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Aenigmachanna mahabali, a new species of troglophilic snakehead (Pisces: Channidae) from Kerala, India
Abstract
Aenigmachanna mahabali, a new species of troglophilic snakehead is described on the basis of a single specimen recovered from a well in Kerala, India, over 200km south of the type locality for the only known species in the genus. The new species can be distinguished from its congener in possessing fewer dorsal fin rays (53 vs 56-57), fewer total vertebrae (61 vs 64), fewer scales in lateral series (76 vs 83-85) and in the pectoral-fin rays being extended beyond the margin of the membrane into filaments.
... The family Aenigmachannidae (dragon snakeheads) comprises an ancient 'Gondwanan' lineage within the acanthomorph clade Labyrinthici (Anabantiformes) . Considered 'living fossils', these bizarre snakehead-like fishes are endemic to south-western peninsular India ), from where a single genus, Aenigmachanna, and two species A. gollum and A. mahabali are currently known (Britz et al. 2019;Kumar et al. 2019). Both species have been known only from their original descriptions, and no further information on their distribution, population status or ecology is available. ...
... Both species have been known only from their original descriptions, and no further information on their distribution, population status or ecology is available. While A. gollum was collected from a paddy-field in the village of Oorakam in Malappuram district, Kerala (Britz et al. 2019), A. mahabali was found in a well in the village of Peringara, in Pathanamthitta district, Kerala (Kumar et al. 2019). ...
... The availability of several individuals (and populations) of Aenigmachanna gollum has resulted in a clearer understanding of intraspecific variation in this poorly-known species. The description of Aenigmachanna gollum was based on two specimens (Britz et al. 2019), and that of Aenigmachanna mahabali on a single specimen (Kumar et al. 2019). Both these studies, therefore, could not adequately consider intraspecific variation. ...
Diversity and distribution of dragon snakeheads of the family Aenigmachannidae,
and the identity of Aenigmachanna mahabali
... T HE family Channidae is represented by 53 species in three genera, Channa with 48 valid species distributed from the Middle East to South-East and Far-East Asia, Parachanna with three species restricted to tropical Africa, and Aenigmachanna with two species from the laterite areas of Western Ghats of India (Britz et al., 2019aKumar et al., 2019;Praveenraj et al., 2019a;Sudasinghe et al., 2020aSudasinghe et al., , 2020b. The Eastern Himalayan region possess a remarkable diversity of endemic snakeheads. ...
A new species of colorful snakehead from Meghalaya, northeastern India is distinguished from all its congeners by possessing a uniform bright blue to bluish-green body, bright-blue dorsal, anal, and caudal fins, submarginally black with white distal margin, series of brown to maroon-red, rounded, oblong or clover-shaped blotches or spots on dorsolateral, postorbital, and ventrolateral region of head, continued on body forming oblique pattern or randomly distributed. The new species superficially resembles C. pardalis and C. bipuli in appearance, but it can be distinguished from both in having brown to maroon-red, rounded, oblong or clover-shaped blotches or spots on head and sides of the body (vs. possession of well-defined, black to brown, rounded to oblong spots), fewer pre-dorsal scales (7 vs. 8-9), more caudal-fin rays (15 vs. 13), and more vertebrae (49 vs. 45). The new species differs from both C. pardalis and C. bipuli by Kimura's two-parameter (K2P) distance of 4.2-4.8 and 4.9-6.0% in the coxI gene sequence. A key to the snakehead Gachua group of the Eastern Himalayan region is provided herein.
... The Western Ghats mountain region is an area with a high level of freshwater fish endemism (Abell et al. 2008) and new species are being described from this part of Peninsular India on a regular basis (Katwate et al. 2014(Katwate et al. , 2018Dahanukar et al. , 2016Britz & Ali 2015;Kumkar et al. 2016;Britz et al. 2018Britz et al. , 2019Kumar et al. 2019). counts were obtained from specimens under transmitted light with the aid of a stereomicroscope. ...
Channa rara, new species, is described from the Jagbudi River in Maharashtra, India. It belongs to the Gachua group and differs from all its members by the possession of one or more ocelli in the posterior part of the dorsal fin in adults (vs. ocelli absent or 1, rarely 2–3 ocelli in juveniles only). It is further distinguished from most species of the C. gachua group by having 6–7 dark concentric bands on the pectoral fins. We review recent descriptions of species of the genus Channa and conclude that C. royi is a synonym of Channa harcourtbutleri, that the diagnosis of C. shingon from C. harcourtbutleri is seriously flawed and that C. torsaensis is not sufficiently diagnosed from C. quinquefasciata. The recently described C. amari is a junior synonym of C. brunnea.
