroborate the distinction between Corella eumyota and Corella antarctica, but also separate the latter into two potential groups, one located in Terre Adélie and the other in the Antarctic Peninsula (AP). Furthermore, the C. antarctica group from the AP was closely related to the allied abyssal species, Corynascidia suhmi from Terre Adélie. Although the number of new sequences is reduced, our results are congruent with a long record of suspicion on the matter and stress the need for deeper and more extensive investigation of this ascidian family.     

The larval development of the spider crab Rochinia gracilipes (Crustacea: Majoidea: Epialtidae: Pisinae) reared in the laboratory

The larval development of the spider crab Rochinia gracilipes Milne-Edwards, 1875 (Crustacea: Decapoda: Brachyura: Majoidea: Epialtidae: Pisinae) is described and illustrated from laboratory-reared larvae. Development consisted of two zoeal stages and one megalopa, following the typical pattern in Majoidea. Zoea I of R. gracilipes, R. debilis and R. carpenteri differed in lengths of the rostral spine of the carapace, in the number of setae and aesthetascs of several head appendages (exopods of antennules, endopods of maxillules, and endopods and scaphognathites of maxillae) and in the length of posterolateral processes of abdominal somites; lateral carapace spines were present only in R. carpenteri and pleopod buds only in R. debilis. Megalopae of Rochinia gracilipes and R. carpenteri differed in several notable characters: a dorsal spine and long rostrum of the carapace, as well as spines in coxa and ischium of pereiopods, appeared only in R. carpenteri, and podobranchiae of the 3rd maxilliped appeared only in R. gracilipes; they also differed in setation of abdomen and pleopods. The comparison of the available information on Pisinae larval development suggested that larval morphology would not help to accurately understand the phylogenetic relationships of this subfamily of spider crabs.     

Sperm ultrastructure in two species of Gyraulus (Gastropoda: Pulmonata: Planorbidae)

Sperm morphology offers a rich source of potentially informative characters for gastropod taxonomy and in this study it was used to provide additional information for Gyraulus (Armiger) crista (Linnaeus, 1758), whose taxonomic position within the Planorbidae Rafinesque, 1815 remains uncertain. Sperm morphology in G. (A.) crista and G. (Gyraulus) albus (Müller, 1774), the type species of the genus, was examined using light microscopy, scanning electron microscopy and transmission electron microscopy. The ultrastructure of spermatozoa in the two species was found to conform to the general pattern characteristic of the Hygrophila Férussac, 1822: the spermatozoa had an anterior head containing an acrosomal complex (apical vesicle and acrosomal pedestal) and cone-shaped nucleus, followed by a very long midpiece with glycogen spirals, and then by a glycogen piece and tail. Although the spermatozoa of the two species shared some common features (one nuclear keel and four glycogen spirals), they differed significantly in length, morphology of the annulus and structure of the spiral surface ridges. There were also some differences in the size and structure of the acrosomal pedestal and the shape of the nucleus. The spermatozoa of the two Gyraulus species are compared with those of other Hygrophila and the possible importance of sperm morphology for the taxonomic status of G. (A.) crista is discussed.     

News from a small island – first record of a freshwater shrimp (Decapoda,Atyidae, Caridina) from Peleng,Banggai Islands,Indonesia

The Indonesian island Sulawesi is well known for its fascinating fauna. Among the atyid and palaemonid freshwater shrimps described from Sulawesi are also a number of endemic species. In contrast, freshwater shrimps have never been reported from the nearby and smaller Peleng Island. Here we describe Caridina thomasi sp. nov. as a first record of an atyid freshwater shrimp from Peleng and compare it with atyids from Sulawesi and other localities. The new species is probably endemic to the island and shows some characters never described in the genus Caridina before. However, a molecular phylogeny of atyid shrimps from the Indo‐West Pacific based on mitochondrial DNA (16S) places C. thomasi within a clade of typical species of Caridina. We tentatively assign the new species to the genus Caridina and discuss the possibility of future changes in the classification of species in this genus.     

