Acanthemblemaria johnsoni Almany & Baldwin 1996

Hastings, Philip A., Eytan, Ron I. & Summers, Adam P., 2020, Acanthemblemaria aceroi, a new species of tube blenny from the Caribbean coast of South America with notes on Acanthemblemaria johnsoni (Teleostei Chaenopsidae), Zootaxa 4816 (2), pp. 209-216 : 214-216

Acanthemblemaria johnsoni Almany & Baldwin 1996

“Black Barnacle Blenny”

( Fig. 4 )

This species was described based on six small specimens (14.1–24.0 mm SL) from Tobago ( Almany & Baldwin 1996). Recent collections from islands off the eastern coast of Venezuela revealed several additional specimens, including large adults. Examination of these and photographs of freshly caught specimens warrant additional notes on this species.

Meristics of specimens from Venezuela are similar to those from Tobago but expand the known range slightly: dorsal-fin spines XXIII–XXV (XXIV in type specimens); 12–13 dorsal-fin rays (12–13); 36–37 total dorsal-fin elements (36–37); and 23–25 anal-fin rays (24–25). The head spination is dense in this species, especially on the frontal wedge and interorbital region ( Fig. 4 ). The tips of the frontal spines in the smallest specimens are fleshy, as described for the holotype and paratypes ( Almany & Baldwin 1996). However the largest specimens have the entire spines fully ossified all the way to the blunt tips. This implies an ontogenetic trajectory of ossification of spines within this species and is analogous to the phylogenetic trajectory of head-spine ossification hypothesized within Acanthemblemaria ( Böhlke 1957; Hastings 1990).

Coloration. Large males completely black on head and body ( Fig. 4A ). Lateral body densely covered with melanophores with hints of bars. Anterior spinous dorsal fin black, grading to less pigmented posteriorly. Soft dorsal-fin rays, caudal-fin rays and posterior anal-fin rays tinged with yellow. Anterior anal fin dark with a darker band distally and a light distal margin. An apparent female ( Fig. 4B ) is much lighter in coloration with a series of seven white blotches along midline starting on cheek and extending to below origin of soft dorsal fin, decreasing in size posteriorly. Those on body set off above and below with dark blotches, two over abdomen and eight above anal fin. Lateral blotches reflected in mottled reddish pigment along spinous dorsal fin. Soft dorsal-fin and anal-fin rays reddish, grading to yellowish posteriorly; caudal-fin rays and caudal peduncle yellowish; pectoral fin reddish. Iris orange with scattered blue.

Distribution and remarks. Acanthemblemaria johnsoni is now known to range from Tobago to islands offshore of eastern Venezuela. It appears to be restricted to the eastern portion of southern Caribbean upwelling system that extends from Trinidad (61.1° W) to Barranquilla, Colombia (75.51° W; Rueda-Roa & Muller-Karger 2013). The common name of “Black Barnacle Blenny” is proposed in reference to the coloration of mature males and the group of tube blennies to which it apparently belongs.

Specimens examined. Acanthemblemaria johnsoni : Tobago: USNM 317211 (4, 19.5–25.5 mm SL; paratypes), North Point ; Venezuela: AMNH 249131 (13, 23.5–35.0 mm SL), North end of Cayo Nordeste , 11° 24.75’ N, 63° 02.83’ W ; SIO 01-176 (1, 34.5), Islas Testigos, approximately 11° 22.34’ N, 63° 7.12’ W ; SIO 06-274 (3, 28– 30 mm SL) , Isla Testigo Grande, 11° 23.2’ N, 63° 7.4’ W .

Figures

FIGURE 4. Color photographs of freshly caught Acanthemblemaria johnsoni, AMNH 247613, from Isla Testigo Grande. A) Male; B) Presumed female. Provided by James van Tassell.