Aeolid nudibranchs (Gastropoda: Opisthobranchia) of the family Glaucidae from New Zealand waters

Two new species of aeolid, a new genus being created for one of them, are described along with another two species, one Phidiana militaris (Alder & Hancock) (= Learchis militaris ) a new record for New Zealand, the other, Glaucus atlanticus , found only once before. Jason mirabilis gen. et sp. nov. is distinguished by a ventral tongue-like process with a ridged chitinous covering which replaces the radula (still present but vestigial) and by the greatly subdivided rhinophoral lamellae. Babaina caprinsulensis sp. nov. differs from its Californian relative in having papillate rhinophores. The New Zealand specimens of Phidiana militaris differ slightly in colouration from those described for elsewhere in the Indo-Pacific.
The Glaucidae is enlarged to include the Babainidae, Facelinidae and Favorinidae, the main familial characteristics being the simple oral glands, sharp radular tooth and pugnacious behaviour. Possible evolutionary trends within the family based on the arrangement of the cerata and penial structure are traced out. The Babaininae, pleuroproctic with a notal ridge and irregular disposition of the cerata, is considered the most primitive subfamily and the Hervellinae, with cerata in single rows, the most advanced. The many facelinid genera previously recognized are reduced to two, Antionetta Schmekel and Phidiana Gray.     

Aeolid nudibranchs (Gastropoda: Opisthobranchia) of the families Flabellinidae and Eubranchidae from New Zealand waters

Four aeolid species, all newly recorded for New Zealand waters, are described. Three are known species; they are Tularia bractea (Burn) and Eubranchus rubeolus Burn from Australia and Eubranchus agrius Marcus from Chile; the New Zealand specimens show slight variation. The fourth species, Coryphella albomarginata sp. nov. , is distinguished from close relatives by the opaque white band along the margin of the foot, two centrally placed (in relation to the main reproductive ducts) bursae copulatrices and several small, blunt denticles on the outer edge of the lateral teeth of the radula. The families to which these species belong, the Flabellinidae (Coryphella albomarginata, Tularia bractea) and Eubranchidae (Eubranchus agrius, E. rubeolus), are recognized and defined and the constituent genera examined and reduced in number. A new genus, Paracoryphella , and family, the Paracoryphellidae, are created for Coryphella islandica Odhner. The classification of the aeolids is reviewed:Odhner's order Aeolidacea is considered a very satisfactory major category, but his grouping of the families into tribes is discarded on the grounds that the diagnostic character, the position of the anus in relation to the cerata, is too variable within individual families.     

Dorid nudibranchs from eastern Australia (Gastropoda, Opisthobranchia)

Collections of nudibranch gastropods made in 1968 are described. All the 18 eastern Australian species of doridaceans (excluding chromodoridiform species) obtained are illustra-ed and investigated anatomically, often for the first time since their original discovery over a century ago. A list of the dorid nudibranches reliably recorded from Australian waters (compiled by R. Burn) supplements the paper.     

Chromodorid nudibranchs from eastern Australia (Gastropoda, Opisthobranchia)*

Collections of nudibranch gastropods made in 1968 and 1969 are described. All the 11 eastern Australian species of Casella, Hypselodoris and Chromodoris obtained are fully illustrated by line diagrams, photographs and water-colours. Two species new for Australia are described, and nine others are re-described. A list of the chromodoridiform species reliably recorded from Australian waters concludes the paper.     

The British species of the aeolidacean family Tergipedidae (Gastropoda: Opisthobranchia) with a discussion of the genera

Recent collections of living material of all the known British species of the family Tergipedidae have enabled a re-evaluation of the significant taxonomic features. Precuthona peachi (Alder & Hancock 1848) is shown to be the fully adult form of Cuthona nana (Alder & Hancock, 1842), although there is evidence of geographical divergence in behaviour and development processes near the western limit of its range on the North American seaboard. Cuthona pustulata (Alder & Hancock, 1852) is found to possess a penial stylet. The investigation of abundant European material of C. pustulata and seven further species of Cuthona provides a new basis for interspecific discrimination.     