... Our discovery of Pangio bhujia in the laterite areas of Kerala follows closely that of two other remarkable subterranean fishes, Aenigmachanna gollum (Britz et al. 2019) and A. mahabali (Kumar et al. 2019) raises the number of subterranean fishes from this part of India to ten. Among the species of Pangio, P. bhujia is easily recognized by the absence of both dorsal and pelvic fins and their skeletal supports (basipterygia and dorsal-fin pterygiophores). ...
A unique, new species of eel loach, Pangio bhujia, is described from Kerala, India. It is the first species of Pangio to be described from subterranean waters. It possesses several unusual characters including absence of both dorsal and pelvic fins, the presence of only 3 pectoral-fin rays, 6 anal-fin rays and a unique count of 38 precaudal + 24 caudal vertebrae.
Despite advances in biodiversity exploration, the origins of Sri Lanka's fauna and flora have never yet been treated in a synthetic work. This book draws together the threads that make up that fascinating 100-million year story. Encompassing the island's entire biota while emphasising the ecology, biogeography and phylogeography of freshwater fishes, it provides a comprehensive context for understanding how the island's plants and animals came to be as they are. The 258-page text contains more than 200 figures, photographs and maps. It provides a clear account of how, when and from where the ancestors of the plants and animals that now inhabit Sri Lanka came. For the first time, the island's unique biodiversity can be understood and appreciated in its historical and evolutionary context in this invaluable sourcebook, designed for scientists, students and biodiversity enthusiasts alike.
Pronounced organism-wide morphological stasis in evolution has resulted in taxa with unusually high numbers of primitive characters. These ‘living fossils’ hold a prominent role for our understanding of the diversification of the group in question. Here we provide the first detailed osteological analysis of Aenigmachanna gollum based on high-resolution nano-CT scans and one cleared and stained specimen of this recently described snakehead fish from subterranean waters of Kerala in South India. In addition to a number of derived and unique features, Aenigmachanna has several characters that exhibit putatively primitive conditions not encountered in the family Channidae. Our morphological analysis provides evidence for the phylogenetic position of Aenigmachanna as the sister group to Channidae. Molecular analyses further emphasize the uniqueness of Aenigmachanna and indicate that it is a separate lineage of snakeheads, estimated to have split from its sister group at least 34 or 109 million years ago depending on the fossil calibration employed. This may indicate that Aenigmachanna is a Gondwanan lineage, which has survived break-up of the supercontinent, with India separating from Africa at around 120 mya. The surprising morphological disparity of Aenigmachanna from members of the Channidae lead us to erect a new family of snakehead fishes, Aenigmachannidae, sister group to Channidae, to accommodate these unique snakehead fishes.
We present the latest version of the Molecular Evolutionary Genetics Analysis (MEGA) software, which contains many sophisticated
methods and tools for phylogenomics and phylomedicine. In this major upgrade, MEGA has been optimized for use on 64-bit computing
systems for analyzing bigger datasets. Researchers can now explore and analyze tens of thousands of sequences in MEGA. The
new version also provides an advanced wizard for building timetrees and includes a new functionality to automatically predict
gene duplication events in gene family trees. The 64-bit MEGA is made available in two interfaces: graphical and command line.
The graphical user interface (GUI) is a native Microsoft Windows application that can also be used on Mac OSX. The command
line MEGA is available as native applications for Windows, Linux, and Mac OSX. They are intended for use in high-throughput
and scripted analysis. Both versions are available from www.megasoftware.net free of charge.
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.
In surveillance of subterranean fauna, especially in the case of rare or elusive aquatic species, traditional techniques used for epigean species are often not feasible. We developed a non-invasive survey method based on environmental DNA (eDNA) to detect the presence of the red-listed cave-dwelling amphibian, Proteus anguinus, in the caves of the Dinaric Karst. We tested the method in fifteen caves in Croatia, from which the species was previously recorded or expected to occur. We successfully confirmed the presence of P. anguinus from ten caves and detected the species for the first time in five others. Using a hierarchical occupancy model we compared the availability and detection probability of eDNA of two water sampling methods, filtration and precipitation. The statistical analysis showed that both availability and detection probability depended on the method and estimates for both probabilities were higher using filter samples than for precipitation samples. Combining reliable field and laboratory methods with robust statistical modeling will give the best estimates of species occurrence.
