Snakehead fishes of the family Channidae are predatory freshwater teleosts from Africa and Asia comprising 38 valid species. Snakeheads are important food fishes (aquaculture, live food trade) and ...have been introduced widely with several species becoming highly invasive. A channid barcode library was recently assembled by Serrao and co-workers to better detect and identify potential and established invasive snakehead species outside their native range. Comparing our own recent phylogenetic results of this taxonomically confusing group with those previously reported revealed several inconsistencies that prompted us to expand and improve on previous studies. By generating 343 novel snakehead coxI sequences and combining them with an additional 434 coxI sequences from GenBank we highlight several problems with previous efforts towards the assembly of a snakehead reference barcode library. We found that 16.3% of the channid coxI sequences deposited in GenBank are based on misidentifications. With the inclusion of our own data we were, however, able to solve these cases of perpetuated taxonomic confusion. Different species delimitation approaches we employed (BIN, GMYC, and PTP) were congruent in suggesting a potentially much higher species diversity within snakeheads than currently recognized. In total, 90 BINs were recovered and within a total of 15 currently recognized species multiple BINs were identified. This higher species diversity is mostly due to either the incorporation of undescribed, narrow range, endemics from the Eastern Himalaya biodiversity hotspot or the incorporation of several widespread species characterized by deep genetic splits between geographically well-defined lineages. In the latter case, over-lumping in the past has deflated the actual species numbers. Further integrative approaches are clearly needed for providing a better taxonomic understanding of snakehead diversity, new species descriptions and taxonomic revisions of the group.
Aim
The Western Ghats Hotspot in peninsular India harbours remarkable diversity and endemism of freshwater fish. However, the ichthyofauna's evolutionary histories and biogeography are poorly known. ...Here, we investigate (a) the diversity, evolutionary history and biogeography of endemic mountain loaches and (b) the potential influence of the physiography of hill ranges, geological barriers and river systems on the diversification and cladogenesis of loaches, in the Western Ghats Biodiversity Hotspot.
Location
Southern Western Ghats mountain ranges (8–13°N latitudes), Western Ghats‐Sri Lanka Biodiversity Hotspot.
Taxa
Mountain loaches Bhavania annandalei and B. australis (Cypriniformes: Balitoridae).
Methods
We carried out a multigene phylogenetic analysis with mitochondrial and nuclear markers using Bhavania specimens collected throughout the genus' range. The Automated Barcode Gap Analysis, Poisson Tree Process and Generalized Mixed Yule‐Coalescent Model were used to delimit species. A Bayesian chronogram was constructed to estimate the time elapsed since the most recent common ancestor of the distinct lineages of Bhavania. Ancestral ranges of distinct lineages of Bhavania were reconstructed using the dispersal–extinction–cladogenesis model.
Results
Phylogenetic analysis of combined mitochondrial and nuclear data, as well species delimitation using the Poisson Tree Process and Generalized Mixed Yule‐Coalescent Model analyses supported eight distinct lineages, which included the narrowly distributed B. annandalei and widely distributed B. australis. The Barcode Gap Analysis, however, supported only seven lineages. Bayesian divergence time dating suggests that the genus originated early in the Neogene and diversified in the Miocene. Ancestral state reconstruction indicated Bhavania diversifed as a result of sympatric, subset and vicariant speciation with five dispersal and one vicariant events across biogeographic barriers and river systems.
Main conclusions
Bhavania australis is a ‘species complex’. Miocene‐associated climatic changes including intensification of the south‐west monsoon likely triggered dispersal and range expansion; subsequent aridification would have led to drying up of riverine connections, formation of land barriers and fragmentation of streams, resulting in cladogenesis. Our results also provide preliminary evidence that Cauvery, one of the largest east flowing rivers of Western Ghats, facilitates an east‐west pathway for dispersal and diversification of endemic lineages of the region.