New records of Conidae (Mollusca: Gastropoda) from the New Zealand region

Abstract

Conus howelli Iredale is recorded from New Zealand. C. howelli and C. raoulensis Powell are considered to be very closely related, and Kermasprella Powell is thus probably a svnonvm of Endemoconus Iredale. C. teramachii (Kuroda) and C. smirna Bartsch ' Rehder are recorded from off northern New Zealand, and the known range of C. kermadecensis Iredale is extended southward.     

Additional dextral triphorids (Mollusca: Gastropoda) from New Zealand

Abstract

Socienna maoria Finlay and Mendax duplicarinata Powell are referred to Metaxia Monterosato. Metaxia solitaria n.sp., Socienna cracens n.sp., and S. cracens regia n.subsp. are described. Additional range data are provided for Metaxia exaltata (Powell).     

Phylogeny and evolution of corambid nudibranchs (Mollusca: Gastropoda)

Organismic diversity, as well as distributional and ecological patterns, can be fully understood in an evolutionary framework only. Reliable phylogenetic trees are required to ‘read history’, but are not yet available for most marine invertebrate groups. Molecular systematics offers an enormous potential, but still fails for ‘all‐species approaches’ on groups with species that are rare or occur in remote areas only, simply because there is no easily collectable material available for sequence analyses. Exploring morphologically aberrant corambid nudibranch gastropods as a case study, we assess whether or not morphology‐based phylogenetic analyses can fill this gap and produce a tree that allows a detailed view on evolutionary history. Morphology‐based parsimony analysis of corambids and potential relatives resulted in a well‐resolved and remarkably robust topology. As an offshoot of kelp‐associated onchidoridid ancestors, and obviously driven by the heterochronic shortening of life cycles and morphological juvenilization in an ephemeral habitat, the ancestor of corambids originated in cool northern Pacific coastal waters. A basal clade (the genus Loy) diverged there, adapting to live on soft bottoms under successive reversals of paedomorphic traits. The more speciose Corambe lineage radiated preying upon short‐lived encrusting bryozoa in a high‐energy kelp environment. Selection favoured transformation of the mantle into a cuticle‐covered shield, and successive paedomorphic translocations of dorid anal gills to the protected ventral side of the body, where compensatory, multiple gills evolved. Corambe species probably first colonized tropical American seas, and then radiated in worldwide temperate waters: this is explained by the excellent long‐distance dispersal abilities afforded by rafting on kelp, with the subsequent divergence of colonizers in allopatry. The competitive coexistence of Corambe pacifica MacFarland & O'Donoghue, 1929 and Corambe steinbergae (Lance, 1962) off California is the result of independent colonization events. The closing of the Isthmus of Panama separated the latter species from a flock that have radiated within warm Atlantic waters since then. Our case study shows that morphological structures, if investigated in depth, bear the potential for an efficient phylogenetic analysis of groups that are still elusive to molecular analyses. Tracing character evolution and integrating a wide range of geographic, biological, and ecological background information allowed us to reconstruct an evolutionary scenario for corambids that is detailed and plausible, and can be tested by future molecular approaches. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 585–604.     

Breaking family ties: taxon sampling and molecular phylogeny of chromodorid nudibranchs (Mollusca,Gastropoda)

Johnson, R. F. (2010). Breaking family ties: taxon sampling and molecular phylogeny of chromodorid nudibranchs (Mollusca, Gastropoda). —Zoologica Scripta, 40, 137–157. Although researchers have debated the monophyly of the diverse chromodorid nudibranchs (Chromodorididae) for over 100 years, the monophyly of this family has not been properly tested. Recent morphological and molecular phylogenetic studies have added to the debate, but have not used appropriate methods to resolve this issue. I investigate how outgroup choice and taxon sampling influences tree topology and in turn the recovery of chromodorid monophyly. As a demonstration of these potential methodological problems, I then present phylogenies resulting from different taxon‐sampling schemes using the same molecular data. Taxon sampling has a strong influence on the resulting phylogenies. With comprehensive taxon sampling and outgroup selection, Cadlina is not a member of the Chromodorididae. The chromodorid nudibranchs without Cadlina are monophyletic and possibly sister to the Actinocyclidae. Additionally, I found, for the first time, support for most current family groupings in the Doridoidea. I propose a new classification in which Cadlina is not considered a member of the Chromodorididae. Instead, I resurrect the family name Cadlinidae to include the genera Cadlina and Aldisa.     