The historical processes underlying high diversity in tropical biodiversity hotspots like the Western Ghats of Peninsular India remain poorly understood. We sampled bush frogs on 13 massifs across the Western Ghats Escarpment and examined the relative influence of Quaternary glaciations, ecological gradients and geological processes on the spatial patterns of lineage and clade diversification. The results reveal a large in situ radiation (more than 60 lineages), exhibiting geographical structure and clade-level endemism, with two deeply divergent sister clades, North and South, highlighting the biogeographic significance of an ancient valley, the Palghat Gap. A majority of the bush frog sister lineages were isolated on adjacent massifs, and signatures of range stasis provide support for the dominance of geological processes in allopatric speciation. In situ diversification events within the montane zones (more than 1800 m) of the two highest massifs suggest a role for climate-mediated forest-grassland persistence. Independent transitions along elevational gradients among sub-clades during the Miocene point to diversification along the elevational gradient. The study highlights the evolutionary significance of massifs in the Western Ghats with the high elevations acting as centres of lineage diversification and the low- and mid-elevations of the southern regions, with deeply divergent lineages, serving as museums.
Freshwater fauna are particularly sensitive to environmental change and disturbance. Management agencies frequently use fish and amphibian biodiversity as indicators of ecosystem health and a way to prioritize and assess management strategies. Traditional aquatic bioassessment that relies on capture of organisms via nets, traps, and electrofishing gear typically has low detection probabilities for rare species and can injure individuals of protected species. Our objective was to determine if environmental DNA (eDNA) sampling and metabarcoding analysis can be used to accurately measure species diversity in aquatic assemblages with differing structures. We manipulated the density and relative abundance of eight fish and one amphibian species in replicated 206-L mesocosms. Environmental DNA was filtered from water samples, and six mitochondrial gene fragments were Illumina-sequenced to measure species diversity in each mesocosm. Metabarcoding detected all nine species in all treatment replicates. Additionally, we found a modest, but positive, relationship between species abundance and sequencing read abundance. Our results illustrate the potential for eDNA sampling and metabarcoding approaches to improve quantification of aquatic species diversity in natural environments and point the way toward using eDNA metabarcoding as an index of macrofaunal species abundance. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
Mitochondrial DNA sequences of approximately 1.5 kbp including the NADH dehydrogenase subunit 2 (ND2) gene and its flanking
gene regions were determined for 20 species from the freshwater fish family Channidae and 3 species from Nandidae, Badidae,
and Osphronemidae. Channa orientalis and C. gachua had an approximately 170-bp insertion between the tRNAMet and ND2 genes, where a 5′-half of the insertion was similar to the 5′-end portion of the ND2 gene and a 3′-half was homologous
to the tRNAMet gene. This insertion may thus have originated from a tandem gene duplication that occurred in a common ancestor of these
two sister species. Molecular phylogenetic analyses from different tree-building methods consistently suggested the mutual
monophyly of the African and Asian taxa and the existence of several clades within the Asian taxa, some of which correspond
to distinct morphological features. Our molecular phylogeny clearly supported multiple independent losses of pelvic fins on
Asian lineages in parallel. Divergence time estimation based on some reasonable assumptions without assuming the molecular
clock suggested the early Cretaceous divergence of the African and Asian channids. The results thus support an ancient vicariant
divergence of the African and Asian channids, rather than the more recent dispersal between African and Eurasian continents.
During the period 2007-2011, two species of an enigmatic genus of siluriform fish, two species of another siluriform fish of the family Clariidae and a blind eel of the synbranchiform fish of the family Synbranchidae, were collected from nine different artificial wells located at the south-eastern part of Thrissur District, Kerala. These include three of the only six species reported from subterranean freshwaters of peninsular India and two undescribed species. Here we examine their morphological and behavioural peculiarities and report on their geography. We also discuss their troglomorphisms in relation with their observed habitat.
