[Ichthyology • 2020] Macrognathus kris • A New, uniquely patterned Spiny Eel (Synbranchiformes: Mastacembelidae) from southern Borneo, Kalimantan Tengah, Indonesia

 Macrognathus kris

 Ng & Tan, 2020

 

 DOI: doi.org/10.11646/zootaxa.4819.1.9 

Abstract

A new species of Macrognathus of the M. aculeatus species group is described from the Kahayan River drainage in southern Borneo, Kalimantan Tengah, Indonesia. Macrognathus kris, new species, is distinguished from all Asian congeners in having the following unique combination of characters: rim of anterior nostril with two fimbriae and two fimbrules; 43–45 rostral tooth plates; 24–25 dorsal spines; 46–55 dorsal-fin rays; 51–59 anal-fin rays; 20–23 principal caudal-fin rays; 76–78 total vertebrae; body depth at anus 11.8–15.9% SL; color pattern consisting of light brown stripe on dorsum and 11–14 irregular pentagonal dark brown blotches on sides of body.

Synbranchiformes, Macrognathus, biodiversity, Pisces

 Macrognathus kris,
A. MZB 10978, holotype, 189.4 mm SL; B. ZRC 51203, paratype, 99.8 mm SL;
C. ZRC 51202, paratype, 227.3 mm SL; D. ZRC 51204, 370.0 mm SL.

Macrognathus kris 

Distribution. This species is currently known only from the Rungan River sub-drainage of the Kahayan River drainage in Central Kalimantan, Borneo ( Fig. 2). We hypothesize that it may occur also in neighboring sub-drainages within the Kahayan River drainage, or even in adjacent river drainages (e.g. the Mentaya River drainage). Further surveys are needed to confirm this.

Habitat. Macrognathus kris inhabits blackwater habitats associated with peat swamp forests. Sungai Panta (where some of the paratypes have been collected) is a blackwater feeder stream flowing into Rungan River, with alluvial forest and flooded forest habitats. Syntopic fish species include: Brevibora cheeya Liao & Tan, Crossocheilus pseudobagarius Duncker, Desmopuntius foerschi (Kottelat), D. johorensis (Duncker), D. rhomboocellatus (Koumans), Eirmotus cf. insignis Tan & Kottelat, Malayochela maassii (Weber & de Beaufort), Osteochilus pentalineatus Kottelat, O. spilurus (Bleeker), Striuntius lineatus (Duncker) ( Cyprinidae), Kottelatia brittani (Axelrod), ...., Betta anabatoides Bleeker, B. edithae Vierke, Luciocephalus aura Tan & Ng, Parosphromenus filamentosus Vierke, Sphaerichthys acrostoma Vierke, S. selatanensis Vierke, Trichopodus leerii (Bleeker) ( Osphronemidae), Achiroides sp. ( Soleidae), and Pao palembangensis (Bleeker) ( Tetraodontidae). The inhabitants are a mix of riverine—with mainly swamp forest and peat swamp—taxa.

Etymology. The kris is a wavy-bladed dagger carried and used by local nobility and warriors. The name is used as a noun in apposition, in allusion to the wavy or zigzag pattern on the body of the spiny eel and the general resting posture of the fish when viewed from above.

 

Heok Hee Ng and Heok Hui Tan. 2020. A New, uniquely patterned Spiny Eel (Teleostei: Mastacembelidae) from southern Borneo, Kalimantan Tengah, Indonesia. Zootaxa. 4819(1); 170-178. DOI: doi.org/10.11646/zootaxa.4819.1.9 

[Ichthyology • 2024] Ophisternon berlini • A New Endogean, Dwarf, and Troglomorphic Species of Swamp Eel of the Genus Ophisternon (Synbranchiformes: Synbranchidae) from Costa Rica: Evidence from Comparative Mitogenomic and Anatomical Data

Ophisternon berlini   

Arroyave, Angulo,  Mar-Silva & Stiassny, 2024

Berlin’s Bloodworm Eel  ||  DOI: 10.1643/i2024055

 

