Giganthias serratospinosus White, 2012, new species
Creators: name: White, William T.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Serranidae
Giganthias
Giganthias serratospinosus

description: Giganthias serratospinosus, new species
Spinyfin Perch
(Figs 1–3, Table 1)
Holotype. MZB 20015, 307 mm TL, 237 mm SL, Tanjung Luar fish landing site, Lombok, East Nusa Tenggara, Indonesia, W. White and Dharmadi, 5th Nov. 2010.
Diagnosis. Dorsal-fin rays IX, 12; anal-fin rays III, 8; pectoral-fin rays 13–14; lateral-line scales 44; gill rakers 30 (10+20); body depth 2.2 in SL; eye large, orbit diameter 3.2 in head length; no prominent spine at angle of preopercle; vomerine tooth patch very small, triangular with rounded edges; no teeth on endopterygoids; scales dorsally on head reaching to about level of mid-eye, head naked anteriorly; maxilla fully scaled; tips of first to fourth dorsal spines and pelvic spine expanded with coarse serrations; fourth dorsal spine longest, 3.5 in head length; longest dorsal-fin soft ray 2.3 in SL; third anal-fin spine longest, 2.3 in head length; caudal fin lunate, lobes not tapering, fin length 3.5 in SL; pectoral fins 1.4 in head length; pelvic fins reaching to level of anus, 4.3 in SL.
Description. Dorsal-fin rays IX, 12; 6th dorsal-fin spine much reduced and immediately anterior to 7th dorsalfin spine; anal-fin rays III, 8; all dorsal and anal-fin soft rays branched, the last to its base; pectoral-fin rays 13–14, all except uppermost branched; pelvic-fin with I spine and 5 branched rays; principal caudal-fin rays 17, the middle 15 branched; upper procurrent caudal rays 8, two posteriormost segmented; lower procurrent caudal rays 7, two posteriormost segmented; lateral-line scales 44; transverse scales above lateral line to dorsal-fin origin 8; two fullsize scales from lateral line to base of middle dorsal-fin spines; 18 scales below lateral line to origin of anal fin; circumpeduncular scales 21; gill rakers 10+20; vertebrae 10+15; supraneural (predorsal) bones 2.
Body moderately deep, its depth 2.2 in SL; body compressed, the width 2.5 in body depth; head length 2.6 in SL; eye large, orbit diameter 3.2 in head length; snout short, 4.3 in head length; interorbital slightly convex, the least width 2.9 in head length; caudal-peduncle depth 2.6 in head length; caudal-peduncle length 2.2 in head length.
Mouth large, the maxilla extending just posterior to a vertical at mid pupil, the upper-jaw length 2.1 in head length; mouth oblique, forming an angle of about 40° to horizontal axis of head and body, lower jaw projecting; upper jaw with a band of about 10 or 11 rows of villiform teeth anteriorly, narrowing to four to five rows posteriorly; front of upper jaw with four low canines on either side; outer and inner row of teeth on teeth bands of upper jaw posterior to canines longer and stouter than remaining band of teeth; lower jaw with similar-sized band of villiform teeth, in 11 to 12 rows anteriorly, narrowing to three or four posteriorly; a patch of 12 large conical teeth in front of anterior band of teeth of lower jaw on each side; patch of villiform teeth on vomer very small, triangular with rounded angles and well-spaced from palatines; patch of villiform teeth on palatines moderately long, slender, not narrowing posteriorly; no separate patch of teeth on endopterygoids.
Nostrils directly anterior to eyes at about mid level of pupil; anterior nostril moderately large, rounded, with an elevated rim and a posterior flap; posterior nostril posterodorsal to anterior nostril, large and kidney-shaped.
Opercle with three flat spines, the uppermost spines broadly triangular and bluntly rounded, the middle spine longer and more pointed reaching slightly more than half way to posterior edge of fleshy opercle; posterior margin of preopercle and margin of interopercle finely serrate, angle of preopercle with two larger serrae.
Scales ctenoid; scales progressively smaller anteriorly on head; predorsal area scaled to about mid level of eye, naked anterior to this; preorbital, lips, throat and mandible naked; small scales basally on soft portions of dorsal and anal-fin spines, progressively smaller scales on caudal fin extending at least three quarters distance to posterior margin; small scales on about basal fifth of pectoral fins; each pelvic fin with two broad, blunt-tipped axillary scales; a small patch of scales of variable size ventrally between bases of pelvic fins. Lateral line continuous, very highly arched below mid dorsal-fin base.