Larval development of Apiomithrax violaceus (A. Milne Edwards, 1868) (Decapoda: Brachyura: Majoidea: Pisidae) reared in laboratory conditions,and a review of larval characters of Pisidae

Apiomithrax violaceus (A. Milne Edwards, 1868 Milne Edwards A 1868 Observations sur la faune carcinologique des Iles du Cap-Vert Nouvelles Archives du Muséum d'Histoire Naturelle, 4, 49–68, pls 16–18  [Google Scholar]) is a pisid majoid crab occurring in tropical and subtropical coastal waters of the eastern and western South Atlantic. Larval development consists of two zoeal stages and a megalopa. Beginning with the first zoea, the duration of each larval stage at 24°C was 3–8 (5±1), 3–5 (4±0.5) and 9–15 (11±2) days, the megalopa and first crab instar appearing 9–11 (10±1) and 20–27 (23±2) days after hatching, respectively. Larval characters agree with those proposed for the Majoidea, in having nine or more setae on the scaphognathite in the first zoea and well-developed pleopods in the second zoea. However, larvae of A. violaceus do not fit larval pisid features. Zoeal stages differ from most other Pisidae in having lateral spines, a long rostral spine extending beyond the antenna, two spines per telson fork and a dorsolateral process on the third abdominal somite. The megalopa differs in having a spine dorsally on the carapace and on the basial segment of the second pereiopod. Two characters that are potentially unique to Apiomithrax include a zoeal antenna with an exopod that is much longer than the protopod, and a rostral spine that is longer than the dorsal spine. These characters should facilitate the identification of this taxon and could also be useful for phylogenetic studies. A review of larvae of 28 species among 14 genera indicated that there is no apparent single larval character that differentiates the Pisidae, with more limited phylogenetic analyses suggesting that this is a paraphyletic group. Apiomithrax, Eurynolambrus, Pisoides, Rochinia and Scyra have the most divergent morphological characters within the family. The analysis and inclusion of additional taxa is likely to shed more light on the sister-group relationships of the Pisidae. However, based on the extent of morphological interspecific variability of known larvae it is likely that the group, as presently defined by adult morphology, is not monophyletic.     

Microscopic morphology of the antennule and antenna of the marine isopod Cirolana harfordi

ABSTRACT

The use of scanning electron microscopy on the cuticle outgrowths called setae (that contain sensilla) in crustaceans is useful for, understanding how crustacean species sense their environment and for taxonomic studies. So far, most of the setal morphology studies have been performed on decapod crustaceans such as lobsters and shrimps and there has been a comparative lack of such research on marine isopods, from which terrestrial isopods such as woodlice or slaters have evolved. In the current study, electron microscopy was used to study the antennal setae of the marine isopod Cirolana harfordi using magnification powers of up to 40, 000. C. harfordi displayed a number of setal types including setae that had a sub-terminal pore that contained a cupule-shaped structure and plumose setae which are pennate in structure and have two rows of setules along the setal shaft in a fashion analogous to a palm leaf. These plumose setae may be useful to the animal in detecting water currents. Differences in the structure and placement of setae on the antennae of C. harfordi as compared to two other marine isopods, Bathynomus pelor and Natatolana borealis (that have had a comprehensive study of antennae setal morphology performed on them in previous studies) indicate that scanning electron microscopy of isopod setae may be useful in taxonomic studies of isopods.     

Individual and geographical variation in the stridulatory file of Omocestus viridulus (L.) (Orthoptera: Acrididae)

Summary

Samples of male specimens of Omocestus viridulus from 14 European countries were used to study the individual and geographical variation in the characters associated with the stridulatory file. Significant overall variation between the samples was demonstrated for the length of file, average density of pegs, length of hind femur and ratio of file length to hind femur length.

This variation was found to be significantly correlated with several environmental factors, particularly annual range of temperature and amount of precipitation. These factors were considered to be good indicators of continentality, specimens from more continental regions having longer hind femora and longer files with a lower density of pegs. File length was found to be inversely correlated with amount of precipitation even when considered as a proportion of the hind femur. Number of pegs was also found to be inversely correlated with precipitation. In showing that femur length and file length increase and density decreases with continentality, the results agree with those of my previous study (Pitkin, 1976), in which British samples were found to have shorter femora and shorter files with a greater density of pegs than German samples.

The present study, while establishing that the stridulatory file varies geographically, does not deny its usefulness as a taxonomic tool, particularly when it is used in combination with other characters. When stridulatory characters are used on their own, individual and geographical variability within the species must clearly be taken into account.     

