Parascombrops philippinensis Gunther 1880
Creators: name: Schwarzhans, Werner W.
name: Prokofiev, Artem M.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Acropomatidae
Parascombrops
Parascombrops philippinensis

description: Parascombrops philippinensis (Günther, 1880)
Figs. 2F, 7J, 8A, 10B, 11E, 13J, 15 G – L, 26, 27, 36, Tables 2–7
Acropoma philippinense Günther 1880: 51 (lectotype designated here: BMNH 1879.5.14.167; Philippines, Challenger station 201, 150– 186 m).
Synagrops malayanus Weber, 1913: 196, fig. 52 (lectotype designated here: ZMA 112.453, Timor Sea, Indonesia, Siboga: stn 302, 216 m).
Note: Synagrops philippinensis is one of the most commonly cited species of the group, often in check-lists without description or figure. If the published accounts did not contain information of most of characters used here for species diagnosis, we were unable to verify the record, so was not included.
Material examined (240 specimens): BMNH 1879.5.14.167, lectotype, 70 mm SL, Philippines, Challenger station 201, 07°03’N, 121°48’E, 150–186 m; BMNH 2016.9.14.1-4, 4 specimens, paralectotypes, 44, 63, 64, 74 mm SL, same data as lectotype; BMNH 1986.10.9.76, 64 mm SL, Sumbawa, Saleh Bay; BMNH 1986.10.9.88, 71 mm SL, off Bali; AMS I.21835-016, 68 mm SL, 09°21’S, 133°12’E, 156–164 m; AMS I.21844-004, 58 mm SL, 10°01’S, 133°54’E, 80–84 m; BSKU 29045, 37603-04, 39445-49, 39477, 39507-10, 39513, 68618, 72773, 74367, 74985, 77449, 77814, 78371, 87910, 88320, 91384, 92536-42, 108395-98, 108634, 112682, 112684, 112688 -89, 112859, 112862, 116496, totally 47 specimens, 40–73 mm SL, all from Kochi (Mimase and Saga fish markets), Japan; CAS 238010, 67.5 mm SL, 13°08’N, 124°04’E, 363–385 m (otolith only); CAS 34418, 3 specimens, 59–65 mm SL, Philippines, off Batanga Islands; NMMB-P3545, 2 specimens, 53–60 mm SL, Kaohsiung, Taiwan, 100 m; IOM, uncatalogued, 126 specimens, 20.5–75.0 mm SL, Nha Trang Bay, Vietnam; NMMB-P7474, 4 specimens, 60.5– 66 mm SL, Da-si fishmarket, Ilan, Taiwan; NMMB-P11346, 4 specimens, 43–63.5 mm SL, Dong-gang, Pingtung, southwestern Taiwan; NMMB-P22436, 54.5 mm SL, Da-si fishmarket, Iland, Taiwan; NMMB-P 23103, 54 mm SL, Dong-gang, Pingtung, southwestern Taiwan; NSMT-P 30481, 59.5 mm SL, Tosa Bay; NSMT-P 53294, 3 specimens, 52–66.5 mm SL, 32°35’N, 129°52’E, 80 m; NSMT-P 53618, 4 specimens, 54–74.5 mm SL, 32°33’N, 129°52’E, 80 m; NSMT-P 57379, 2 specimens, 33.5– 37 mm SL, 33°18’N, 133°33’E, 99 m; NSMT-P 59313, 3 specimens, 50.5– 57 mm SL, Tosa Bay, 150 m; NSMT-P 65240, 76 mm SL, Kyushu, Kagoshima, Iwamoto fish market; NSMT-P 69717, 43.5 mm SL, 31°29’N, 127°10’E, 105 m; NSMT-P 78079, 64 mm SL, Tosa Bay, 130 m; NSMT-P 78351-52, 2 specimens, 56.5– 62 mm SL, Tosa Bay, 150 m; NSMT-P 92053, 2 specimens, 34.5– 48 mm SL, Sagami Bay; NSMT-P 96964, 3 specimens, 40.5– 45 mm SL, 07°50’N, 118°00’E; NSMT-P 101146, 56 mm SL, 21°50’N, 117°00’E; USNM 99325, 4 specimens, 72.5–80.5 mm SL, 08°48’N, 123°31’E, 366 m; ZMA 112.453, lectotype of Synagrops malayanus, 52 mm SL, Timor Sea, Indonesia, Siboga: stn 302, 10°27’S, 123°28’E, 216 m; ZMA 112.454 paralectotype of Synagrops malayanus, 54 mm SL, Savu Sea, Lobetobi Straits, Indonesia, Siboga: stn 303, 08°27’S, 122°54’E, 247 m; ZMUC P44326-37 coll. Prokofiev, 12 specimens, 40–50 mm SL, Nha Trang, Vietnam.
Diagnosis. Small, moderately deep-bodied species with slightly convex dorsal head profile. Anal fin II + 7. Pectoral fin with 14–16 rays, pectoral-fin length 21.5–27.2% SL. Gill rakers 15–18. Pseudobranchial filaments 15–24. First anal-fin pterygiophore long, straight, with rather broad hollow tip. Palatines and ectopterygoids narrow, usually with 1, rarely 2, rows of denticles. Orbital diameter 9.9–12.9% SL. Snout about 65–90% of orbital diameter. Posterior edge of maxillary plate straight. No longitudinal ridges on preopercular lobe. Otolith moderately elongate (OL:OH = 1.6–1.85).