A new highly troglomorphic and diminutive swamp eel inhabiting muddy subsoil in remnants of a tropical rainforest in the Caribbean versant of Costa Rica is described. Comparative anatomical and mitogenomic data support the distinctiveness of the new species and its placement in the genus Ophisternon. The new species is unique among Neotropical congeners in having: 1) a greatly elevated number of precaudal vertebrae, 2) proportionally longer and larger premaxillary, dentary, palatine, and ectopterygoid teeth, 3) palatine and ectopterygoid teeth in a single row, and 4) a small, narrow, and crescent-shaped gill membrane opening. A novel phylogenetic hypothesis of synbranchid relationships proposed herein, derived from comparative mitogenomic data, adds to a body of evidence demonstrating that Ophisternon is not monophyletic (with respect to Synbranchus). This phylogeny, however, strongly supports the monophyly of Neotropical Ophisternon, with the new species resolved as sister to a clade consisting of Ophisternon infernale + Ophisternon aenigmaticum. A pattern of northwestern lineage dispersal and cladogenesis within the Neotropical clade of Ophisternon after its divergence from Synbranchus is inferred from our phylogenetic results and present-day species distributions. Our findings also reinforce the notion that the classification of synbranchid fishes is in dire need of a systematic and comprehensive revision, particularly with respect to the limits and composition of the genera with presence in the Neotropics.

Type locality of Ophisternon berlini, new species.
 (A) Vantage point view of the Destierro River within the premises of Las Brisas Nature Reserve near collecting sites. (B) One of the artificial lentic bodies of water inside the reserve near collecting sites. (C, D) Photographs of the 2021 collecting site ... displaying the muddy nature of the soil at the time of collection. (E) Live specimen of Ophisternon berlini, new species, freshly dug out from the abovementioned site.

Unearthing of specimens of Ophisternon berlini, new species. Photograph displaying the process of pulling out live specimens of the new species from a block of mud collected at the type locality.

Ophisternon berlini, new species 

Berlin’s Bloodworm Eel

 

Diagnosis.— Ophisternon berlini is assigned to the genus Ophisternon by having a pectoral girdle connected to the skull by a forked posttemporal joining the supracleithrum at the level of the third vertebra vs. posteriorly displaced to the level of the fifth vertebra with posttemporal reduced to a simple rod and disconnected from the supracleithrum in Synbranchus (Fig. 4) and a branchiostegal membrane opening slit-like vs. small pore-like in Synbranchus (Fig. 5). Ophisternon berlini is unique among its Neotropical congeners in having: 1) an elevated number of precaudal vertebrae: ∼100 vs. ...

Etymology.— The specific epithet (a noun in the genitive case) is a patronym honoring Mr. Erick Berlin, a strong supporter of conservation and scientific research of Costa Rican biodiversity, discoverer of the population of swamp eel herein formally described, and owner of La Brisas, a private nature reserve that contains the type locality of the new species.

Jairo Arroyave; Arturo Angulo; Adán Fernando Mar-Silva and Melanie L. J. Stiassny. 2024. A New Endogean, Dwarf, and Troglomorphic Species of Swamp Eel of the Genus Ophisternon (Synbranchiformes: Synbranchidae) from Costa Rica: Evidence from Comparative Mitogenomic and Anatomical Data. Ichthyology & Herpetology. 112(3); 375–390. DOI: 

doi.org/10.1643/i2024055

[Ichthyology • 2024] Sinobdella longitubulus • A New Species of Spiny Eel (Pisces: Mastacembelidae) from the Zhu-Jiang Basin, southern China, with A Note on the Type Locality of S. sinensis (Bleeker, 1870)

 

 Sinobdella longitubulus Shan & Zhang,   

in Shan, Li et Zhang, 2024.

长管华刺鳅  ||  DOI: 10.3897/BDJ.12.e123990

Abstract

Background: The spiny eel genus Sinobdella belongs to the family Mastacembelidae of the order Synbranchiformes. Kottelat and Lim (1994) utilised Rhynchobdella sinensis as the type species to propose the genus. Currently, it contains a single species widespread in eastern and southern China and northern Vietnam.

New information: Sinobdella longitubulus, a new species of spiny eel, is here described from the Xi-Jiang of the Zhu-Jiang Basin in Guangxi Zhuang Autonomous Region, southern China. It differs from the single congeneric species S. sinensis in having a more or less white-brown reticulated pattern on the flank, two tubular anterior nostrils longer than or equal to the rostral appendage, an anal fin heavily mottled with dark brown markings and white spots and bearing a narrow white distal margin; shorter pre-anal length; and fewer abdominal vertebrae. The validity of this new species is corroborated by its monophyly recovered in a COI gene-based phylogenetic analysis and its significant sequence divergence with S. sinensis. A note on the type locality of S. sinensis is also given; its type specimen is possibly from mountain streams of Jiangxi Province, in the lower Chang-Jiang Basin.