Three more new species of Cyrtodactylus (Squamata: Gekkonidae) from the Salween Basin of eastern Myanmar underscore the urgent need for the conservation of karst habitats

An integrative phylogenetic taxonomic analysis recovers three additional new species of karst-associated Cyrtodactylus Gray (Squamata: Gekkonidae) – C. bayinnyiensis sp. nov., C. chaunghanakwaensis sp. nov. and C. naungkayaingensis sp. nov. – from a narrow zone in the Salween Basin of Kayin and Mon states in eastern Myanmar from which nine new species were recently described. This degree of unprecedented diversity and site-specific endemism will no doubt continue to rise when at least 44 unsurveyed karstic habitat-islands in this same area are also explored. These data indicate that karst habitats not only serve as foci for speciation, but their rugged terrain spares them from agricultural development and, as such, they are the only habitats in the Salween Basin wherein much of the pre-agricultural herpetofauna can survive. This continues to underscore the fact that karst habitats in Myanmar harbour a significant portion of that country’s herpetofauna, some of which remains undescribed. Despite eastern Myanmar constituting some of the most extensive karstic regions in South-east Asia, they are the least legally protected, with only 1% of their terrain recognised as vulnerable. Until karst habitats in Myanmar are thoroughly investigated, a significant portion of this country’s herpetological diversity will remain underestimated and unprotected. Therefore, issues associated with karst conservation and management in Myanmar should be elevated to a new level of urgency.     

Aylax hypecoi Trotter (Hymenoptera,Cynipidae) in Europe: Redescription,with taxonomic and biological notes

Aylax hypecoi (Trotter) (Hymenoptera, Cynipidae, Aylacini), a poorly known cynipid wasp inducing galls on Hypecoum species (Papaveraceae), was described from North Africa and also doubtfully recorded from Greece about a century ago. The species has now been found in Bulgaria and thus its presence in Europe is confirmed for the first time. The species is redescribed and illustrated with SEM pictures of the adult female; galls are also described and illustrated. Data on distribution and biology are given, and its taxonomic and phylogenetic position are discussed. Aylax spirorhynchusii Diakontshuk, , another aylacine species, recorded from Transcaucasus and Middle Asia as a gall‐inducer on Spirorhynchus sabulosus Kar. and Kir. (Brassicaceae) is a synonym of Aylax hypecoi and the host plant record stated is a possible misidentification.     

A revision of Caridina yunnanensis and its allied species (Crustacea: Decapoda: Caridea: Atyidae) from Yunnan,southern China,with description of one new species

The taxonomy of the Caridina yunnanensis and its allied species (Caridea: Atyidae) from Yunnan Province in southern China, is revised. A neotype for C. yunnanensis Yu, 1938, is designated. Additional information is provided on C. disparidentata Liang, Yan and Wang, 1984; C. dianchiensis Liang and Yan, 1985; C. mongziensis Liang, Yan and Wang, 1987; and C. disjuncta Cai and Liang, 1999. One new species, Caridina impensa, is described. A key to members of the species group is included.     

A new genus of Atlantic octocorals (Octocorallia: Gorgoniidae): systematics of gorgoniids with asymmetric sclerites

Gorgonian corals from the families Gorgoniidae and Plexauridae are among the most abundant and diverse shallow‐water cnidarians found along tropical and temperate Atlantic coasts and reefs. Some morphological traits in the Gorgoniidae comprise a taxonomic challenge due to their morphological plasticity as well as a lack of discrete character states among most genera. Some gorgoniids have asymmetrical sclerites in the surface coenenchyme, a character trait that consists of a continuum among several genera and can cause confusion with members of the family Plexauridae. The collection of a unique gorgoniid in Tobago (Trinidad and Tobago), which contains this trait but also maintains affinities to many different genera, stimulated a wider morphological comparison of gorgoniids using scanning electron microscopy (SEM). Using the morphology of asymmetrical sclerites, gorgoniids could be grouped in four monophyletic clades that were compatible with recent molecular phylogenies and provide a provisional subfamilial classification: (1) a derived clade including gorgoniids with scaphoid sclerites, comprising the reef fauna from the western Atlantic (e.g. Gorgonia, Pseudopterogorgia [ = Antillogorgia], Pterogorgia, and Phyllogorgia); (2) a related group with taxa containing capstan sclerites including genera with short capstans and/or disk‐spindles sclerites such as Pacifogorgia and Leptogorgia ( = Lophogorgia); (3) a clade of gorgoniids with asymmetrical spiny sclerites including the Atlantic genus Muriceopsis and the Indopacific Pinnigorgia together with the distant single species from the new genus and species Tobagogorgia hardyi (it is worth noting that Muriceopsis was previously classified in the Plexauridae, but there is overwhelming molecular support that groups it with the Gorgoniidae and morphological evidence that suggests affinity with Pinnigorgia); and finally (4) a basal clade with long and spiny spindles, which includes some African species such as Filigorgia angolana and F. schoutedeni as well as other new combinations (all species previously classified as Leptogorgia but not phylogenetically related). The combined set of sclerites of Tobagogorgia (e.g. both asymmetrical and irregularly bent spindles) separates it from the diagnostic characters of related genera such as Muriceopsis and Pinnigorgia. The latter two genera are also profusely branched, including pinnate patterns, whereas T. hardyi has only one or two branches. Externally, T. hardyi looks like some Leptogorgia colonies that branch minimally but it is clear that the sclerites are very different and thus also their phylogenetic divergence.     

