Parascombrops mochizukii Schwarzhans, Prokofiev & Ho, new species
Creators: name: Schwarzhans, Werner W.
name: Prokofiev, Artem M.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Acropomatidae
Parascombrops
Parascombrops mochizukii

description: Parascombrops mochizukii Schwarzhans, Prokofiev & Ho, new species
Figs. 7E, 9E, 13E, 14H – I, 20, 37, Tables 2–7
Synagrops spinosus non Schultz 1940: Mochizuki & Gultneh 1989: 421; Hatooka 2002: 685.
Material examined (3 specimens). Holotype NMMB-P 782, 166 mm SL, off Dong-gang, Pingtung, southwestern Taiwan, 0 4. Dec. 1987. Paratypes: NMMB-P3887, 98 mm SL, Dong-gang, Pingtung, southwestern Taiwan, 29. Mar. 1964; NMMB-P 22743, 109 mm SL, Dong-gang, Pingtung, southwestern Taiwan, coll. H.- C. Ho, 0 5. Jan. 2015.
Diagnosis. Slender species with slightly convex dorsal head profile. First dorsal fin and anal with 2nd spine serrated along anterior edge. Pectoral fin rays 15–18, pectoral length 22.5–25.0% SL. Gill rakers 14–17.
Pseudobranchial filaments 29–31. First anal-fin pterygiophore long, slender, pointed, tip not hollow. Vomer triangular, anteriorly 2–3 rows granular teeth and posteriorly one or two long teeth. Ectopterygoid with 3 or 4 rows of granular teeth. Orbital diameter 11–13% SL; head length 37–40% SL; predorsal length 39.5–42.5% SL. Preopercular lobe with one longitudinal ridge and sometimes one spike. Otolith moderately elongate (OL:OH = 1.7).
Description. Counts and measurements (including data from Mochizuki & Gultneh (1989)) (see also summary Tables 2–7). Counts: D1: IX; D2: I + 9; A: II + 7; V: I + 5; P: 15 (15–18); developed gill rakers 14 (14–17); pseudobranchial filaments 31 (29–31). Morphometrics (% of SL): orbit 10.8 (10.8–12.8); snout 9.7 (8.7–9.8); head length 37.6 (37.0–39.8); pectoral length 22.4 (22.4–24.7); maximal body depth 28.5 (28.2–28.7); predorsal length 42.2 (39.5–42.2); preventral length 37.7 (36.1–38.3); preanal length 66.9 (64.5–68.5). Snout bluntly pointed; interorbital space slightly convex. Posterior edge of maxilla weakly concave with postero-dorsal and posteroventral angles slightly sharpened and postero-ventral angle extended downward and slightly backward resulting in slightly oblique posterior rim of maxilla. Preopercular lobe with one longitudinal ridge and sometimes one spike; denticles of hind margin serration not extending into crests on preopercular lobe; inner edge of preopercle with 5 small denticles not extending along ventral branch. Two anal-fin spines, the second serrated. Second spine of first dorsal fin serrated. Pelvic fin spine serrated along its outer edge. First anal fin pterygiophore long, straight, with sharply pointed tip, not hollow, reaching last pair of pleural ribs. First haemal spine with a narrow posterior expansion.
Dentition. Premaxilla with a pair of strong canines near symphysis, followed posteriorly by a wide band of minute conical teeth. Dentary with a pair of strong canines and a band of small conical teeth near symphysis, followed posteriorly by a row of small conical teeth and 3 to 4 enlarged canines. Vomer triangular, anteriorly with 2–3 rows granular teeth and posteriorly with 1 or 2 long teeth on each side. Palatines narrow, with 1 or 2 rows of granular teeth and anteriorly with 2 or 3 long teeth. Ectopterygoid widened, with 2–4 rows of denticles. Tongue toothless.
