Comprehensive Description
provided by Smithsonian Contributions to Zoology
Blenniella cyanostigma (Bleeker)
Salarias cyanostigma Bleeker, 1849:18 [Pagotang, Javae meridionalis; lectotype, RMNH 4794, designated below].
Salarias fronto Günther. 1861:256 [Java; lectotype BMNH 1845.6.22.196, designated below].
Salarias andamensis Day, 1870:611 [Andaman Islands; neotype USNM 112032, designated below].
Salarias striolatus Day, 1876:333 [Andamans; several syntypes presumably at ZSI; lectotype designation below. ZSI 2011].
Salarias andamanensis Day, 1876:332 [inadmissible emendation of Salarias andamensis Day, 1870].
Entomacrodus calurus Fowler. 1904:555 [Padang, Sumatra; holotype. ANSP 27807].
DESCRIPTION.—Dorsal fin (Tables 6 and 7). XII to XIV, 19 to 22 = 32 to 35 (XIII in 93% of 168 specimens examined for character; 19 segmented rays and 32 total elements in only 2 specimens); mean numbers of total elements higher for males than for females from all 5 localities where means for both sexes are available (statistically significantly higher for 2 of the localities); membrane between spinous and segmented-ray portions notched 60% to more than 75% length of first segmented ray (usually more than 75% length); membrane from posteriormost ray attaching to point ranging from slightly in advance of caudal-fin base to out on dorsal edge of caudal fin (out up to 22% length of fin in males, up to 9% in females; usually attached at or anterior to origin of caudal-fin base in both sexes).
Anal fin (Tables 6 and 7). II,19 to 22 (19 in only one, female, specimen); mean numbers of segmented elements higher for males than for females from all 5 localities where means for both sexes are available (statistically significantly higher for 2 of the 5 localities); posteriormost element usually not split to base (89% of 145 specimens examined for this character); fin bound by membrane to caudal peduncle in only 1 specimen. Skin covering distal half of anterior segmented anal-fin rays of few1 large or mature males thickened or inflated, weakly crinkled along edges.
Pectoral-fin rays 10, 13 to 15 (14 bilaterally in 90% of 80 specimens examined for this character; 10 only unilaterally and in only one specimen (probably aberrant), 15 only unilaterally and in only two specimens.
Pelvic-fin rays I,3.
Caudal fin. Dorsal procurrent rays 4,6 or 7, ventral procurrent rays 5 to 7, total procurrent rays (Table 8) 10 to 14 (, , or in 93% of 145 specimens examined for this character); segmented rays 13 in all 84 specimens examined for this character.
Vertebrae (Tables 6 to 8). 11 to 12+27 to 29 = 38 to 40 (11 precaudal vertebrae in 98% of 132 specimens examined for this character), mean numbers of total (and caudal) vertebrae higher for males than for females for 4 of 5 localities where means for both sexes are available (statistically significantly higher for 2 of the 4 localities); posteriormost pleural rib on 12th or 13th from anteriormost centrum (on 12th in 97% of 133 specimens examined for this character); posteriormost epineural on 23rd to 29th from anteriormost centrum (on 24th to 29th in 98 of 99 specimens examined for this character).
Cirri. Nape cirrus absent. Orbital cirrus a simple filament, always shorter than orbital diameter in females, occasionally equal to or slightly longer than orbital diameter in males. Nasal cirri short, simple to palmate, with 2 to 6 branches (rarely simple or with 6 branches).
Lateral line. Continuous canal anterodorsally with simple pores extending posteriorly to point between vertical from between bases of 6th and 7th dorsal-fin spines to vertical between bases of 9th and 10th spines (extending posterior to vertical from base of 7th spine in 92% of specimens examined for this character), then continuing posteroventrally and posteriorly as series of 1 to 6 short, disconnected, horizontally bi-pored canals (tubes) in skin; posteriormost tube in area between vertical from base of 7th spine and vertical from between bases of 12th and 13th spines (posterior to vertical from 9th spine in 85% of specimens).
Mandibular pores 4 to 6 (Table 8; 5 bilaterally in 69% of 169 specimens examined for this character, and at least unilaterally in 90% of the specimens).
Six or 7 sensory pore positions between 1 and 5 o'clock on postorbital margin (6 in 84 of 86 specimens examined for this character), 0 to 2 positions occupied by pairs of pores (2 positions in 87% of specimens; no pairs in only 2 specimens).
Posterior canines present in specimens longer than 26 mm SL, variably present in specimens as small as 25.0 mm SL.
Margins of both lips entire.
Crest. Males ≥25.1 mm SL with well-developed blade-like crest; only smaller male, 18.8 mm, with definite, dark, raised ridge where crest would form; highest crest, 2.9 mm, but crests uncommonly higher than 2.2 mm. Females ≥24.9 mm SL with distinct crest, except one female, 28.1 mm, with scarcely noticeable raised line in place of crest; highest crest 1.0 mm, but most crests <0.6 mm; crests lower than those of males of comparable SL.
