Siphamia randalli, Gon & Allen, 2012

Gon, Ofer & Allen, Gerald R., 2012, 3294, Zootaxa 3294, pp. 1-84 : 56-60

Siphamia randalli new species

Figures 27, 28b; Table 10

Holotype: ROM 60957, 23.2 mm, female, Society Islands , Moorea, NW tip of Cook Bay, off green channel marker, R. Winterbottom et al., 17 December 1989.

Paratypes: BPBM 8627 , 21.7 mm, male, Society Islands , Moorea , Papetoai Bay, Point Papeere, outer edge of inshore reef, 13 m, rotenone, J.E. Randall, 14 September 1967 ; BPBM 11548 , 163 : 13.4–28.7 mm, Society Islands , Tahiti, east coast of Mahaena, 30 m, in association with Astropyga radiata on soft mud bottom , R. U. Gooding and J. Bennett, 25 March 1971 ; BPBM 13917 , 18.9 mm male and 22.05 mm female, Cook Islands, Rarotonga , off oil tanker buoy near harbour entrance, 17 m, small pocket of sand with surrounding coral, rotenone, J.E. Randall and D. Cannoy, 10 March 1971 ; BPBM 13972 , 15.7 mm, data as BPBM 13917, but on 11 March 1971 ; CAS 84289, 14.3 mm, Society Islands , Tahiti , Papeari Harbour, Temarauri Pass, low coral head in shallow water falling off steeply on seaward side to near shore, 0–5 m, rotenone, Bingham and Adrien, 10 July 1957 ; ROM 84960, 30 : 13.2–25.0 mm, collected with holotype ; ROM 60958, 18.6 mm, male, Society Islands , Moorea, lagoon east of Cook Bay , R. Winterbottom et al., 8 December 1989 ; SAIAB 1943 , 11 : 12.7–27.5 mm, collected with BPBM 11548 ; SAIAB 87417 , 5 : 13.5–17.0 mm, Society Islands , Moorea, Cook’s Bay, E side of pass, 25 m, G. Bernardi and C. Lantz, 26 July 2008 , in association with Acanthaster planci ; USNM 207069 , 22.7 mm, female, collected with BPBM 11548 . As well as AMS I.45072-001, 2: 14.5–20.7 mm, female and male, respectively; BMNH 2009.11 .27.2, 2: 17.4–23.0 mm, male and female, respectively ; MNHN 2009-1670 , 2 : 16.6–18.8 mm, females ; NSMT-P 96741 , 2 : 19.6–21.6, male and female, respectively ; WAM P. 33142-001, 2: 20.0– 20.6 mm, males; KPM- NI 24916 & 24917, 2: 20.3–21.8 mm, females; all originally from BPBM 11548 .

Diagnosis: Dorsal rays VII+I,9; anal rays II,8; pectoral rays 14–15; tubed lateral-line scales 9–12; median predorsal scales 3–5; total gill rakers 2–4 + 10–12 = 13–16; developed gill rakers 1–2 + 9–11 =10–12; gill rakers on ceratobranchial 8 (rarely 9). Body depth 2.45–3.0 in SL and body width 1.7–2.15 in the depth; eye diameter 2.9–3.3 in head length; first dorsal spine 2.1–3.8 in second spine; second dorsal spine 4.4–6.4, spine of second dorsal fin 4.0–4.5, and second anal spine 4.7–5.6, all in head length; pectoral-fin length 4.1–4.6 and pelvic-fin length 3.8–4.4 in SL; caudal-peduncle length 1.2–1.9 in distance between pelvic spine insertion and anal-fin origin; light organ 1.65–2.7 in caudal peduncle length. Preopercular edge with 19–25 small serrations; preopercular ridge smooth. Tip of light organ on each side of tongue bound by membrane.

Colour in life: unknown.

