Danio feegradei Hora, 1937

Kullander, Sven O. & Britz, Ralf, 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), pp. 233-247 : 234-238

Danio feegradei Hora, 1937

( Figs. 1–4 )

Material examined. All from Myanmar, Rakhine State. BMNH 2011.3.24.7–28, 17, 28.0– 57.5 mm SL; NRM 66246, 5, 39.3–50.0 mm SL. South stream Daung Chaung, 18°2'17"N, 94°30′26″E. 1 Dec 2009, R. Britz.— BMNH 2015.3.3.7–58, 52, 25.1–45.3 mm SL. Delmound Chaung,18°46′42″N, 94°17′6″E. 27 Nov 2009, R. Britz.— BMNH 2015.3.3.59, 1, 28.7 mm SL. Chaung Ma Gyi Chaung Leldee village, 18°35′7″N, 94°22′11″E. 28 Nov 2009, R. Britz.— BMNH 2015.3.3.60–99, 38, 29.5–51.6 mm SL; BMNH 2015.3.3.171–177, 7, 55.7–67.5 mm SL. Three different sites along Thandwe Chaung, 18°24′33″N, 94°28′46″E. 29 Nov 2009, R. Britz.— BMNH 2015.3.3.100–128, 29, 20.2–38.8 mm SL. Ka Din Lay Chaung, 18°18′39″N, 94°27′51″E. 30 Nov 2009, R. Britz.— BMNH 2015.3.3.138–144, 7, 29.6–39.2. North stream Kyauk Tan village, 18°2′40″N, 94°29′39″E. 1 Dec 2009, R. Britz.— NRM 45660, 1, 22.8 mm SL. Thade River drainage: Yan Khaw Chaung, ca 4 km on logging road from Gwetauk village, 23 km on road Taunggok-Pyay, 18°47′48″N, 94°21′46″E. 21 Mar 1998, S. O. Kullander & R. Britz.—ZSI F. 12477/1. Holotype, 37.2 mm SL, Sandoway (=Thandwe). Jun–Aug 1936, E. S. Feegrade (Photograph only).

Diagnosis. Distinguished from all other species of Danio except D. absconditus by the presence of a large, elongate black spot at the base of the caudal fin (vs. absence; or minute and inconspicuous in D. jaintianensis (Dey) , D. choprae Hora and D. flagrans Kullander ; or small, round and margined by a lighter zone in D. erythromicron (Annandale)) , a small black or grey cleithral spot and a light (orange in life) spot immediately above the cleithral spot (vs. absent; or present, large and not bordered by light spot in D. assamila Kullander , D. catenatus Kullander , D. concatenatus Kullander , D. dangila , and D. sysphigmatus Kullander ; or minute, not separated from P stripe and not associated with light spot in D. meghalayensis Sen & Dey ). Distinguished from all Danio except D. absconditus , D. assamila , D. catenatus , D. concatenatus , D. dangila , D. meghalayensis and D. sysphigmatus by the presence of a complete lateral line (vs. abbreviated or absent) and 14–16 circumpeduncular scales (vs. 10–12). Distinguished from D. absconditus by absence of dark vertical bars on abdominal sides (vs. presence of about 7–11 distinct dark bars), and presence of a dark area along the middle of the side, with two or three irregular horizontal rows of white dots (vs. absence of continuous dark area on anterior side and absence of white dots on the side).

Description. General body features and pigmentation are illustrated in Figures 1–3 . Measurements are summarized in Table 1 .

Body compressed, elongate, sexes isomorphic. Head laterally compressed, slightly deeper than wide. Snout short, obtuse, about equal to eye diameter. Mouth terminal, oblique in profile, jaws about equal in anterior extension or lower slightly projecting. Small bony knob at dentary symphysis, fitting into notch in upper jaw. Maxilla reaching slightly beyond vertical from anterior margin of orbit. Lower jaw ending anteriorly at about upper 1/3 of eye¸ posteriorly below about middle of orbit. Lower jaw with anterior lateral lobe margined with sharp, pointed tubercles; similar tubercles also distributed over anterior portion of dentary in varying number and density. Rostral barbel long, reaching to or very slightly beyond preopercular margin; maxillary barbel long, reaching slightly beyond posterior margin of pectoral-fin base, to about 1/3 of length of pectoral fin.

