Laboratory spawning and development of the Bahama lancelet, Asymmetron lucayanum (cephalochordata): fertilization through feeding larvae

Here we report on spawning and development of the Bahama lancelet, Asymmetron lucayanum. Ripe adults collected in Bimini spawned the same evening when placed in the dark for 90 minutes. The developmental morphology is described from whole mounts and histological sections. A comparison between development in Asymmetron and the better known cephalochordate genus Branchiostoma reveals similarities during the early embryonic stages but deviations by the late embryonic and early larval stages. Thus, the initial positions of the mouth, first gill slit, and anus differ between the two genera. Even more strikingly, Hatschek's right and left diverticula, which arise by enterocoely at the anterior end of the pharynx in Branchiostoma, never form during Asymmetron development. In Branchiostoma, these diverticula become the rostral coelom and preoral pit. In Asymmetron, by contrast, homologs of the rostral coelom and preoral pit form by schizocoely within an anterior cell cluster of unproven (but likely endodermal) origin. Proposing evolutionary scenarios to account for developmental differences between Asymmetron and Branchiostoma is currently hampered by uncertainty over which genus is basal in the cephalochordates. A better understanding of developmental diversity within the cephalochordates will require phylogenetic analyses based on nuclear genes and the genome sequence of an Asymmetron species.     

A Key and Diagnostic Compendium to the Species of the Genus Tylenchorhynchus Cobb, 1913 (Nematoda: Belonolaimidae)

An identification key to 111 species of Tylenchorhynchus is given. Tylenchorhynchus is defined as containing only those species with four incisures in the lateral field. A compendium providing the most important diagnostic characters for use in identification of species is included as a supplement to the key. Some species in a related but unnecessary genus were placed in the genus Tylenchorhynchus, based on morphological structures and logical groupings of the species. Bitylenchus iphilus is transferred to Tylenchorhynchus. The diagnosis of Tylenchorhynchus is emended, and a list of all the valid species of the genus is given. The characters most useful for separating species are the stylet length, shape of lip region, number of lip annules, shape of tail and tail terminus, number of tail annules, and position of vulva (V%). As defined in the paper, the genus currently is composed of 111 valid species.     

Molecular phylogeny and taxonomy of wood mice (genus Apodemus Kaup, 1829) based on complete mtDNA cytochrome b sequences, with emphasis on Chinese species

Phylogenetic relationships among 15 species of wood mice (genus Apodemus) were reconstructed to explore some long-standing taxonomic problems. The results provided support for the monophyly of the genus Apodemus, but could not reject the hypothesis of paraphyly for this genus. Our data divided the 15 species into four major groups: (1) the Sylvaemus group (A. sylvaticus, A. flavicollis, A. alpicola, and A. uralensis), (2) the Apodemus group (A. peninsulae, A. chevreri, A. agrarius, A. speciosus, A. draco, A. ilex, A. semotus, A. latronum, and A. mystacinus), (3) A. argenteus, and (4) A. gurkha. Our results also suggested that orestes should be a valid subspecies of A. draco rather than an independent species; in contrast, A. ilex from Yunnan may be regarded as a separate species rather than a synonym of orestes or draco. The species level status of A. latronum, tscherga as synonyms of A. uralensis, and A. chevrieri as a valid species and the closest sibling species of A. agrarius were further corroborated by our data. Applying a molecular clock with the divergences of Mus and Rattus set at 12 million years ago (Mya) as a calibration point, it was estimated that five old lineages (A. mystacinus and four major groups above) diverged in the late Miocene (7.82-12.74 Mya). Then the Apodemus group (excluding A. mystacinus) split into two subgroups: agrarius and draco, at about 7.17-9.95 Mya. Four species of the Sylvaemus group were estimated to diverge at about 2.92-5.21 Mya. The Hengduan Mountains Region was hypothesized to have played important roles in Apodemus evolutionary histories since the Pleistocene.     