Keywords: Sinobdella, new species, taxonomy, Zhu-Jiang Basin

 Sinobdella longitubulus, holotype, IHB 202303066738, 153.3 mm SL, dorsal (a), lateral (b) and ventral (c) views. China: Guangxi Province: Guigang City: Pingnan County: Lilia Village: Datong-Jiang, a stream tributary to Meng-Jiang flowing into Xi-Jiang of Zhu-Jiang basin.

 Sinobdella longitubulus, IHB 202303066740, 148.7 mm SL, China: Guangxi Province: Guigang City: Pingnan County: Lilia Town: Datong-Jiang: Zhu-Jiang Basin;

Sinobdella longitubulus Shan & Zhang sp. nov.

Diagnosis: Sinobdella longitubulus is clearly distinguished from the single congeneric species (S. sinensis) by having a more or less white-brown reticulated pattern (vs. many dark brown vertical bars, with very narrow light yellow interspaces) on the flank (Fig. 2), two tubular anterior nostrils longer than or equal to (vs. shorter than) the rostral appendage (Fig. 3), an anal fin heavily mottled with dark brown markings and white spots and bearing a narrow white distal margin (vs. black with a relatively wide light white distal margin) (Fig. 2); shorter pre-anal length (53.3-56.2 vs. 56.3-60.6 % SL; see Fig. 4) and fewer abdominal vertebrae (32-33, mean = 32.9 vs. 34-36, mean = 35.1) (Table 1).

...

Etymology: The epithet name, used here as a noun, is derived from the Latin word longus (= long) and tubulus (= pipe), alluding to two longer tubes modified from anterior nostrils. The common Chinese name here suggested for this new species is “长管华刺鳅”.

 Peng Shan, Guangyu Li and E Zhang. 2024. Sinobdella longitubulus, A New Species of Spiny Eel (Pisces, Mastacembelidae) from the Zhu-Jiang Basin, with A Note on the Type Locality of S. sinensis (Bleeker, 1870). Biodiversity Data Journal. 12: e123990. DOI: 10.3897/BDJ.12.e123990

[Ichthyology • 2021] Rakthamichthys mumba • A New Species of Hypogean Eel (Synbranchiformes: Synbranchidae) from Mumbai, Maharashtra, India

Rakthamichthys mumba 

Jayasimhan, Thackeray, Mohapatra & Kumar, 2021

  facebook.com/meenkaran

 

Rakthamichthys mumba a new species of synbranchid, hypogean, eel is described from Mumbai City, Maharashtra, India, based on morphological and genetic analysis. It differs from all other species of the genus Rakthamichthys by a combination of characters viz., absence of eyes, jaws equal in forward extent, gill aperture crescentric shaped, cephalic-lateralis system distinct with prominent cephalic pores and a vertebral count of 164 (80-83 preanal + 81-84 caudal vertebrae). The new species differs from a pair-wise sequence of 21.6-22.8% in the COI gene sequence from other members of the genus Rakthamichthys.

  Jayasimhan Praveenraj, Tejas Thackeray, Anil Mohapatra and Annam Pavan-Kumar. 2021. Rakthamichthys mumba, A New Species of Hypogean Eel (Teleostei: Synbranchidae) from Mumbai, Maharashtra, India. Aqua. 50(3); 

  facebook.com/meenkaran/posts/4342289312553404

 twitter.com/FishInTheNews/status/1443128423292055554

doi.org/10.23788/IEF-1163

instagram.com/p/CUYpWRlI-vJ

aqua-aquapress.com/product/aqua-273_rakthamichthys-mumba

    

[Ichthyology • 2020] Rakthamichthys gen. nov. • Osteology of ‘Monopterus’ roseni with the Description of A New Genus (Synbranchiformes: Synbranchidae), and Comments on the Generic Assignment of the Amphipnous Group Species

Rakthamichthys digressus (Gopi. 2002)

in Britz, Dahanukar, Standing, Philip, Kumar & Raghavan, 2020. 