Lateral line complete, comprising 34 (4), 35 (5), 36 (8) scales; descending anteriorly for about 6 scales, posteriorly paralleling ventral profile. Median predorsal scales 16 (1), 17 (6), 18 (9), 20 (1). Scales in transverse series from dorsal-fin origin to pelvic-fin origin ½6+1+1½ (17); scales below lateral line not much smaller than above. Prepelvic scales rounded, about 17–19 along midline; pelvic-fin bases covered by overlapping scales arranged in three rows. Circumpeduncular scale rows 14 (13), 15 (3), 16 (1). Pelvic axillary scale present. A row of scales along anal-fin base.

Dorsal-fin rays ii.8 ½ (22); anal-fin rays iii.12 ½ (9), iii.13 ½ (13); pectoral-fin rays 1.9.i (1), i.9. ii (7), i.10. i (9); pelvic-fin rays i.7 (17). Principal caudal-fin rays 10+9 (22); procurrent caudal-fin rays dorsally 6 (1), 7 (2), 8 (15), 9 (4), ventrally 7 (4), 8 (15), 9 (1), 10 (2). Dorsal-fin origin at highest point of dorsum, slightly posterior to half distance from snout tip to caudal-fin base, and slightly anterior to vertical from anal-fin origin. Pectoral-fin origin slightly anterior to vertical through posterior margin of opercle; branched rays forming straight or slightly rounded margin, leading unbranched ray longest, not produced, not reaching insertion of unbranched pelvic-fin ray.

Tubercles absent from pectoral fin. Pectoral-fin axial lobe well developed. Pelvic-fin origin situated slightly anterior to midbody, well anterior to dorsal-fin origin. Pelvic-fin margin subtruncate, leading unbranched ray or both leading unbranched ray and first branched ray longest, but not prolonged, reaching urogenital opening. Caudal fin moderately forked, lobe tips subacuminate, lower lobe appearing broader than upper.

Vertebrae 17+19=36 (4), 18+18=36 (10), 18+19=37 (8); predorsal vertebrae 14 (14), 15 (8); vertebrae contained within caudal peduncle 7 (6), 8 (13), 9 (2). Ceratobranchial 5 tooth formula 5,3,2-2,4,5 (NRM 55111, 45.2 mm SL).

Colouration in preservative. Sexual dimorphism not observed. Dorsum above midaxis pale greyish. Darkbrown middorsal stripe anterior to dorsal fin, along dorsal-fin base and dorsal margin of caudal peduncle. Cleithral spot minute, black, margined anterodorsally by minute white or silvery spot. Blackish or dark brown P stripe from caudal-fin base anteriad to about middle of side, but vanishing in wide greyish or brownish area covering anterior side, between levels of midaxis and pectoral-fin base. P stripe margined dorsally by almost depigmented I stripe extending the length of the caudal peduncle, and continued on base of caudal fin; similar less distinct I-1 stripe posteriorly on caudal peduncle. On and slightly above P stripe forward, a row of about 8 to 15 small white or silvery spots, posteriorly round, anteriorly extended vertically; larger spots may have darkened borders resembling rings with lighter centre. Similar series of light spots one scale row ventrally; some spots in this row with open lower margin to light abdomen; posterior spots above anal-fin base mostly very small, indistinct. Between upper and lower rows of light spots variable number of scattered small spots occasionally arranged in horizontal series. Abdomen unpigmented, yellowish white. Region immediately above anal fin and on lower half of caudal peduncle pale yellowish white, with sparse dark pigmentation. A black or dark-brown, slightly elongate spot at middle of caudal-fin base, bordered by lighter zones above and below. Caudal fin hyaline with faint dusky bands crossing upper and lower lobe, extending along middle rays. Dorsal fin dusky basally, with faint D stripe, distal half hyaline. Anal fin dusky basally, faint A stripe bordered distally by a thin white stripe, distal 1/3 of fin hyaline.