Otolith morphology (n = 1, plus 1 broken). Otolith moderately elongate, thin, large, 9 mm length in the paratype of 98 mm SL and certainly more than 12 mm in the broken specimen of the holotype. OL:OH = 1.7; OL:OT about 5. Dorsal rim with shallow, rounded mid-dorsal region and pronounced, high postdorsal angle close to posterior rim. Ventral rim moderately deep, deepest anterior of its middle. Rostrum well developed, moderately long, pointed; no excisura or antirostrum. Posterior rim broadly rounded. All rims smooth except for slightly crenulated posterior rim. Inner face moderately convex with slightly supramedian positioned sulcus. Sulcus shallow, with narrow, long, slightly deepened cauda and wide, shallow ostium. Ostium less than twice as wide as cauda, with distinct, dorsally reduced colliculum. Cauda tapering, with very slightly downward bend at tip, terminating close to posterior tip of otolith. CaL:OsL = 1.15. Dorsal depression feeble. Ventral furrow feeble, not much moving inwards and upwards posteriorly as approaching caudal tip. Outer face slightly concave, with some short radial furrows along the rims.
Coloration (in alcohol). Preserved fishes uniform pale orange. Dorsal surface from nape to insertion of second dorsal fin with dark rims around scale pockets; occiput with numerous diffuse small melanophores. Fins pale, with numerous minute, diffuse melanophores; first dorsal-fin membrane darker than other fins. Mouth pale, roof of mouth dark. Branchial cavity dark; peritoneum black.
Size. Large fishes reaching sizes up to 166 mm SL.
Discussion. Parascombrops mochizukii is very similar to P. spinosus, the only Atlantic species of the genus, which in the past has been regarded as conspecific (Mochizuki & Gultneh 1989). Both species differ from all other Parascombrops species, except P. serratospinosus, in the presence of serrations on the second spine of the first dorsal and the anal fins. However, P. mochizukii differs from P. serratospinosus in having the first spine of the second dorsal fin not serrated, a higher number of pseudobranchials (29–31 vs 16–21), the presence of preopercular ridges (vs absent), and a sharply pointed, not hollow, first anal-fin pterygiophore (vs broad-tipped and hollow). The differences between P. mochizukii and P. spinosus are subtle but consistent, judging from the few available specimens of P. mochizukii. Parascombrops mochizukii has a larger orbit 10.8–12.8% SL (vs 8.6–10.9% SL), longer head 36.5–39.8% SL, (vs. 31.3–35.2% SL), greater predorsal length 39.2–42.2% SL (vs 33.3–39.8% SL), slightly higher number of pseudobranchial filaments 29–31 (vs 24–28), the large otolith relative to head length (measured from x-rays, from snout to first vertebra) of 28–29% HL (vs 24–27% HL) and the slightly more compressed otolith, OL:OH = 1.70 (vs 1.75–1.8) with a strong postdorsal angle and a shallow mid-dorsal rim (vs low postdorsal angle and high mid-dorsal region). No doubt, both species form a sister species pair (see discussion in chapter Biogeography).
Geographic and bathymetric distribution. Parascombrops mochizukii was first recorded by Mochizuki & Gultneh (1989) as Synagrops spinosus, from off central Japan and in the South China Sea southeast of Hainan. Unfortunately, we were unable to examine these specimens. The three specimens cited here are from Taiwan, roughly mid-way between the two earlier records. Reported from 100 to 500 m depth (Hatooka 2002).
Etymology. Named in honor of Kenji Mochizuki, Chiba (Japan), for his many contributions to the knowledge of acropomatid fishes. He was also the first to record specimens of this species from the West Pacific, then regarded as representing Synagrops spinosus.
description: Published as part of Schwarzhans, Werner W. & Prokofiev, Artem M., 2017, Reappraisal of Synagrops Günther, 1887 with rehabilitation and revision of Parascombrops Alcock, 1889 including description of seven new species and two new genera (Perciformes: Acropomatidae), pp. 1-74 in Zootaxa 4260 (1) on pages 37-39, DOI: 10.5281/zenodo.571305