Partial revision of the genus Fabia Dana, 1851 (Crustacea: Brachyura: Pinnotheridae)

Eight species are now assigned to Fabia Dana, 1851. The present partial revision accepts five, F. byssomiae (Say, 1818), F. concharum (Rathbun, 1893), F. emiliai (de Melo, 1971), F. subquadrata Dana, 1851 (type species) and F. tellinae Cobb, 1973, and recommends a future study to determine whether the Brazilian species F. emiliai, is a junior synonym of F. byssomiae. In addition, a new species, F. carvachoi, from the Gulf of California, México is described. The six species are diagnosed and/or described and figured.     

Cleavage pattern in Oscarella species (Porifera,Demospongiae, Homoscleromorpha): transmission of maternal cells and symbiotic bacteria

The cleavage and the first stages of development of larvae in five Oscarella species, from the north-west Mediterranean, O. lobularis, O. tuberculata, O. imperialis, O. microlobata and Oscarella sp., are investigated. Eggs are isolecithal, and rich in yolk inclusions. The cleavage is holoblastic, equal and asynchronous. During cleavage, there is no central cavity (blastocoel). The result of cleavage is the formation of a solid morula constituted by equal blastomeres. The polarity of the blastomeres is not expressed prior to the beginning of larva differentiation, i.e. approximately up to 64-cell stage. The superficial membrane of the blastomeres shows numerous filopodia which form blastomere contact. Symbiotic bacteria and cells with inclusions of the maternal mesohyl are present in the intercellular spaces of the embryo from the beginning of cleavage. Whereas maternal symbiotic bacteria are present in the embryo of the five species studied, maternal cells with inclusions are absent from two species (O. tuberculata and O. microlobata). The most original feature of early development in the genus Oscarella is the formation of a coeloblastula larva from a morula due to the progressive migration of the internal cells to the periphery.     

Taxonomy,phylogeny and distribution of the longicorn beetle genus Allotisis Pascoe (Coleoptera: Cerambycidae: Phoracanthini)

The genus Allotisis Pascoe is revised. Diagnosis of Allotisis is given, three known species are redescribed and six species are described as new : A. repleta, A. notabilis, A. rara, A. labyrinthina, A. monteithi and A. furva. All species are from Australia. Thoris moerens Blackburn is synonymous with A. unifasciata. A key to the nine species is provided. Phylogenetic analysis suggests that this genus be divided into two species groups, monteithi-group and unifasciata-group. Several subgroups are also identified. Biogeographic distribution of these species groups and subgroups is discussed.     

Notes on Geryon tridens (Decapoda,Brachyura) from west of Ireland

Summary

One hundred and eighty males and 23 female specimens of Geryon tridens from 60 to 110 miles west of Ireland were examined in July 1968.

The carapace length/width relationship was calculated as;

and

where y = carapace length and x = carapace width.

Eleven per cent of the males captured had moulted recently, and one female had recently carried eggs.

The average size of crabs was found to increase from east to west, and it is suggested that the present sample is taken from the western side of the main population. There was no relationship between average size and the depth of the water in which they were caught.     

Hispid cotton rat ( Sigmodon hispidus ) in Nebraska: distribution, reproduction, and seasonal activity

The hispid cotton rat ( Sigmodon hispidus ) has occurred in Nebraska for about 50 years and entered the state from the south via northward movements through Kansas. However, little is known about its status or distribution in the state in recent decades. We conducted surveys for S. hispidus in southern Nebraska at historical sites and sites without previous records to determine its current status. From 2004 to 2008, we documented cotton rats at 9 of 12 historical sites in south-central and extreme southeastern parts of the state, and we captured this species at 13 new sites in southwestern and south-central Nebraska. In the past 3 decades, the distribution of S. hispidus has expanded westward but not northward in the state. An explanation for such a shift is unclear. At this northern edge of its geographical range, pregnant females were captured from early April to early October, and nonreproductive females were captured from November to January. Males with enlarged testes occurred from late March to September. Aspects of its natural history in Nebraska are similar to those reported in Kansas.     

A new species of freshwater crab (Decapoda: Brachyura: Potamidae) from Dongyin Island,Matsu, Taiwan,defined by morphological and molecular characters,with notes on its biogeography

A new species of freshwater crab, Nanhaipotamon dongyinense sp. nov. (Decapoda: Brachyura: Potamidae), is described from Dongyin Island, Matsu, Taiwan. Based on morphological and molecular (mitochondrial 16S rRNA) evidence, it can be distinguished from its congeners. The biogeography of the species, found on an island 50 km from mainland China, is also discussed.     

