Sameer M. Padhye

Cyclestheria hislopi (Crustacea: Branchiopoda): A group of morphologically cryptic species with origins in the Cretaceous

Cyclestheria hislopi is thought to be the only extant species of Cyclestherida. It is the sister taxon of all Cladocera and displays morphological characteristics intermediate of Spinicaudata and Cladocera. Using one mitochondrial (COI) and two nuclear (EF1α and 28S rRNA) markers, we tested the hypothesis that C. hislopi represents a single circumtropic species. South American (French Guiana), Asian (India, Indonesia, Singapore) and several Australian populations were included in our investigation. Phylogenetic and genetic distance analyses revealed remarkable intercontinental genetic differentiation (uncorrected p-distances COI>13%, EF1α>3% and 28S>4%). Each continent was found to have at least one distinct Cyclestheria species, with Australia boasting four distinct main lineages which may be attributed to two to three species. The divergence of these species (constituting crown group Cyclestherida) was, on the basis of phylogenetic analyses of COI and EF1α combined with molecular clock estimates using several fossil branchiopod calibration points or a COI substitution rate of 1.4% per million years, dated to the Cretaceous. This was when the South American lineage split from the Asian-Australian lineage, with the latter diverging further in the Paleogene. Todays circumtropic distribution of Cyclestheria may be best explained by a combination of Gondwana vicariance and later dispersal across Asia and Australia when the tectonic plates of the two continents drew closer in the early Miocene. The lack of morphological differentiation that has taken place in this taxon over such a long evolutionary period contrasts with the high level of differentiation and diversification observed in its sister taxon the Cladocera. Further insights into the evolution of Cyclestheria may help us to understand the evolutionary success of the Cladocera.

A new species of Streptocephalus (Crustacea: Anostraca: Streptocephalidae) from the Western Ghats, India, with a key to the Asian species

We present and describe the fairy shrimp Streptocephalus sahyadriensis sp. nov. from the Western Ghats of India. This species is most similar to S. simplex Gurney, 1906 and S. dichotomus Baird, 1860 sharing similar basic antennal appendage morphology. However, S. sahyadriensis sp. nov. differs in the form of the ornamentation on the peduncle and the arrangement and form of spines on the antennal appendage. The three species also have different egg surface morphologies. The Asian species of Streptocephalus are discussed and a key to species is provided.

First faunal inventory of large branchiopods (Crustacea: Branchiopoda) of Western Maharashtra, India with taxonomical and distributional comments

An updated inventory of large branchiopods of the Western Maharashtra state, India is presented for the first time. Employing current identification keys, we have detailed the egg morphology of Eulimnadia indocylindrova, which shares some similarities with E. geayi from South America and E. alluaudi from Madagascar, based on these egg characters. A thorough re-description of few morphological traits of the same species is also presented. We also have described the female of a Cyzicus species seen rarely from the studied region. Distributional comments on few species are also reported.

Review of the large branchiopod crustacean fauna of the Indian subcontinent (Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cyclestherida)

The large branchiopod crustaceans (fairy shrimp, tadpole shrimp, and clam shrimp) of India have been examined with varying degrees of scientific rigour since the late 1800s. Although 86 nominal species have been reported for India, the validity of many is in question – particularly for the clam shrimp. Most Indian endemic taxa are poorly described; some lack type material or the type material has been lost. Most recent revisions of key groups have made no attempt to validate identifications using existing type material, or even to procure topotype material. Worse, recent reviews treat old synonyms as valid names without any analysis or explanation. We provide a review of the taxa from the Indian subcontinent (Bangladesh, India, Nepal, Pakistan, and Sri Lanka) taking a strongly conservative approach to assessing the reported species. We recognize only 42 species: 16 anostracans, 2 notostracans, 3 laevicaudatans, 21 spinicaudatans (with reservations), and a single species of cyclestherid. This should establish a base point for future work on the branchiopods of the subcontinent.

