8
A revision of the Trimmatom nanus species complex (Pisces, Gobiidae), with descriptions of three new species and redefinition of Trimmatom RICHARD WINTERB~TOM Department of Ichthyology and Herpetology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ont., Canada M5S 2C6 WINTERBOTTOM, R. 1989. A revision of the Trimmutom nanus species complex (Pisces, Gobiidae), with description of three new species and redefinition of Trimmutom. Can. J. Zool. 67: 2403 -2410. Trimmutom is rediagnosed to include gobiids in which the first element of the anal fin is a bilaterally paired ray, the fifth pelvic ray is unbranched and reduced to 15% or less of the length of the fourth, the head, pectoral-fin base, and breast are scaleless, there are no head pores, and the gill opening extends anteroventrally at least to below the vertical limb of the preopercle. The Trimmatom nanus species complex is considered to be monophyletic by virtue of an unbranched fourth pelvic-fin ray. Trimmatom macropodus, n. sp., recorded from Taiwan, the Philippines, the Coral Sea, and the Great Barrier Reef, has a scaled body and the first three pelvic-fin rays are branched. Trimmatom zapotes, n.sp., from the Caroline and Gilbert islands and Great Barrier Reef, has a scaled body and all pelvic-fin rays are unbranched. Among the three scaleless species, Trimmutom oficius is restricted to the Chagos Archipelago and has two dark saddles crossing the bases of fin rays in the second dorsal fin. Trimmatom sagma, n.sp., from the Cocos-Keeling Islands, the Philippines, and the Moluccas, has a single dark saddle across the base of the second dorsal fin and a unique dorsal pterygiophore formula. Trimmatom nanus lacks dark saddles over the dorsum. The known geographic range of this species is greatly expanded, from the type locality in the Chagos Archipelago to include the Philippines, Papua New Guinea, the Caroline Islands, the Gilbert Islands, Fiji south to South Minerva Reef, Lord Howe Rise, the Coral Sea, western Australia, and the Maldives. WINTERBOTTOM, R. 1989. A revision of the Trimmutom nanus species complex (Pisces, Gobiidae), with description of three new species and redefinition of Trimmatom. Can. J. Zool. 67 : 2403 -2410. On trouvera ici une nouvelle diagnose de Trimmutom qui peut inclure les gobiidks chez lesquels le premier klkment de la nageoire anale est un rayon bilatkral pair, le cinquikme rayon pelvien est simple, la tete, la base de la nageoire pectorale et la poitrine sont sans kcailles, il n'y a pas de pores ckphaliques, et l'ouverture branchiale est prolongke antiroventralement, au moins jusque sous la partie verticale du prkopercule. Le complexe d'espkces Trimmutom nanus est monophylktique car c'est le seul groupe h posskder un rayon 4 simple sur la nageoire pelvienne. Trimmatom macropodus, n.sp., trouvk en Taiwan, aux Philippines, dans la mer de Corail et sur la Grande Barrikre, a des kcailles sur le corps et les trois premiers rayons de sa nageoire pelvienne sont fourchus. Trimmatom zapotes, n.sp., des iles Caroline et Gilbert et de la Grande Barrikre, a des kcailles sur le corps et tous les rCgions de sa nageoire pelvienne sont simples. Chez les trois espkces sans icailles, Trimmutom oficius est restreinte h l'archipel des Chagos et elle posskde deux selles fonckes h la base des rayons de la seconde nageoire dorsale. Trimmatom sagma, n.sp., des i'les Cocos-Keeling, Philippines et Moluques, a une seule selle foncke h la base de la seconde nageoire dorsale et posskde une formule ptkrygiophore qui lui est propre. Trimmutom nanus n'a pas de series foncCes sur le dos. La rkpartition gkographique de celle espkce est beaucoup plus vaste qu'on ne l'avait cdi h ce jour, et elle recouvre, en plus de la localitk type dans les iles Chagos, les Philippines, la Papouasie-Nouvelle-Guinke, les iles Carolines, les iles Gilbert, les iles Fiji, les rkcifs de Minerve sud, le haut fond de Lord Howe, la mer de Corail, la partie occidentale de 1'Australie et les Maldives. [Traduit par la revue] Introduction Trimmatom was described by Winterbottom and Emery (1981) for two species of highly specialized gobiids (T. nanus and T. oficius) from the Chagos Archipelago, central Indian Ocean. The genus was characterized by possessing unbranched fin rays in the second dorsal, anal, pectoral, and pelvic fins, a scaleless body, a gill opening extending anteroventrally to below the pupil, no head pores, and fusion of hypurals 1 -4 with each other and with the ural complex. Further collecting and examination of available material have revealed one new species that accords with the original definition of Trimmutom. In addition, two more undescribed species form a monophy- letic group (here called the Trimmatom nanus species group) with the three species mentioned above. Trimmu eviotops plus another six undescribed species (to be treated in a subsequent publication) form the sister group of the Trimmutom nanus breast, and pectoral base scaleless; no head pores; and gill opening extending anteroventrally to below the vertical limb of the preopercle or below the pupil. The first ,three character states are here considered autapomorphies of Trimmutom, the last two are shared with Trimmu (which has not been shown to be monophyletic, but together with Trimmutom probably forms a monophyletic unit). The Trimmutom nanus species complex is considered to form a monophyletic unit on the basis of the apomorphic con- dition of an unbranched fourth pelvic-fin ray. It is the purpose of this paper to provide descriptions and names for the three undescribed species in this complex to make them available for a study of the osteology, phylogeny, and biogeography of this group currently in progress. Materials and methods species group. These two species groups are here placed in In the genus Trimmutom the first element in the anal fin is bilater- Trimmutom, which is redefined as a genus of gobiids with the ally paired, and may be segmented. It is here counted as a fin ray characters: first of the fin is a rather than a spine (the normal condition in gobiids). The first ele- segmented or unsegmented, bilaterally paired element (as ment of the second dorsal fin in some species may also be bilaterally opposed to a spine); fifth pelvic-fin ray ~nbranched and paired and segmented or unsegmented. Wherever specimen condition reduced to 15% or less of the length of the fourth ray (as allowed it, counts of pectoral-fin rays and of scales were made on opposed to 50% or more of the length of the fourth ray); head, both sides of the body. Lateral scales were counted anteriorly from Printed in Canada 1 Imprim6 au Canada Can. J. Zool. Downloaded from www.nrcresearchpress.com by SAVANNAHRIVNATLABBF on 11/14/14 For personal use only.

