Gregory A. Kolbasov

REANALYSIS OF THE RELATIONSHIPS AMONG THE CIRRIPEDIA AND THE ASCOTHORACIDA AND THE PHYLOGENETIC POSITION OF THE FACETOTECTA (MAXILLOPODA: THECOSTRACA) USING 18S rDNA SEQUENCES

Abstract Until now morphological and molecular datasets have failed to agree on phylogenetic relationships within the Crustacea Thecostraca (=Facetotecta, Ascothoracida, and Cirripedia). Three recent phylogenetic studies using 18S ribosomal DNA sequences from selected Cirripedia (Thoracica, Rhizocephala, and Acrothoracica) and Ascothoracida revealed Acrothoracica and Ascothoracida as a monophyletic group. This result disagrees with several larval and spermal morphological features supporting Cirripedia as a monophyletic group. We reanalyzed the same molecular data set including a new Facetotecta sequence using neighbor-joining and maximum likelihood, but incorporating the model of evolution that fits the data best, and maximum parsimony approaches. Our results strongly support the morphological hypothesis that the cirripedes form a monophyletic group, with the Acrothoracica as sister group to the Thoracica + Rhizocephala. Moreover, all the phylogenies showed the Facetotecta as the sister group to the remaining Thecostraca (Ascothoracida + Cirripedia).

The Chemoreceptive Lattice Organs in Cypris Larvae Develop from Naupliar Setae (Thecostraca: Cirripedia, Ascothoracida and Facetotecta)

Abstract Lattice organs are peculiar chemoreceptors found only in the Crustacea Thecostraca (Facetotecta, Ascothoracida, Cirripedia). In these taxa, five pairs occur in the head shield (carapace) of the terminal larval instar (y-cyprid, ascothoracid larva, cyprid), which is the settlement stage. Lattice organs represent an autapomorphy for the Thecostraca but their evolutionary origin and possible homologues in other Crustacea remain obscure. We have used scanning electron microscopy to describe the setation pattern of the head shield in late nauplii of one species of Ascothoracida, one species of Facetotecta and several species of the Cirripedia Thoracica, Acrothoracica, and Rhizocephala. The naupliar head shield always carries two pairs setae situated anteriorly near the midline. Each of these setae carry a single pore, and positional, structural and ontogenetic evidence show that these setae are homologous in all the examined species and that they represent precursors of the two anterior pairs of lattice organs of the succeeding larval stage, viz., the ascothoracid larva (Ascothoracida), y-cyprid (Facetotecta), and cyprid (Cirripedia). This leads us to infer that lattice organs are among the most highly modified sensilla in all Crustacea and they have in most cases lost all external resemblance to a seta. The nauplii of the Rhizocephala carry an additional three pairs of setae situated more posteriorly on the head shield and they could be precursors of the three posterior pairs of lattice organs. All other species examined lack these posterior setae, except the Facetotecta which have one posteriorly situated pair.

Facetotectan larvae from the White Sea with the description of a new species (Crustacea: Thecostraca)

From a number of partial moult series obtained by laboratory culture of plankton-caught specimens, and based on drawings from whole-mounted material, we describe all the larval instars, including the y-cypris, of a new species of Facetotecta. The mid-length constriction of the antennulary aesthetasc and the shape of the head shield separate the y-cypris in our material from all other forms of y-cyprids previously assigned to species. The morphology of the present y-nauplii and y-cypris is compared with that of previously described facetotectan larvae.

Serratotantulus chertoprudae gen. et sp. n. (Crustacea, Tantulocarida, Basipodellidae): A new tantulocaridan from the abyssal depths of the Indian Ocean

A single tantulus larva was found at the abyssal depth of the Indian Ocean attached to a harpacticoid host of the family Cletodidae. It represents a new genus and species of Tantulocarida, family Basipodellidae. Its ultrastructure was studied with SEM. This genus can be easily distinguished from the other genera of Basipodellidae by the pore pattern, bilobed oral disk with strong longitudinal ridges and the posterior projection of the cephalic shield. A morphological analysis of two related families Basipodellidae and Deothertridae shows that they represent polyphyletic taxa and need further revision.

External morphology of Arcticotantulus pertzovi (Tantulocarida, Basipodellidae), a microscopic crustacean parasite from the White Sea

The material on Arcticotantulus pertzovi, a parasite of the harpacticoids Bradya typica and Pseudobradya acuta, was collected in the White Sea (the White Sea Biological Station, Moscow State University) in 2004–2006. The morphology of the tantulus larva, the “parthenogenetic female,” and the male was studied using SEM. The data obtained add significant details to the previous description of the species. For instance, the tantulus has at least 11 cephalic pores (AI-AIV, DI-DIV, LI-LIII), while the endopod of thoracopod II has a pair of setae. A freeswimming male of A. pertzovi was reared for the first time for Tantulocarida. It has a cephalothorax incorporating the cephalic and two thoracic segments, 6 thoracomeres (including those of the cephalothorax) with natatory thoracopods, the 7th trunk segment with a short penis, and an unsegmented abdomen bearing furcal rami with three setae. There are four pairs of aestetascs representing antennular rudiments. The head shield of cephalothorax is covered with cuticular ridges and bears 7 pairs of pores with setae. Both the cephalon of tantulus and cephalotorax of male lack the lattice organs, which represent the synapomorphy of the class Thecostraca. According to its morphological characteristics, A. pertzovi may belong to the families Deoterthridae or Basipodellidae; the former family is most probably an artificial taxon.

