Finspot Eviota

This species is most closely related to the Eviota prasina complex, but differs from it in the following characters: usually A I,9 rather than I,8; pelvic fin often with a rudimentary fifth ray, which is usually absent in E. prasina; first filamentous dorsal spine with alternating dark and light spots to tip; occipital spots dark, prominent in adults but faint in young; dark peduncle spot more circular than chevron shaped; dark subcutaneous bars on posterior part of trunk 5/5, not 4/5 (Ref.

Dorsal spines (total): 7; Dorsal soft rays (total): 9 - 10; Analspines: 1; Analsoft rays: 8 - 9

The smallest gravid female 1.74 cm SL (Ref. 5293). Found in coral reef, benthic (Ref. 75154).

Eviota variola

MATERIAL EXAMINED.—170 specimens from 3 localities in the southernmost part of the Great Barrier Reef, Australia, totaling 87 males, 41 females, 42 juveniles; total size range 7.8–21.5; largest male 21.5, largest female 20.8; smallest gravid female 17.4.

Holotype: USNM 219238 (20.3), male; One Tree I., 22 Nov 1969, B. B. Collette, 1385, FT-409.

Paratypes: ONE TREE ISLAND: USNM 219239, 3 (12.9–17.8), 1 juv., 1 male (17.6), 1 female (17.8); same data as holotype. CAS 13783, 48 (8.9–21.5), 18 juv., 19 males (21.5), 11 females (19.1); same data as holotype. LACM 33723–28, 6 (11.2–19.0), 1 juv., 2 males (18.1), 3 females (19.0); Australian Museum staff, DFH 72–79. BPBM 22576, 2 (15.3, 17.4), juv. and female; 14 Jan 1973, J. E. Randall. AMS I.20204-018, 15 (7.8–21.0), 7 juv., 6 males (21.0), 2 females (20.8); 20 Nov 1969, F. Talbot 404. AMS I.20202–014, 23 (11.3–20.4), 1 juv., 12 males (19.4), 10 females (20.4); 4 Oct 1971, D. F. Hoese, 71–24. ANSP 141142, 2 (12.4, 15.2), juv. and male; 18 Nov 1966, V. G. Springer, 66–3. USNM 219244, 1 (14.1), juv.; 18 and 19 Nov 1966, V. G. Springer, 66–4 and 66–5, collections mixed. USNM 219241, 43 (9.7–20.9), 6 juv., 32 males (20.9), 5 females (19.4); 27 Nov 1966, V. G. Springer, 66–9. USNM 219240, 5 (11.9–17.9), 4 males (13.8), 1 female (17.9); 30 Nov 1966, V. G. Springer, 66–13. USNM 219243, 2 (14.3, 14.5), males; 9 Dec 1966, V. G. Springer, 66–18. HERON ISLAND: BPBM 22564, 2 (12.1, 12.8), juv. and female; 7 Oct 1964, Snider. LACM 32819–1, 13 (9.0–20.2), 4 juv., 5 males (18.3), 4 females (20.2); Dec 1961, G. Bartholomew. USNM 219242, 1 (18.5), female; 21 Feb 1967, J. Choat.

Other Material.—AMS IB.6251, 3 (17.3–19.6), 2 males (19.6), 1 female (18.2); Swain Reefs, Gillett Cay, 1962, AMS expedition.

DIAGNOSIS.—This species is most closely related to the E. prasina complex but differs from it in the following characters: anal fin rays usually I,9 rather than I,8; pelvic fin usually with a rudimentary fifth ray, usually absent in E. prasina; first filamentous dorsal spine with alternating dark and light spots to tip; occipital spots dark, prominent in adults, faint in young; dark peduncle spot more circular than chevron shaped; dark subcutaneous bars on posterior portion of trunk 5/5, never 4/5.

DESCRIPTION.—Data for certain characters are compared with populations of E. prasina in Tables 9–12. Dorsal fin VI-I,9(8), VI-I,10(28); anal fin I,8(10), I,9(26); pectoral fin 16(8), 17(24), 18(4); pelvic fin I,4(10), I,4 + a rudiment(26); fourth ray of pelvic fin with 4–10 branches; segments between consecutive branches of the fourth pelvic fin ray number 1–5, usually 2–3; pelvic fin membrane reduced; branched caudal fin rays 12(5), 13(11), 14(10), 15(2); segmented caudal fin rays 17(36); lateral scale rows 23(2), 24(22), 25(2); transverse scale rows 7(8), 8(3); scales with about 25–31 ctenii, 10–14 primary radii; breast scaleless.

First and second dorsal spines filamentous in males, maximum length of first spine, when depressed, extends to base of seventh dorsal fin ray; no spinous dorsal fin elongation in females; pelvic fins may extend beyond origin of anal fin.

The cephalic sensory pore system is pattern 2. Cutaneous papilla system is pattern B.

Genital papilla in male broad, the tip fringed and moderately indented, and with fimbriations on outer edges; fimbriations lacking in small males; papilla usually not extending beyond first anal ray; female papilla bulbous, reaching to first anal ray, the tip with 6–8 fingerlike projections.

One gravid female was 17.4 mm SL.

Vertebrae 10(13) precaudal and 16(13) caudal, total 26(13).

COLOR IN PRESERVATION.—The general color pattern of this species closely resembles that of E. prasina. As in E. prasina, there are differences in coloration related to sex and quality of preservation. Certain specific color marks vary with SL. These prominent color patterns are compared in Figure 46 a–e for E. prasina, and FIGURES 43 and 44 for E. variola. Additionally E. variola has prominent dark and light spots on the first filamentous dorsal spine, from the base to its extremity.

