Dendrochirus barberi (Steindachner, 1900)

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 : 12-16

Dendrochirus barberi :

general morphology

We measured 12 postflexion and transforming larvae from 8.6–14.0 mm ( Fig. 4a–e ). Mean HL 32% SL; snout length typically 65–75% OD; mean BDc 34% SL; body depth at CP 51% BDc; CP about 15% deeper than long ( Table 2 ). Rays of pectoral fin elongate, tips of longest extend to or slightly beyond last pterygiophore of dorsal-fin base in smallest larva; mean depth of pectoral-fin base 49% BDc ( Table 2 ). All larvae with pronounced “hump” in dorsal profile of snout due to elevated rostral cartilage; terminal margin of maxilla extends to about mid-orbit. PPO spines about evenly spaced along shelf margin, upper 3–4 subequal, lowermost shortest ( Fig. 4a ). Smallest larva with oblong loop in fore- and mid-gut; hindgut slender, terminates beyond mid-body; gut with rugose folds in early transformers (~9.0 mm). Gas bladder unpigmented, obscured by abdominal musculature in transformers. Seven BR.

Pigmentation

Head and visceral mass unpigmented or nearly so, body sparsely pigmented until early transformation ( Fig. 4b ). Smallest postflexion larva (8.6 mm) with pigment on dorsolateral surface of hindgut, this pigment obscured by thickening abdominal musculature in largest transformer ( Fig. 4 c-e). Externally, early transformers with small pigment on pterygiophore of 10 th dorsal spine, and third and last two pterygiophores of soft dorsal-fin base; expanded melanophore on third, fourth, and last two pterygiophores of anal-fin base; and small ventral blotch near mid-CP ( Fig. 4c ). Laterally, series of three close-set “dash-like” melanophores along body midline on penultimate and antepenultimate myomeres of CP, which by 11.0 mm, coalesce into narrow, elongate streak. Transformers also add large circular melanophore to dorsal surface of head (midbrain region), small cluster to anterodorsal margin of upper lip, and five partial saddles along dorsal margin of body: anterior saddle near origin of spinous dorsal fin, posterior saddle near terminal margin of soft dorsal-fin base ( Fig. 4 c-e). By 11.0 mm, CP with dorsal series of three melanophores perpendicular to longitudinal axis of body near mid-peduncle, one medial and one on each side of body midline; another pigment embedded in CP midline near anteriormost developed upper secondary element. By 12.0 mm, two stripes present across head: anterior stripe between orbital margins, posterior stripe between bases of parietal spines. Small dorsal blotch also added near mid-CP, its position about one myomere caudad of opposing blotch on ventral margin. Largest transformer (14.0 mm) adds pigment on snout near upper lip, dorsal margin of lower lip near symphysial knob, angle of lower jaw, near anteroventral and ventral margins of orbit, to cheek near lower margin of APO, and diagonal streak between posterior margin of orbit and APO ( Fig. 4e ). Ventrolateral margin of lower lip lightly mottled near mid-lip.

Fin development and pigmentation

Smallest larva with full complement of pterygiophores in dorsal- and anal-fins; caudal fin with 5+5 weakly segmented, and 2+2 unsegmented rays ( Table 3 ). Dorsal and anal spines feeble, first two dorsal spines of similar length, last three elements of spinous dorsal fin ray-like. Pterygiophore of first dorsal spine inserted above lower posttemporal ridge; gap between first and second dorsal spine narrower than between subsequent spines. Tips of dorsal- and anal-fin rays from behind about mid-base extend to terminal margin of hypural plate. Transformers with all dorsal spines and first two anal spines well developed, and a full complement of 7+7 primary caudal rays (inner 6+6 segmented), plus 3+3 secondary elements (20 total as in adults). Second dorsal spine about 25% longer than first; second anal spine nearly two times longer than first; third element of anal fin ray-like, untransformed in largest larva. Pterygiophore of first anal spine inserted below 12 th to 13 th dorsal spine; if 12 spines, inserted below 12 th dorsal spine to first ray. Pterygiophore of first “true” ray of anal fin inserted below first to second ray of soft dorsal fin, terminal pterygiophore of anal-fin base inserted below penultimate to antepenultimate pterygiophores of soft dorsal fin. Largest transformer adds pigment along outer third of shaft of first and second dorsal rays, and shaft and on membrane between fourth through sixth rays of anal fin. Last ray of dorsal fin attached by short membrane to body wall, last anal ray free; caudal fin unpigmented in largest transformer.

Smallest larva with all pectoral- and pelvic-fin elements well formed. Although upper four rays of pectoral fin broken off near mid-shaft, diffuse blotch of pigment on inner third of shaft and membrane between rays 5–6, 10–11, and along outer margin of shaft and membrane between rays 7–8. Early transformers with pigment along shaft and membrane of rays 2–3, near outer third of shaft of rays 9–11, and near outer margin of rays 12–15 ( Fig. 4c ). Largest transformer with pigment consolidating into series of oblong blotches in two uneven rows near mid-fin and outer margin ( Fig. 4e ); lower four rays of pectoral fin slightly thickened; longest rays extend to or slightly beyond last pterygiophore of dorsal-fin base.