Description. Counts and measurements are summarized in Tables 2–7. Snout bluntly pointed; interorbital space slightly convex. Posterior edge of maxilla almost straight to very weakly concave, with postero-dorsal and postero-ventral angles rounded to sharpened, and postero-ventral angle not extended; posterior rim of the maxilla vertical. Preopercular lobe without longitudinal ridges; denticles of hind margin serration variably expressed, not extending into crests on preopercular lobe; inner edge of preopercle with 2–5 small denticles not extending along ventral branch. Two anal-fin spines. First anal-fin pterygiophore broad, long, straight, with broad hollow tip, reaching last pair of pleural ribs. First haemal spine with a variably developed but mostly weak posterior expansion. Pelvic fin spine serrated along its outer edge; all other fin spines smooth.
Dentition. Premaxilla with a pair of strong canines near symphysis, followed posteriorly by a wide band of minute 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 2–4 enlarged canines. Vomer V-shaped with 1–2 rows of granular teeth anteriorly and 1–3 long teeth posteriorly on each side. Palatines narrow, with 1 row of granular long teeth anteriorly and 1–2 rows granular teeth posteriorly. Ectopterygoid narrow, with 1, rarely 2, rows of denticles. Tongue toothless.
Otolith morphology (n = 31). Otolith moderately slender, thin, up to about 6 mm length. OL:OH = 1.6–1.85; OL:OT about 7–8. Dorsal rim shallow, with feeble mid-dorsal angle and distinct postdorsal angle very close to posterior rim. Ventral rim deepest slightly in front of its middle, below collum of sulcus. Rostrum well developed, long, sharply pointed; weak excisura and antirostrum. Posterior rim blunt to nearly vertically cut. All rims smooth or slightly undulating. Inner face slightly convex with slightly supramedian-positioned sulcus. Sulcus shallow, with narrow, long, slightly deepened cauda and wide, shallow ostium. Ostium about twice as wide as cauda or less, with distinct colliculum. Cauda slightly widened posteriorly, almost straight and with rounded tip, terminating close to posterior tip of otolith. CaL:OsL = 1.05–1.25. Dorsal depression long, narrow. Ventral furrow distinct, close to ventral rim of otolith anteriorly, running parallel and at some distance to ventral otolith rim at mid section and posteriorly and approaching caudal tip. Outer face slightly concave, rather smooth.
Size. Small fishes, to about 80 mm SL.
Discussion. Parascombrops philippinensis is similar in size to P. pellucidus and P. parvidens (for distinction see respective discussions to the two species). It is tempting to interpret P. philippinensis as small, juvenile or subadult specimens of larger species such as P. argyreus or P. nakayamai, of which few similarly small specimens have been found. However, there are several significant differences that can not all be explained by ontogenetic changes. In the case of P. argyreus one of the distinctive characters, the number of pseudobranchial filaments, varies to some extent with ontogenetic growth and hence is difficult to use for diagnosis, requiring comparison of specimens of similar size (Fig. 27). The most reliable characters for distinction are the absence of longitudinal ridges on the preopercle in P. philippinensis (vs present in P. argyreus), the shape of maxilla (see Figs. 8A, E; 11E, D) and the shape of the first anal-fin pterygiophore. Parascombrops philippinensis differs from P. nakayamai in a shorter snout (snout 65–90% of orbital diameter vs 87–113%), in the dentition of the vomer, palatines and ectopterygoids (Figs. 9F, 10B), notably in the narrower ectopterygoid tooth patch with 1–2 rows of granular teeth (vs 3–4 rows) and in the higher number of gill rakers (15–18 vs 11–15). The dentition of the vomer and the gillraker count can reflect ontogenetic changes and may not always be relaible characters for distinction (Fig. 27). The snout / orbit diameter relation shows a rather sharp boundary (Fig. 27) and therefore, together with the development of the dentition on the ectopterygoid, represent the best characters for distinction between the two species.
A re-examination of the type material of Synagrops malayanus (Fig. 26C – D) revealed no morphological differences to P. philippinensis and can be attributed to the range of variation seen in that species. We therefore follow Schultz (1940), Katayama (1960) and Mochizuki (1989) in synonymizing Synagrops malayanus with Parascombrops philippinensis.
Geographic and bathymetric distribution. Parascombrops philippinensis is a widely distributed and common species in the low latitude tropics of the Western Pacific, between 80 and 385 m depth, although probably less widely distributed than may be assumed from earlier published check-lists. The latter is a result of many small specimens of Synagrops having been recorded as this species, but have not been subject to this review. Parascombrops philippinensis is particularly common in the seas around the Philippines, Vietnam and eastern Indonesia and off the southern coast of Japan and Taiwan. We have no record of geographical overlap with P. argyreus, but there is geographical overlap with P. nakayamai in Taiwan and southern Japan. We also have no record of geographical overlap with P. pellucidus, but it does overlap with P. glossodon and P. parvidens across the entire area of distribution of the two latter (see Figs. 35–37).
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 48-51, DOI: 10.5281/zenodo.571305