Heteroclinus heptaeolus (Ogilby, 1885)

Hoese, Douglass F., Hay, Amanda & Dibattista, Joseph D., 2024, A review of the Heteroclinus heptaeolus complex (Pisces: Blennioidei: Clinidae), with three new species and discussion of use of proportions in taxonomic studies, Zootaxa 5432 (3), pp. 301-348 : 305

Heteroclinus heptaeolus complex

Species in this complex share the following features. Orbital tentacle, when present, slender, often spoon-shaped, without distinct lateral lobes. Nasal tentacle short, simple to weakly bilobed. Teeth villiform, teeth in each row touching and rows very close together. Three dorsal rays, with last two close-set and widely separate from first ray, which closely follows last dorsal spine. All head canals with uniserial pores. First dorsal origin above a point just behind posterior end of eye to above posterior margin of preoperculum. Head and body strongly compressed. First 3 dorsal spines separate from second dorsal fin with membrane from first dorsal connecting just before to slightly above lower base of first spine of second dorsal fin. First dorsal fin low, subequal to height or up to 40% higher than second dorsal fin height, not sexually dimorphic. First dorsal fin originating over the preoperculum behind the eye, with pterygiophores articulating directly with the posterior region of the skull, with variation between species in pterygiophore development and position of the second dorsal spine ( Figure 2 ). First pterygiophore of second dorsal fin inserted after third neural spine, followed by no pterygiophore after fourth neural spine and with one pterygiophore of each of remaining spines inserted between successive neural arches. All dorsal spines with lobes at distal tip bound in dorsal membrane. Anal fin membrane deeply incised, with membrane connecting to following rays well below the tip. Mouth small, ending below or slightly in front of eye. Lateral line well developed, in two sections, the anterior section arched from above operculum curving downward below end of pectoral fin reaching the midline of the body and a second section extending posteriorly to the end of the caudal fin base; anterior lateral line scales overlapping with a single, median posterior pore, posterior scales separate with a median pore at each end. Last two dorsal and anal rays widely separated from preceding ray ( Figure 3 ). Last anal ray connected by membrane to middle of caudal peduncle. Pelvic fin with one small spine and 3 unbranched stout rays, inner ray 0.4–0.7 length of pelvic fin, fin not reaching to anus. Dorsal, anal, pectoral and caudal rays unbranched. Caudal fin rounded to truncate. Circumorbital head pores uniserial (12–20 pores). Dorsal fins III, XXIII–XXVIII, 3; anal rays II, 15–22; segmented caudal rays 9–12, usually 10; pectoral rays 11–13, pelvic fin I,3; total gill rakers on outer face of first arch 6–12.

Figures

FIGURE 2. Radiograph of skulls of species of the Heteroclinus heptaeolus complex, showing modification and position of pterygiophores and first 3 dorsal spines on skulls of various species.

FIGURE 3. Radiograph of Heteroclinus whitleyi, n. sp., showing vertebrae and wide separation of the last two dorsal rays from the anterior ray and the less prominent separation of the last two anal rays.