Basal chromodorid sperm ultrastructure (Nudibranchia, Gastropoda, Mollusca)

The relationship between three genera considered basal in the Chromodorididae (Cadlina, Tyrinna, Cadlinella) has not yet been resolved by traditional morphological means. Here we examined the sperm ultrastructure of Tyrinna nobilis, Tyrinna evelinae, Cadlina flavomaculata and Cadlina cf. nigrobranchiata, with the expectation of finding phylogenetically informative characters. No Tyrinna or Cadlina species showed sperm similarities to Cadlinella. Both Cadlina species and Tyrinna nobilis (but not T. evelinae) exhibited coarse striations in the acrosomal pedestal. The putative fibers that occurred between the coarse striations of the pedestal are condensed into a layer in Cadlina and Tyrinna, but not in other species that also have coarse striations (Gymnodoris), and may constitute evidence for a close relationship. Tyrinna evelinae possessed fine acrosomal striations, which was shared with other Chromodorididae, Actinocyclidae and the cryptobranchs Rostanga and Aphelodoris. We also examined the sperm ultrastructure of 'Chromodoris' ambiguus, an animal which has shown molecular affinities to species of Cadlina, and not Chromodoris. The sperm of 'C'.' ambiguus did not exhibit the typical Cadlina characteristics, but also showed important differences to other investigated Chromodoris species.

Characterization of Kudoa monodactyli n. sp (Myxosporea : Multivalvulida) from the muscle of Monodactylus argenteus (Teleostei : Monodactylidae) from Moreton Bay, Queensland, Australia

Kudoa monodactyli n. sp. is described from the somatic musculature of Monodactylus argenteus from several localities in southern Queensland, Australia. This is the first record of a myxozoan parasite from the family Monodactylidae. The spores typically have five polar capsules, making this species similar to the four other five-valved Kudoa species (K. neurophila, K. muscularis, K. shulmani, K. cutanea) that have been described to date. However, morphometric measurements particularly of spore length and width make the species from M. argenteus distinct from the other species. Comparison of the small subunit ribosomal DNA sequence of this species with its congeners for which sequence data are available, provides further evidence of novelty. Kudoa monodactyli n. sp. displays 38 (of 1,554) nucleotide differences compared with rDNA sequence of Kudoa neurophila, which on phylogenetic analysis places these species in clades exclusive of each other. Phylogenetic analyses also provide evidence that the number of valves per spore in this genus is an imperfect indicator of relatedness.

Molecular characterization of Thelastomatoidea (Nematoda : Oxyurida) from cockroaches in Australia

A molecular approach was used to genetically characterize 5 species (Aoruroides queenslandensis. Blattophila sphaerolaima, Cordonicola gibsoni, Desmicola ornato and Leidynemella fusiformis) belonging to the superfamily. Thelastomatoidea fi (Nematoda: Oxyurida), a group of pinworms that parasitizes terrestrial arthropods. The D3 domain of the large subunit Of nuclear ribosomal RNA (LSU) was sequenced for individual specimens, and the analysis of the sequence data allowed the genetic relationships of the 5 species to be studied dagger. The sequence variation in the D3 domain within individual species (0-1-8%) was significantly less than the differences among species (4(.)3-12(.)4%). Phylogenetic analyses, Using maximum parsimony, maximum likelihood, and neighbour-joining, tree-building methods, established relationships among the 5 species of Thelastomatoidea and Oxyuris equi (a species of the order Oxyurida). The molecular approach employed provides the prospect for developing DNA tools for the specific identification of the Thelastomatoidea, irrespective of developmental stage and sex, as a basis for systematic, ecological and/or population genetic investigations of members within this superfamily.