The presence, size, and intensity of the salient color marks are reviewed below in the order presented for E. prasina. Occipital spots: 2 prominent, dark, irregularly round spots dorsolaterally behind eye, the posterior one larger, the anterior one often weakly integrated with chromatophores dorsally over head; a pair of dark spots, smaller than occipital spots, dorsally just behind eyes (Figures 43–44), common also to E. prasina. The occipital spots in the adult male of E. variola are more intense than those of adult males of E. prasina, with the exception of specimens of E. prasina found in the southern portion of the western Indian Ocean population, where the spots are intense. These spots are most poorly developed in the Lord Howe–Norfolk Islands population of E. prasina.

Cheek Spots: About 4–10 irregularly shaped clusters of small to large chromatophores on cheek and opercle, less intense than occipital spots in adults; spots rarely replaced by uniformly scattered chromatophores as sometimes occurs in E. prasina.

Predorsal Area: Region from origin of first dorsal fin to eyes has weak to moderate groups of chromatophores, suggestive of transverse bars, that are usually more pronounced anteriorly on nape; sometimes predorsal area with fine scattered chromatophores, or area occasionally pale except for the pair of spots behind eyes. Predorsal area more heavily marked in many collections of E. prasina.

Spots along Dorsal Midline of Trunk: A linear series of about 12–14 weak, dark spots along dorsal midline extending from origin of first dorsal fin posteriorly to area just before procurrent caudal rays, faint in most specimens and obscure in some, more so anteriorly; the spots never as prominent as in some E. prasina collections.

Spots on Pectoral Base: A dark spot on upper and lower part of pectoral base, each consisting of a cluster of usually large chromatophores, separated by an area of fine chromatophores, or less commonly by a paler brown area. Sometimes spots replaced by uniformly scattered chromatophores, particularly in juveniles.

Caudal Peduncle Spot: A conspicuous, black, more or less circular-shaped spot located medially on caudal peduncle on about the third scale row anterior to base of caudal fin and overlying dark posteriormost subcutaneous bar; spot equal to or larger than pupil, sometimes deeper than wide, occasionally chevron shaped.

Dark Spots on Ventral Midline: A series of 5 spots, mostly subcutaneous, extend from origin of anal fin posteriorly on peduncle to area below midcaudal peduncle spot.

Subcutaneous Bars: Trunk with 5 dark subcutaneous bars integrated with the 5 ventral midline spots; bars usually conspicuous, rarely staggered and never 4 above on trunk and 5 below, as described for E. prasina from certain localities. The 3 lower and 2 upper subcutaneous bars on belly are present as in E. prasina, these usually weaker than those on posterior part of trunk and more enlarged and prominent in mature females. Two weak subcutaneous spots on posterior part of nape beneath the 2 narrow elongate midline spots that are usually present, as in E. prasina.

Scale Pigmentation: Scale pockets weakly margined with dark chromatophores, somewhat more evident on upper part of trunk.

First Dorsal Fin: Outer half, or more dark brown; usually with a series of 4 or 5 light spots at base, the largest equal to the pupil in size, located at the base of the first spine, and behind the third, fifth, and sixth spines; spots separated by brownish pigmentation that is sometimes integrated with the dark spots along dorsal midline of trunk; brown pigmentation may be irregular on anterior basal part of fin; a series of small dark and light spots on first spine of large males; when spine filamentous, spots continue to tip and spots usually visible on second spine of larger specimens and on filament, if present; small intense black spots, usually 2, on membrane above pale basal area posterior to the second and third spines, commonly present in juveniles and smaller males but lacking in large females.

Second Dorsal Fin: Dusky to light brown, the rays mostly clear; some specimens with outer one-half shaded in brown, the basal portion uniformly shaded with fine light brown to dusky chromatophores, or in some specimens with irregular shading of fine dusky chromatophores; in a few specimens the deeper brown shading is on the lower half, the outer portion having less dense and light brown to dusky chromatophores. Light round to elongate spots occur near midportion of fin in some specimens, mostly located over the rays and adjoining membrane; about 5 small light spots at base of fin, between dark dorsal trunk spots, smaller than those at base of first dorsal fin; a series of light and dark spots sometimes on spine of second dorsal fin, similar to those on spine of first dorsal fin.

Anal Fin: Dark brown to blackish, always darker than second dorsal fin, usually uniformly colored, the basal portion light brown or light dusky in some specimens, the fin margin clear or light. Females with slightly less pigmentation.

Caudal Fin: Dusky to light brown with small dark and light spots on rays, mostly on upper basal area of fin, spots sometimes absent.

Pectoral and Pelvic Fins: Membrane clear, the rays of pectoral fin with fine, weak, dark chromatophores.

SEXUAL DIMORPHIC FEATURES.—The prominent features are the fimbriate genital papilla, the filamentous first dorsal fin, and the darker coloration of the male. The occipital spots are most intense in males; the fins, particularly the anal fin, are somewhat lighter in females; the subcutaneous belly bars are wider and more prominent on females; the intense black spots, commonly present on the spinous dorsal fin of juveniles and smaller adult males, are lacking in adult females. The general body condition, including the fins, appears to be ragged or frayed in females as compared to the males.

GEOGRAPHIC DISTRIBUTION.—Taken only from the following localities of the southern Great Barrier Reef, Australia: One Tree and Heron Islands of the Capricorn Group and Gillett Cay, Swain Reefs (Figure 45).

ETYMOLOGY.—The specific name variola is a Latin word (spotted) and refers to the spots on the first dorsal spine and filament.