Color pattern (in preservative). Males (Figure 7a). Head: variably dusky, usually without distinct dark markings; opercle uncommonly with small, faintly-to-darkly dusky spot dorsally; small, faintly-dusky, elliptical or almond-shaped spot just posteroventral to orbit often present, often almost unnoticeable; ventral surface often with pale areas, particularly anteriorly; upper lip occasionally with 3 barely recognizable, dusky bands; crest more or less uniformly dusky, never with well-delineated, narrow, pale distal margin. Body: well-preserved specimens with up to 9 dusky bands on midside, 6 or 7 bands posterior to vertical at dorsal-fin notch; bands anterior to notch and on caudal peduncle frequently faint or missing; dorsal body contour with several dusky saddles extending onto dorsal fin basally; saddles sometimes paired and connected to body bands; anterior 4 body bands below segmented-ray portion of dorsal fin may each incorporate vertical pair of small, dark ocelli (rarely more than 3 ocelli pairs total, with half pair represented by ventral member), ventral member of each pair at ventral margin of band, dorsal member usually completely enveloped by band; additional ocellus occasionally present above dorsal member of each ocelli pair; other ocelli, barely noticeable, sometimes at mid-left and mid-right margins of 1 or 2 bands; occasionally up to 4 short, very fine, faintly dusky pinstripes in region below posteriormost 4 dorsal-fin spines and anteriormost 2 segmented dorsal-fin rays. Dorsal fin: spinous portion dusky, darker distally, occasionally with interrupted, very fine, dark, distal edge or subdistal stripe and/or pale distal edge; segmented-ray portion irregularly dusky, with fine, dark, interrupted pinstripes coursing through basal third of fin. Caudal fin: several faint, fine, dusky spots on each ray of dorsal half (but distal margin unmarked dorsally) forming up to about 6 irregular bands; ventral half dusky with small, pale spots sometimes in membranes between rays. Pectoral and pelvic fins unremarkable, except one specimen with 4 or 5 fine, dark spots on each pectoral fin.
Remarks: J.L.B Smith (1959, fig. 5, as Istiblennius andamanensis) gives a drawing of a male that must have been based on a fresh specimen. It exhibits several more stripes on the side, each extending for a greater length of the body than those of preserved specimens, and also numerous pale spots posteriorly on the body. The fainter of the stripes (2 on body dorsally, 3 ventrally) and the pale spots (but not the ocelli in the bands) apparently fade in preservation, as evidenced by a color photograph, in our possession, of a fresh specimen from Kenya, which shows similar stripes and spots to those in Smith's illustration, but which are not in evidence in the same specimen preserved.
Based on a color slide, a freshly dead male from Ras Iwetme, Kenya, exhibits a complex color pattern: Several reddish orange spots posterior to eye, on cheek, and surrounding dark-blue spot on opercle; iris bright yellow ventrally, with reddish brown spots separated by small, pale-bluish spots dorsally; reddish brown spot present just dorsoposterior to orbit; orbital cirrus pink; crest variably tinted, with broad, pale, subdistal margin and narrow, reddish brown distal margin; remainder of head toned dark greenish brown dorsally, faintly pale yellowish ventrally. Anterior half of body dark-greenish gray-blue dorsally, gray ventrally, dorsal area forming diffuse broad bands, ventral area interrupted by paler areas, forming several alternating pale and grayish stripes; two short, fine, black pinstripes present; anterior body color grading into brown on posterior half of body, darker bands and numerous small, white or pale-bluish spots, including ocelli, incorporated in bands. Both dorsal fins dark brown basally, segmented-ray portion with black, oblique pinstripes; dorsal to basal area, spinous portion anteriorly with variegated reddish brown spots grading into greenish brown spots posteriorly, distal margin narrowly bright white; segmented-ray portion, dorsal to dark basal area, tones of complex green broken into spots by irregular, slender, pale stripes; fin becoming reddish distally with narrow, pale distal margin. Caudal fin variably brownish and greenish, interrupted by numerous pale spots basally, spots gradually coalescing posteriorly, forming all pale distal margin. Anal fin darkly toned basally with interrupted bright-pale subdistal stripe and dark distal membranes; fin paler posteriorly with greenish tones.
Table 6.—Frequency distributions for certain meristic characters in male specimens of Blenniella cyanostigma and B. caudolineatus from various localities. Underlining of means indicates significant differences between means of sexes from same locality (p ≤ .05).