Origin of dorsal fin over upper opercular spine; dorsal-fin spines very robust; first dorsal spine slightly more than half length of second dorsal spine, bifurcate distally with several small serrations; fourth dorsal spine longest, 3.5 in head length; tips of first to fourth dorsal spines expanded with coarse serrations on distal and anterior margins, most prominent on second and third spines; fifth dorsal-fin spine without an expanded tip, a single serration on tip giving impression of being double-tipped; sixth dorsal-fin spine broken at base (evident from x-ray), much reduced, slender, just anterior to seventh spine, about three quarters length of adjacent spines; no soft rays filamentous, the third and fourth rays longest, 2.3 in head length; origin of anal fin below base of third dorsal-fin soft ray; anal-fin spines robust, strong; first anal-fin spine short, about two thirds length of second; third anal spine slightly longer than second, 3.6 in head length; third anal-fin soft ray longest, 2.5 in head length; caudal fin lunate, the lobes not tapering, the fin length 3.5 in SL; caudal concavity 2.5 in head length; pectoral fins pointed, asymmetric, the fifth ray longest, reaching to above first anal-fin spine, 1.4 in head length; pelvic-fin spine robust, tip expanded with serrate anterior and distal margins; second ray of pelvic fins longest.
Colour. When fresh: Body orange dorsally, paler pinkish orange ventrally; nape and anterior back below spinous dorsal fin yellowish; several yellow blotches on head, anterior to eye, on upper lip and maxilla, just posterior to eye, and as a bar on preopercular margin; dorsal fin yellow, membranes of the soft portion pinkish; caudal fin pinkish orange, its upper tip yellow; anal fin mostly pale pinkish, spines whitish; pectoral fins yellow; pelvic fins whitish.
Distribution. Currently known only from East Lombok in the Nusa Tenggara region of Indonesia. The type specimen was collected from the fish market at Tanjung Luar (East Lombok) and caught by handline fishers operating in local waters. Thus, it was not translocated from other fishing areas like much of the landed catch.
Etymology. Named based on combination of the Latin serratus (serrate) and spina (spine) in allusion to the serrate tips to the anterior dorsal and pelvic spines which is a key diagnostic feature of this genus of anthiine fish.
Comparison with other species. Following a detailed examination and comparison with the description of the similar-sized specimens of the type species, G. immaculatus, by Katayama (1954) it was apparent that this specimen represented a new species of Giganthias. The two type specimens of G. immaculatus described by Katayama (1954) were collected in 1952 off Japan. This species has also been recorded off Taiwan (Lee, 1990; Shen, 1993) as well as the Izu and Ryukyu Islands (Masuda et al., 1984; Nakabo, 2002). The illustrated specimen of G. immaculatus in Masuda et al. (1984, pl. 119a) differs from the illustrated type specimen and the colour image in Lee (1990). The Masuda et al. (1984) specimen has a much lower anterior head profile, much shorter and higher soft dorsal and anal fins and a larger caudal fin. A more detailed examination of this specimen is needed to determine if it is conspecific with G. immaculatus.
The new species recorded from off Lombok in eastern Indonesia during this study is significantly extends the known range of this genus. No accurate depth information is available for type specimens of either of the Giganthias species. The specimen from Indonesia was collected by a hook and line fisher operating on a deep coral reef and was caught along with a number of other serranid species: Caprodon schlegelii, Liopropoma spp., Odontanthias spp. and Selenanthias analis.
Giganthias serratospinosus differs from G. immaculatus in having the first four dorsal spines with expanded and coarsely serrated tips (vs. only the third spine). Both type specimens and an additional two specimens collected from Japan (Okinawa fish market) do not possess serrations on the other dorsal spines (Katayama, 1954). It also differs in the following characteristics: dorsal-fin soft rays 12 (vs. 13); pectoral-fin rays 13–14 (vs. 16); dorsal spines shorter (3rd and 4th spines 9.2 and 11.0% SL vs. 14.3 and 15.7% SL, respectively, based on HUMZ 50344); pre-pelvic length 42.3 vs. 36.8–38.6% SL, 2.4 vs. 2.6–2.7 in SL; pelvic-fin spine shorter, its length 15.4 vs. 16.7– 19.0% SL, 2.5 vs. 1.9–2.2 in head length; and slightly deeper body 44.7 vs. 41.3–43.5% SL. The number of pectoral-fin rays has been shown to be a very useful meristic character for anthiine fishes, e.g. Odontanthias (Randall & Heemstra, 2006) which vary by less than 2 rays between some species with no overlap. It should be noted though that the Randall & Heemstra (2006) pectoral-fin counts were often on low samples sizes and more overlap may be found with more samples examined. The two type specimens (Katayama, 1954), one Taiwanese specimen (Lee, 1990) and two additional Japanese specimens (W. Anderson, unpubl. data) of G. immaculatus all possessed 16 pectoral-fin rays vs. the 13 or 14 in the new species.
Lee (1990) included a good quality colour image of G. immaculatus from Taiwan, allowing a comparison of the fresh colouration of the two species. The colour of these two species is very similar. Although the yellow markings on the head of G. serratospinosus, are more conspicuous, this is probably reflective of the very fresh condition of this specimen. The yellow upper caudal lobe of G. serratospinosus is not evident in the fresh image of G. immaculatus, and the pectoral fin is much more yellow in the new species. Based on the two colour images available for comparison, the coloration of the two species is very similar.
description: Published as part of White, William T., 2012, Giganthias serratospinosus, a new serranid (Perciformes: Serranidae: Anthiinae) from the island of Lombok in Indonesia, pp. 61-66 in Zootaxa 3161 on pages 63-65, DOI: 10.5281/zenodo.209785