Abstract
Sri Lanka’s biota is derived largely from Southeast Asian lineages which immigrated via India following its early-Eocene contact with Laurasia. The island is now separated from southeastern ...India by the 30 km wide Palk Strait which, during sea-level low-stands, was bridged by the 140 km-wide Palk Isthmus. Consequently, biotic ingress and egress were mediated largely by the climate of the isthmus. Because of their dependence on perennial aquatic habitats, freshwater fish are useful models for biogeographic studies. Here we investigate the timing and dynamics of the colonization of—and diversification on—Sri Lanka by a group of four closely-related genera of cyprinid fishes (
Puntius
sensu lato). We construct a molecular phylogeny based on two mitochondrial and two nuclear gene markers, conduct divergence timing analyses and ancestral-range estimations to infer historical biogeography, and use haplotype networks to discern phylogeographic patterns. The origin of
Puntius
s.l. is dated to ~ 20 Ma. The source of diversification of
Puntius
s.l. is Sri Lanka-Peninsular India. Species confined to perhumid rainforests show strong phylogeographic structure, while habitat generalists show little or no such structure. Ancestral range estimations for
Plesiopuntius bimaculatus
and
Puntius dorsalis
support an ‘Out of Sri Lanka’ scenario. Sri Lankan
Puntius
s.l. derive from multiple migrations across the Palk Isthmus between the early Miocene and the late Pleistocene. Species dependent on an aseasonal climate survived aridification in rainforest refugia in the island’s perhumid southwest and went on to recolonize the island and even southern India when pluvial conditions resumed. Our results support an historical extinction of Sri Lanka’s montane aquatic fauna, followed by a recent partial recolonization of the highlands, showing also that headwater stream capture facilitated dispersal across basin boundaries.
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•Eleven distinct lineages were delimited in the endemic genus Mesonoemacheilus.•Time-tree estimates a Paleogene (~38 mya) origin of the genus Mesonoemacheilus.•Mesonoemacheild loaches ...diversified during the Neogene and Quaternary.•Inter-drainage exchange and vicariance are likely mechanisms of diversification.
Rivers draining the Western Ghats (WG) mountain ranges in peninsular India harbor an exceptionally diverse, unique and evolutionarily distinct assemblage of lower vertebrates with high levels of endemism, attributed to their evolution and potentially long history of isolation during the Late Cretaceous or Early Tertiary. A molecular phylogeny of hillstream loaches of the genus Mesonoemacheilus endemic to the WG revealed the presence of four clades which we designate as ‘species groups’. A consensus of various species delimitation methods indicates the likelihood of ‘at least’ seven more undescribed species within Mesonoemacheilus. Molecular clock analysis dates the basal clade around 38 mya in the Paleogene, and subsequent diversification in the Neogene and Quaternary periods resulting in the current genetic diversity. Biogeographic analysis suggests that vicariance events which separated the rivers on either side of the two geological barriers/gaps, the Palghat and Shencottah, in the Neogene, as well as range contractions and cladogenetic events contributed to the current patterns of diversity and distribution of this genus. Our results also provide preliminary indications on the interconnections and faunal exchange between historical river drainages in the WG region.
The cyprinid genus
Dawkinsia
comprises 13 species distributed in lowland streams and rivers in southern peninsular India and Sri Lanka. Eleven species are endemic to India, largely restricted to ...streams draining the Western Ghats, while one is confined to the Knuckles Hills of Sri Lanka. One species,
D. filamentosa
, has a wide range, straddling the island and mainland. Here, based on 135 samples representative of all 13 species, collected from 45 locations in India and 17 in Sri Lanka, we present phylogenetic and phylogeographic analyses of
Dawkinsia
. We use two mitochondrial markers—
cytochrome b
and
cytochrome c oxidase subunit 1
.
Dawkinsia
is recovered as paraphyletic with respect to
Sahyadria
, with strong node support. The ‘filamentosa group’ which includes both Sri Lankan and Indian taxa (
D
.
filamentosa
,
D
.
crassa
,
D
.
rohani
,
D
.
exclamatio
,
D
.
srilankensis
,
D
.
tambraparniei
,
D
.
arulius
,
D
.
rubrotincta
and
D
.
uttara
) is recovered as the sister group of
Sahyadria
, a genus confined to the Western Ghats. The ‘assimilis group’, which consists entirely of Indian endemics (
D
.
assimilis
,
D
.
austellus
,
D
.
apsara
and
D
.
lepida
), is recovered as the sister group of the ‘filamentosa group’ +
Sahyadria
. Ancestral-range estimates indicate two colonization events from India to Sri Lanka, across the Palk Isthmus. The first of these, in the Pliocene, involved the common ancestor of
D. tambraparniei
and
D. srilankensis
, while the second was of
D. filamentosa
in the late Pleistocene.
Dawkinsia filamentosa
shows little phylogeographic structure within or between Sri Lanka and India. Ancestral-range analyses suggest that neither the Palghat nor Shencottah Gaps acted as barriers to the north–south dispersal of
Dawkinsia
along the Western Ghats. Instead, these valleys appear to have offered lowland passages for west–east colonization by some ancestral species across the Western Ghats ridge. Despite the Palk Isthmus having been subaerial for much of the Plio-Pleistocene and serving as the only terrestrial biotic corridor connecting Sri Lanka to the Asian mainland, it appears to have served also as a climatic filter to dispersal following the aridification of south-eastern India during the Late Miocene/early Pliocene.
