Devario anomalus, Conway, Kevin W., Mayden, Richard L. & Tang, Kevin L., 2009

Conway, Kevin W., Mayden, Richard L. & Tang, Kevin L., 2009, Devario anomalus, a new species of freshwater fish from Bangladesh (Ostariophysi: Cyprinidae), Zootaxa 2136, pp. 49-58 : 50-57

Devario anomalus , new species

( Figs. 1 , 2 )

Holotype. UF 174139, 71.6 mm SL; Bangladesh: Chittagong Division, stream crossing highway at market southeast of Cox’s Bazar, 21° 21' 18.40" N, 92° 1' 29.90" E., 9 December 2007, R. L. Mayden et al.

Paratypes. UF 172447, 4, 69.2–81.0 mm SL; same data as holotype. ZRC 51881, 1, 57.0 mm SL; same data as holotype.

Other material: UF 174140, 1, ethanol preserved specimen; same data as holotype.

Diagnosis. A large species of Devario , distinguished from all other species of the genus by its unique colour pattern, consisting of 5–8 dark, irregular, vertical bars, restricted to the anterior half of the body and widely separate from a short, broad P-stripe, originating level with or posterior to the origin of the anal fin. Devario anomalus is easily distinguished from D. aequipinnatus by its shorter P-stripe (P-stripe originating on lateral body surface posterior to dorsal-fin origin, vs. P-stripe originating on lateral body surface anterior to dorsal-fin origin) and by its interrupted P-1 stripe (P-1 stripe represented by a series of faint blotches along its entire length, vs. P-1 stripe continuous or interrupted along anteriormost portion only). Devario anomalus is distinguished from D. devario by the presence (vs. absence) of maxillary barbels, the presence (vs. absence) of an infraorbital process on IO1, and by its lower number of lateral-line scales (33–35 vs. 44–46), branched dorsal-fin rays (12 vs. 16–17), branched anal-fin rays (14 vs. 16–17), and circumpeduncular scale rows (12 vs. 16).

Description. General body shape as in Figures 1 and 2 . Morphometric and meristic data provided in Tables 1 and 2 .

Head and body compressed. Body depth greatest at pelvic-fin origin. Dorsal body surface profile slightly more rounded than ventral body surface profile. Snout short, slightly greater in length than eye diameter. Mouth supraterminal. A large, rounded symphysial knob present on lower jaw, fitting into shallow groove on inner margin of upper jaw with mouth closed. Two pairs of barbels. Rostral barbels reaching to or slightly past anterior margin of orbit. Maxillary barbels short, less than half as long as rostral barbels. A large anterior indentation (danionin notch, sensu Roberts, 1986) present along ventromedial edge of dentary. Infraorbital process present on posterior edge of IO1. Anteroventralmost point of supraorbital entering orbit. Dorsal surface of head with well developed skin grooves along supraorbital shelves. A single row of small, conical tubercles present along upper margin of lower jaw.

holotype range mean st. dev.

Standard length (mm) 71.6 69.2–81.0

Dorsal fin with iii.11 (2) or iii.12 (4) rays. Anal fin with iii.13 (3) or iii.14 (3) rays. Principal caudal-fin rays 10+9. Pelvic-fin rays i.7, pectoral-fin rays i.12. Pectoral-fin origin slightly anterior to vertical through posteriormost point of opercular opening, not reaching to pelvic-fin origin when depressed. Pelvic-fin origin well in advance of dorsal-fin origin, posteriormost tip of pelvic fin reaching to vertical through dorsal-fin origin when adpressed. Dorsal-fin origin anterior to anal-fin origin, its distal margin straight to weakly convex. Anal-fin origin opposite to point of insertion of 4th branched dorsal-fin ray, its distal margin straight. Caudal fin forked, its lobes rounded distally, upper lobe slightly longer than lower lobe.

Lateral line complete, declining steeply for first 7–8 scales, perforating 33(2), 34(3) or 35(1) body scales along its length, plus 2(5) or 3(1) scales on base of caudal fin. Twelve scale rows around caudal peduncle, ½7/ 1/1(5) or ½6/1/1(1) transverse scale rows between dorsal-fin origin and mid-ventral scale row, 12 around caudal peduncle; 16 predorsal scales; 12(2), 13(3) or 14(1) scales sheathing base of anal fin.

Coloration. In preservative, body background colour light olive dorsally, light cream ventrally. A dark cleithral spot present at posterodorsal corner of opercular opening. Numerous (5–8), blue/black irregular vertical bars on anterior half of body, extending across midline. A short, thick P-stripe originating on side of body, level with or posterior to anal-fin origin, continuing to end of median caudal-fin rays. P-stripe separated from posteriormost vertical bar by a short gap (6–7 scales in length). Anteriormost part of P-stripe dissociated into a series of spots in larger specimens. P+1 stripe separated from P-stripe by a narrow interspace, originating on side of body, level with or posterior to posteriormost vertical bar, continuing to end of caudal peduncle as a faint greyish-blue streak. Anteriormost part of P+1 stripe dissociated into a series of blue-black spots in larger specimens. P-1 stripe short, represented by a series of faint blotches below anteriomost part of P+1 stripe only, from which it is separated by a thin interspace. Numerous small blotches posterior to posteriomost vertical bar and anterior to origin of P-stripe, possibly representing anterior continuation of Pstripe and P-1 stripe. Median fins with light scattering of small melanophores along interradial membranes, except anterodistalmost tips of dorsal and anal fins, which are devoid of pigment. Paired fins without pigmentation.