Two new genera of the family Pilumnidae (Crustacea: Decapoda: Brachyura) from Queensland,Australia

Two new genera of Pilumnidae each with a single new species are described from southeastern Queensland waters. Priapipilumnus is defined by the greatly swollen base and simple blunt apex of the male first pleopod and the concomitant posteriorly protruding, bilobed, third abdominal segment. Takedana is separable by the very short spinous anterolateral margins, the swollen branchial regions, the moderately short walking legs, and the strongly spined chelae. Actumnus pugilator is reassigned to Bathypilumnus Ng and Tan, 1984.     

The zoeal development of Nanocassiope granulipes (Sakai, 1939) (Crustacea: Decapoda: Brachyura: Xanthidae) described from laboratory-reared material

Ovigerous crabs of Nanocassiope granulipes (Sakai, 1939) were collected in South Korean waters and their larvae reared in the laboratory. Four zoeal stages are described and illustrated in detail. Morphological characteristics of zoea I, such as the antennal exopod, the endopod of the second maxilliped and the telson, are compared with other known first-stage zoeas from the Xanthinae. The firststage zoea of N. granulipes appears to be similar to those of Leptodius exaratus (H. Milne Edwards, 1834) and Macromedaeus distinguendus (de Haan, 1835).     

Foregut structures of freshly moulted exuviae from Maja crispata,Cancer pagurus and Pseudosesarma moeschi (Decapoda: Brachyura)

Periodic moulting is vital for the growth of crustaceans. The process is characterized by a complete replacement of the mineralized exoskeleton, including eyestalks, legs, the pleon as well as the foregut and hindgut. In the present study a series of freshly moulted brachyuran exuviae [Maja crispata Risso, 1827; Cancer pagurus Linnaeus, 1758 and Pseudosesarma moeschi (De Man, 1888)] were investigated concerning the remaining calcified foregut structures. All investigated exuviae show part or complete degradation of the lateral expanded ossicles of the gastric mill (e.g. ossicles II, V and IX). Most of the ossicles of the pyloric filter are unaffected by the degradation processes. Reduction of the calcium content and the increasing flexibility of the foregut ossicles enable the passage of the bigger “old” foregut through the smaller oesophagus of the newly formed foregut. The gastric teeth of the examined exuviae are not influenced by the moulting process.     

The occurrence,mechanics and significance of burying behaviour in crabs (Crustacea: Brachyura)

Although the terms burrowing and burying are often used interchangeably in the literature, there are clear distinctions between these two types of behaviour in terms of their ecological, mechanical and physiological implications. Both types of behaviour are widely observed in the Brachyura. In comparison to the well researched area of burrowing in crabs, information on burying is relatively dispersed. This review will examine the extent of burying behaviour in brachyurans, and the physiological and ecological consequences of the behaviour within the group. At least nine of the 50 families of brachyuran crabs have either been observed to bury in soft substrata or are suspected, on morphological grounds, of burying. There appears to be no specific morphological adaptations for burying in brachyurans, apart from those features associated with respiration whilst buried in the sediment. Buried individuals must ensure constant access to oxygenated water in the face of mechanical problems resulting from direct contact with the sediment, i.e., the threat of clogging. Burying taxa deal with this challenge through accessory respiratory channels and altered respiratory rhythms. The evolutionary implication of the burying habit is equivocal. Burying taxa are amongst the most speciose and numerically dominant brachyuran groups in marine systems, all reaching their greatest diversity and abundance in soft substrata. Burying may be an ancestral condition, with many of these groups evolving in habitats characterized by soft sediment.     

The soil mite family Eremaeidae (Acari: Oribatida) in Mongolia,with remarks on distribution and diversity of known genera

The oribatid mite family Eremaeidae is represented in Mongolia by eight species in three genera. Three new species, Eueremaeus tenuisensillatus sp. nov., Eu. crassisetosus sp. nov. and Eu. laticostulatus sp. nov., collected from cool temperate forests, dry steppe and semi-desert habitats in central and southern Mongolia, are described on the basis of adults. Five known species, Eremaeus hepaticus C. L. Koch, Eu. oblongus (C. L. Koch), Eu. granulatus (Mihel?i?), Proteremaeus mongolicus (Golosova) and P. punctulatus Bayartogtokh are redescribed; the first three of these are recorded for the first time from Mongolia. Taxonomic status of Eu. granulatus (Mihel?i?) and Eu. silvestris (Forsslund) is discussed, and the latter is considered a junior synonym of the former species. The following new combinations are proposed: Eueremaeus brevifer (Mahunka), Eueremaeus fossulatus (Kunst) and Eueremaeus roissi (Piffl). A key to Mongolian species of Eremaeidae is given. Data on distribution and diversity of Eremaeidae of the world are discussed.     

A new genus and species of pinnotherid crab from Karachi,northern Arabian Sea (Crustacea,Decapoda, Brachyura)

A new monotypic genus, Sindheres, is established to accommodate a new species, S. karachiensis, of pinnotherid crab from the northern Arabian Sea. The new genus resembles Nepinnotheres Manning, 1993 in having the dactylus of the third maxilliped inserted near the mid-length of the ventral margin of the propodus but it differs in having a sub-hexagonal carapace.     

