[Ichthyology • 2021] Priocharax britzi • A New Miniature Species of Priocharax (Characiformes: Characidae) from the upper rio Ipixuna, Purus Drainage, Brazil

Priocharax britzi

Mattox, de Souza, Toledo-Piza & Oliveira, 2021

 DOI: 10.1590/1982-0224-2021-0048

Abstract

A new species of miniature fish of the characid genus Priocharax is described from a small lake near the rio Ipixuna, rio Purus drainage, Amazonas State, Brazil. It is distinguished from all congeners except P. pygmaeus by the lower number of teeth on the maxilla and dentary. It differs from P. pygmaeus by the presence of two postcleithra and 22–27 branched anal-fin rays (vs absence and 19–22). The new species is further distinguished from other species of Priocharax by a combination of characters involving the number of pelvic-fin rays and branched anal-fin rays, the number of postcleithra, the shape of postcleithrum 3, and the absence of the claustrum. Molecular evidence based on COI sequences of all valid species of Priocharax also corroborates the validity of this new species.

Keywords: Biodiversity; Miniaturization; Ontogenetic truncation; Osteology; Taxonomy

FIGURE 1: Priocharax britzi,
A. Holotype, male, MZUSP 125822, 13.7 mm SL; Brazil, Amazonas, Canutama, small lake approximately 400 m from the rio Ipixuna, after bridge crossing this river, on the right side of the Transamazônica Road (BR–230) going from Humaitá to Lábrea, rio Ipixuna drainage.
B. Live paratype photographed immediately after capture.

Priocharax britzi, new species

   

Diagnosis: Priocharax britzi is distinguished from all congeners except P. pygmaeus by the lower number of teeth in the maxilla (21–30 vs 32–58) and dentary (26–29 vs 33–55). It differs from P. pygmaeus in the presence of two postcleithra (vs absence) and by having 22–27 (modes 25 and 26) branched anal-fin rays (vs 19–22, mode 19). The new species is further distinguished from P. nanus and P. varii by having i,5 pelvic-fin rays (vs i,6) and a slender and sinuous postcleithrum 3 (vs postcleithrum 3 relatively thick and straight), from P. ariel by the presence of 22–27 branched anal-fin rays (vs 16–22) and the presence of two postcleithra (vs absence). Priocharax britzi is further distinguished from P. varii by the absence of the adipose fin (vs presence) and from P. nanus by the absence of the claustrum (vs presence). Complementarily, Priocharax britzi has a shorter snout relative to the orbital diameter when compared to all congeners except P. nanus. This difference is reflected in the range of the proportion of snout length in relation to orbital diameter and its mean which is 45–59 (mean = 53.6; SD = 3.8) in P. britzi vs 60–76 (mean = 65.5; SD = 4.9) in P. pygmaeus, 54–81 (mean = 67.0; SD = 5.1) in P. varii and 54–84 (mean = 68.4; SD = 6.3) in P. ariel. The molecular analyses provide additional support towards the recognition of the new species.

Etymology. Priocharax britzi is named after Dr. Ralf Britz, noteworthy ichthyologist and a dear friend. Dr. Britz has mastered the world of small fishes and has described more than 20 miniature species, including two species of Priocharax. A noun in the genitive case.

FIGURE 9: Small lake approximately 400 m from the rio Ipixuna, Canutama, Amazonas, Brazil, the type locality of Priocharax britzi.

George Mendes Taliaferro Mattox, Camila da Silva de Souza, Mônica Toledo-Piza and Claudio Oliveira. 2021. A New Miniature Species of Priocharax (Characiformes: Characidae) from the upper rio Ipixuna, Purus Drainage, Brazil.  Neotrop. ichthyol. 19(2); DOI: 10.1590/1982-0224-2021-0048    

[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

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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

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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 • 2020] Aenigmachannidae • A New Family of Snakehead Fishes (Teleostei: Channoidei) from Subterranean Waters of South India

Aenigmachanna gollum

Britz, Anoop, Dahanukar & Raghavan 2019

Aenigmachannidae 

Britz, Dahanukar, Anoop, Philip, Clark, Raghavan & Rüber, 2020

 Gollum Snakehead Fishes

  DOI: 10.1038/s41598-020-73129-6 

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Abstract

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.

Aenigmachanna gollum.
(a) 60.6 mm individual alive (KUFOS 2019.8.226), green arrow marks position of vent; (b) CT scan image of skeleton of 90.2 mm holotype (BNHS FWF 966), green arrow marks position of vent and red arrow the first caudal vertebra; (c) CT scan image of head of holotype, yellow arrows mark postorbital process and posterior tip of greatly elongated maxilla; (d) CT scan image of caudal skeleton of holotype, note absence of Day’s bone and presence of distally bifurcated haemal spine (yellow arrow) on second preural centrum; (e) CT scan image of iodine stained 124.5 mm specimen (KUFOS 2019.8.225) in lateral view, swim bladder is shown in blue above the digestive system (green), note swim bladder ending at level of 8th postanal vertebra.