In life, dorsal surface of body light brown, lateral and ventral surface of body with a silvery pink sheen. Anterior vertical bars and P-stripe light charcoal grey. A reflective bronze to metallic green shine appearing along midline of body in certain light conditions, masking P+1 and P-1 stripes. Anterodistalmost tip of dorsal and anal fins white.

Distribution and habitat. Devario anomalus is known only from the type locality ( Fig. 3 ), a small coastal stream originating in the hill tracts south of Cox’s Bazar, southern Chittagong Division. The new species was collected from a small pool at the base of a waterfall ( Fig. 4 ) and from a short stretch of stream downstream of the waterfall and upstream of the highway crossing. Other fish species collected at the type locality include Puntius ticto and an unidentified species of gerreid.

Etymology. From the Greek ἀνώμαλος (anomalos), meaning uneven or irregular, in reference to the irregular vertical bars on the anterior half of the body of this species. An adjective.

Remarks. In her morphological phylogenetic analysis of the interrelationships of danionin cyprinids, Fang (2003) restricted the generic name Danio to those danionins in possession of an “A”-stripe (a dark stripe extending along the middle of the anal-fin rays and ending at the distal tip of the last branched anal-fin rays) and two or more stripes on the caudal-fin rays. The remaining species of Danio were referred to the genus Devario , a monophyletic group supported by a suite of characters ( Fang, 2003: fig. 1) including the following: (1) maxillary barbels shorter than orbit diameter (Fang’s character 2: state 1), (2) a P-stripe extending onto the caudal-fin base (character 14: 1), and (3) infraorbital 5 not or only slightly reduced (character 18: 1). The new species, Devario anomalus , can be assigned to the genus Devario (sensu Fang, 2003) by the presence of short maxillary barbels (much shorter in length than the diameter of the orbit), a P-stripe extending to the caudal-fin base, and an IO5 similar in width to that of IO4 ( Fig. 5 ), an assignment that finds support in the results of our molecular phylogenetic analysis ( Fig. 6 ).

Rahman (1989) reported two species of Devario from Bangladesh: D. aequipinnatus auct. and D. devario . Devario anomalus is easily distinguished from these two species, and all other species of Devario , by its unique colour pattern, consisting of 5–8 dark, irregular, vertical bars, restricted to anterior half of body and widely separate from a short, thick P-stripe, originating on side of body, level with or posterior to the origin of the anal fin. Devario anomalus is further distinguished from D. aequipinnatus auct. by its shorter P-stripe (Pstripe originating on lateral body surface posterior to dorsal-fin origin, vs. P-stripe originating on lateral body surface anterior to dorsal-fin origin) and by its interrupted P-1 stripe (P-1 stripe represented by a series of faint blotches along its entire length vs. P-1 stripe continuous or interrupted along anteriormost portion only). It can be further distinguished from D. devario by the presence (vs. absence) of maxillary barbels and an infraorbital process on IO1, and by differences in several meristic counts, including its lower number of lateral line scales (33–35 vs. 44–46), branched dorsal-fin rays (11–12 vs. 16–17), branched anal-fin rays (13–14 vs. 16–17), and circumpeduncular scale rows (12 vs. 16).

The description of the new species brings the total number of species of Devario known from Bangladesh to three. Two nominal species of Devario described by Bleeker (1860) are also reported from Bangladesh, viz. D. buchanani and D. macclellandi . Devario buchanani was created by Bleeker (1860: 283) as a replacement name for Cyprinus devario Hamilton and as such is an objective synonym of D. devario . Bleeker (1860: 283) also created the name D. macclellandi based on the illustration of Cyprinus devario ( Fig. 6 ) originally prepared by Hamilton and published by McClelland (1839: plate 45 [incorrectly labelled as 56 on plate], figure 8). Devario devario has priority over D. macclellandi and as such the latter is placed in the synonymy of the former ( Barman, 1991; Menon, 1999). Devario anomalus can be distinguished from the nominal forms of Devario from Bangladesh by the same characters that distinguish it from D. devario .

The third nominal species of Devario described by Bleeker (1860) is also worthy of mention here. Bleeker (1860) introduced the name Devario cyanotaenia based directly on the illustration of a specimen of Devario from Assam ( Fig. 6 ) originally prepared by Hamilton and described by McClelland as Perilampus (= Devario ) ostreographus ( McClelland, 1839: plate 45 [incorrectly labelled as 56 on plate], figure 9). Devario ostreographus is currently placed in the synonymy of D. devario ( Barman, 1991; Eschmeyer et al., 1998; Fang, 2001) but is easily distinguished from this species based on differences in colour pattern (sides marked with several lateral stripes in D. ostreographus , vs. sides marked with a single interrupted stripe in D. devario ) and by its lower number of total rays in the dorsal and anal fins (McClelland lists the total number of dorsal and anal fin rays as 12 and 16 respectively for D. ostreographus vs. 18 and 18 for D. devario ). Based on these differences D. ostreographus should be removed from the synonymy of D. devario and considered valid pending further investigation of the nominal species of Devario from Assam. Devario cyanotaenia should be considered a synonym of D. ostreographus .

