Siphamia majimai Matsubara and Iwai

Gon, Ofer & Allen, Gerald R., 2012, 3294, Zootaxa 3294, pp. 1-84 : 52-54

Siphamia majimai Matsubara and Iwai

Figures 20f–h, 25

Siphamia majimai Matsubara and Iwai, 1958: 603 , fig. 1 (type locality, Urasokari , Amami Oshima, Japan; holotype, FAKU 1746 ).

Siphamia zaribae Whitley, 1959a: 323 (type locality, Heron Island , Queensland, Australia; holotype, AMS IB.4129).

Diagnosis: Dorsal rays VI+I,9–10; anal rays II,8; pectoral rays 14–16; tubed lateral-line scales 0–2; median predorsal scales about 4 (missing in all specimens); total gill rakers 2–4 + 7–11 = 9–14; developed gill rakers 0–1 + 6–7; gill rakers on ceratobranchial 6–7. Body very short and deep, the depth 2.1–2.7 in SL and body width 2.0– 2.5 in the depth; head relatively large, 2.1–2.4 in SL; eye diameter 2.8–3.7 in head length; first dorsal spine 1.5–2.2 in second spine; second dorsal spine 2.5–4.0, spine of second dorsal fin 3.4–6.6, both in head length; pectoral-fin length 3.6–4.4 and pelvic-fin length 4.3–5.8 in SL; caudal-peduncle length 1.3–2.1 in distance between pelvic spine insertion and anal-fin origin. Preopercular edge with 11–26 serrations; preopercular ridge smooth. Scales cycloid very thin, weakly ossified and covered by thin skin. Head with complex network of small sensory papillae; most body scales with vertical lines of papillae, but lateral-line scales also with horizontal series along middle of scale. Tip of light organ on each side of tongue bound by membrane.

Colour when fresh (from colour slides by J.E. Randall): pale brown, sometimes with purplish tinge, and with variable amount of dark dots of various sizes that may expand to make body black; some faint reddish dots may be present on body and head; fin membrane usually pale; fin spines and rays with dark pigment basally, and with orangebrown dots along their margin, sometimes interspersed with blackish dots; basal dark pigment of fins (except pectoral fin) may spread up the fin making it dark; light organ silvery with dark vertical or slanted striations.

Colour in alcohol: Usually brown to dark brown with darker dots of various sizes on head and body; ventral part of head sometimes paler; dark dots on body may be arranged in 1–3 more or less distinct series sometimes forming dark stripes, the most distinct one usually along middle of caudal peduncle; dorsal and anal fins usually dark brown on proximal third to half of fins, but may be entirely dark; pelvic-fin base with dark brown dots, the rays pale to dusky near base; pectoral-fin pale to dusky proximally; caudal fin pale to dusky, sometimes with dark dots along rays; peritoneum, intestine and stomach with dark dots of various sizes, the latter two sometimes pale ventrally.

Smallest specimen examined, AMS IB.4243, 9.8 mm, from Heron Island, Queensland, and largest specimen, USNM 357890, 28.5 mm, from the southwest coast of Taiwan.

Remarks: See Tables 1–3 for frequency distributions of pectoral rays, lateral-line scales and gill rakers. Three specimens (of 147) had unusual first dorsal fins. In one fish (USNM 341599, 16.1 mm) the sixth spine was missing resulting in a fin with five spines; in two other fish (USNM 357890, 21.6 mm and BPBM 23370, 21.0 mm) an additional seventh spine was present at the end of the fin in a position equivalent to the eighth spine of the general apogonid dorsal-fin spine scheme (sensu Fraser 1972). The second lateral-line scale, when present, can have a complete or incomplete tube. The preopercle edge sometimes appears smooth due to the presence of mucus or worn serrations. In the latter case small ridges perpendicular to the bone’s edge indicate where serrations were. The papillae on the body scales are minute, difficult to see and frequently damaged; we observed the full extent of the papillae lines only on three specimens. Unlike the live colour description above, the photograph in Masuda et al. (1984) depicts whitish fins. Photos of this species from Japan ( Masuda and Kobayashi 1994; Fishpix 1998 –2004) and Taiwan ( Kuiter and Kozawa 1999) show small red dots on the second dorsal, anal and caudal fins of live and freshly killed specimens. In pale specimens the dark pigment along the bases of the second dorsal, anal, pelvic and caudal fins is coalesced into dark dots.