Description of Pomphorhynchus spindletruncatus n. sp. (Acanthocephala: Pomphorhynchidae) from freshwater fishes in northern Iraq,with the erection of a new pomphorhynchid genus,Pyriproboscis n. g., and keys to genera of the Pomphorhynchidae and the species of Pomphorhynchus Monticelli, 1905

The status of species of Pomphorhynchus Monticelli, 1905 is examined and 23 species are recognised as valid. These include P. spindletruncatus n. sp., which is described herein from two species of freshwater fishes in northern Iraq, Aspius vorax Heckel and Barbus xanthopterus (Heckel) (Cyprinidae). Only one other species, P. yunnanensis Wang, 1981, has a spindle-shaped trunk similar to that of P. spindletruncatus, but is distinguished from it by a distinctly different proboscis armature. A key separating the new taxon from other species of Pomphorhynchus is included. P. heronensis Pichelin, 1997 is reassigned to a new pomphorhynchid genus, Pyriproboscis n. g., based on its unique proboscis shape and armature, short proboscis receptacle and tubular cement glands. A key to the genera of the Pomphorhynchidae is also included.     

On a collection of Acrania (Phylum Chordata) from the Solomon Islands

A collection of acraniates from Marovo Lagoon in the New Georgia Group of the Solomon Islands is described. Five species are recorded— Asymmetron lucayanum, A. cultellus, Branchiostoma malayana, B. indicum and B. lanceolatum or B. haeckeli: each is discussed briefly in relation to its taxonomic and biogeographic interest.     

A revision of the genus Mecistostethus Marseul (Histeridae, Histerinae, Exosternini)

We revise the genus Mecistostethus Marseul, sinking the monotypic genus Tarsilister Bruch as a junior synonym. Mecistostethus contains six valid species: Mecistostethus pilifer Marseul, Mecistostethus loretoensis (Bruch), comb. n., Mecistostethus seagorumsp. n., Mecistostethus carltonisp. n., Mecistostethus marseulisp. n., and Mecistostethus flechtmannisp. n. The few existing records show the genus to be widespread in tropical and subtropical South America, from northern Argentina to western Amazonian Ecuador and French Guiana. Only a single host record associates one species with the ant Pachycondyla striata Smith (Formicidae: Ponerinae), but it is possible that related ants host all the species.     

Three New Species of Minoninae (Turbellaria, Proseriata, Monocelididae) from the North Sea, with Remarks on the Taxonomy of the Subfamily

Three new species of Minoninae are described and a new genus is proposed for one of them: Minona degadti sp.n., Duplominona septentrionalis sp.n. and Duploperaclistus circocirrus gen. et sp.n. All three species occur in sublittoral sandy habitats in the Southern Bight of the North Sea, but D. circocirrus has also been found at a littoral station. The taxonomy within the subfamily Minoninae is discussed. Seven genera are considered as valid, and they are briefly diagnosed. " Peraclistus ituipus" sensu Westblad (1952) (= Duplominona westbladi Karling, 1966) is included in the new genus as Duploperuclistus westbladi (Karling, 1966) comb.n.     

ON THE STATUS OF THE GENERIC NAMES OF THE NUDIBRANCH GENERA CATRIONA, CRATENA, HERVIA, RIZZOLIA AND TRINCHESIA

The genus Catriona Winckworth (1941) is synonymous with TrinchesiaPruvot-Fol (1951) but not with Trinchesia von Jhering (1879). It has priority over Trinchesia Pruvot-Fol. The genus Cratena Bergh (1864) is valid and synonymous withRizzolia Trinchese (1877) but not with Hervia Bergh (1871). The genus Hervia Bergh (1871) is synonymous with Facelina Alderand Hancock (1855), but not all species of Hervia can be includedin the latter genus, and these should, therefore, be distributedamong other genera, some of which are listed. (Received 8 October 1954;     

中国海鼓虾科阿莱鼓虾属分类研究(甲壳亚门,十足目)