Head anatomy of a channid (Parachanna, left side) and Aenigmachanna (right side) in comparison. Neurocranium of Parachanna africana, (MTD-F39824, c&s, nasals not removed) 150 mm (a,c,e) and Aenigmachanna gollum, (KUFOS 2019.8.224) 81.8 mm in dorsal (a,b), lateral (c,d) and ventral (e,f) view. 

Cleared and stained jaws and hyopalatine arch in lateral view of 

(a) Aenigmachanna gollum, (KUFOS 2019.8.226) 60.6 mm, 

(b) Parachanna africana, (MTD-F39824) 150 mm 

and (c) Channa punctata, (MTD-F39825) 118 mm. 

Lateral views of skeleton of the generalized percomorph Lates (a), the anabantoid Ctenopoma (b), the aenigmachannid Aenigmachanna (c) and the channid Parachanna (d).
 Green arrow marks position of vent, red arrow position of first caudal vertebra (anterior most vertebra with haemal spine). Note more or less equal separation of vertebral column in Lates (a) and Ctenopoma (b) into abdominal and caudal vertebrae (a,b,d adapted from33) with position of vent and first caudal vertebra close to each other and caudal and postanal region of vertebral column of similar length. Note partial abdominalisation of postanal vertebral column in Aenigmachanna and almost complete abdominalisation in Parachanna.

Taxonomy

Aenigmachannidae new family 

 (Gollum snakehead fishes)

Type genus: Aenigmachanna Britz, Anoop, Dahanukar & Raghavan 2019

Diagnosis: A family of the acanthomorph clade Labyrinthici (Anabantiformes), as evidenced by the shared derived possession of a parasphenoid tooth patch (Fig. 2d,f). Aenigmachannidae are distinguished from all other Labyrinthici by the following autapomorphies: (a) a very long maxilla reaching caudally beyond the anterior margin of the preopercle (Figs. 1b,c, 3a), (b) presence of a prominent postorbital process on the maxilla (Figs. 1c, 3a), (c) the frontal suturing with the parasphenoid forming a complete interorbital septum (Fig. 2f), (d) the unique count of 29–32 abdominal and 29–31 caudal vertebrae (Fig. 1b), (e) a series of five median predorsal bones (supraneurals or rayless pterygiophores) in front of the dorsal fin (f) 83–85 scales in a lateral series, and (g) a high number of 40–44 anal-fin rays (Fig. 1a,b). It differs further from all Anabantoidei and Channidae by the swim bladder being short (Fig. 1e), not reaching the parhypural and by the absence of a suprabranchial cavity and organ (Fig. 2h,j). Aenigmachannidae share with Channidae long nasal tubes (Fig. 1a), cycloid scales, the absence of fin spines in dorsal- and anal-fins (Fig. 1a), an increase in the number of vertebrae, a single posterior swimbladder extension combined with abdominalisation of the anterior ten postanal vertebrae (Fig. 1), and five branchiostegal rays, but differ from them by the autosphenotic being excluded from the skull roof and the frontal broadly sutured only to the pterotic (Fig. 2a–f), prootic and basioccipital forming equal parts of the bulla for the sacculith (Fig. 2b,c), the presence of numerous caudal vertebrae and therefore the lack of an abdominalisation of the posterior vertebral column (Fig. 1b), and by absence of the uncinate process of the metapterygoid (Fig. 3a), absence of Day’s bone (Fig. 1d), and of a body lateral-line canal.

Phylogenetic relationships of Aenigmachannidae (marked in red) based on 46 morphological characters. Shown is the strict consensus tree of two most parsimonious trees (tree length = 64 steps, consistency index (CI) = 0.72, retention index (RI) = 0.89). Numbers at nodes correspond to bootstrap values (1000 replicates). Plesiomorphic character states of Aenigmachanna in relation to Channidae discussed in the text are shown on the tree with corresponding numbers.

 

Ralf Britz, Neelesh Dahanukar, V. K. Anoop, Siby Philip, Brett Clark, Rajeev Raghavan and Lukas Rüber. 2020.  Aenigmachannidae, A New Family of Snakehead Fishes (Teleostei: Channoidei) from subterranean waters of South India. Scientific Reports. 10, 16081. DOI: 10.1038/s41598-020-73129-6

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Neue Familie für den Gollum-Schlangenkopffisch

nachrichten.idw-online.de/2020/09/30/neue-familie-fuer-den-gollum-schlangenkopffisch/

[Ichthyology • 2020] Unexpected Species Diversity within Sri Lanka’s Snakehead Fishes of the Channa marulius Group (Teleostei: Channidae)

Channa marulius
C. cf. ara
C. ara

in Sudasinghe, Adamson, Ranasinghe, et al., 2020. 

