New Species And A Review Of The Deep-Sea Fish Genus Asquamiceps (Salmoniformes, Alepocephalidae)

A new species of Asqllamiceps with a striking cobalt blue head is described from specimens collected at bathypelagic (ca. 2,000 m) depths in the Atlantic Ocean. The new species is compared to the five nominal species in the genus and a key to Asqllamiceps is presented. One nominal species. A. indagatio, is treated as a junior synonym of A. velaris. The anatomy of A. caerlilells suggests a relatively primitive grade within the family. The caudal skeleton, with two to four ural centra, four uroneurals, and the distal edge of the lower hypurals ahead of the distal edge of the upper hypura]s, is one of the most primitive known in the family. Most derived characters found, such as no mesocoracoid, two epurals and no pelvic splint, are reductional. Suspected relationships of Asqllamicep~\u27 are with Einara, COllocara. Leptoderma, and AlIlostomomorpha

Systematics Of The Pearlfishes (Pisces, Carapidae)

A review of taxonomy, anatomy, ontogeny, ecology, and phylogeny of the ophidiiform family Carapidae was conducted using over 2,300 larval, juvenile and adult specimens. A cladistic classification based on swimbladder morphology, developmental and osteological characters of the vertebral column, fins, pectoral and pelvic girdles, gill arches, ethmoid, jaws, and habitat is presented. A total of 31 species (6 new names and one unnamed larval form) in seven genera are recognized in two subfamilies. A species previously assigned to Echiodon is made the type of a new monotypic genus. Species of the tribe Carapini are rearranged in the genera Carapus and Encheliophis largely on the basis of swimbladder morphology. Larvae are described for all genera except Encheliophis whose larvae are predicted to resemble those of Carapus. The vexillifer larva is unique to carapids. The tenuis juvenile stage, however, may be restricted to the ecologically specialized genera, especially Carapus and Encheliophis. The family is distributed over broad depth (0-2,000 m) and latitudinal (ca. 65-degrees-N to 60-degrees-S) ranges. In general taxa with more plesiomorphic characters are found in deeper water and higher latitudes while taxa with more apomorphic characters are found in tropical, shallow water. Highly specialized inquiline behavior is found in both tribes of the Carapinae and our phylogenetic hypothesis specifies independent acquisition of molluscan inquilinism, at least. Within the Carapini the genus with the most apomorphic characters, Encheliophis, is the most successful holothurian inquiline and the only holothurian inquiline in the Indo-Pacific. Species in its sister genus, Carapus, switch to non-holothurian primary hosts (asteroids or ascidians) when sympatric with Encheliophis in the Indo-Pacific. Atlantic species of Carapus retain holothurians as primary hosts. The distribution of sister species is usually allopatric and suggests that the presence or absence of inquiline behavior has no bearing on mode of speciation. Vicariance of sister species is frequently along depth or latitudinal gradients. There are no amphi-American sister species; the sister group of all eastern Pacific species or populations of carapids is either another Pacific form or an Atlantic-Pacific clade

Description And Occurrence Of Vexillifer Larvae Of Echiodon (Pisces, Carapidae) In The Western North-Atlantic And Notes On Other Carapid Vexillifers

Five hundred twenty-two vexillifers of an unnamed species of the carapid genus Echiodon are reported from ichthyoplankton collections made in the Caribbean Sea, Gulf of Mexico, Middle Atlantic Bight, Sargasso Sea, and Scotian Shelf. These are compared with 36 vexi1lifers and one juvenile of the only other known western Atlantic carapine, Campus ber- I/ludensis, as well as two small unidentified western Atlantic vexillifers, and eight eastern Pacific vexillifers of E. exsiliul/l. Vexillum placement relative to anal-fin origin, myomeres, and vertebral centra appears to be a useful character for separating Echiodon vexillifers from other western Atlantic carapids. The vexillum in Echiodon is posteriad of a vertical through the anal-fin origin, over myomeres 9 to 12 and centra 10 or II. The vex ilium of Echiodoll sp. was examined in detail and is bilateral, each component of which consists of a distal and proximal element. The paired proximal elements rest on a distal cartilaginous radial which is supported by a slipper-shaped, compound cartilaginous proximal radial (pterygiophore) in Echiodoll sp. and by a rod-shaped, simple proximal radial in C. bl\u27Ymudellsis. The structure is covered by a fleshy sheath which is highly ornamented in C. bermudellsis but less so in Echiodoll sp. The presumed origin of percoid predorsal bones from an ancestor with vexillar supporting structures is questioned. Most available vexillifers of Echiodoll sp. were captured in the eastern Gulf of Mexico. Additional larger size classes were taken from off Bermuda and north of Cape Hatteras to the Scotian Shelf. These and several other subtropical teleost larvae appear to be regularly dispersed northward by the Gulf Stream

Observations On Structure And Evaluation Of Possible Functions Of The Vexillum In Larval Carapidae (Ophidiiformes)