Tips of longest rays of pelvic fin extend to or slightly beyond mid-anal-fin base, innermost ray joined to abdomen by short membrane in smallest larva. Pigment on inner third of membrane that connects innermost ray to abdominal wall, this pigment more pronounced in transformers. By 11.0 mm, pigment present near mid- and outer-margin of shaft of innermost ray, and along outer 25% of shaft and on membrane between rays 3–4; pelvic spine extends <70% of distance to origin of anal-fin base when pressed against body. Late transformers with pigment on webbing between pelvic spine and outermost ray.

Cephalic and opercular spination; supraocular and nasal cirri; and sensory pore development

Smallest larva with five PPO and three APO spines, PPO’s subequal, each <35% OD ( Fig. 4a ). PPO-1 and -2 along upper margin: PPO-1 about mid-orbit, directed dorsoposteriorly; PPO-2 directed posteriorly. PPO-3 through -5 along lower margin: PPO-3 below shelf angle nearly aligned with dorsal margin of maxilla; PPO-4 near lower margin of pectoral-fin base directed posteroventrally; PPO-5 near angle of lower jaw, directed ventrally. APO-1 and -2 along upper margin of shelf, nearly overlay PPO counterparts; APO-3 along lower margin, closer to PPO-4 than -3. Largest transformer with APO-1 closer to PPO-2, and APO-2 between PPO-3 and -4; transformers lack supplemental spine at base of PPO-1 found in juveniles and adults.

Most cranial ridges and spines weakly developed until early transformation.Smallest larva with outer interorbital, supraocular, postocular, pterotic, lower posttemporal, infraorbital, parietal, and nuchal ridges; and parietal and nuchal spines ( Fig. 4a ). Parietal ridges weakly dentate, terminate at conjoined base of parietal and nuchal spines. Nuchal spines external to parietals, subequal in length, and lie flatter against cranium (i.e., ≤15° above longitudinal axis of head) than in P. volitans . Anterior margin of parietals weakly serrate; posterior margin smooth; nuchal margins smooth at all sizes examined. Low, outer interorbital ridges originate above mid-orbit, diverge outward toward posterolateral margin of cranium, connect to coronal base, then bifurcate into low coronal and tympanic ridges. By 11.5 mm, transformers with short, flimsy spine on terminal margin of each ridge lies nearly flat against cranium, best observed by lifting with probe.

Supra- and postocular ridges project outward over eyes like “blinders,” each ridge with dorsoposteriorly directed spine in smallest larva. Supraocular ridge rises to acute peak along anterodorsal margin of orbit, descends thereafter to become postocular ridge; postocular ridge rises to acute peak near mid-orbit, descends along posterior margin of orbit; height of both ridges gradually reduced during transformation to become low continuous ridge with scalloped outer margin in largest transformer. Smallest larva with pterotic and lower posttemporal ridges swollen, laterally projecting, increase in height in posterior direction, short terminal spine on each ( Fig. 4a ). Height of lower posttemporal ridge nearly twice that of pterotic ridge in early transformers; largest transformer with posterior half of pterotic ridge weakly dentate. Transformers add supracleithral ridge by 10.0 mm. Below orbit, smallest larva with low IO ridge, small spine on IO 1-U1, IO 1-L1, and ventrally near terminal margin of IO 4; IO 1-L1 overlaps dorsal margin of upper lip in transformers. By 11.0 mm, two small spines added on lateral margin of ridge along IO 3, posterior spine slightly larger than anterior spine.

Smallest larva with cephalosensory canal along IO 1 and outer margin of PPO. Canal along PPO with single pore above PPO-1, between PPO-2 and -3, and between -3 and -4 ( Fig. 4a ). Transformers add sensory canal along postocular, pterotic, and lower posttemporal ridges; along lower margin of operculum; and on snout and frontal region of head above nares. By 11.0 mm, transformers with V-shaped tooth patch on vomer, and short cirrus on dorsal rim of anterior nostril, and above eye (i.e., nasal and supraocular cirri; Fig. 4c ). Largest transformer with supraocular cirrus>50% OD, well pigmented; tip of unpigmented nasal cirrus extends to about mid-orbit if pressed against forehead. Transformers lack nasal, opercle, interopercle, and subopercle spines; and sphenotic and medial interorbital ridges.

Figures

FIGURE 4. Dendrochirus barberi larvae.A. cranial & opercular spination at 8.6 mm; B. 9.1 mm; C. 11.0 mm; D. 12.2 mm; E. 14.0 mm. Pigment enhanced in some images for detail purposes.All lengths in mm standard length (SL). Scale bar = 1.0 mm.