DOI: 10.23788/IEF-1163

 facebook.com/RajeevRaghavan98 

We provide a detailed description of the head and shoulder girdle osteology of the holotype of the synbranchid ‘Monopterus’ roseni Bailey & Gans. Collected from a well in Kerala, this subterranean synbranchid shows a number of unique and highly derived characters in the gill arch skeleton. In ‘Monopterus’ roseni, basibranchial 2 does not articulate with basibranchial 1, but is situated more posteriorly between the proximal ends of hypobranchials 2, with which it articulates; and ceratobranchial 2 does not articulate with hypobranchial 2, but is offset posteriorly so that the distal tip of hypobranchial 2 is situated in between the proximal ends of ceratobranchial 1 and 2. Based on these striking osteological differences and a combination of additional diagnostic characters, we erect the new genus Rakthamichthys with the type species Monopterus roseni. We also include the other two southern Indian subterranean species formerly referred to as M. indicus Eapen (= M. eapeni Talwar) and M. digressus Gopi in the new genus Rakthamichthys along with the northeast Indian M. rongsaw Britz, Sykes, Gower & Kamei. Rakthamichthys also differs genetically from the other Asian genera of synbranchids, Monopterus and Ophichthys, by an uncorrected p-distance of 18.9-23.9 % in the cox1 barcoding gene. We further resurrect the genus name Typhlosynbranchus Pellegrin for the two West African species ‘M.’ boueti and ‘M.’ luticolus. 

Rakthamichthys roseni (Bailey & Gans 1998) 

Rakthamichthys digressus (Gopi. 2002) 

 Ralf Britz, Neelesh Dahanukar, Ariane Standing, Siby Philip, Biju Kumar and Rajeev Raghavan. 2020. Osteology of ‘Monopterus’ roseni with the Description of Rakthamichthys, New Genus, and Comments on the Generic Assignment of the Amphipnous Group Species (Teleostei: Synbranchiformes). Ichthyological Exploration of Freshwaters. IEF-1163; 1-16. DOI: 10.23788/IEF-1163

 pfeil-verlag.de/publikationen/osteology-of-monopterus-roseni-with-the-description-of-rakthamichthys-new-genus-and-comments-on-the-generic-assignment-of-the-amphipnous-group-species

 facebook.com/RajeevRaghavan98/posts/10157306987080938

Researchgate.net/publication/347975439_Rakthamichthys_new_genus

Swamp eel: Blood-red subterranean dweller is newest fish genus discovered

 phys.org/news/2021-01-swamp-eel-blood-red-subterranean-dweller.html

    

[Ichthyology • 2018] New Populations of the Rare Subterranean Blind Cave Eel Ophisternon candidum (Synbranchidae) reveal Recent Historical Connections throughout north-western Australia

 Ophisternon candidum (Mees, 1962)

in Moore, Humphreys & Foster, 2018. 

 DOI: 10.1071/MF18006  

twitter.com/DrKMAbrams
 FishesofAustralia.net.au

Abstract

The enigmatic blind cave eel Ophisternon candidum is one of Australia’s least known fishes and is one of only three vertebrates in Australia with an entirely subterranean existence. For more than half a century, O. candidum was thought to be restricted to some 100 km of coastal cave systems in north-western Australia. Herein we report on two new populations, each separated by hundreds of kilometres, and provide the first complete list of all known records of subterranean Ophisternon in Western Australia. Using morphological and molecular data, we show that these populations are conspecific, with one population showing evidence of genetic differentiation. Geological and biogeographic explanations are explored, along with conservation considerations. All populations face actual and potential threats, especially from mining activities, and there is a need for management and conservation strategies specific to each population.

Keywords: anchialine, Barrow Island, biogeography, Cape Range, conservation, genetics, Pilbara.

 Ophisternon candidum Western Australian Museum (WAM) P.34487-001 (364-mm total length) photographed live in an aquarium.