Colour when fresh (from colour slides by J.E. Randall and R. Winterbottom): pale brown, sometimes with purplish tinge, and with variable amount of dark dots of various sizes overlaid with scattered orange-brown dots; lower part of pupil and eye sometimes edged with orange-brown pigment ( Fig. 28b); premaxilla with blackish dots anteriorly, forming dark line posteriorly; branchiostegal rays with dark dots; fins with orange-brown dots mostly along margins of spines and rays, denser at caudal-fin base; light organ silvery with dark vertical striations.

Colour in alcohol: usually pale brown to brown with variable amount of dark brown dots of different sizes; occasionally dark brown all over, except snout and top of head, with or without pale patches on body; snout and top of head with fewer, larger and more spaced dark dots; dark cheek mark usually present; dark brown dots on branchiostegal rays and along margin of preopercular ridge; anterior dorsal and pelvic spines usually with dark dots at least near base; pelvic-fin base dark brown; fins otherwise pale; peritoneum with dense dark brown dots of various sizes; stomach and intestine with smaller dark dots.

Smallest specimen, SAIAB 1943, 12.7 mm, and largest specimen examined BPBM 11548, 28.7 mm, both from the same collection site in Tahiti.

Description: Proportional measurements of the holotype and selected paratypes are given in Table 10. Dorsal rays VII+I,9; anal rays II,8; last soft ray of dorsal and anal fins branched to base; pectoral rays 15 (14–15), two uppermost and lowermost rays unbranched; pelvic rays I,5, all soft rays branched; principal caudal rays 17, damaged; upper and lower procurrent caudal rays 7; tubed lateral-line scales 12 (9–11); vertical scale rows 24 (23–24); horizontal scale rows at level of second dorsal fin origin 6 (6–7); median predorsal scales lost (3–5); circumpeduncular scales 12; developed gill rakers 1 + 9 (1–2 + 9–11); gill rakers on ceratobranchial 8 (8–9); branchiostegal rays 7.

Body compressed and relatively slender, its depth 2.7 (2.45–3.0) in SL and its width 1.9 (1.7–2.15) in depth; head length 2.1 (2.0–2.3) in SL; snout length 5.2 (4.4–5.8), eye diameter 3.2 (2.9–3.3), and interorbital space 5.1 (4.6–5.05), all in head length.

Mouth terminal, oblique and large; maxilla reaching posteriorly to vertical at rear edge of pupil (slightly beyond in one specimen); upper jaw length 2.1 (1.9–2.1) and lower jaw 1.8 (1.6–1.8) in head length; both jaws with band of small, conical teeth; upper jaw band with 2 series at symphysis, increasing to 4 series at middle of jaw; lower jaw band with 3 series at symphysis tapering to 1 series posteriorly; inner series teeth of both jaws enlarged; vomer and palatines with single series of small conical teeth.

Rear nostril close in front of eye at level of dorsal edge of pupil, its vertical diameter about 6 times in pupil diameter; anterior nostril about the same size, with slightly raised fleshy rim, at level of middle of eye and slightly closer to tip of snout than to rear nostril.

Posterior preopercular edge almost completely serrate; ventral edge serrate on posterior half to two thirds; total serrations 22 (19–25) and largest ones around angle; preopercular ridge smooth; exposed edge of posttemporal with 3 (2–3, smooth in 2 paratypes) minute serrations.

Body scales large, thin and easily shed; scales spinoid, with 0–2 minute spines on middle portion of posterior edge; tubed lateral-line scales with vertical line of minute papillae along middle of scale above and below tube; caudal fin with low scaly sheath of 2 scale series across its base; other fins without scales or scaly sheath.