Hatching phenology, life history and population dynamics of the Oriental clam shrimp Eulimnadia indocylindrova Durga Prasad and Simhachalam with notes on phenology patterns in the Spinicaudata

ABSTRACT We studied the natural history, hatching phenology and egg bank composition of the Oriental spinicaudatan clam shrimp Eulimnadia indocylindrova Durga Prasad and Simhachalam using both field studies and ex situ sediment rehydration. Field observations revealed that hatching began very early (1–2 days) after inundation, and continued for about 5 days. Mature adults could be observed by 10 days, and they survived up to 16 days. The population showed a largely hermaphrodite-biased sex ratio (male:hermaphrodite 1:3) observed over three years, with a decrease in number of males throughout the hydroperiod. Both amphigenic and monogenic hermaphrodites were observed. The total lifetime fecundity recorded was about 300 eggs laid in multiple clutches. The egg bank composition showed a high proportion of intact eggs, indicative of predictable hydrations and low sediment adversity. Hatching began on the first day post-inundation for all successive cyclical hydration treatments, with peak hatching on days 2 and 3. Hatching rate was highest (57% of total hatching in successive cycles) for the first hydration, decreasing subsequently for the further hydrations. Hatching duration decreased with successive hydrations and was the longest (around 7 days) for the first hydration. Maximum hatching (93%) occurred in the first 10 days for the continuous hydration treatment. Overall, the total emergence of nauplii in successive hydrations was larger than that observed for the continuous hydration treatment, indicative of a risk-spreading strategy across hydroperiods. Early and concentrated naupliar emergence, along with decreased hatching durations for successive cycles, was observed for all the hydrations. A survey of literature revealed a general lack of data on hatching phenology of clam shrimps, particularly from tropical and sub-tropical regions. Based on the available data, it appears that hatching patterns, particularly high, early hatching fractions, are commonly observed in Spinicaudata species, and do not seem to differ much across biogeographical regions.

A new species of genus Eulimnadia Packard, 1874 (Branchiopoda: Spinicaudata: Limnadiidae) from India with an updated key for some Indian species

We describe a new species of Eulimnadia, Eulimnadia bondi sp. nov., from the state of Goa, India. This is the 8th species to be described from the country and first from this state. This species differs from all other Indian species in having unique egg morphology-cylindrical egg with dilated borders at both ends and a specific internal eggshell structure. Specimens showed intra-population morphological variation as observed in other species from the genus. Eulimnadia bondi sp. nov. egg resembles the South American E. colombiensis and the Australian E. australiensis. These species are however distinguished on egg morphological details and by some morphological characteristic of adults. Based on the available information, we present an overview of the distribution of the different Indian Eulimnadia species and an updated identification key based on egg morphology.

Note on Kurzia ( Kurzia ) latissima (Kurz, 1875) (Branchiopoda: Anomopoda: Chydoridae) from India

Members of the chydorid genus Kurzia Dybowski & Grochowski, 1894 (Branchiopoda: Anomopoda) are typically known from the Holarctic and the Neotropics (Rajapaska & Fernando 1986; Hudec 2000; Elmoor-Loureiro 2002; Kotov, 2004). One representative of the sub genus Kurzia, Kurzia (Kurzia) latissima (Kurz 1875) has been reported from India, in the Oriental Zone. These reports either have unreliable or no illustrations (Rane, 1983; Michael & Sharma 1988; Padhye & Dumont 2015). Recently, Chatterjee et al. (2013) have stated that records of K. latissima from India appear morphologically similar to K. latissima s.str. but have not elaborated on it. The aim of this correspondence is to present an initial diagnosis and provide illustrations of a Kurzia latissima-like population from the Northern Western Ghats, Maharashtra Province, India, along with comments on its distribution.

CORRECTIONS TO A 2003 CHECKLIST OF THE CLADOCERA OF INDIA

The nomenclatural validity of some Indian species of Cladocera listed by Raghunathan & Kumar (2003) is examined and corrected. The reasons for the numerous shortcomings of the checklist are analysed.