Deepak Apte

SPECIATION AND DISPERSAL ALONG CONTINENTAL COASTLINES AND ISLAND ARCS IN THE INDO-WEST PACIFIC TURBINID GASTROPOD GENUS LUNELLA

Species trees were produced for the Indo‐West Pacific (IWP) gastropod genus Lunella using MrBayes, BEAST, and *BEAST with sequence data from four genes. Three fossil records were used to calibrate a molecular clock. Eight cryptic species were recognized using statistical methods for species delimitation in combination with morphological differences. However, our results suggest caution in interpreting ESUs defined solely by the general mixed Yule Coalescent model in genera like Lunella, with lower dispersal abilities. Four almost entirely allopatric species groups were recovered that differ in ecology and distribution. Three groups occur predominantly along continental coastlines and one occurs on island arrays. Sympatric species occur only in the torquata and coronata groups along coastlines, whereas species in the cinerea group, distributed in two‐dimensional island arrays, occur in complete allopatry. Dispersal along island arcs has been important in the maintenance of species distributions and gene flow among populations in the cinerea group. The emergence of new islands and their eventual subsidence over geological time has had important consequences for the isolation of populations and the eventual rise of new species in Lunella.

Ecological determinants and stochastic fluctuations of Tridacna maxima survival rate in Lakshadweep Archipelago

Compounding effects of slow life-history traits and adult-specific overharvesting have caused a range-wide decline of several giant clam populations. Erratic changes in these populations reported at isolated reefs, are attributable to stochastic fluctuations in recruitment and survival rates. These population rate parameters may be adversely influenced by the considerable and increasing human–reef economic interactions in tropical waters. The unsubstantiated knowledge on such influences hinders conservation management of species-habitat linkages particularly for species like the small giant clam (Tridacna maxima). Our study reports small giant clam survival rate, its ecological determinants and stochastic fluctuations from shallow lagoon waters of Lakshadweep Archipelago; a natural habitat not subjected to commercial giant clam harvesting. Survival rate was estimated by monitoring the status of identified individuals in belt-transects through successive years 2005–2009. The role of different factors in explaining the variation in survival rates was investigated at relevant scales: anthropogenic pressure at the population level in the reef, clam density at sub-population level in the belt-transects, and variables related to clams at the individual level. Effects were quantified through univariate regression techniques and Kaplan–Meier estimator coupled with generalized linear (logit link) models. Small giant clam survival rate in the reef decreased and its spatio-temporal fluctuations increased along the increasing gradient of human populations. Survival was density-independent. Size/age specific survival followed Siler distribution characterized by very low early-age survival, increased adult-age survival, and low older-age survival. Anchorage in coral substrate exerted a curvilinear effect, where survival of moderately anchored clams > loosely anchored clams >> deeply embedded clams. Our study recommends regular population monitoring in densely inhabited islands to detect incipient changes, which can subsequently be confronted by scientific lagoon bed management.

Integrative taxonomy of the genus Onchidium Buchannan, 1800 (Mollusca, Gastropoda, Pulmonata, Onchidiidae)

Abstract In an effort to clarify the species diversity of onchidiid slugs, the taxonomy of the genus Onchidium Buchannan, 1800 is revised using an integrative approach. New, fresh specimens were collected in a large number of places, including type localities. The genus Onchidium is redefined here as a clade including only three species which are strongly supported by both morphological and molecular data. All three species were already named: the type species Onchidium typhae Buchannan, 1800, Onchidium stuxbergi (Westerlund, 1883), and Onchidium reevesii (J.E. Gray, 1850). With the exception of a re-description of Onchidium typhae published in 1869, all three species are re-described here for the first time. First-hand observations on the color variation of live animals in their natural habitat are provided. The anatomy of each species is described. Important nomenclatural issues are addressed. In particular, Labella Starobogatov, 1976 is regarded as a junior synonym of Onchidium and Labella ajuthiae (Labbé, 1935) and Onchidium nigrum (Plate, 1893) are regarded as junior synonyms of Onchidium stuxbergi. The nomenclatural status of several other species names is discussed as well. Many new records are provided across South-East Asia and precise ranges of geographic distributions are provided for the genus Onchidium and its three species. Distinctive features that help distinguish the genus Onchidium from other onchidiids are provided, as well as an identification key for the three species.

A new genus and four new species of onchidiid slugs from South-East Asia (Mollusca: Gastropoda: Pulmonata: Onchidiidae)

ABSTRACT The taxonomy of the Onchidiidae has remained extremely confusing for decades. As part of an on-going systematic revision of the entire family, a new genus, Melayonchis Dayrat and Goulding gen. nov., and four new species (Melayonchis eloisae Dayrat sp. nov., Melayonchis siongkiati Dayrat and Goulding sp. nov., Melayonchis annae Dayrat sp. nov., and Melayonchis aileenae Dayrat and Goulding sp. nov.) are described. Species are delineated using an integrative approach, based on morphological characters and DNA sequences. First-hand field observations and pictures of live animals are provided in order to help future species identification. All four Melayonchis species live in mangrove forests. The geographic distribution of Melayonchis ranges from the Andaman Sea to the South China Sea through the Strait of Malacca. Records are based on entirely new collections from the Andaman Islands, Peninsular Malaysia, Singapore, Brunei Darussalam and Vietnam. The nomenclature of all existing onchidiid species- and genus-group names from that region is addressed, as well as intraspecific character variation within Melayonchis. www.zoobank.org/urn:lsid:zoobank.org:pub:671922DB-C6C1-44A5-B2CD-A3A3127CB668

Vallicula multiformis Rankin, 1956 (Ctenophora, Platyctenida): first record from the Indian Ocean

The benthic ctenophore Vallicula multiformis Rankin, 1956 is recorded for the first time in the Arabian Sea, from the Gulf of Kutch, west coast of India in March 2013. This occurrence represents a remarkable extension of its geographic distribution that until now included only known the Pacific and Atlantic oceans.