Eastern Australian Pleurobranchomorpha (Gastropoda, Opisthobranchia)

Collections of pleurobranchomorph gastropods made in 1968 are described, and compared with material in the British Museum (Natural History) and with live Mediterranean specimens examined in the Naples Aquarium. All the eastern Australian species obtained are illustrated by line diagrams. Three species new for Australia are described, one is transferred to another known species, and six others are re-described. A list of the 12 species (with synonyms) reliably reported for eastern Australian waters concludes the paper, together with a key for their identification.     

Recent and Tertiary Seguenziidae (Mollusca: Gastropoda) from the New Zealand region

Abstract

The family Seguenziidae is represented in the New Zealand region by the following new species (fossil taxa asterisked): Seguenzia glabella*, S. prisca*, S. serrata*, S. conopia, S. fulgida, S. chelina, S. transenna, S. textilis, S. compta; Seguenziella (n.gen.) patula; Seguenziopsis (n.gen.) bicorona; Carenzia venusta, C. fastigiata; Thelyssina (n.gen.) sterrha; Ancistrobasis dilecta, A. regina; Fluxinella (n.gen.) lepida, F. lenticulosa, F. maxwelli*; Calliobasis (n.gen.) eos*, C. chlorosa, C. miranda.     

The introduced slugs of New Zealand (Gastropoda: Pulmonata)

Abstract

Eleven species of slug introduced into the New Zealand fauna are discussed: Testacellidae - Testacella haliotidea Draparnaud, 1801 (T. vagans Hutton, 1882 n.syn.); Arionidae - Arion intermedius (Normand, 1852), A. hortensis Férussac, 1819 (A. incommodus Hutton, 1879 n.syn.); Milacidae - Milax gagates (Draparnaud, 1801), M. budapestensis (Hazay, 1881), M. sowerbyi (Férussac, 1823); Limacidae - Deroceras reticulatum (Müller, 1774) (Limax molestus Hutton, 1879 n.syn.), D. panormitanum (Lessona & Pollonera, 1882), Limax maximus Linnaeus, 1758, Lehmannia flava (Linnaeus, 1758), L. nyctelia (Bourguignet, 1861). Of these, T. haliotidea, M. budapestensis, M. sowerbyi, D. panormitanum, and L. nyctelia are recorded from New Zealand for the first time. A key for the identification of these species is provided. Species thought to be doubtfully established are discussed, and a list is given of recent interceptions at New Zealand ports.     

Phylogeography and phyloecology of dorid nudibranchs (Mollusca, Gastropoda)

Dorid nudibranchs exhibit a number of anatomical and physiological adaptations that reflect a complex evolutionary history. The lack of a fossil record means that all available information on the evolution of this group comes from phylogenetic evidence. Deep imbalances in the phylogeny of dorid nudibranchs indicates that this group has probably undergone random extinction events and subsequent speciation of derived lineages. Sister-group relationships between eastern Pacific, Atlantic and tropical Indo-Pacific taxa [(eastern Pacific, Atlantic) Indo-Pacific], repeated throughout several lineages of dorid nudibranchs, provide solid evidence of two consecutive vicariant events: (1) the closure of communication between the tropical Indo-Pacific region and the Atlantic and eastern Pacific, which began during the Oligocene–Miocene transition and was completed with the formation of the East Pacific Barrier, and (2) the rise of the Panama isthmus. The absence of solid dates for the effective isolation of the eastern Pacific and the central Pacific does not allow estimations of the time of diversification of dorid nudibranchs. Phylogenetic evidence indicates that omnivorism and de novo synthesis of chemical defences are probably the plesiomorphic conditions in dorid nudibranchs. It is also likely that all sponge-feeding cryptobranch dorids have a common ancestor, but other cases of sponge feeding in phanerobranch dorids have arisen independently. The numerous instances in which de novo synthesis was replaced by sequestration of chemicals from the prey are evidence of a great metabolic versatility in dorid nudibranchs.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 551–559.     

