Comparative morphology of the otolith of the triplefins (family: Tripterygiidae)

Otolith morphology may provide useful information about the triplefin fish family Tripterygiidae. A comparative study of the otolith of 40 tripterygiid species was conducted to identify the most appropriate taxonomical characters that can separate the species and genera of the family Tripterygiidae. Among other otolith characters, it is possible to distinguish characters that clearly define a taxonomic group (genus or species), and other characters that are shared by several genera, but may be only useful to define certain species within a genus. Ontogenetic changes in the otolith of the triplefin fishes studied are evident. The otolith of the juvenile Ucla xenogrammus was the most similar to the adult otolith, while otolith of the juvenile Blennodon dorsale was the least similar to the adult otolith.     

Oncodiscus sauridae Yamaguti, 1934 from Saurida undosquamis in Kuwait and a revision of the genus Oncodiscus (Cestoda: Bothriocephalidae)

Oncodiscus sauridae Yamaguti, 1934 is described and figured in detail from specimens collected from Saurida undosquamis (new host) and S. tumbil in the Arabian Gulf and Australian waters, respectively (new geographical localities). O. fimbriatus and O. waltairensis are regarded as synonyms of O. sauridae. O. maharashtrae is regarded as species inquirenda. The diagnosis of the genus Oncodiscus is emended.     

Use of morphological and molecular data to identify three new sibling species of the genus Munida Leach, 1820 (Crustacea,Decapoda, Galatheidae) from New Caledonia

Three cryptic species of the genus Munida from New Caledonia, previously identified as M. tuberculata Henderson, , M. notata Macpherson, and M. clinata Macpherson, , are described and illustrated. The three species are identified by subtle and constant morphological characters, which match clear differences in molecular sequences (16S rDNA and COI genes). The results also confirm the importance of several of these characters (e.g. length of the antennular and antennal spines) in the taxonomy of the genus Munida.     

Stenothoidae (Crustacea: Amphipoda) of hydrothermal vents and surroundings on the Mid‐Atlantic Ridge,Azores Triple Junction zone

Four new species of Stenothoidae were collected from the Azores Triple Junction zone during different French cruises on the Mid‐Atlantic Ridge. One of the species belongs to the genus Torometopa (T. saldanhae) and is the first record of this genus in the Atlantic Ocean. The three other species belong to the genus Stenothoe (S. divae, S. marvela, and S. menezgweni). It is not possible to determine from morphological and ecological characters whether these amphipod species are endemic to hydrothermal systems or are bathyal species that may be found away from vent sites.     

Phylogenetic analysis of the subgenus Lampetis (Spinthoptera) (Coleoptera: Buprestidae) of North and Central America,and the West Indies

Phylogenetic relationships between species of Lampetis (Spinthoptera) of North and Central America and the West Indies were analysed by cladistic methods, based on 65 characters from the external morphology and male genitalia. Eleven species of different generic groups of the subtribe Dicercina were considered as outgroups, including also species of Lampetis (Lampetis) and one South American species of L. (Spinthoptera). The monophyly of Lampetis (Spinthoptera) is supported by two synapomorphies, but this subgenus appears to be more closely related to species of Psiloptera rather than to Old World species of Lampetis (Lampetis), suggesting that Lampetis (Spinthoptera) may be segregated from Lampetis as a different genus. The species of Lampetis (Spinthoptera) from North and Central America and the West Indies do not represent a monophyletic taxon, because L. (S.) tucumana (South American outgroup) is nested within them. Comparison of these results with a previous panbiogeographic analysis indicate that several generalized tracks possess species from different clades, thus suggesting an ancient radiation of this taxon in Mesoamerica and the Mexican Transition Zone.     

A revision of the south Asian sisorid catfish genus Sisor (Teleostei: Siluriformes)

The south Asian sisorid catfish genus Sisor is revised. Three new species are described in this study: S. chennuah from the Brahmaputra River drainage, and S. rheophilus and S. torosus from the Ganges River drainage. The body depth, snout length, eye size, shape of the nuchal plate and the numbers of pectoral spine serrations and lateral line ossicles are found to be diagnostic characters for the species. Sisor rabdophorus is redescribed and a neotype designated.     

Assessment of morphometric characters to delimit species of Apolpium Chamberlin, 1930 (Pseudoscorpiones,Olpiidae)

ABSTRACT

Pseudoscorpiones is a mesodiverse order of Arachnida, with more than 3600 described species in the world. Species delimitation is sometimes difficult due to the high variability of some characters, difficulty in finding informative and useful characters for species differentiation and the subjectivity of individual specialists. The aim of this work is to explore and to evaluate the role of morphometric characters in species delimitation within the genus Apolpium (Olpiidae). Measurements of 17 structures of 57 individuals were taken and their length/width ratios calculated. Cluster analyses, principal components analyses, discriminant function analyses and non-metric multidimensional scaling were carried out. The results showed low resolution for the number of species currently recognised in the genus. These results highlight the importance of looking for other morphological characters, and also for a more rigorous assessment of previously used characters for defining species.     