Colour in life ( Figs. 2–3 ). Aquarium specimens: Epaxially dull olivaceous, grading to grey on dorsum; hypaxially pale slate grey with blue tinge, abdomen white. Interstripe I expressed as short rosy, almost pink stripe on caudal peduncle and adjacent caudal fin, anteriorly as rows of spaced oval spots. Similar spots along abdominal side in single principal row and several scattered. Bright orange spot close to cleithrum at interspace I level, bordered posteroventrally by small cleithral spot varying in intensity between black and grey. Dorsal fin hyaline, distal margin pale yellow. Anal fin hyaline, A stripe white in female, orange-red in male. Stripe across pelvic fin white in female, orange-red in male. Caudal fin with slightly elongate black spot at middle of base, bordered by light stripe above and below; lobe margins pale red in male. Pectoral fin pale yellow in male.

Type material. The holotype is presently in a poor state of preservation, partly covered by mould, fins damaged, and no remnants left of the colour pattern ( Fig. 4 ). It is useless as a reference specimen for the species, but the detailed description and excellent drawings provided by Hora (1937) make the designation of a neotype unnecessary.

Geographical distribution ( Fig. 5 ). Danio feegradei is known only from a small section of the western slope of the Rakhine Yoma, recorded from small coastal streams near Kyeintali north to the Thade River drainage.

Figures

FIGURE 1. Danio feegradei. BMNH 2011.3.24.7 – 28, 50.2 mm SL. Myanmar, Rakhine State, Daung Chaung.

FIGURE 2. Danio feegradei. Adult male in live coloration. Aquarium specimen, not preserved.

FIGURE 3. Danio feegradei. Adult female in live coloration. Aquarium specimen, not preserved.

FIGURE 4. Danio feegradei. Holotype, ZSI F. 12477 / 1, 37.2 mm SL. Myanmar, Rakhine state, Thandwe.

FIGURE 5. Map of southwestern part of Myanmar showing collecting localities of Danio absconditus and D. feegradei.

Tables

TABLE 1. Morphometry of Danio feegradei. Measurements are in per cent of standard length, except for standard length (in mm). SD, standard deviation; r, Pearson’s correlation coefficient. Linear regression against SL calculated from measurements in mm, coefficients (a, b).

	N	min	max	mean	SD	a	b	r
Standard length (mm)	17	28.0	57.5	44.7	8.8
Body depth	17	27.3	31.2	28.9	1.2	0.670	0.273	0.974
Head length	17	23.0	26.9	24.5	1.2	1.999	0.198	0.990
Snout length	17	6.0	7.4	6.7	0.4	0.379	0.058	0.959
Head depth	17	16.0	18.7	17.4	0.9	1.252	0.145	0.966
Head width	17	12.9	14.9	13.8	0.6	0.596	0.124	0.978
Upper jaw length	17	9.2	11.1	10.0	0.6	0.983	0.077	0.984
Lower jaw length	17	10.8	13.2	11.9	0.7	1.288	0.089	0.982
Orbital diameter	17	6.6	9.3	8.0	0.8	1.442	0.046	0.944
Interorbital width	17	9.9	11.6	10.7	0.5	0.707	0.091	0.976
Caudal peduncle length	17	17.4	21.6	19.3	1.2	1.466	0.158	0.956
Caudal peduncle depth	17	11.8	14.2	13.2	0.6	-0532	0.145	0.984
Dorsal-fin base length	17	12.1	14.0	13.1	0.4	-0.356	0.139	0.992
Anal-fin base length	17	17.7	20.7	18.9	0.8	0.083	0.187	0.978
Predorsal length	17	58.4	62.9	61.0	1.3	0.617	0.595	0.996
Preanal length	17	63.8	67.2	65.5	1.1	-0.035	0.656	0.996
Prepelvic length	17	45.6	50.1	47.9	1.3	1.233	0.450	0.989
Pectoral-fin length	17	21.6	25.7	23.9	1.2	1.833	0.196	0.975
Pelvic-fin length	17	14.9	17.0	15.9	0.6	0.327	0.151	0.978
Rostral barbel length	17	13.7	18.0	15.4	1.2	-0.104	0.157	0.942
Maxillary barbel length	17	23.2	32.8	26.3	2.2	2.810	0.197	0.930