Glenn I. Moore, William F. Humphreys and Ralph Foster. 2018. New Populations of the Rare Subterranean Blind Cave Eel Ophisternon candidum (Synbranchidae) reveal Recent Historical Connections throughout north-western Australia. Marine and Freshwater Research. DOI: 10.1071/MF18006

 researchgate.net/publication/326173234_New_populations_of_Ophisternon_candidum

twitter.com/BiolSci_UWA/status/1015541639241084929

twitter.com/DrKMAbrams/status/1019469227948851200

FishesofAustralia.net.au/home/species/3203

Abstract: The blind cave eel, Ophisternon candidum (Mees in J R Soc West Aust 45: 24–32,1962), is a rare groundwater inhabitant found in geographically isolated populations of north-west Australia. The species is listed as vulnerable under Commonwealth legislation and is a priority consideration when environmental disturbance by resource companies is proposed. Detection of this species for Environmental Impact Assessment (EIA) and monitoring is difficult because individuals are naturally rare or traditional sampling techniques are ineffective. To properly manage the species, information on population distribution and connectivity is critical. We sought to examine whether environmental DNA (eDNA) of O. candidum could be detected and whether positive detection was correlated with previous locations where the species had been physically caught. We developed new eDNA species-specific PCR assays to screen groundwater sampling points and we detected O. candidum DNA in three boreholes where the species has previously been collected and five additional groundwater sampling points. Our results demonstrated that the newly designed assays were effective for detecting this rare and vulnerable subterranean species. This work sets a benchmark for the application of eDNA species-specific PCR assays for EIA and monitoring, and has potential for these assays to be expanded more broadly to high-throughput eDNA metabarcoding for subterranean groundwater communities in the future.
Keywords: Groundwater, Single-species detection assays, Metabarcoding, Environmental Impact Assessment, Monitoring, Stygofauna

Nicole E. White, Michelle T. Guzik, Andrew D. Austin, Glenn I. Moore, William F. Humphreys, Jason Alexander and Michael Bunce. 2020. Detection of the rare Australian endemic blind cave eel (Ophisternon candidum) with environmental DNA: implications for threatened species management in subterranean environments. Hydrobiologia. DOI: 10.1007/s10750-020-04304-z

Shy species detected through new DNA technique
phys.org/news/2020-06-shy-species-dna-technique.html 

Abstract: The rare blind cave eel Ophisternon candidum is restricted to a few populations and was originally described on the basis of only two specimens. The holotype and paratype were re-examined to provide revised and additional morphometrics. Nine more recently collected specimens, across a range of sizes, were also examined to provide an updated and expanded description of morphometrics for the species. Sensory head pores were identified and described for the first time in this species and a series of fresh colour photographs of both juvenile and adult specimens are provided suggesting ontogenetic ocular degeneration and vascularisation that may have evolved in response to a life in darkness.

Keywords: Anchialine, Pilbara, X-ray, Head pores, Anommatophasma

Glenn I. Moore. 2018. New morphological data and live photographs of the rare subterranean blind cave eel Ophisternon candidum (Synbranchidae) from north-western Australia. Ichthyological Research. DOI: 10.1007/s10228-018-0647-2

[Ichthyology • 2018] Monopterus rongsaw • A New Species of Hypogean Swamp Eel (Synbranchiformes: Synbranchidae) from the Khasi Hills in Northeast India

Monopterus rongsaw

Britz, Sykes, Gower & Kamei, 2018

pfeil-verlag.de  nhm.ac.uk 

 A new species of hypogean swamp eel, Monopterus rongsaw, is described from the Khasi Hills in Meghalaya, India. It was discovered while digging rock-strewn and moist soil close to a small stream during attempts to find caecilians. The new species differs from other synbranchids by the combination of absence of skin pigmentation, the eyes being tiny and covered by skin, and a count of 92 precaudal and 69 caudal vertebrae.

Ralf Britz, Dan Sykes, David J. Gower and Rachunliu G. Kamei. 2018. Monopterus rongsaw, A New Species of Hypogean Swamp Eel from the Khasi Hills in Northeast India (Teleostei: Synbranchiformes: Synbranchidae). Ichthyological Exploration of Freshwaters. IEF-1086:1-12

DOI: 10.23788/IEF-1086   pfeil-verlag.de/publikationen/monopterus-rongsaw-a-new-species-of-hypogean-swamp-eel-from-the-khasi-hills-in-northeast-india-teleostei-synbranchiformes-synbranchidae/

New species of blind eel that burrows through the soil discovered

nhm.ac.uk/discover/news/2018/september/new-species-of-blind-eel-that-burrows-through-the-soil-discovere.html