A revision of Eumedonus H. Milne Edwards, 1834 and Gonatonotus White, 1847 (Crustacea: Decapoda: Brachyura: Eumedonidae), two genera of crabs symbiotic with sea urchins

The eumedonid genera Eumedonus H. Milne Edwards, 1834 and Gonatonotus White, 1847, are revised. Members of both genera are obligate symbionts with sea urchins. Eumedonus is separated from Gonatonotus mainly by the presence or absence of crests on the merus of the ambulatory legs. Eumedonus, as here defined, contains five species, viz. E. niger H. Milne Edwards, 1834 (type species), E. vicinus Rathbun, 1918, E. zebra Alcock, 1895, E. brevirhynchus n. sp., and E. intermedius n. sp. Gonatonotus, as here re-diagnosed, includes three species, viz. G. pentagonus White, 1847 (type species), G. granulosus (MacGilchrist, 1905), n. comb. and G. nasutus n. sp.     

A new genus of freshwater crab (Crustacea: Decapoda: Brachyura: Potamidae) from Thailand,with a description of a new species

A new genus, Stelomon, is established for the Thai freshwater crabs Potamon kanchanaburiense Naiyanetr, 1992, and P. pruinosum Alcock, 1909. The unique structure of the male first pleopod is the key diagnostic generic character. One new species, which differs in the form of the male first pleopod, is also described. A key to the species of Stelomon is included.     

Two species of deep-sea flabelliferan isopods from Taiwan (Crustacea: Peracarida: Aegidae,Anuropidae)

Aega falcata sp. nov. is described from two female specimens from about 500m off Taiwan. The species' most distinctive feature, which readily distinguishes it from all others described, is the flattened falcate plates of the two basal articles of the antennular peduncle. Three specimens of Anuropus pacificus Lincoln and Jones, 1973, are recorded from 400 to 500m. These include a male, an ovigerous and a larvigerous female having numerous manca in the broodpouch. Given the rarity of specimens of Anuropus, all three forms, as well as the manca, are described in some detail.     

A new species of Himalayapotamon Pretzmann, 1966 (Crustacea: Brachyura: Potamidae) marking the westernmost distribution of the genus,with notes on its geographical range evolution

ABSTRACT

We describe a new species of freshwater crab, Himalayapotamon robertsianum sp. nov. from Punjab province of Pakistan, based on morphological characters of the carapace and the first gonopod. The new species demarcates the westernmost distribution limit of the genus. Additionally, we analysed partial sequences of the 16S rRNA locus for some species of the genus Himalayapotamon (p-distances, Bayesian phylogenetical inference), indicating that Himalayapotamon separates into an eastern and a western clade. Based on these results, we propose a biogeographical scenario that can explain the occurrence of the genera Himalayapotamon and Potamon within the same river system: we assume an ancestral widespread distribution of Himalayapotamon in the palaeo-Ganges. When drainage rearrangement diverted the western tributaries of the Ganges into the Indus since the latest Miocene, Himalayapotamon diverged into two clades. Consequently, the western clade is now sharing the Indus drainage with Potamon.

urn:lsid:zoobank.org:pub:80B52E6C-0120-4669-A6B0-9F0DA5918EE3     

Genetic diversity of freshwater crabs (Brachyura: Sesarmidae) from central Jamaica with description of a new species

Jamaica is the only island of the Greater Antilles where freshwater streams are not populated by representatives of the old lineage of freshwater crabs, the Pseudothelphusidae. Instead, a very diverse fauna of endemic sesarmid crabs inhabits freshwater and terrestrial habitats throughout the island, thereby showing complete independence from the sea. They have been reported thriving in bromeliad leaf axils, rock rubble, empty snail shells, caves and mountain streams. Otherwise, the Sesarmidae are typical inhabitants of soft‐sediment littoral habitats like marshes and mangroves. For many years, crabs from Jamaican mountains streams had been considered to belong to a single species, Sesarma bidentatum Benedict . However, recent morphological and molecular studies have shown that crabs from mountain streams of different regions of the island belong to different species. Consequently, four new crab species have been described over the last 10 years. In this study, we give evidence that freshwater streams in central Jamaica also host two different species of crabs. In streams draining to the north we exclusively found the species S. windsor Türkay and Diesel, , while streams draining to the south were inhabited by a closely related but undescribed species of crab. The southern species is here described as new and is referred to as Sesarma meridies sp. n. Morphological and molecular (12S and 16S mtDNA) evidence is provided that allows these two species of freshwater crabs from central Jamaica to be distinguished. The species richness of Jamaican endemic sesarmids thereby increases to 10, which makes the island unique in terms of its diversity of land‐dwelling crabs.