This species belongs to the S. tubifer species group. It is the only member of this group with six spines in the first dorsal fin and with the longest second dorsal spine; all other species of this group have seven spines and a shorter second dorsal spine (3.5–6.6 in head length). The dark striations on the light organ distinguish it from species of the S. tubulata group that have six first dorsal-fin spines and a dark-dotted light organ.

The brief original description of Siphamia zaribae ( Whitley 1959a) was followed by a more detailed one in the same year ( Whitley 1959b). In the detailed description Whitley distinguished S. zaribae from S. majimai by its larger eye, higher second dorsal fin and slenderer caudal peduncle. He also noted a difference in the configuration of the nostrils between the two species. Matsubara and Iwai (1958) described the nostrils of the holotype of S. majimai as “set in nearly vertical series” and the anterior nostril as closer to the eye than to the tip of the snout. We did not examine the holotype of S. majimai , but in all our material, including a paratype of this species and both types of S. zaribae , the anterior nostril is distinctly in front of the rear nostril and is closer to the tip of the snout than to the eye. The holotype of S. majimai also has an unusually low second dorsal fin. Whitley (1959b) apparently based his conclusion that the second dorsal fin of S. zaribae is higher on the figure of S. majimai and overlooked the relevant data. Matsubara and Iwai (1958) stated that the height of the holotype’s fin was 15.6% SL, but their range for the paratypes was 23.4–25.5% SL. We found a range of 23.6–25.8% SL in specimens originally identified as S. zaribae , including the holotype, from Heron Island. For the depth of the caudal peduncle Matsubara and Iwai (1958) measured 10.9% SL in the holotype and 11.7–12.8% SL in the paratypes of S. majimai while Whitley’s (1959b) measurement of the holotype of S. zaribae was 11.5% SL, thus contradicting his statement regarding the discrepancy between the two species. Whitley’s difference in the eye diameter is also suspect because he used an estimate rather than an accurate measurement. We found a similar range for the eye diameter in our Japanese material (13.4–13.9% SL) and in specimens from Heron Island (13.0–15.2% SL). Our search for morphometric characters to separate these two species failed to produce any reliable character leading us to conclude that only a single species is represented.

Inaccuracies in the original description of both S. majimai and S. zaribae misled recent authors. Whitley (1959b) followed by Munro (1960) stated that the preopercular edge was smooth except for three small serrations at the angle of the bone. Our examination of the holotype and paratype of S. zaribae , as well as from across the geographical range of this species, revealed serrations along the lower half to two thirds of the posterior edge and a serrate ventral edge. Munro (1960) incorrectly interpreted Whitley’s (1959a, b) count of transverse scale series as a count of lateral line scales. Matsubara and Iwai (1958) counted 23–24 scales in the “indiscernible” lateral line of S. majimai , but did not specifically say that the lateral line lacked tubes. They also counted a total of nine gill rakers in the holotype and one paratype of their species. Although they did not specify whether this was a total count or only developed rakers, the count of one raker on the upper limb implies the latter. Their lateral line and gill raker counts were apparently taken at face value by Hayashi (1984) and Randall et al. (1997). However, S. majimai has 0–1, rarely two, tubed lateral-line scales and a maximum of eight developed gill rakers ( Tables 2, 3). The illustration of S. majimai in Shen et al. (1993) depicts a fish with six first dorsal-fin spines, but their text describes a species with seven spines and 1+5 developed gill rakers, a combination we have not come across in our material. The illustration of this species in Allen and Swainston (1988) shows a species with seven first dorsal-fin spines.