阿莱鼓虾属 Arete Stimpson曾被多个研究者作为Athanas Leach角鼓虾属的异名处理(Banner and Banner,1960,1973;Chace,1988;Miya and Miyake,1968),作者认为Kemp(1915)描述Athanus polymorphus多形角鼓虾出现的第2胸足腕节4节为形态变异,第2胸足腕节分节情况完全可以将两属分开,阿莱鼓虾属应该做有效属处理.文中记述了中国海分布的3个种.borradailei,A.dorsdis,A.indicus,其中A.Borradailei为中国海首次报道.文中详细描述A.borradailei,并提供了世界阿莱鼓虾属种的检索表.所有研究标本保存在中国科学院海洋研究所.     

A revision of the genus Eutobrilus Tsalolikhin, 1981 (Nematoda, Triplonchida)

A revision of the genus Eutobrilus Tsalolikhin, 1981 is made on the basis of the author’s and literature data. The diagnosis of the genus has been partially changed. Species diagnostic characteristics have been analyzed, and the species inventory has been made. Fifteen valid species have been included into the genus. A key to the valid species is presented.     

On the Validity of the Genus Cochlidiosperma Reichenb. (Scrophulariaceae) as Supported by Additional Palynological Evidence

The pollen grains of Cochlidiosperma (Veronica) hederifolia and C. (Veronica) cymbalaria were examined under SEM and TEM. They differ vastly from those of all the others in Veronica (sensu Elenevskij, 1977, 1978). The taxonomic relationship between the group and the other Veronica spp. is discussed with respect to both gross morphology and pollen characters. Justification for the restoration of the genus as a valid taxon is argued and, finally, a number of new combinations are proposed. The group under consideration was sometimes treated as a separate genus but more often given different ranks in the genus Veronica, which has been a controversial group as to its concept and subdivision. No detail discussion has been made before on the relationship between the group and Veronica. Main purpose of the present mork is to examine pollen morphology and gross morphology of the group and to discussits relationship with Veronica.     

A new species of Monoplacophora, redescription of the genera Veleropilina and Rokopella, and new information on three species of the class

Vema levinae Warén, sp. n. is described from a submarine volcano off western Mexico. The type species of Rokopella and Veleropilina are redescribed, the usage of the names is discussed and Rokopella and Veleropilina are recognized as valid genera in Neopilinidae. Rokopella euglypta (Dautzenberg & Fischer, 1897) is redescribed from shells and a single live specimen taken from seamounts south of the Azores, from a depth of 1200–1600 m. Tectura reticulata Seguenza, 1876 (Gastropoda, 'Acmaeidae', southern Italy, Upper Pliocene/Lower Pleistocene) is considered to have been based on the monoplacophoran species previously known as Neopilina zografi from the Mediterranean, and is classified in the genus Veleropilina. Veleropilina zografi (Dautzenberg & Fischer, 1896) is redescribed based on shells from several seamounts south of the Azores. It is considered distinct from Rokopella euglypta and classified in the genus Veleropilina. An undescribed species of Veleropilina from a seamount off southern Baja California is reported, figured and discussed but not formally described.     

Harpactus Shuckard, 1837, the valid name for the genus currently called Dienoplus Fox, 1894 (Hymenoptera: Sphecidae)

Harpactus Shuckard, 1837 (an unjustified emendation of the preoccupied name Arpactus Jurine, 1807) is an available name and must be restored as the valid name for the genus now called Dienoplus Fox, 1894. The latter name has been incorrectly interpreted as valid by Pate (1937), de Beaumont(1954a)and all subsequent authors.     