[Ichthyology • 2016] Monopterus luticolus • A New Species of Swamp Eel (Teleostei: Synbranchidae) from Cameroon

Monopterus luticolus 

Britz, Doherty-Bone, Kouete, Sykes & Gower, 2016

Monopterus luticolus, new species, is described from Cameroon. Most of the seven known individuals were discovered in inundated soil while digging for caecilian amphibians. Monopterus luticolus differs from the two other nominal African synbranchid species in the number of vertebrae and details of its osteology. The spatial dissociation of ceratobranchial 1 from hypobranchial 1 and its close association with hypobranchial 2 and ceratobranchial 2 demonstrate that M. luticolus is a member of the ‘Amphipnous group’.

Fig. 2. Monopterus luticolus, BMNH 2016.7.6.3, paratype, 158 mm TL; Cameroon: Mundame, life colouration. Note bright red colour caused by well vascularized skin. 

Etymology. The species name is derived from the Latin word for mud, lutus, and the verb colere, to dwell, referring to the habitat in which the new species was collected. A noun in apposition.

Distribution. Monopterus luticolus is known only from four localities in the proximity of Mount Cameroon at altitudes of 35-170 m above sea level (Fig. 5).

 Ralph Britz, Thomas Doherty-Bone, Marcel Kouete, Dan Sykes and David Gower. 2016. Monopterus luticolus, A New Species of Swamp Eel from Cameroon (Teleostei: Synbranchidae). Ichthyol. Explor. Freshwaters. 27(4); 309-323. 

http://www.pfeil-verlag.de/04biol/pdf/ief27_4_04.pdf

   

  

[Ichthyology • 1980] Revision of the Asian Mastacembelid Fish Genus Macrognathus

3 species of Macrognathus

• Macrognathus aculeatus — the southern Malay peninsula, Sumatra, Borneo and Java

• Macrognathus aral — the Indian subcontinent, including Sri Lanka and Burma

• Macrognathu siamensis — the Chao Phrya and Mekong basins of Thailand and Kampuchea (Cambodia)

Abstract

The highly specialized Asian mastacembelid genus Macrognathus, hitherto considered monotypic, comprises three morphologically distinct species with nearly contiguous ranges: M. aral, from the Indian subcontinent, including Sri Lanka and Burma; M. siamensis, from the Chao Phrya and Mekong basins of Thailand and Kampuchea, and the northernmost part of the Malay peninsula; and M. aculeatus, from the southern Malay peninsula, Sumatra, Borneo and Java. The species differ sharply in number of rostral toothplates and other meristic characters as well as in coloration. The specific status of M. aculeatus from Java, and that of M. dhanashorii from Assam (placed here as a synonym of M. aral), should be reconsidered when adequate study material becomes available. Mastacembelidae form two groups, possibly phyletic, based on structure of the rim of the anterior nostril. All or almost all African Mastacembelus and several Asian species (usually the larger species, including M. mastacembelus) have the nostril rim with two flaps and two fimbriae, whereas Macrognathus and several smaller species of Asian Mastacembelus (including M. pancalus and M. circumcinctus) have the nostril rim with six fimbriae.

Roberts, Tyson R. (1980). "A Revision of the Asian Mastacembelid Fish Genus Macrognathus". Copeia (American Society of Ichthyologists and Herpetologists) 1980 (3): 385–391. doi:10.2307/1444512. JSTOR http://jstor.org/stable/1444512.

[Ichthyology • 2005] ปลาหลดพรุ | Macrognathus tapirus • Kalimantan Barat (Borneo), Indonesia

ปลาหลดพรุ | Macrognathus tapirus

Kottelat & Widjanarti, 2005

Occurs in rivers among leaf litter or dense vegetation, over muddy substrate.