Siphamia majimai has been found in the Ryukyu and Ogasawara islands of Japan, Taiwan, Vietnam, Indonesia, Philippines, northwestern Australia to Queensland and Tonga ( Fig. 6). It has been observed in association with and collected from Diadema sea urchins at a depth range of 1–18 m on different bottoms, including silty sand and mud, rocks and rubble with caves, reef with live and dead coral, and vertical wall with coral and encrusting algae. Matsubara and Iwai (1958) reported mouth brooding in males of this species.

Material examined: INDONESIA: Bali, NTM S.11203-001, 2: 12.3–12.4 mm. Padar Island , WAM P.30958- 001, 19: 16.0– 25.6 mm. Molucca Islands, Ambon Island , BPBM 34180 , 8 : 12.1–21.8 mm . VIETNAM: Cu Lao Thu , CAS 83959, 2 : 19.2–21.1 mm . TAIWAN: Shia-shiu-chuan, USNM 300657 , 3 : 22.4–23.9 mm. SW coast , USNM 357890 , 6 : 16.8–28.5 mm ; USNM 374675 , 18.0 mm. Kenting National Park , BPBM 35126 , 2 : 19.6–21.4 mm. South coast, Maopitou , BPBM 23370 , 3 : 18.3–21.0 mm . PHILIPPINES: Batanes, Batan Island , USNM 298226 , 23.6 mm. Luzon, NE of Bolinao, Santiago Island , AMS I.21903-069, 14.2 mm. Marinduque Island , USNM 93400 , 16.5 mm. Negros , USNM 262448 , 2 : 14.3–15.5 mm ; USNM 262449 , 20.1 mm ; USNM 358001 , 11 : 11.6–19.8 mm . JAPAN: Ryukyu Islands, Amami-oshima , BMNH 1959.1 .6.1, male, 16.8 mm (paratype of S. majimai ). Ogasawara Islands, Ani-jima , BPBM 35127 , 19.3 mm. Chichi-jima , BPBM 35096 , 25.9 mm. NORTHERN TERRITORY: New Year Island , NTM S.10591-017, 2: 6.9–8.3 mm. Wigram Island , NTM S.13226- 013, 3: 14.9–15.9 mm. Marchin Bar Island , NTM S.13234-021, 8: 9.8–17.7 mm. WESTERN AUSTRALIA: Dampier Archipelago, Angel Island , AMS I.20353-001, 9: 14.1–22.2 mm. Kendrew Island , AMS I.24986-005, 17.2 mm; Elphick’s Knob , WAM P.22472-001, 23.2 mm. Exmouth Gulf , AMS I.20352-001, 6: 14.9–22.7 mm. QUEENSLAND: Cape Grenville , AMS I.33703-029, 20.9 mm. Swain Reef , AMS IB.6025-6027, 21: 15.0– 23.2 mm; USNM 197787 , 29.5 mm. Heron Island , AMS IB.4129 and IB.4132 (holotype and paratype, respectively, of S. zaribae ) ; AMS IB.4206-4208, 13: 20.3–28.3 mm; AMS IB.4243, 5: 9.8–17.0 mm; AMS IB.5404, 20.5 mm; AMS I.16238-001, 2: 19.5–21.5 mm; USNM 197785 , 16.6 mm ; USNM 197786 , 2 : 16.3–26.6 mm. One Tree Island , AMS I.17185-001, 26.3 mm. Fairfax Island , USNM 374479 , 4 : 15.6–16.0 mm ; USNM 374480 , 8 : 10.4–17.7 mm . NEW CALEDONIA: NW of Pass de Dumbea , ROM 65758, 19.5 mm . TONGA: Tongatapu Group, Malinoa Island , USNM 341599 , 3 : 12.7–18.7 mm .