Comparative material. Danio aequipinnatus auct. Ganges River Drainage: KU 29524, 20; Nepal: Sankhuwasabha, Sabha River, east of Tumlingtar, 18 August 1996, D. Edds. KU 29529, 3; Nepal: Sankhuwasabha/Bhojpur, Tumlingtar, Arun River at confluence with Sabha River, south of Tumlingtar, 19 August 1996, D. Edds. Non-Gangetic material: UF 172449, 11; Bangladesh: Chittagong, rice paddy and creek along highway east of Cox’s Bazar, 9 December 2007, R. L. Mayden et al.

Devario devario . Brahmaputra River Drainage: UMMZ 187873, 1, cleared and stained; Bangladesh: Comilla, Pond at Hajiganj (ca. 18 miles north of Chandpur, 24 May 1968, Z. Anwar. UMMZ 208891, 11, 45–54 mm SL; Bangladesh: Rangpur, Jabuneswari River, downstream from Badarganj Ghat, 3 April 1978, W. Rainboth & A. Rahman. Ganges River Drainage: KU 28906, 7; Nepal: Chitwan/Nawalparasi, Narayani River at Gharial Conservation Project Camp, 8 April 1996, D. Edds. KU 28959, 12; Nepal: Nawalparasi, Narayani River at Sakar Dinai, 10 April 1996, D. Edds. Meghna River Drainage: UF 172524, 4; Bangladesh: Sylhet, 5 December 2007, R. L. Mayden et al. UMMZ 208778, 15, 53–67 mm SL; Bangladesh: Sylhet, Piyain Gang River at Songram Punij, 21 February 1978, W. Rainboth & A. Rahman.

Figures

FIGURE 1. Holotype of Devario anomalus, UF 174139, 71.6 mm SL; Bangladesh: Chittagong Division.

FIGURE 2. Devario anomalus in life. a. UF 174139, holotype, 71.6 mm SL; Bangladesh: Chittagong Division. b. UF 17244, paratype; same data as holotype.

FIGURE 3. Waterfall at small stream south of Cox’s Bazar, type locality of Devario anomalus.

FIGURE 4. Infraorbital series, right side in lateral view (image reversed) of Devario anomalus, UF 174140, 76.0 mm SL.

FIGURE 5. Molecular phylogeny of the Cyprinidae obtained from maximum likelihood (ML) and parsimony (MP) analyses of 1497 base pairs of RAG 1. Best ML tree topology recovered from 20 independent searches is shown on the left; lnL = - 14340.169. Strict consensus of six most-parsimonious trees is shown on the right (TL = 2581 steps; CI = 0.406; RI = 0.571). Numbers along branches indicate bootstrap support (values below 50 % are not shown). Devario anomalus, highlighted in bold, is recovered within Devario in both analyses (indicated by the grey box).

FIGURE 6. Original illustrations of Cyprinus devario (top) and Perilampus ostreographus (below) as reproduced by McClelland (1839: plate 45 [incorrectly labeled as 56 on plate]).

Tables

TABLE 1. Morphometric data for Devario anomalus (holotype and 5 paratypes).

Percent of standard length
Head length	23.2	22.8–24.5	23.5	0.6
Body depth	27.8	25.0–26.8	26.7	1.0
Predorsal length	60.2	58.4–60.2	59.1	0.7
Preanal length	63.3	63.0–65.2	64.0	1.0
Prepelvic length	45.4	44.2–46.7	45.4	0.8
Caudal peduncle length	16.6	16.6–17.8	17.0	0.5
Caudal peduncle depth	13.5	12.1–13.5	12.8	0.6
Length of dorsal-fin base	18.4	18.4–20.2	19.8	0.9
Length of anal-fin base	21.8	20.4–21.8	21.0	0.6
Pectoral-fin length	19.4	18.1–20.7	19.2	1.0
Pelvic-fin length	14.1	12.2–14.7	13.9	1.0

TABLE 2. Meristic characters of Devario anomalus holotype and 5 paratypes.

	holotype	paratypes
Lateral-line scales	33	33–35
Midlateral scales	31	31–33
Scale rows between dorsal and anal-fin origins	9	8–9
Predorsal scale rows	16	15–16
Circumpeduncular scale rows	12	12
Anal-fin base scales	14	12–14
Dorsal-fin rays	iii.11	iii.11–12
Anal-fin rays	iii.14	iii.13–14
Principal caudal-fin rays	10+9	10+9
Pectoral-fin rays	i.12	i.12
Pelvic-fin rays	i.7	i.7