DOI: 10.11646/zootaxa.4747.1.4 

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Abstract

The taxonomic status of the large snakeheads of the Channa marulius group that occur in Sri Lanka is reviewed and clarified. Two species are recognized from the island, based on both morphological and molecular (cytochrome c oxidase subunit 1: cox1) differentiation: C. marulius Hamilton from the northern dry zone and C. ara Deraniyagala from the middle and lower regions of the Mahaweli basin. Channa ara is endemic to Sri Lanka and can be distinguished from its Marulius group congeners, C. marulius, C. aurolineata and C. auroflammea, by having fewer dorsal- and anal-fin rays, fewer lateral-line scales and fewer vertebrae; from C. marulioides by a different adult colour pattern; and from C. pseudomarulius by having more vertebrae. At the cox1 barcoding locus, Channa ara is at least 3.6% genetically different from C. marulius, and at least 8% different from the other described species in the group. Specimens collected from the southwestern wet zone in Sri Lanka are a puzzling third component of the Marulius group’s diversity, uncovered in this study, and identified here as C. cf. ara. Whilst genetically more similar to C. marulius, C. cf. ara possesses fewer dorsal- and anal-fin rays, fewer lateral-line scales and fewer vertebrae and is therefore morphologically more similar to C. ara. Channa ara can be distinguished from C. cf. ara, however, by differences in circumpeduncular scale count, adult colour pattern, and by an uncorrected pairwise genetic distance of 3.7% in cox1 sequences. A neotype is designated for Ophicephalus marulius ara Deraniyagala.

Keywords: Pisces, Channa ara, C. pseudomarulius, C. marulius, bullseye snakehead, integrative taxonomy, DNA barcoding, Western Ghats-Sri Lanka biodiversity hotspot

FIGURE 3. Live colouration of Channa ara.
A, juvenile, ~80 mm SL, Badulu Oya, Mahaweli River; B, large adult, ~650 mm SL, Victoria Reservoir, Mahaweli River, photo courtesy of Kumudu Wijesooriya.

Live colouration of Channa cf. ara.

Hiranya Sudasinghe, Eleanor A. S. Adamson, R.H. Tharindu Ranasinghe, Madhava Meegaskumbura, Chiho Ikebe and Ralf Britz. 2020.  Unexpected Species Diversity within Sri Lanka’s Snakehead Fishes of the Channa marulius Group (Teleostei: Channidae). Zootaxa. 4747(1); 113–132. DOI:  10.11646/zootaxa.4747.1.4  

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researchgate.net/publication/339616960_Unexpected_species_diversity_within_Sri_Lanka's_snakehead_fishes_of_the_Channa_marulius_group

[Ichthyology • 2019] Channa rara • A New Species of Snakehead Fish (Labyrinthici: Channidae) from the Western Ghats region of Maharashtra, India

Channa rara

Britz, Dahanukar, Anoop & Ali, 2019

DOI: 10.11646/zootaxa.4683.4.8

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Abstract

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.

Keywords: Pisces, taxonomy, endemism, Western Ghats-Sri Lanka biodiversity hotspot

FIGURE 2. Channa rara, live colouration.
(A) BNHS FWF 1003, holotype, 87.6 mm SL, India: Maharashthra: Jagbudi River near Khopi Village, note series of small dark spots along base of dorsal fin, large ocellus-like blotch at posterior dorsal fin.
(B) juvenile, not preserved, ca. 30 mm SL, note numerous black blotches in dorsal, anal, and caudal fins.
(C) small juvenile released from mouthbrooding male, not preserved, ca. 12 mm SL.

FIGURE 3. Channa rara, variation of live colouration.
(A) BNHS FWF 1004-1005, paratypes, 90.3 mm SL (left) and 82.1 (right), note presence of two (left) and three (right) posterior ocellus-like dorsal-fin blotches.
(B) BNHS FWF 1004-1005, paratypes, 90.3 mm SL (left) and 82.1 (right) illustrating ventral head colouration.

Ralf Britz, Neelesh Dahanukar, V.K. Anoop and Anvar Ali. 2019. Channa rara, A New Species of Snakehead Fish from the Western Ghats region of Maharashtra, India (Teleostei: Labyrinthici: Channidae). Zootaxa. 4683(4); 589–600. DOI: 10.11646/zootaxa.4683.4.8

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[Ichthyology • 2019] Aenigmachanna gollum • A New Genus and Species of Subterranean Snakehead (Teleostei: Channidae) from Kerala, South India

Aenigmachanna gollum

Britz, Anoop, Dahanukar & Raghavan, 2019

DOI: 10.11646/zootaxa.4603.2.10  

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Abstract

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.