On the Identity and Nomenclature of Paracanthonchus caecus (Bastian, 1865), with a Redefinition of the Genus Paracanthonchus Micoletzky (Nematoda, Cyatholaimidae)

A historical review of the systematics of Paracanthonchus caecus (Bastian, 1865) and a comparison of specimens from different localities show that this "species" in fact comprises four distinct species. Paracanthonchus caecus Micoletzky, 1924 nec P. caecus (Bastian, 1865) is designated as the valid type species of the genus Paracanthonchus. P. heterodontus (Schulz, 1932) and P. thaumasius (Schulz, 1932) are re-established. P. caecm sensu Gerlach 1965 is considered as a distinct species: P. gerlachi sp.n. P. canadensis sp.n. is described and is very close to P. caecus Micoletzky, 1924. The subspecies P. caecus opthalmophorus (Steiner, 1921), different from the typical caecus by the presence of ocelli, is considered as a different species; we therefore propose P.ophthalmophorus (Steiner, 1921) stat.n. The genus Paracanthonchus is redefined.     

Species in the genus Turritopsis (Cnidaria, Hydrozoa): a molecular evaluation

Mitochondrial ribosomal gene sequences were used to investigate the status of several populations of hydromedusae belonging to the genus Turritopsis (family Oceaniidae). Several nominal species have been described for this genus, but most of them had been synonymized and attributed to one cosmopolitan species, Turritopsis nutricula . A recent revision based on morphological and reproductive characters, however, has shown that many different populations can be distinguished and that several of the nominal Turritopsis species are likely valid biological species. Our investigation using molecular sequence data of 16S mitochondrial gene confirms these results. The Mediterranean Turritopsis must be attributed to Turritopsis dohrnii and the Turritopsis of New Zealand must be referred to Turritopsis rubra . The situation of the Japanese Turritopsis is more complex, though all sampled populations are clearly distinct from T. nutricula , a species likely confined to the Western Atlantic. The Japanese Turritopsis fall into three widely separated lineages. One of them, corresponding likely to Turritopsis pacifica , is closely related to T. rubra . A second clade, which potentially represents an as yet undescribed species, produces smaller medusae than T. pacifica and is morphologically distinguishable from it. Finally, a third group was distinguished by a single haplotype sequence that is identical with a Mediterranean sample of T. dohrnii . It is postulated that the last group of Japanese Turritopsis is likely a recent introduction, most probably by human activity. A survey of all known and potentially valid Turritopsis species is given in table format to facilitate identifications and future revisory work.     

A discussion on the Heteracanthocephalidae Petrochenko, 1956 (Acanthocephala: Palaeacanthocephala)

Several heteracanthocephalid specimens were recovered from the flatfish Rhombosolea leporina (Günther), a host of Heteracanthocephalus peltorhamphi (Baylis, 1944) Petrochenko, 1956 from New Zealand. Unlike H. peltorhamphi, these new specimens have trunk spines. Measurements and proboscis armament of the new specimens are consistent with the worms being Aspersentis minor Edmonds & Smales, 1992 originally described from the Australian flounder Rhombosolea tapirina Günther. A review of the family Heteracanthocephalidae Petrochenko, 1956 was undertaken to assess the validity of its four genera and eight species. The validity of Aspersentis megarhynchus (Linstow, 1892) Golvan, 1960 (syn. Echinorhynchus megarhynchus Linstow, 1892) is questioned. E. megarhynchus is not considered to be an heteracanthocephalid and is relegated to a species inquirenda. A. megarhynchus (Linstow, 1892) of Golvan (1960) nec E. megarhynchus Linstow, 1892 is considered a synonym of A. austrinus Van Cleave, 1929. The monotypic genus Heteracanthocephalus Petrochenko, 1956 is proposed as a synonym of Aspersentis Van Cleave, 1929 because there appear to be insufficient morphological differences between them. Aspersentis peltorhamphi n. comb. is proposed for Heteracanthocephalus peltorhamphi. The monotypic genus Sachalinorhynchus Krotov & Petrochenko in Petrochenko, 1956 is considered valid, but the other heteracanthocephalid genus, Bullockrhynchus Chandra, Rao & Shyamasundari, 1985, also monotypic, is not. B. indicus Chandra, Rao & Shyamasundari, 1985 possesses more features resembling rhadinorhynchids than heteracanthocephalids but only females are known, and therefore the genus and species cannot be placed. There are currently four valid species of Aspersentis and one of Sachalinorhynchus.