Elongate dorsal appendages adorn pelagic larvae of many fishes from disparate taxa, among them larvae of the family Carapidae, wherein the singular, elongate appendage is termed a vexillum, The vexillum is a complex larval specialization of the dorsal fin and is characteristic of all carapid genera, It is motile, well vascularized, and innervated by a branch of a cranial nerve with no apparent spinal innervation. Histological studies of Echiodon dawsoni and Carapus bermudensis vexilla show a two layered epidermis with mucous cells, an arteriole and venuole, two myelinated peripheral nerve fascicles, and two collagenous central shafts. No taste buds, free neuromasts or organized chemoreceptors were found on the vexillum, including its fleshy tabs; collateral branches of the nerve fascicles may end as free-nerve endings. In situ observations of living pearlfish larvae revealed a remarkably long and ornamented vexillum that assumed variable postures. The data suggest that carapid vexilla serve multiple functions, including predator deception, sensation, and hydrodynamic effects

Systematic and Evolutionary Insights Derived from mtDNA COI Barcode Diversity in the Decapoda (Crustacea: Malacostraca)

Background: Decapods are the most recognizable of all crustaceans and comprise a dominant group of benthic invertebrates of the continental shelf and slope, including many species of economic importance. Of the 17635 morphologically described Decapoda species, only 5.4% are represented by COI barcode region sequences. It therefore remains a challenge to compile regional databases that identify and analyse the extent and patterns of decapod diversity throughout the world. Methodology/Principal Findings: We contributed 101 decapod species from the North East Atlantic, the Gulf of Cadiz and the Mediterranean Sea, of which 81 species represent novel COI records. Within the newly-generated dataset, 3.6% of the species barcodes conflicted with the assigned morphological taxonomic identification, highlighting both the apparent taxonomic ambiguity among certain groups, and the need for an accelerated and independent taxonomic approach. Using the combined COI barcode projects from the Barcode of Life Database, we provide the most comprehensive COI data set so far examined for the Order (1572 sequences of 528 species, 213 genera, and 67 families). Patterns within families show a general predicted molecular hierarchy, but the scale of divergence at each taxonomic level appears to vary extensively between families. The range values of mean K2P distance observed were: within species 0.285% to 1.375%, within genus 6.376% to 20.924% and within family 11.392% to 25.617%. Nucleotide composition varied greatly across decapods, ranging from 30.8 % to 49.4 % GC content. Conclusions/Significance: Decapod biological diversity was quantified by identifying putative cryptic species allowing a rapid assessment of taxon diversity in groups that have until now received limited morphological and systematic examination. We highlight taxonomic groups or species with unusual nucleotide composition or evolutionary rates. Such data are relevant to strategies for conservation of existing decapod biodiversity, as well as elucidating the mechanisms and constraints shaping the patterns observed.FCT - SFRH/BD/25568/ 2006EC FP6 - GOCE-CT-2005-511234 HERMESFCT - PTDC/MAR/69892/2006 LusomarBo

Sex Differences in the Brain: A Whole Body Perspective

Most writing on sexual differentiation of the mammalian brain (including our own) considers just two organs: the gonads and the brain. This perspective, which leaves out all other body parts, misleads us in several ways. First, there is accumulating evidence that all organs are sexually differentiated, and that sex differences in peripheral organs affect the brain. We demonstrate this by reviewing examples involving sex differences in muscles, adipose tissue, the liver, immune system, gut, kidneys, bladder, and placenta that affect the nervous system and behavior. The second consequence of ignoring other organs when considering neural sex differences is that we are likely to miss the fact that some brain sex differences develop to compensate for differences in the internal environment (i.e., because male and female brains operate in different bodies, sex differences are required to make output/function more similar in the two sexes). We also consider evidence that sex differences in sensory systems cause male and female brains to perceive different information about the world; the two sexes are also perceived by the world differently and therefore exposed to differences in experience via treatment by others. Although the topic of sex differences in the brain is often seen as much more emotionally charged than studies of sex differences in other organs, the dichotomy is largely false. By putting the brain firmly back in the body, sex differences in the brain are predictable and can be more completely understood

Temporal variability of settlement in Carapidae larvae at Rangiroa atoll

Carapidae (or pearlfish) are eel-like fishes living inside different invertebrates, such as holothurians, sea stars or bivalves. In some Polynesian areas where they live in sympatry, several species (Carapus homei, Carapus mourlani, Carapus boraborensis and Encheliophis gracilis) are able to inhabit the same host species. The heterospecific infestation rate is very rare, suggesting that the four species can compete for their hosts. Some differences in settlement period, breeding period and in pelagic larval duration (PLD) could allow better characterisation of the life history of each species. More than 700 larvae were collected during an entire year on the Rangiroa atoll (French Polynesia). Each species was identified; their settlement pattern was examined and their PLD was deduced from otolith (sagittae) increments. In the four collected species, the settlement pattern differed: C. homei and C. mourlani settle on the reef during the entire year, and show an asynchronous and diffuse breeding cycle. C. boraborensis and E. gracilis have a shorter settlement period which could be compatible with breeding synchronisation. As most reef fishes, Carapidae larvae mainly settle during moonless nights. Moreover, each species presents some plasticity, allowing it to settle on the reef under suitable conditions