Keywords: Western Ghats-Sri Lanka biodiversity hotspot, relict lineages, laterite, aquifer, Pisces

Ralf Britz, V.K. Anoop, Neelesh Dahanukar and Rajeev Raghavan. 2019. The Subterranean Aenigmachanna gollum, A New Genus and Species of Snakehead (Teleostei: Channidae) from Kerala, South India. Zootaxa. 4603(2); 377–388. DOI: 10.11646/zootaxa.4603.2.10 

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[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 • 2018] Dario neela • A New Species of Badid Fish (Percomorpha: Badidae) from the Western Ghats of India

Dario neela

Britz, Anoop & Dahanukar, 2018

   DOI:  10.11646/zootaxa.4429.1.6 

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Abstract

Dario neela, is described from a small tributary stream of the Kabini River in northern Kerala, India. It can be distinguished from congeners by the male colouration in life, which shows wide rims of iridescent blue in all median fins and the pelvic fin. It is further distinguished from all species of Dario, except D. urops by the number of abdominal vertebrae (14 vs. 11–13), and from all Dario species except D. urops and D. huli by the presence of a conspicuous black blotch on the caudal-fin base. Dario neela is distinguished from D. urops by the absence of the horizontal suborbital stripe and presence of a series of up to eight black bars on the body; and from D. huli by 27–28 vertebrae and 27 scales in a lateral row and the absence of teeth from hypobranchial 3. Dario neela is genetically divergent from both Western Ghats congeners in the mitochondrial CO1 gene, showing an uncorrected p-distance of 5.9% with D. urops and 13.1% to D. huli.

 Keywords: Pisces, taxonomy, freshwater fishes, Western Ghats–Sri Lanka biodiversity hotspot

FIGURE 2. Dario neela; India: Kerala;  holotype, male [BNHS FWF 612], 31.2 mm SL, slightly oblique lateral view. 

Dario neela, new species

Etymology. The species name neela is derived from the Malayalam word mnoe, ‘Nīla’, for blue and alludes to the striking iridescent blue colour of males. A noun in apposition.

....

Ralf Britz, V. K. Anoop and Neelesh Dahanukar. 2018. Dario neela, A New Species of Badid Fish from the Western Ghats of India (Teleostei: Percomorpha: Badidae). Zootaxa. 4429(1); 141–148.  DOI:  10.11646/zootaxa.4429.1.6

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[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 • 2015] Description of Danio absconditus and Redescription of D. feegradei (Teleostei: Cyprinidae), from the Rakhine Yoma Hotspot in south-western Myanmar

Danio absconditus Kullander & Britz, 2015

Danio feegradei Hora, 1937

DOI: 10.11646/zootaxa.3948.2.5

Abstract

Danio feegradei Hora is redescribed based on recently collected specimens from small coastal streams on the western slope of the Rakhine Yoma, ranging from the Thade River drainage southward to slightly north of Kyeintali. Danio absconditus, new species, is described from the Kyeintali Chaung and small coastal streams near Gwa, south of the range of D. feegradei. Both species are distinguished from other Danio by the presence of a dark, elongate or round spot at the base of the caudal fin and a cleithral marking composed of a small black spot margined by a much smaller orange spot. Danio feegradei is characterized by the colour pattern, with series of white spots along the otherwise dark side; D. absconditus by about 7-–11 dark vertical bars on the abdominal side. Within Danio, the presence of a complete lateral line, cleithral spot, and 14 circumpeduncular scales is shared with D. dangila and similar species, but these character states may be plesiomorphic as suggested by the shared presence of cleithral spot and complete lateral line in Devario and Betadevario. In other Danio the cleithral spot is absent, the lateral line is short or absent, and the circumpeduncular scale count is lower (10–12). Twenty teleost species are reported from streams on the western slope of the Rakhine Yoma, all probably endemic. The parapatric distribution of D. absconditus and D. feegradei is unique within the genus, and may be partly explained by changes in eustatic sea levels.

Keywords: colour pattern, freshwater fish, morphology, species discrimination, taxonomy

Kullander, Sven O. & Ralf Britz. 2015. Description of Danio absconditus, new species, and Redescription of Danio feegradei (Teleostei: Cyprinidae), from the Rakhine Yoma Hotspot in south-western Myanmar.
Zootaxa. 3948(2): 233–247. DOI: 10.11646/zootaxa.3948.2.5

http://www.mapress.com/zootaxa/2015/f/zt03948p247.pdf

http://zoobank.org/urn:lsid:zoobank.org:pub:AF652D3A-05D0-4781-86A7-0813B4CE8E47