Southern India, one of the last strongholds of the endangered Asian elephant (Elephas maximus), harbours about one-fifth of the global population. We present here the first population genetic study of free-ranging Asian elephants, examining within- and among-population differentiation by analysing mitochondrial DNA (mtDNA) and nuclear microsatellite DNA differentiation across the Nilgiris-Eastern Ghats, Anamalai, and Periyar elephant reserves of southern India. Low mtDNA diversity and 'normal' microsatellite diversity were observed. Surprisingly, the Nilgiri population, which is the world's single largest Asian elephant population, had only one mtDNA haplotype and lower microsatellite diversity than the two other smaller populations examined. There was almost no mtDNA or microsatellite differentiation among localities within the Nilgiris, an area of about 15,000 km2. This suggests extensive gene flow in the past, which is compatible with the home ranges of several hundred square kilometres of elephants in southern India. Conversely, the Nilgiri population is genetically distinct at both mitochondrial and microsatellite markers from the two more southerly populations, Anamalai and Periyar, which in turn are not genetically differentiated from each other. The more southerly populations are separated from the Nilgiris by only a 40-km-wide stretch across a gap in the Western Ghats mountain range. These results variably indicate the importance of population bottlenecks, social organization, and biogeographic barriers in shaping the distribution of genetic variation among Asian elephant populations in southern India.
Aenigmachanna gollum, new genus and species, is described from Kerala, South India. It is the first subterranean species of the family Channidae. It has numerous derived and unique characters, separating it from both the Asian Channa Scopoli and the African Parachanna Teugels & Daget. Uniquely among channids, A. gollum has a very slender (maximum body depth only 11.1–11.3% SL), eel-like body (head length 20.8–21.6% SL), large mouth (jaw length 60.4–61.1 % HL), 43–44 anal-fin rays, 83–85 scales in a lateral series, an unusual colour pattern and it lacks pored lateral-line scales on the body and body buoyancy. In addition, it is distinguished by its DNA barcode sequence, which is 15.8–24.2% divergent from other species of the family Channidae. Morphological modifications usually associated with a subterranean life, such as reduction of eyes and enhancement of non-visual senses (taste, smell, mechanosensory systems) are absent in A. gollum. However, it shares with subterranean fishes a slight reduction of its pigmentation in comparison to epigean channids.
Life in caves means life in perpetual darkness. This has two dramatic effects on animals: it eliminates the need to see and reduces the availability of food as there is no local photosynthesis. Food availability for cave dwellers is often seasonal, episodic or unscheduled. Like other cave animals, fish species adapted for cave life exhibit a suite of sensory, morphological, physiological and behavioral traits that are shared among species from phylogenetically distant families. Most cave fishes are entirely or partially blind. The most extreme of them, the obligatory cave-dwelling fish that spend their entire life in caves, are the subject of this primer. At present, over 200 such cavefish species have been described, and all of them have evolved independently from surface ancestors. Thus, each cavefish species is a replicate of the same natural experiment, testing the evolutionary response of a sighted surface fish to the absence of light and the limitations on food in a subterranean environment. The evolutionary responses converge on loss of eyes and pigmentation and the augmentation of other senses, such as taste, smell or mechanosensation, as well as a more efficient metabolism, changes in feeding behavior, altered activity levels, loss of circadian rhythmicity and increased wakefulness. However, not all of these troglomorphic traits are present in every cavefish species.
Pomfrets (Genus Pampus) are commercially important fishes in the Indo Pacific region. The systematics of this genus is complicated due to morphological similarities between species. The silver pomfret from Indian waters has long been considered to be Pampus argenteus. The objective of the study was to utilize the mitochondrial COI gene to establish the molecular identity of the silver pomfret distributed in Indian waters and to resolve the phylogenetic relationships among Pampus species in the world based on sequence data in the NCBI database. Seven valid Pampus species are identified in this study. The mean genetic divergence value calculated between clades representing these species was 7.9%. The mean genetic distance between the so-called Pampus argenteus from Indian waters and sequences attributed to P. argenteus from the South China Sea, where the neotype of this species was collected, was found to be greater than 12%, strongly supporting the likelihood of the Indian species being distinct. The Indian Pampus species show very close affinity to P. cinereus, with inter species differences less than 2%. The taxonomic identity of the silver pomfret in India is also discussed here, in light of molecular and morphological evidence.