Checklist of free-living marine nematodes from intertidal sites along the central west coast of India

The present study provides a checklist of free-living marine nematode species from nine intertidal sites located along the central west coast of India covering an area between latitudes 16°33′08.47″ N and 16°38′50.75″ N and longitudes 073°19′30.13″ E and 073°23′34.97″ E. The list includes 33 species of marine nematodes belonging to 20 genera and 13 families. The occurrence of nematode species identified appears to be correlated to character of the sediments across sampled intertidal sites. Ten families were encountered in sandy sites while in muddy sites the number was ten. Three families, namely Camacolaimidae, Ironidae, and Microlaimidae, were exclusive to the sandy sites, while Anoplostomatidae, Comesomatidae, and Linhomoeidae were only found across muddy sites. Some of the dominant free-living marine nematode groups encountered across all sites was represented by the genera Ptycholaimellus , Viscosia , Oncholaimus , Halalaimus , and species such as Sphaerolaimus balticus and Metachromadora suecica .

A revision of Peronina Plate, 1893 (Gastropoda : Euthyneura : Onchidiidae) based on mitochondrial and nuclear DNA sequences, morphology and natural history

Abstract. Peronina Plate, 1893 is a genus of onchidiids that live on the mud in mangrove forests. Peronina can be identified in the field by the lung opening at the margin between the ventral hyponotum and the dorsal notum, and by the distinctive scalloped notum edge. This genus was previously known only from the holotype of the type species, Peronina alta Plate, 1893, from eastern India. Onchidium tenerum Stoliczka, 1869 is moved to Peronina and applies to the same species as Peronina alta. Peronina species are described using an integrative approach (natural history, comparative anatomy and DNA sequences). Mitochondrial COI and 16S sequences and nuclear ITS2 and 28S sequences are used to independently test species boundaries. Mitochondrial sequences yielded three units separated by a large barcode gap, but nuclear sequences yielded two units. Because these two units are congruent with differences in the male copulatory apparatus, they are accepted as species. Explanations for highly divergent COI haplotypes within one species are discussed. Peronina tenera (Stoliczka, 1869) is distributed in the Bay of Bengal and the Strait of Malacca, while P. zulfigari Goulding & Dayrat, sp. nov. is endemic to the Strait of Malacca. The two species differ internally but are cryptic externally.

First record of Thysanozoon brocchii (Platyhelminthes: Polycladida) from Indian waters

This work reports the occurrence of Thysanozoon brocchii from the rocky intertidal coast of Ratnagiri and Dwarka, the West Coast of India, for the first time. Two morphotypes were found, the first morph has a buff brownish papillate dorsal surface, with few specimens having white spots. The second morph has light coloured papillae which form a distinct cross marking along the dorsal surface. The species possesses double male copulatory apparatus with seminal vesicle, prostatic vesicle and sclerotized stylet. This cosmopolitan species has previously been recorded from Italy and Mediterranean, Japan, South and West Africa, Florida, New Zealand, Brazil, and United Kingdom. Synonymized species and older descriptions have been compared to examine similarities and dissimilarities. Considering the existence of varied colour morphs of this species, a detailed comparative analysis of morphological characters, reproductive histology and molecular framework is recommended.

Cassiopea andromeda (Forsskål, 1775) in the Gulf of Kutch, India: initial discovery of the scyphistoma, and a record of the medusa in nearly a century

BackgroundCassiopea andromeda is reported here after long gap of almost a century from the Gulf of Kutch, Gujarat. This is the first record of scyphistoma form of the species from India and first record of the medusa from the Arambhada coast.ResultsAn upside down scyphozoan jellyfish Cassiopea andromeda belong to family Cassiopeidae. Identification and description of medusa and scyphistomae were given based on morphological characters.ConclusionsThis paper discusses about the variation in colour form, aggregation of medusae and morphology of polyp.

Intertidal hydroids (Cnidaria: Hydrozoa: Hydroidolina) from the Gulf of Kutch, Gujarat, India

Investigations on hydroids in the vast Indo-Pacific region have been carried out since the 18th Century, and the fauna is at least moderately well-known. By comparison, those of India are much less studied (Nagale & Apte, 2013a), with species of the south-west and south-east coasts having received the most attention (Mammen, 1963, 1965a, b). The earliest records of these cnidarians from the State of Gujarat, northwest India, are based on collections in 1905–1906 by James Hornell, described by Thornely (1916). She reported 17 species from locations including Dwarka, Adatra and Poshitra. Otherwise, little is known about the hydroid fauna of the State of Gujarat. The objective of this study was to more fully investigate intertidal hydroids found in the Gulf of Kutch, Gujarat.