New Thelastomatoidea (Nematoda : Oxyurida) from Australian burrowing cockroaches (Blaberidae : Geoscapheinae, Panesthiinae)

Four new species and two new genera of thelastomatoid are described from several species of Australian burrowing cockroaches (Blattodea: Panesthiinae; Geoscapheinae). Corpicracens munozae n. g., n. sp., Pseudodesmicola botti n. g., n. sp. and Cephalobellus nolani n. sp. are described from Geoscapheus dilatatus (Blattodea: Geoscapheinae) from Mendooran, New South Wales; one new thelastomatid, Blattophila praelongicauda n. sp., is described from Panesthia cribrata from Lamington National Park, Queensland. Corpicracens munozae n. g., n. sp. is long and slender, with a monodelphic female reproductive system, a clavate corpus with a slight posterior pseudobulb, oval eggs flattened at the poles, and a relatively robust, subulate tail. Pseudodesmicola botti n. g., n. sp. is slightly more robust in body, also has a monodelphic reproductive system, a cylindrical corpus with a posterior pseudobulb, ovoid eggs and a very long, subulate tail. Cephalobellus nolani n. sp. is distinguished from other members of the genus by its relatively short and broad body and egg shape. Lastly, Blattophila praelongicauda n. sp. is distinguished from other members of the genus by having eggs with a single, polar operculum, tail length, and position of the vulva, nerve ring and excretory pore. An additional species, known by a single specimen from Panesthia tryoni tryoni from the same locality is characterised but not named. The species found are all relatively rare parasites of Australian burrowing cockroaches, each having a prevalence of less than 10%.

Stephanostomum talakitok n. sp (Digenea : Acanthocolpidae) from the golden trevalley, Gnathanodon speciosus (Perciformes : Carangidae), from Ningaloo Reef, Western Australia

A new species, Stephanostomum talakitok n. sp., is described from the golden trevally Gnathanodon speciosus, Ningaloo Reef, Western Australia. It has 36 (34-40) circum-oral spines and the vitellarium reaches to no less than 10-17% of the hindbody length from the ventral sucker. It differs from other species of Stephanostomum with these characteristics by combinations of the gradual diminution of the circum-oral spine size to a small mid-ventral spine, the contiguous gonads with no intervening vitelline follicles, the sucker-ratio and various other ratios, including the distance between the ventral sucker and the ovary and the distance the cirrus-sac reaches into the hindbody, both as a proportion of body length.

Thelastomatoidea (Nematoda : Oxyurida) of the Australian giant burrowing cockroach, Macropanesthia rhinoceros (Blaberidae : Geoscapheinae)

The thelastomatoid fauna of Macropanesthia rhinoceros was examined from 13 localities across its range in Queensland, Australia. Nine species of thelastomatoids, including two representing new genera, Geoscaphenema megaovum n. g., n. sp. and Jaidenema rhinoceratum n. g., n. sp., were found. Macropanesthia rhinoceros is reported as a new host for seven species previously recorded from Panesthia cribrata (Blaberidae: Panesthiinae) and P. tryoni tryoni, viz, Blattophila sphaerolaima, Leidynemella fusiformis, Cordonicola gibsoni, Travassosinema jaidenae, Coronostoma australiae, Hammerschmidtiella hochi and Desmicola ornata. Overall estimated richness for the system ranged from 10.1-13.5 species. The high degree of parasite faunal overlap between M. rhinoceros and the two Panesthia species is surprising given the disparate ecological niches that they occupy; P. cribrata and P. tryoni tryoni burrow in, and feed upon, moist decaying wood and require a climate that is moist all year round, whereas M. rhinoceros burrows in loose soil, feeds on fallen leaf litter and is tolerant of much drier environments.

Comparative neurocranial morphology of angelsharks from the south-western Atlantic Ocean (Chondrichthyes, Elasmobranchii, Squatinidae): implications for taxonomy and phylogeny

Neurocrania of three species of angelsharks from the south-western Atlantic Ocean, occurring off south-eastern and southern Brazil, are described. A detailed morphological description is provided of the neurocranium of Squatina guggenheim and compared with S. argentina and S. occulta. Despite being generally conservative, the neurocranium of Squatina presents significant differences among these species which aid in their identification, which is otherwise problematical. The main distinctions were found in rostral projections, anterior fontanellae, supraorbital crests, upper and lower postorbital processes, otic capsules, suborbital crests, and pterotic processes. Squatina guggenheim and S. occulta share more neurocranial characters when compared to S. argentina. No basal angle was found, but we confirm the presence of a very much reduced and barely noticeable basioccipital fovea in Squatina; systematic implications within elasmobranchs of these and other features are discussed.