Feeds on insects and crustaceans

Kottelat, M. and E. Widjanarti. 2005. The fishes of Danau Sentarum National Park and the Kapuas Lakes area, Kalimantan Barat, Indonesia. Raffles Bull. Zool. Supplement (13):139-173.

http://www.eol.org/pages/1156355

http://www.fishbase.gr/summary/SpeciesSummary.php?id=62647

[Ichthyology • 2008] Macrognathus pentophthalmos Gronow | Sri Lankan spiny eel (Teleostei: Mastacembelidae), and its enigmatic decline

Macrognathus pentophthalmos

Abstract

The Sri Lankan population of the spiny eel previously assigned to Macrognathus aral Schneider (Teleostei: Mastacembelidae) is shown to be a distinct species, for which the name M. pentophthalmos Gronow is available. Macrognathus pentophthalmos is distinguished from its closest congener, M. aral, by having 14–16 dorsal spines and a pre-dorsal length of 43.3–46.8% of standard length (SL) (vs. dorsal spines 18–22 and pre-dorsal length 35.5–40.8% SL in M. aral). Macrognathus pentophthalmos differs from its only other Indian congener, M. guentheri Day, among other characters, by having 24 pairs of rostral tooth plates (vs. rostral tooth plates absent). With the present designation of a neotype, Rhynchobdella orientalis Bloch & Schneider (type locality East Indies to Sri Lanka) becomes an objective junior synonym of M. aculeatus Bloch. Although assessed as ‘common’ in 1980, the population of M. pentophthalmos suffered a precipitous decline in the following decade, the causes of which are unknown. The species may now be extinct.

Key words: Macrognathus aral, Macrognathus guentheri, Macrognathus malabaricus, Macrognathus ocellatus, Macrognathus orientalis, neotype

Pethiyagoda, R. Silva, A. Maduwage, K & Kariyawasam, l. 2008. The Sri Lankan spiny eel, Macrognathus pentophthalmos (Teleostei: Mastacembelidae), and its enigmatic decline. Zootaxa, 1931: 37-48.: http://mapress.com/zootaxa/2008/f/z01931p048f.pdf

http://mczbase.mcz.harvard.edu/SpecimenDetail_body.cfm?collection_object_id=1777808

[Ichthyology • 2009] Macrognathus pavo • from Rakhine Yoma mountain range in western Myanmar

Macrognathus pavo differs from all other Asian mastacembelids by the presence of only 4-6 dorsal-fin spines (vs 11-42).

A characteristic feature of spiny eels is their long snouts or trunks which are highly sensitive and are used to probe around for insects and worms. © Ralf Britz

Macrognathus pavo make alert and attractive aquarium subjects. © Ralf Britz

Macrognathus pavo is only known from this mountain stream, Kyeintali Chaung in the Rakhine Yoma mountain range in western Myanmar. © Ralf Britz

ปลาหลดลายนกยูง: Macrognathus pavo

Macrognathus pavo : nhm.ac.uk Species of the day

The first images of live individuals of 4 new spiny eels from Myanmar and India identified by Museum scientist Dr Ralf Britz. From the top they are Macrognathus pavo, M. dorsiocellatus, M. obscurus and M. lineatomaculatus. © Photo of M. obscurus courtesy of Ye Hein Htet

First images of 4 new spiny eels | http://t.co/uQoIAY6 via Natural History Museum

Four new spiny eels described: http://www.practicalfishkeeping.co.uk/content.php?sid=2650

Abstract

The species of the Macrognathus aculeatus group from Myanmar are reviewed and three new species are described. Macrognathus dorsiocellatus, new species, previously identified as M. aral, is distinguished by rostral tooth plates 19-23, dorsal fin spines 14-22, 7-11 small ocelli along soft dorsal fin, with ventrally open, incomplete white rim; M. obscurus, new species, is distinguished by rostral tooth plates 8-10, dorsal fin spines 20-22, ocelli along dorsal fin developed as small irregularly arranged dark spots or absent, M. pavo, new species, is distinguished by the presence of only 4-6 dorsal-fin spines, only 6-8 rostral tooth plates and details of the colour pattern. In addition, M. lineatomaculatus, new species, is described from India and Nepal and it is distinguished by rostral tooth plates 15-17, dorsal fin spines 19-22, and large black blotches along dorsal fin. The systematic position of M. caudiocellatus is reviewed and the species is retransferred to Mastacembelus.

Britz, R. 2009. Species of the Macrognathus aculeatus group in Myanmar with remarks on M.caudiocellatus (Teleostei: Synbranchiformes: Mastacembelidae). Ichthyological Exploration of Freshwaters. 20: 295-308.

http://www.pfeil-verlag.de/04biol/pdf/ief20_4_02.pdf