A new genus of viviparous gyrodactylid (Monogenea) from the Great Barrier Reef,Australia with descriptions of seven new species

Acanthoplacatus gen. nov., a new genus of viviparous gyrodactylid, is described from the fins and skin of siganid fishes from the Great Barrier Reef, Australia. The genus is characterized by a muscular, tube-like haptor with 16 marginal hooks on the posterior margin. The ventral lobe of the haptor is located anteriorly relative to the dorsal lobe and contains a pair of hamuli and a ventral bar with posteriorly-projecting ventral bar membrane. A dorsal bar is absent. Five pairs of posterior gland cells surround the posterior terminations of the gut. The male copulatory organ is a muscular, non-eversible bulb with several spines around the distal opening. Species of Acanthoplacatus have a bilateral excretory system consisting of six pairs of flame cells and a pair of excretory bladders. Seven new species are described: Acanthoplacatus adlardi sp. nov. and A. amplihamus sp. nov. from Siganus punctatus (Forster, 1801), A. brauni sp. nov. from S. corallinus (Valenciennes, 1835), A. parvihamus sp. nov. from S. vulpinus (Schlegel and Mueller, 1845), A. puelli sp. nov. from S. puellus Schlegel, 1852, A. shieldsi sp. nov. from S. lineatus (Valenciennes, 1835) and A. sigani sp. nov. from S. fuscescens (Houttuyn, 1782). Species can be discriminated by shape and size of the hamuli, marginal hooks and ventral bar and by male copulatory organ sclerite morphology. Three species (A. brauni sp. nov., A. shieldsi sp. nov. and A. sigani sp. nov.) were assessed for seasonal variation of sclerite size. Ten of thirteen morphological characters showed seasonal variation in size for at least one of the species. The characters were longer in winter except dorsal root tissue cap width. Only one character, marginal hook length, showed significant seasonal variation for all three species. Species of Acanthoplacatus were observed to attach using only the marginal hooks and the role of hamuli in attachment is unclear. The dorsal fin of the host is the preferred site for most species but the anal fin, caudal fin and body surfaces are preferred by some species. Prevalences for species range from 57 to 100%.     

Reproduction,planula development,and substratum selection in three species of Stylactaria (Cnidaria: Hydrozoa) from Hokkaido,Japan

Modes of reproduction, morphology and behaviour of planulae, and substratum specificity were studied and compared in three species of the hydrozoan genus Stylactaria from Hokkaido, S. conchicola, S. uchidai, and S. multigranosi. Observed differences in these attributes provide additional characters for discrimination of the three species. Stylactaria conchicola is oviparous, its planulae are sedentary, and its hydroid is substratum specific (living only on shells of the gastropod Homalopoma amussitatum). Stylactaria uchidai differs in being ovoviviparous, in having crawling planulae, and in being a substratum generalist. Stylactaria multigranosi is parthenogenetic, its planulae are sedentary, and it is substratum specific (occurring exclusively on the gastropod Nassarius multigranosus). Only female colonies of S. multigranosi are known, and gonophores of this species differ from those of S. conchicola and S. uchidai in being eumedusoid rather than styloid. Correlations were noted between attributes of the planula larva and substratum specificity in the three species. The cnidome differences between the species suggest that penetrant nematocysts are particularly important for sedentary planulae colonizing moving substrata. These characters are also considered useful in the taxonomy of species of Stylactaria. The phylogenetic significance of different gonophore types in the genus is considered.     

A new species of Stenhelia (Copepoda,Harpacticoida) from a hydrothermal,active, submarine volcano in the New Ireland Fore-Arc system (Papua New Guinea) with notes on deep sea colonization within the Stenheliinae

A new species of harpacticoid copepod, Stenhelia gundulae (Stenheliinae), is described from Edison seamount, a hydrothermal active submarine volcano in the New Ireland Fore-Arc system (Papua New Guinea). Some species groups are identified within the genus Stenhelia. The new species is assigned to the ‘S. normani group’, which is characterized within a more inclusive taxon by the male P5 exp being fused to the basis and lacking two outer spines. The species most closely related to S. gundulae s.n. appear to be S. giesbrechti T. and A. Scott, 1896, S. tethysensis Monard, 1928 and S. normani T. Scott, 1905 including its former subspecies S. polluta Monard, 1928 and S. acutirostris Willey, 1935. The other known deep sea species of Stenhelia, S. noodti Schriever, 1982, S. islandico Schriever, 1982, S. lima Becker and Schriever, 1979 and S. diegensis Thistle and Coull, 1979, on the other hand belong to a different lineage, the ‘S. longicaudata group’ which is characterized by the apomorphic shape of the P1. It is hypothesized that deep sea colonization within the Stenheliinae occurred independently at least twice in two different lineages.     

