Abstract
TABLE 5. Discrimination of early life stages of Pterois volitans, Dendrochirus barberi, D. hemprichi, D. “ bellus,” and D. zebra from non-pteroine scorpaenids in the Western North Atlantic. Scorpaenids typically have five spines along the posterior shelf of the preopercle (PPO), although early larvae of some taxa may have three, and add one or two spines in subsequent life stages. “Elongate” spine(s) refer to those about two or more times longer than the next longest spine, or all spines that extend well beyond the posterior margin of the operculum or ventral margin of body, depending on orientation. “Robust” spines refer to “elongate” spines, as defined above, that are structurally stout and broadbased, whereas spines of short to moderate length are typically “slender” with a relatively narrow base. “Elongate” fins refer to those whose tips extend to, and typically well beyond, the posterior margin of the anal-fin base, whereas “short” fins may extend to, but seldom beyond, the origin of the anal-fin base. The pectoral fins are precocious, unless otherwise noted. “Shield” of pigment refers to the extent of pigmentation over the dorsolateral surface of the visceral mass in early larvae, which may be reduced or augmented with scattered blotches of pigment in larger larvae of some taxa. The parietal spines are typically two or more times longer than the nuchals, unless otherwise noted. Classification of subfamilies within Scorpaenidae follows van der Laan et al. (2023). Abbreviations: parietal spines (P), nuchal spines (N), anal-fin origin (AFO), anal-fin base (AFB). Characters compiled from Sánchez & Acha (1988); Moser (1996); Hardy (2005); Fahay (2007); Baldwin (2013); Kojima (2014); Mertzlufft (2021); and include the personal observations of the senior author.
TaxonRelative size & lengthOpercle spine(s)Visceral massPectoral finsSlit behind 4 th gill archOther characteristics(P)arietal & (N)uchal spinesPPO spines“Shield” of pigmentContour & length PigmentationPteroinaePterois volitansP> NMiddle pair longer than outer; none distinctly elongateNoneNoElongate, fan-shaped; tips to or beyond terminal margin of AFBLight to mottledNoPigmentation sparse, typically concentrated along body midlines (until late transformation). Elevation of parietal & nuchal spines ~30° above longitudinal axis of head.Dendrochirus spp.N ≥ PUpper 3–4 subequal, none distinctly elongate; all about evenly spacedNoneNoElongate, fan-shaped; tips to or beyond terminal margin of AFBLight to mottledNoPigmentation sparse until transformation, then saddles along dorsal & ventral margins. Elevation of parietal & nuchal spines low on head (≤15°).(P)arietal & (N)uchal spinesPPO spines“Shield” of pigmentContour & lengthPigmentationScorpaeninaePontinus spp.P> NOne or more elongate & robust, spine near shelf angle typically longestPair near upper margin onlyNo 1Wing-shaped (upper rays longer than lower); tips to about mid-AFBVariable, develops through sequential stagesYesInitially, three robust PPO’s about evenly spaced along shelf. Some species may have one or more enlarged APO & supplemental PPO spines. Supraocular spine stout, may be forward-angled (if unbroken). Parietals enlarged, stout, nuchals minute (develop late). Pigment on spinous dorsalfin becomes streak or blotch. Liver area may be dark or dusky.Scorpaena spp.P> NVariableUpper & lower marginsYesFan-shaped; tips to AFO seldom beyondSome to most of fin darkNoTips of pelvic fins short of anus. Inner half to most of pectoral fins well pigmented, distal margin may be unpigmented or sparsely so.Scorpaenodes spp.N ≥ P2–4 stout, moderately elongate spinesPair near upper margin onlyNo 1Fan-shaped; tips to about mid-AFBSome to most of fin darkPresent or absentParietal ridge crest-like, nuchal & parietal spines pronounced. Heavy pigmentation makes pectoral fins appear superficially larger than in other genera.SebastinaeHelicolenus dactylopterusP> N3–5 relatively stout, middle longest; none distinctly elongateSingle, small to tiny near upper margin only, if presentYesFan-shaped; tips to or slightly beyond AFOSparse to noneYesCharacteristic mass of spongy tissue below spinous dorsalfin base. Caudal fin precedes pectoral fin development.(P)arietal & (N)uchal spinesPPO spines“Shield” of pigmentContour & lengthPigmentationSebastes spp. 2P> NVariable, spine atSingle, small toYesFan-shaped; tips to orSparse to noneNoProminent cluster of pigments onangle often longest;tiny near upperslightly beyond AFOdorsal surface of head; postanalnone distinctlymargin only, ifseries of melanophores alongelongatepresentdorsal & ventral midlines ofbody. Caudal fin developmentprecedes that of pectoral fin.High count of 29–32 myomeres.SetarchinaeEctreposebastesP> NInitially, threeUpper & lowerNo 1Elongate, fan-shaped;Most of fin,YesSupraocular spine may be stout,imusrobust, about evenlymarginstips to or beyondbut becomesforward-angled (if unbroken).spaced, longest nearterminal margin of AFBmore distal atParietals about three times longerangle; one or twolarger sizesthan nuchals. Tip of lower jawadded in later lifejuts out slightly beyond upperstagesjaw. Cranium cavernous, weaklyossified, transparent.SetarchesP> NUpper 3–4 subequal,Upper & lowerUnknownElongate, fan-shaped;UnknownYesHigh modal count of 22–24guentheri 3all about evenlymarginstips likely to or beyondpectoral-fin rays. Craniumspaced; noneterminal margin of AFBcavernous, weakly ossified,distinctly elongatetransparent. Pigment scatteredover upper & lower surfaces ofvisceral mass likely.
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1 Deeply embedded medial blotch just above pectoral-fin base expands to cover dorsal surface of gas bladder (Moser et al. 1977)
2 Nuchals, if present, small to tiny & form late, often posterior to base of parietals
3 Some characters based on limited description in Mertzlufft (2021)