The teleostean family Balitoridae comprises small-sized freshwater fishes adapted to swift-flowing torrential mountain streams in South and South-East Asia. Little is known about their molecular ...phylogenetics and evolutionary biogeography, and much of the scientific literature that references them is focused on morphological taxonomy. In this paper, we generate CO1 sequences for the endemic balitorid lineages of the Western Ghats (WG) Hotspot in India, particularly for the endemic genera, Bhavania, Ghatsa and Travancoria. Integration of these data into a phylogeny revealed that the endemic WG genera together form a well-supported monophyletic clade that shows, subject to our limited taxon sampling, a sister-group relationship to the Southeast Asian genus Pseudohomaloptera. Three WG endemic species of the genus Balitora, namely B. chipkali, B. jalpalli and B. laticauda, though morphologically distinct, have low genetic divergence and barcode gap, suggestive of recent speciation. Interestingly, a fourth WG endemic, B. mysorensis, formed a clade with two species of Balitora from Eastern-Himalaya and Indo-Burma. We also show that all available CO1 sequences assigned to WG endemic balitorid genera in GenBank are misidentifications, and provide diagnostic characters for the accurate identification of these taxa in the future.
In this note we provide the first report of stinkhorn fungus Aseroë coccinea from northern Western Ghats of India and first report of this species from outside its type locality in Japan. In addition ...to the morphological characters, we also provide sequences for two molecular markers and provide a phylogenetic tree, which questions the generic position of the species. Our report highlights the need for more exploratory surveys for understanding diversity, distribution and taxonomy of Phallales and in general fungal diversity of India.
The world’s largest subterranean fish was discovered in 2019, and was tentatively identified as a troglomorphic form of the golden mahseer,
Tor putitora
. Detailed analyses of its morphometric and ...meristic data, and results from molecular analyses now reveal that it is a new species of the genus
Neolissochilus
, the sister taxon of
Tor.
We formally describe the new species as
Neolissochilus pnar
, honouring the tribal communities of East Jaintia hills in Meghalaya, Northeast India, from where it was discovered.
Neolissochilus pnar
possesses a number of characters unique among species of
Neolissochilus
, with the exception of the similarly subterranean
N. subterraneus
from Thailand. The unique characters that diagnose
N. pnar
from all epigean congeners comprise highly reduced eye size to complete absence of externally visible eyes, complete lack of pigmentation, long maxillary barbels, long pectoral-fin rays, and scalation pattern.
Neolissochilus pnar
is distinguished from the hypogean
N. subterraneus
, the type locality of which is a limestone cave ~2000 kms away in Central Thailand, by a lesser pre-pelvic length (47.8–49.4
vs.
50.5–55.3 %SL), a shorter caudal peduncle (16.1–16.8 vs. 17.8–23.7 %SL), and shorter dorsal fin (17.4–20.8 vs. 21.5–26.3 %SL). In addition,
Neolissochilus pnar
is also genetically and morphologically distinct from its close congeners with a raw genetic divergence of 1.1–2.7% in the COI gene with putative topotype of
N. hexastichus
and 2.1–2.6% with putative topotype of
N. hexagonolepis
.
We studied reversed sexual dimorphism (RSD) and foraging behavior of Barn Owls (Tyto alba). Bill length, tarsus length, wing chord, tail length, and mass of Barn Owls showed RSD. Mass of the prey ...items brought by the males was significantly less than that brought by females, which may be attributed to the positive correlation between size of the owl and prey mass. However, male owls had a significantly higher frequency of visits with prey than did females. There was relatively little overlap in the species and mass of prey captured by males and females, suggesting that food-niche partitioning between the sexes may exist, possibly to reduce intersexual food competition. Further, because these differences were also observed between the male and female owls within each pair, our findings support reproductive role division as a possible explanation for RSD in Barn Owls.
Abstract
The diving beetle genus
Peschetius
Guignot, 1942 (Coleoptera: Dytiscidae) in India is reviewed. Integrative taxonomic approach using morphology, multivariate morphometry and genetic analysis ...of cytochrome oxidase subunit 1 revealed the presence of four species, two of which are described here as new:
Peschetius bistroemi
sp. nov.
from southern Western Ghats (Kerala) differs from all known congeners with distinctly broadened male antennomeres IV and V, shape of the prosternal process and the male genitalia;
P. nilssoni
sp. nov.
from northern Western Ghats, Rajasthan and Madhya Pradesh is similar to the widespread Indian
P. toxophorus
Guignot, 1942, from which it differs in habitus, elytral colour pattern and the shape of the male genitalia. New records are presented for the remaining Indian species, namely
P. quadricostatus
(Aubé, 1838) and
P. toxophorus
. All species are diagnosed, illustrated and a key to their identification is provided.
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