The complete larval development of Sadayoshia edwardsii (37) (Decapoda: Anomura: Galatheidae) described from laboratory‐reared material

The complete larval development of Sadayoshia edwardsii (Miers, ) is described and illustrated from laboratory‐reared material. The development comprises four zoeal and one megalopal stages. Diagnostic zoeal characters of Sadayoshia are provided and these are compared with other galatheid genera for which the larval morphology is known. Zoeas of S. edwardsii are readily distinguished from those of other galatheid species by the setation of the maxillular endopod together with the basis and endopod of the first maxilliped. The megalop of S. edwardsii has a flattened, triangular‐shaped rostrum, which differs remarkably from that of the adult. Although the rostral shape resembles that of Galathea megalops, the armature of the lateral margins is different between megalops of the two genera. The present larval study suggests that Sadayoshia is more closely allied to Galathea than to Munida.     

Observations on the “tenuis group” (Eutardigrada,Macrobiotidae) and description of a new Macrobiotus species

A new species of the tardigrade genus Macrobiotus is described. The species, designated M. ciprianoi n. sp., was isolated from a mixture of Provence broom leaf litter and mosses, and from rock mosses collected in the Sierra de Guadarrama, Madrid (Spain). Given that Macrobiotus ciprianoi n. sp. shares several characters to members of the “tenuis group”, we assessed the taxonomic homogeneity of the group. The new species differs from those of the “tenuis group” according to a unique set of characters related with claw shape, features of the buccal‐pharyngeal apparatus, and egg morphology. Our analysis of holotypes and/or paratypes of “tenuis group” species and other Macrobiotus species with similar characters (M. bondavallii and M. caelicola) reflects the heterogeneity of this group of species as currently described.     

Designation of a neotype for Synodontis schall (Bloch and Schneider, 1801) and description of two new species of Synodontis (Siluriformes: Mochokidae)

A morphometric study of 105 specimens of Synodontis schall, including most type specimens of all nominal species considered junior synonyms of S. schall has been undertaken. Two new species S. ouemeensis and S. kogonensis are described from the Ogun (Nigeria), Oueme (Benin) and Mono (Togo) basins, and the Kogon and Fatala (Guinea) basins, respectively. A neotype is designated for S. schall. The two new species differ from S. schall mainly by the width of the premaxillary toothplate (12.9–24.3% HL for S. schall vs. 21.6–32.7% HL), and can be distinguished one from the other by differences in orbit diameter (20.5–26.8% HL for S. ouemeensis vs. 19.4–21.0% HL for S. kogonensis) and prepectoral length (23.4–28.2% SL for S. ouemeensis vs. 21.6–23.3% SL for S. kogonensis).     

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.     

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.     

Macro- and microscopic morphology of the reproductive system of Leptinaria unilamellata (d’Orbigny, 1835) (Mollusca: Pulmonata: Subulinidae)

Many tropical terrestrial gastropods, such as Subulinidae, are recognized and classified by their shells, as is the case for Leptinaria unilamellata (d’Orbigny, 1835), a hermaphroditic pulmonate snail restricted to tropical America. We aimed to characterize the morpho-anatomy and histology of the reproductive system of L. unilamellata. We compared the results obtained from L. unilamellata with the available data on the reproductive system of other subulinid species. The main distinctive characters are those of the penial complex, such as the proportion of the length of the penial complex and the length of the free oviduct, presence of a flagellum, site of insertion of the bursa copulatrix duct relative to the site of insertion of the penial complex and presence and extension of the penial sheath.     

Morphometry and chaetotaxy of the nymphs of Ectemnostega (Ectemnostegella) quechua (Bachmann 1961) (Insecta: Hemiptera: Heteroptera: Corixidae)

The egg and the five nymphal instars of Ectemnostega quechua are described and illustrated for the first time. The eggs of Ectemnostega have a short stalk, and the shape, size and chorionic structure differ among groups of species. The nymphal characters most useful in identifying instars I–V of Ectemnostega are: body length; number of rostrum sulcations; number of setae on inner surface of protibiotarsus; spines and setae, and spines on posteroventral surface of mesofemur and mesotibia, respectively; setae on posterodorsal surface of mesotibia and mesotarsus; spines and setae on anteroventral surface and setae on posterior surface of metatibia; swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and the grade of development of wing pads. The nymphs of E. quechua can be easily distinguished from other species of Ectemnostega by the number of spines and setae on the posteroventral surface of mesofemur.     

The cuticle of two species of Bothrodendron [Lycopsida: Lepidodendrales]

Summary

The variability of four characters commonly used in the separation of species of Limnodrilus has been described, and their relative values assessed. The number of setae per bundle is useless as a specific character; the shape of the setae can serve to distinguish only a single species and the length: breadth ratio of the penial sheath is more useful as an additional or confirmatory character. The shape of the penial sheath proved to be the most important character, but even this was not completely reliable, and it is concluded that several characters must be used in the identification of species of Limnodrilus. It is suggested that structures other than the cuticular derivatives should be examined and that a similar study be carried out on North American species.