Trachyscorpia cristulata (Goode & Bean, 1896) Sebastolobinae

Ditty, James G., Malca, Estrella & Vásquez-Yeomans, Lourdes, 2024, The lionfishes: Comparative development of Pterois volitans, Dendrochirus barberi, and D. hemprichi (Scorpaeniformes: Scorpaenidae: Pteroinae) and discrimination of their early life stages from non-pteroine scorpaenid genera in the Western North Atlantic, Zootaxa 5446 (1), pp. 1-41 : 21-22

Trachyscorpia cristulata and Phenacoscorpius nebris

Early life stages of deep-water members of Idiastion kyphos Eschmeyer, 1965 , Neomerinthe spp. , Phenacoscorpius nebris Eschmeyer, 1965 ( Scorpaeninae ), Setarches guentheri Johnson, 1862 ( Setarchinae ), and Trachyscorpia cristulata ( Goode & Bean, 1896) (Sebastolobinae) , included in Sebastinae by Hardy (2005), have not been described, to our knowledge. While a visiting scientist at the Smithsonian Institution (NMNH), the senior author examined the smallest available specimen of T. cristulata (32.0 mm SL; USNM 72979; collected 14 February 1902 off Key West, Florida) and P. nebris (40.0 mm SL; USNM 422671; collected 24 May 2013 off Curacao); small juveniles of the other aforementioned taxa were not available in NMNH collections for examination. Our intent was to generate a suite of characteristics to enable recognition and discrimination of late postflexion and transforming larvae of T. cristulata and P. nebris from other scorpaenids in the WNA.

Trachyscorpia cristulata with cranial spines strongly developed. Elevated parietal ridge terminates in longer nuchal than parietal spines; parietals behind nuchals. Opercle with pair of ridges or struts, upper ridge directed dorsoposteriorly, lower ridge directed posteriorly, short spine at outer margin of each. Pair of spines on IO1 overlap dorsal margin of maxilla, and series of eight laterally projecting spines of varying length along remainder of IO ridge. Other ridges and spines are as described by Ginsburg (1953) and Eschmeyer (1969), and include preorbital (i.e., IO1), supraocular, postocular, nasal, tympanic, pterotic, sphenotic, lower posttemporal, supracleithral, and cleithral; juvenile lacks upper posttemporal spine. PPO-1 longest, aligned with IO ridge, spine directed dorsoposteriorly; length of supplemental spine at its base about one-third that of PPO-1; PPO-1 about two times longer than PPO-2; PPO-2 through -4 similar in length, PPO-5 shortest. Length of supraocular cirrus about one-third OD. Ocular surface with ring of papillae; longer on anterior than posterior half of eye.

Dorsal-fin count XII, 9; spines increase in length from first to third, progressively shorter thereafter; penultimate spine about one-third that of terminal spine. Anal-fin count III, 5; length of first anal spine about 35% of second; second and third subequal, second notably thicker than third. Pectoral-fin ray count 23, fin length uncertain, rays broken on both sides of body; however, fins typically extend to or just short of anus in juveniles, with longest rays toward upper part of fin ( Ginsburg 1953; Eschmeyer 1969). About 30% of innermost pelvic ray attached by membrane to abdomen, based on ray length. Tips of longest pelvic rays extend to anus in specimen examined, but well short of anus in adults ( Ginsburg 1953; Eschmeyer 1969). Lateral line extends to base of caudal fin; middle primary caudal rays longer than those toward outer margins. Lacks small slit behind fourth gill arch. Body and fin pigmentation pattern difficult to assess due to long-term preservation; however, head and body peppered with melanophores of various sizes similar to that of juvenile sebastolobines from eastern Pacific (see Moser 1996).

Phenacoscorpius nebris with cranial spines strongly developed. Parietal and nuchal spines conjoined at base, parietals anterior to and longer than nuchals. Opercle with pair of ridges or struts, upper ridge directed dorsoposteriorly, lower ridge directed posteriorly, short spine at outer margin of each. Pair of spines on IO1 (i.e., preorbital of Eschmeyer 1965) overlap dorsal margin of maxilla, and ridge behind IO1 has five relatively stout, laterally projecting spines (i.e., suborbital and postorbital series of Eschmeyer 1965). Other spines as described by Eschmeyer (1965, 1969) include nasal, preocular, supraocular, postocular, tympanic, pterotic, upper and lower posttemporal, supracleithral, and cleithral.

Length of PPO spines differs between left and right sides of head. PPO-1 longest on left side, aligned with IO ridge, length of supplemental spine at its base about one-half that of PPO-1; PPO-2 blunt, “knob-like,” considered absent by Eschmeyer (1965); length of PPO-3 about one-half that of PPO-1; PPO-4 and -5 progressively shorter, lowermost covered by epithelium. PPO-1 and supplemental spine on right side as described above for left side, but PPO-2 longer than -1; PPO-3 blunt, “knob-like,” resembles PPO-2 on left side; PPO-4 and -5 progressively shorter, blunt. Supraocular cirrus short, multifurcate. Three-row arc of short papillae on surface of anterior half of eye; small flap on upper anterior and lower posterior margins of orbit. Small cirrus along IO1; small pigmented flap on ventral margin of lower nostril.

Dorsal-fin count XII, 9; spines increase in length from first to third, gradually decrease thereafter, penultimate spine about one-half that of terminal spine. Anal-fin count III, 5; second anal spine thicker, 20% longer than third. Pectoral-fin ray count 16, fins placed low on body just above and slightly behind pelvic fins. Melanophores pepper base and inner third of pectoral-fin rays; fins also have two narrow “bands” of pigment near mid-fin. All pectoral rays extend to or slightly beyond anus, with tips of rays 9 through 11 beyond first anal spine.About 50% of innermost pelvic ray attached by membrane to abdomen based on ray length, middle three rays longer than innermost and outermost, all rays well short of anal-fin base. Lateral line incomplete, 3–4 tubed scales immediately behind head. Small slit present behind fourth gill arch.

Body and fin pigmentation as described for a 29.3 mm Phenacoscorpius megalops Fowler, 1938 (listed as P. nebris in Eschmeyer & Randall 1975: fig. 11). Saddle of pigment near dorsal-fin origin, dark blotch on membrane between fifth and ninth dorsal spines, and dusky band between soft dorsal and anal fins that extends onto associated bases and inner half of rays; also, a band of pigment on CP at base of caudal fin composed of large melanophores. All areas of head peppered with melanophores, including membrane surrounding orbit and lower surface of iris; visceral mass with scattered blotches of pigment.