Dorsal-fin origin over third lateral-line scale and slightly behind vertical through upper pectoral-fin base; first dorsal spine damaged (2.1–3.8) in second spine; second dorsal spine 4.6 (4.4–6.4) and third dorsal spine longest 3.0 (2.45–3.3) in head length; spine of second dorsal fin 4.2 (4.0–4.5) and longest dorsal soft ray 1.9 (1.9–2.2) in head length; first anal spine 2.0 (1.2–4.2) in second spine; second anal spine 4.8 (4.7–5.6) and longest anal ray 2.4 (2.3–2.85) in head length; pectoral and pelvic fins reaching front edge of anus; pectoral fin length 4.3 (4.1–4.6) in SL; pelvic fin origin on vertical though upper pectoral-fin base; pelvic fin length 3.8 (3.9–4.4) in SL and pelvic spine length 1.65 (1.35–1.6) in fin’s length; caudal fin with shallow fork and rounded lobes, 2.9 (3.0–3.3) in SL.

Dorsal profile of head straight, predorsal distance 2.2 (2.1–2.5), preanal distance 1.5 (1.4–1.6) and prepelvic distance 2.5 (2.2–2.6) in SL; caudal peduncle depth 1.4 (1.3–1.9) in its length; the length 5.0 (4.6–5.9) in SL and 1.7 (1.2–1.9) in distance between pelvic-fin base and anal-fin origin; latter distance 3.3 (3.1–3.9) in SL; light organ 1.9 (1.65–2.7) in peduncle length and 13.55 (9.1–12.2) in SL.

Colour in alcohol: dark brown except for snout, top of head and opercle area immediately above and below opercular spine; abdominal area blackish; small, irregular pale patches along middle of body; pale areas with dark dots of various sizes, those on snout and top of head larger and more spaced; two irregular series of melanophores above lateral line from dorsal-fin origin to upper caudal-fin base; inconspicuous dark brown stripe from origin of first dorsalfin base to about middle of second dorsal-fin base; branchiostegal rays and edge of preopercular ridge dark brown; thin dark line along posterior portion of premaxilla; first dorsal fin and pelvic-fin spine with dark dots proximally; peritoneum brown with dark brown dots of various sizes; intestine and stomach paler and with smaller dark dots; dark striated light organ from below pectoral-fin base to about two thirds of caudal peduncle length.

Remarks: See Tables 1–3 for frequency distributions of pectoral rays, lateral-line scales and gill rakers. The last (12 th) lateral-line scale of the holotype has a short tube on the posterior part of the scale resulting in a discontinuous canal between the last two lateral-line scales. Several paratypes had two series of teeth on the posterior part of the palatines. The anterior nostril of several specimens was at mid-distance between the tip of the snout and the rear nostril. The dark brown colour of the holotype (in alcohol) is due to most of its melanophores being in an expanded state. Similar melanophores are also responsible for the irregular dark brown marks observed on the body of several specimens.

Siphamia randalli closely resembles S. fraseri . Both species share a relatively slender body shape and possess a similar number of tubed lateral-line scales and high number of developed gill rakers. However, S. fraseri differs in having a longer light organ on the caudal peduncle, 1.1–1.4 in caudal peduncle length ( Fig. 3b) and in having more serrations (25–35) along the edge of the preopercle. Another similar species that is also relatively close geographically is S. fuscolineata , which is separated by its modally higher tubed lateral-line scale count, lower developed gill-raker count ( Tables 2, 3) and longer light organ (1.3–2.3 in caudal peduncle length). It is the only species of Siphamia currently known from French Polynesia.

This species is known from Moorea and Tahiti in the Society Islands, and from Rarotonga in the Cook Islands ( Fig. 8). It was collected at 0–30 m, on muddy bottom where it was found in association with the sea urchin Astropyga radiata , the crown-of-thorns starfish Acanthaster planci ( Stier et al. 2009) , as well as on coral with sand mostly on the seaward edge of the reef.

Etymology: This species is named randalli in honour of Dr. John E. Randall of Honolulu, Hawai’i, for his numerous and noteworthy contributions to our knowledge of reef fish taxonomy. Jack, as he is known to friends and colleagues, is a genuine inspiration to everyone in the field of ichthyology. Moreover, Dr. Randall’s Siphamia collections at BPBM and specimen photographs, including this species, have formed an essential part of our revision.