Biodiversity and biogeography of the coral boring barnacles of the genus Berndtia (Cirripedia: Acrothoracica) in the West Pacific, with description of three new species

Acrothoracican barnacles of the genus Berndtia are exclusive coral borers and the type species is Berndtia purpurea Utinomi, 1950a, reported in the corals Lepastrea purpurea and Psammocora profundacella in Wakayama, Japan. We confirmed the type is only from the coral Lepastrea purpurea and is distributed from Japan, Taiwan to Hong Kong. In contrast, B. purpurea from Psammocora belongs to a new species Berndtia haradai sp. nov., which is distributed from Japan to Okinawa. The other new species identified in the present study, Berndtia denticulata sp. nov. is common in Okinawa but also collected on the Pacific side of the Philippines. Berndtia utinomii sp. nov. is found on NE coast of Taiwan, Kochi and Wakayama in Japan and Vietnam but is absent from Okinawa. All described species are diagnostic in the coloration and morphology of the opercular bars in live specimens, morphology of posterior lobes of operculum and the number of notches in maxillules. http://zoobank.org/urn:lsid:zoobank.org:pub:8B6FE5B4-C5DD-48DE-B91A-39BBBAF87636

Microdajus tchesunovi sp. n. (Tantulocarida, Microdajidae) – A new crustacean parasite of from the White Sea

A new species of Tantulocarida, Microdajus tchesunovi sp. n., was found on tanaid host, Typhlotanais sp. of the family Nototanaidae, collected from silty sediment in the Kandalaksha Bay in the White Sea. Several tantulus larvae, developing males at different stages of metamorphosis, and early stages of parthenogenetic females were found attached to different sites of their hosts. Ultrastructure of the new species was studied with SEM. Microdajus tchesunovi sp. n. can be easily distinguished from other species of the genus Microdajus Greve by the presence of a pair of longitudinal dorsal lamellae at the anterior end of the cephalon. It is also characterized by the presence of an endopod seta on the sixth thoracopod and the absence of thoracopodal endites. A morphological comparison of species of the family Microdajidae is presented in tabular form.

Cuticular Structures of some Acrothoracican Dwarf Males (Crustacea: Thecostraca: Cirripedia: Acrothoracica)

Abstract The external morphology of the dwarf males of Lithoglyptes mitis , Lithoglyptes bicornis , Kochlorine hamata , Kochlorine sp., Cryptophialus hoegi , Cryptophialus sp., and Trypetesa lampas was examined under SEM. New data on the cuticular structures are compared with existing information on acrothoracican and thoracican males. The structure of the male mantle differs among acrothoracican families and thus may have taxonomic value.

Cryptic diversity of the acrothoracican barnacle Armatoglyptes taiwanus in the Indo-Pacific waters, with description of a new species from the Mozambique Channel collected from the MAINBAZA cruise

ABSTRACT Cirripedes of the superorder Acrothoracica are normally found as epizoic borings on marine calcareous substrates. Armatoglyptes taiwanus (Utinomi, 1950) is a lithoglyptid acrothoracican barnacle reported from different parts of the Indo-Pacific. Recent studies have demonstrated phylogenetic breaks between the Indian and Pacific Oceans populations in widespread Indo-Pacific marine organisms due to isolation events during the Pleistocene glaciations. It is possible that A. taiwanus represents a cryptic species complex in the Indo-Pacific, which the previous studies have failed to identify from morphology alone. In the present study, we analyzed the morphology and the sequence divergence of the 12S rDNA of A. taiwanus from the Indo-Pacific region, including Taiwan and the Philippines in the Pacific, and Phuket Island (Thailand) and the Mozambique Channel in the Indian Ocean, to test whether A. taiwanus is a cryptic species across its geographical range. The results showed that A. taiwanus has a homogeneous population structure in Taiwan, the Philippines, and Phuket Island (sequence divergence < 1%). Specimens from the Mozambique Channel, although morphologically similar to A. taiwanus, have a greater sequence divergence of 9.4% from A. taiwanus in the Pacific, and thus appeared to represent a new species, described herein as Armatoglyptes flexuosus n. sp. Although both species are morphologically similar, A. flexuosus n. sp. has more strongly bent/recurved posterior processes of the opercular bars and feebler armament of the orificial knob than does A. taiwanus from Taiwan (type locality). Phylogenetic analysis showed that populations of A. flexuosus n. sp. from the Mozambique Channel and A. taiwanus from the Pacific region are indeed closely related. Populations of their common ancestor may have become isolated and underwent speciation during the Pleistocene glaciations.

A new species of Synagoga (Crustacea: Thecostraca: Ascothoracida) parasitic on an antipatharian from the Azores and Cape Verde Islands, with notes on its morphology, sexuality, host specificity, and biogeography

A new ascothoracidan species has been discovered in the Macaronesia region of the eastern Atlantic Ocean at SCUBA depths. Ten specimens including both sexes of the new species, described herein as Synagoga grygieri sp. nov., were collected from colonies of the antipatharian Antipathella wollastoni (Gray, 1857). Two previously described species of Synagoga, morphologically the most generalized ascothoracidan genus, were found as ectoparasites of an antipatharian and an alcyonacean, respectively, whereas all other records of this genus have been from marine plankton. Synagoga grygieri sp. nov. currently appears to be endemic to Macaronesia, but its true distribution may be wider as its host is known to range from the Mediterranean to the west coast of Africa, and a potentially synonymous congener of the host ranges somewhat northward. The new species is described as having separate males and females, although protandry cannot be fully excluded. This is the first study of a new form of Synagoga to be based on more than a few mature specimens of a single sex or on a single juvenile. Furthermore, it is the first in which SEM has been used to document features other than carapace ornamentation, in particular the distal antennular armature, frontal filament complex, and details of the mouth parts. On the carapace of adult stages, the first and third pairs of lattice organs are oriented with the terminal pore anterior, as in S. millipalus Grygier & Ohtsuka, 1995.