Females (Figure 7b,c). Head: variably dusky, usually without distinctive marks; small, dusky spot occasionally ventroposterior to orbit; corner of mouth and adjacent area between mouth corner and ventral orbital margin occasionally noticeably pale, set off by dorsal, dusky area above corner of mouth and diffuse, dusky band extending from ventral orbital margin across upper lip. Body: most noticeable markings 5 or, uncommonly, 6 more or less evenly spaced, dark pinstripes extending posteriorly from area below 5 posteriormost dorsal-fin spines for varying distances to area below posterior third or fourth of base of segmented-ray portion of fin, there breaking up into numerous dark spots and dashes; stripe along body midline and 2 stripes above it, always present and darkest; up to 6 or 7 faintly dusky bands on midside anterior to and underlying dark pinstripes; bands occasionally forked ventrally, with disjunct small, paired saddles along dorsal body contour. Dorsal fin: spinous portion irregularly dusky, usually darkest distally, occasionally with 1 or 2 rows of diffuse, irregularly shaped, dusky spots distally; segmented-ray portion varying from almost unmarked (uncommonly) to, usually, bearing 2 or 3 rows of dark spots centered on rays. Anal fin faintly dusky, darkest distally. Caudal fin with up to about 8 irregular, vertical columns of dark spots centered on rays. Pectoral and pelvic fins essentially unmarked.
Table 7.—Frequency distributions for certain meristic characters in female specimens of Blenniella cyanostigma and B. caudolineatus from various localities. Underlining of means indicates significant differences between means of sexes from same locality (p ≤ .05).
J.L.B. Smith (1959, pl. 16: fig. 7) provides a color illustration (painting) of a fresh female from Ibo, Mozambique. The illustration indicates brownish purple stripe on body dorsal to dorsalmost (3rd) dark pinstripe, slender reddish bands dorsally on head, bluish spot on cheek, another spot ventroposterior to orbit. All these marks, except occasionally the last, are not indicated by preserved specimens.
Size. Largest available specimen: male, 81 mm SL; males commonly exceeding 60 mm SL; largest female, 60 mm SL, few females exceeding 55 mm. Smallest available specimens: male, 18.8 mm SL; female, 24.9 mm SL; ophioblennius-stage specimens unknown.
COMPARISONS AND RELATIONSHIPS.—Based on overall similarity, (and our phylogenetic analysis, q.v.) Blenniella cyanostigma appears to be the sister species of the allopatric B. caudolineata. The latter species has long been considered a junior synonym of the former. J.L.B. Smith (1959:242) first recognized two species in the complex based on differences in the color patterns of the females. Smith, however, believed that “andamanensis” (a junior synonym of cyanostigma), applied to the Indian Ocean species and cyanostigma to the Pacific species. He apparently included Java as a Pacific Ocean locality.
Table 8.—Frequency distributions for certain characters of specimens of Blenniella cyanostigma and B. caudolineata from various localities (total mandibular pores = right + left sides*; total procurrent caudal-fin rays = dorsal + ventral rays).
The most apparent difference between B. cyanostigma and B. caudolineata is in the color pattern of the females (see Table 5 for comparison of males with those of similar species). Female cyanostigma have 5 or 6 more or less equally spaced, fine, dark stripes on the side of the body, whereas female caudolineata only have 3 or 4, the ventralmost of which is separated from the next more dorsal stripe (at the body midline) by a space about twice as deep as each of the two spaces separating the three stripes dorsal to the ventralmost stripe. The two species are further distinguished in that cyanostigma has strongly modally 5 mandibular sensory pores on each side and caudolineata has strongly modally 6 (Table 8, presented as total mandibular pores, right + left sides). There is also a strong tendency for cyanostigma to have modally fewer dorsal + ventral procurrent caudal-fin rays than caudolineata (Table 8), a reflection of the occurrence of modally 6 dorsal procurrent rays in cyanostigma and modally 7 in caudolineata.
Many male specimens of cyanostigma lack any indication of a dark spot on the opercle and the spot, when present, is usually small; however, the lectotype of cyanostigma, at least, has a relatively large spot (see also nomenclatural discussion). In caudolineata, the opercle spot varies from absent (uncommonly) to well-developed, occupying most of the opercular surface dorsally.
DISTRIBUTION (Figure 65).—Blenniella cyanostigma is essentially restricted to the Indian Ocean, extending from the east coast of Africa to the west coast of Sumatra, and from there to Java and Bali. J.L.B.Smith (1959:242) stated that the distribution included the Seychelles, but we have seen no specimens from those islands. He also reported the species from as far south as Bazaruto (~22.5°S), Mozambique, on the African coast, but we have seen no specimens from farther south than Pinda (~17°S). The Bazaruto record seems reasonable, and we have included it on the distribution map. There is an apparent distributional gap in the central Indian Ocean (Seychelles, Laccadive, Maldive, Chagos islands), which separates the distribution into western and eastern sections. There is little evidence that the gap serves as a barrier to gene flow between the sections.
NOMENCLATURAL
- bibliographic citation
- Springer, Victor G. and Williams, Jeffrey T. 1994. "The Indo-West Pacific blenniid fish genus Istiblennius reappraised : a revision of Istiblennius, Blenniella, and Paralticus, new genus." Smithsonian Contributions to Zoology. 1-193. https://doi.org/10.5479/si.00810282.565