Environmental control versus phylogenic fingerprint in ontogeny: The example of the development of the stalk in the genus Guillecrinus (stalked crinoids,Echinodermata)

The stalk morphology of the deep‐sea stalked crinoid Guillecrinus changes a lot from juvenile to adult. As a result of its unusual morphology among the extant crinoids, its taxonomic and phylogenetic affinities remain unsettled. Distinctive morphological changes characterize the various growth stages in stalked crinoids. We conduct and discuss a detailed ontogenetic analysis of the stalk of the two species (Guillecrinus neocaledonicus and G. reunionensis) of this Indo‐Pacific genus, which was observed in its environment during submersible dives off New Caledonia. Analyses examined (1) morphological changes, (2) the degree of change in morphology, (3) architectural constraints, and (4) the functional constraints related to environmental factors. The relations between three levels of integration were examined: the ossicle (columnal), the stalk, and the complete individual. The changes in level of organization were estimated. The analysis reveals that the external stalk morphology of Guillecrinus goes from a pronounced xenomorphic type in juveniles, characterized by diversified columnal articulations, which provide the proximal and distal part of the stalk with a considerable degree of flexibility, to a dominant homeomorphic type in adults, characterized by columnal articulations which allow little or no movement. This ontogenetic change through a mosaic of heterochronic developments corresponds with a change in the hydrodynamic environment, from a turbulent to a laminar water flow, and from nutritional contraints. The extensive development of deep ligament fossae in adults and in the distal stalk of juveniles corresponds to a relatively low allocation of energy to the skeleton, rather than a functional necessity. Proximal columnals in juvenile Guillecrinus display characteristics of adult Hyocrinidae. Distal columnals exhibit the typical morphology observed in Bourgueticrinina. Juveniles stages of both proximal and distal columnals show a high degree of specialization (derived characters). Well‐supported classifications have typically placed the Bourgueticrinina and the Hyocrinidae in two very dissimilar groups. Specific characteristics from the three very different families Bathycrinidae, Guillecrinidae and Hyocrinidae appear to be expressed either separately (Hyocrinus or Bathycrinus) or together (Guillecrinus). Their expression appears to depend on functional and environmental constraints. The transformation of columnals from juvenile to adult shows the important role of hypermorphic processes. However, no evidence of phylogenetic recapitulation was observed. Does the evidence presented here support or disprove current taxonomic interrelationships? How does morphology relate to ontogeny? Is heterochrony involved?     

A revision of the Caridina serrata species group,with descriptions of five new species (Crustacea: Decapoda: Caridea: Atyidae)

The taxonomy of the Caridina serrata species group (Caridea: Atyidae) is revised. Neotypes of C. serrata Stimpson, 1860, and C. cantonensis Yu, 1938, are designated. Additional information on Caridina sphyrapoda Liang and Zhou, 1993 is provided. Five new species of the Caridina serrata species group are described, namely Caridina nanaoensis from Guangdong Province, C. apodosis from Hong Kong, and C. yulinica, C. wumingensis and C. mutata from Guangxi Province, all in southern China. A key to all members of the species group is included.     

Synopsis and taxonomic revision of three genera in the snake tribe Sonorini

ABSTRACT

Delimiting species is a crucial goal of integrative biology, and yet can be misled by homoplasy and high levels of morphological variation. The snake tribe Sonorini contains three genera that have long confounded taxonomists: Chilomeniscus, Chionactis and Sonora. Dynamic colour evolution in this group, including rampant geographic variation in colour and colour polymorphism, has led to a chaotic taxonomy. We used mitochondrial and high-throughput nuclear data (ddRADseq) and complete taxonomic sampling of each genus to reconstruct phylogenetic relationships and systematically revise the genus. Our research revealed that Sonora is paraphyletic with regards to Chilomeniscus and Chionactis and that at least one species (S. semiannulata) is paraphyletic with respect to at least one other recognized species. Additionally, we found substantial undescribed genetic diversity within multiple species which is incongruent with morphological variation in coloration. Accordingly, we proposed synonymizing Chionactis and Chilomeniscus with Sonora, which has taxonomic priority over both genera. As we found genetic evidence that supported some of the historically delimited diversity within multiple taxa, we revised species-level taxonomy accordingly. This new taxonomy recognizes a revised genus of Sonora that contains 15 species of diminutive and often brightly coloured snakes that are distributed from central Mexico to north-western USA.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:45A553D8-6435-4E0A-84ED-DF31E2CCD872     