Reproduction in some New Zealand Cymatiidae (Gastropoda:Prosobranchia)

The behaviour during reproduction of four species of New Zealand cymatiids is described revealing a year-long courtship period in Cabestana spengleri. Charonia species, Mayena australasia and Monoplex australasiae have only a brief period of courtship prior to egg laying. The female of all species remains with the egg mass until the embryos hatch. This period may be as long as three months in the case of Mayena australasia. Protection of the egg mass seems to be the reason for this brooding behaviour as development proceeds normally in the absence of the female. Anatomically, the genital system of these mesogastropods is approaching the condition seen in more advanced neogastropods particularly with regard to the female.     

A note on some sacoglossan penial styles (Gastropoda: Opisthobranchia)

A penial style is a hollow, cuticular extension of the vas deferens present in most sacoglossan sea-slugs and also in many eolids and some dorids. During copulation a style projects beyond the tip of the distended penis and is used to transfer sperm either by hypodermic injection, or by conducting the sperm to a bursa copulatrix. The flexible styles of bivalved gastropods are described for the first time and new details are given for some other sacoglossan styles. The evolution of penial styles and their uses in taxonomy are discussed.     

Substratwahlversuche mit Microhedyle milaschewitchii Kowalevsky (Gastropoda,Opisthobranchia: Acochlidiacea)

Zusammenfassung Microhedyle milaschewitchii Kow. aus einem sublitoralen Schellsandvorkommen bei Rovinj (Jugoslawien) bevorzugte in Zweifachwahlversuchen eine Korngröße von 0,5–2 mm, die mit 73,1% im natürlichen Substrat vorherrscht. Die Tiere verhielten sich zum Licht neutral und zeigten im Vergleich zu Protodrilus keine extreme Thigmotaxis. Sterile Sande werden ebenso wie getrockneter Sand gegenüber natürlichem Substrat abgelehnt, sind aber nach zehntägiger Inkubation mit Sandbakterien diesem gleichwertig. Zwischen bakterienhaltigem Quarzsand und Kalksand zeigte sich keine signifikante Präferenz. Für die Besiedlung eines Substrates scheinen optimale Korngröße und lebende Mikroorganismen maßgebend zu sein.

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Summary Microhedyle milaschewitchii Kow. obtained from a sublittoral shellsand near Rovinj (Yugoslavia) prefers a grain size range of 0.5 to 2 mm in simple-choice experiments. This fraction predominates in the natural substrate (73.1%). Light did not affect the behaviour of the animals which are much less thigmotactical than Protodrilus. Sterile sands are rejected when offered together with natural substrate, but are equally attractive after having been incubated with sand bacteria for ten days. Similarly dried sand is not accepted by the animals. There is no significant preference between quartz and chalk sands, both containing bacteria. Optimal grain size and living microorganisms apparently are essential for the colonization of a substrate.

     

The recent New Zealand species of Triforis (Gastropoda: Triforidae)

Paramendax apicina Powell and Mendax attenuatispira Powell are referred to genus Triforis Deshayes; T. antepallaxa, T. blacki, and T. tui are described as new; and a species close to the South Australian Triforis epallaxa (Verco) is recorded from New Zealand waters. Paramendax Powell is transferred from the Cerithiopsidae to the Triforidae as a subgenus of Triforis. It is suggested that the Recent South African Cerithiella nonnitens Barnard is referable to Triforis.