The ability to determine relationships of Cenozoic fossil fishes relies heavily on having osteological information from their extant relatives with which to compare the fossil remains. For many higher teleost fishes, these osteological data do not exist. For example, †Parachanna fayumensis, from Eocene and Oligocene deposits of Egypt, was placed in the Recent snakehead genus Parachanna, but in the absence of data from extant members of the genus, this hypothesis could not be tested. Three other fossil channids were each given their own new genera, without an analysis of their relationships to one another or to the living genera. In order to properly test the relationships of these fossil species, the osteological information for living species is needed. This paper documents the osteology of the African snakehead, Parachanna obscura, for the first time. The documentation of the osteology forms the basis of a phylogenetic study of the relationships of the African fossil, †Parachanna fayumensis, with living African snakeheads. This study supports the generic placement of †P. fayumensis as being correct, as well as reciprocal monophyly of the two living snakehead genera and monophyly of the family. Monophyly of the Asian genus Channa and the relationships of the other fossil species need to be further assessed using a broader range of species, but this preliminary study is an essential first step. Apomorphic osteological characters are given for the family and genera, as well as a discussion of the biogeographical relationships of species of Parachanna.
This is the report of a new species of catfish, Kryptoglanis shajii nov. gen. and nov. sp., distinguished from all other genera of siluriform fishes by the combination of the following morphological
characters: viz. the absence of dorsal fin; the presence of four pairs of barbels; an upwardly directed mouth, with a distinctly
projecting lower jaw; subcutaneous eyes; anal fin completely confluent with the caudal fin; anal and caudal fins together
carry 70–74 fin rays; and no spines in any of the fins. Kryptoglanis, which has a maximum recorded size of 59.1 mm in standard length, was collected from a well fed by subterranean springs.
The type locality is a well located at the extreme western part of Western Ghats, near Chalakudy in Thrissur district, Kerala
State, India.
Channa panaw sp. nov. (Channidae) is described from 32 specimens collected from the Irrawaddy and Sittang River basins, Myanmar. It is
distinguishable from all known congeners by the combination of the following characters: 32–35 dorsal fin rays, 23–24 anal
fin rays, 17–20 pectoral fin rays, 39–41 lateral line scales, 39–41 total vertebrae, one large scale on each side of the lower
jaw (rarely 2 on one side), pelvic fin length always more than 50% of pectoral fin length, and 7–12 irregular black blotches
on the upper half of the body.
Freshwater snakehead fishes (Channidae) provide an interesting target for phylogenetic analysis for the following reasons, their unusual biology, potential for cryptic diversity and availability of a good fossil record. Here, a multi-locus molecular phylogeny was constructed and calibrated using two fossil dates to estimate divergence times within the family. Sampling aimed to explore interspecific divergence of Channa species across Southeast Asia and intra-specific variation where species possessed natural geographical ranges that were extensive. Results contradict divergence times estimated previously independently from single locus mitochondrial data or the fossil record and suggest that after divergence from African taxa 40-50 Ma, evolution of Asian snakeheads has been heavily influenced by multiple broad scale dispersal events across India and Southeast Asia. A similar pattern of divergence within multiple clades suggests that west-east dispersal was limited for many taxa during the Miocene. Deep intra-specific divergence was inferred for C. striata, indicating that long historical periods of isolation ( approximately 8Ma) have not resulted in the evolution of reproductive isolation within this species. Results support suggestions that C. marulia like fishes in northern Cambodia may constitute an undescribed species, and that Indian C. diplogramma warrants taxonomic recognition as being distinct from Southeast Asian C. micropeltes, with the two taxa last sharing a common ancestor in the mid- to late-Miocene.
http://deepblue.lib.umich.edu/bitstream/2027.42/57162/1/OP726.pdf
A new species of the blind fish horaglanis Menon (Siluroidea: Claridae) from Parappukara (Trichur District) and a new report of horaglanis krishnai Menon from Ettumanur (Kottayam district)
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Babu, K.K.S. & Nayar, C.K.G. (2004) A new species of the blind fish horaglanis Menon (Siluroidea: Claridae) from Parappukara (Trichur District) and a new report of horaglanis krishnai Menon from Ettumanur (Kottayam district), Kerala. Journal
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The labyrinthici of Ceylon
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A new synbranchid fish, Monopterus digressus from Kerala, Peninsular India. Records of the Zoological Survey of India
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Gopi, K.C. (2002) A new synbranchid fish, Monopterus digressus from Kerala, Peninsular India. Records of the Zoological
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BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT
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The structural and drainage patterns of the Western Ghats in the vicinity of the Palghat Gap
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Subterranean fishes of the world. Electronic Version
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Inland fishes of India and adjacent countries
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Parachanna nom. nov. for the African snake-heads and rehabilitation of Parachanna insignis (Sauvage,1884) (Pisces, Channidae)
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