New species of Brodskius,Rythabis, and Omorius (Crustacea: Calanoida) from deep Antarctic waters

Three new species of rare benthopelagic clausocalanoidean genera with sensory setae on the maxilla are described from female specimens collected during the German Antarctic expeditions ANDEEP I–III in 2002 and 2005, mainly from abyssal depths close to the sea bed. Brodskius abyssalis sp. nov. differs from congeners by the lack of rostral filaments, two setae on the second segment of antenna exopod, thread‐like tips of maxillary worm‐like sensory setae, and the length of spines of P5 exopod. Rythabis assymmetrica sp. nov. is distinguished from other species in the genus by asymmetrical posterior corners of the prosome, the shape of spermathecae, and setal numbers on the maxillulary distal basal endite plus endopod. Omorius curvispinus sp. nov. is characterized by strongly curved setae of the maxillipedal syncoxa, a comparatively long seta on the basis of antenna, a slightly swollen genital double‐somite, and the shape of spermathecae. The genera Brodskius, Omorius, and Rythabis are recorded for the first time from the southern hemisphere.     

Redescription of the species of Passalus Fabricius, 1792 (Coleoptera: Passalidae) described by Walter Douglas Hincks (1906–1961) deposited in the Museum of the University of Manchester

ABSTRACT

As part of the effort to study Passalus Fabricius, 1792, we are redescribing and re-illustrating the species of the genus described by Walter Douglas Hincks deposited the Museum of the University of Manchester. Applying characters not yet described for these species as well as morphometric measures we hope to support future taxonomic and phylogenetic studies.     

Population characteristics of four deep‐water pandalid shrimps (Decapoda: Caridea) in the northern Aegean Sea (NE Mediterranean)

The population characteristics of four deep‐water pandalid shrimps (Decapoda: Caridea) were studied in the northern Aegean Sea in samples collected annually (1997–2000) in summer, through experimental trawl, at depths down to 600 m. Females were larger than males in Plesionika martia and Plesionika heterocarpus; no significant differences in size of males and females were found in Chlorotocus crassicornis and Plesionika antigai. A trend of increasing size with depth was observed, as well as a linear increase in the proportion of females with increasing size. Sex ratio was skewed towards females at all depths in P. antigai, while in P. heterocarpus and C. crassicornis males dominated the intermediate depths. Negative allometries were apparent in the carapace length–weight relationships in males of all species. Isometric relationships were found in females apart from in P. heterocarpus. The population patterns conform to relevant Mediterranean reports. However, some population differences exist that may reflect the distinct environmental conditions prevailing in the study area.     

Morphometric differentiation between two sympatric Macrobrachium Bates, 1868 shrimps (Crustacea: Decapoda: Palaemonidae) in West‐African rivers

A comparative morphometric study was performed on two species of shrimps, Macrobrachium macrobrachion (Herklots, 1851) and Macrobrachium vollenhovenii (Herklots, 1857). In total, 714 specimens (563 males and 151 females) originating from four rivers in Ivory Coast were analysed. The morphometry was carried out on 33 measurements; seven meristic and four morphological characters and ratios were calculated from the measurements. Data were analysed using univariate, bivariate and multivariate statistics. Meristic and morphological characters did not allow separation of distinct species. However, metric variables and ratios clearly discriminated the two species. The characters (merus/palm, carpus/palm, palm width/palm length, carpus width/carpus length, palm width) related to the form and the size of second pereiopods could be used for the discrimination of both species. This study, by allowing accurate identification of these species, will facilitate future research.     

New species of the cicada genus Semia Matsumura (Hemiptera: Cicadidae) from China and a phylogeny of Semia spp. and their relatives based on molecular data

Two new cicada species, Semia brevidilata, sp. nov. and Semia tibetensis, sp. nov., are described from China. Semia majuscula, a newly recorded species to China, is re-described, as some new characteristics are recognised which may be useful for further taxonomic and phylogenetic analysis of this genus and its allies. Partial mitochondrial cytochrome oxidase subunit I (COI) sequences of five Semia species and relatives belonging to the genera Pomponia Stål and Psithyristria Stål are further analysed to confirm the validity of related new species and to provide a useful reference for the identification of Semia. A key to all species of Semia is provided, and the phylogenetic relationships among species of Semia and their relatives are discussed.

http://zoobank.org/urn:lsid:zoobank.org:pub:64144283-8CCE-4687-9D07-2033939165E7