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Page 1: A revision of the Trimmatom nanus species complex (Pisces, Gobiidae), with descriptions of three new species and redefinition of Trimmatom

A revision of the Trimmatom nanus species complex (Pisces, Gobiidae), with descriptions of three new species and redefinition of Trimmatom

RICHARD WINTERB~TOM Department of Ichthyology and Herpetology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ont.,

Canada M5S 2C6

WINTERBOTTOM, R. 1989. A revision of the Trimmutom nanus species complex (Pisces, Gobiidae), with description of three new species and redefinition of Trimmutom. Can. J. Zool. 67: 2403 -2410.

Trimmutom is rediagnosed to include gobiids in which the first element of the anal fin is a bilaterally paired ray, the fifth pelvic ray is unbranched and reduced to 15% or less of the length of the fourth, the head, pectoral-fin base, and breast are scaleless, there are no head pores, and the gill opening extends anteroventrally at least to below the vertical limb of the preopercle. The Trimmatom nanus species complex is considered to be monophyletic by virtue of an unbranched fourth pelvic-fin ray. Trimmatom macropodus, n. sp., recorded from Taiwan, the Philippines, the Coral Sea, and the Great Barrier Reef, has a scaled body and the first three pelvic-fin rays are branched. Trimmatom zapotes, n.sp., from the Caroline and Gilbert islands and Great Barrier Reef, has a scaled body and all pelvic-fin rays are unbranched. Among the three scaleless species, Trimmutom oficius is restricted to the Chagos Archipelago and has two dark saddles crossing the bases of fin rays in the second dorsal fin. Trimmatom sagma, n.sp., from the Cocos-Keeling Islands, the Philippines, and the Moluccas, has a single dark saddle across the base of the second dorsal fin and a unique dorsal pterygiophore formula. Trimmatom nanus lacks dark saddles over the dorsum. The known geographic range of this species is greatly expanded, from the type locality in the Chagos Archipelago to include the Philippines, Papua New Guinea, the Caroline Islands, the Gilbert Islands, Fiji south to South Minerva Reef, Lord Howe Rise, the Coral Sea, western Australia, and the Maldives.

WINTERBOTTOM, R. 1989. A revision of the Trimmutom nanus species complex (Pisces, Gobiidae), with description of three new species and redefinition of Trimmatom. Can. J. Zool. 67 : 2403 -2410.

On trouvera ici une nouvelle diagnose de Trimmutom qui peut inclure les gobiidks chez lesquels le premier klkment de la nageoire anale est un rayon bilatkral pair, le cinquikme rayon pelvien est simple, la tete, la base de la nageoire pectorale et la poitrine sont sans kcailles, il n'y a pas de pores ckphaliques, et l'ouverture branchiale est prolongke antiroventralement, au moins jusque sous la partie verticale du prkopercule. Le complexe d'espkces Trimmutom nanus est monophylktique car c'est le seul groupe h posskder un rayon 4 simple sur la nageoire pelvienne. Trimmatom macropodus, n.sp., trouvk en Taiwan, aux Philippines, dans la mer de Corail et sur la Grande Barrikre, a des kcailles sur le corps et les trois premiers rayons de sa nageoire pelvienne sont fourchus. Trimmatom zapotes, n.sp., des iles Caroline et Gilbert et de la Grande Barrikre, a des kcailles sur le corps et tous les rCgions de sa nageoire pelvienne sont simples. Chez les trois espkces sans icailles, Trimmutom oficius est restreinte h l'archipel des Chagos et elle posskde deux selles fonckes h la base des rayons de la seconde nageoire dorsale. Trimmatom sagma, n.sp., des i'les Cocos-Keeling, Philippines et Moluques, a une seule selle foncke h la base de la seconde nageoire dorsale et posskde une formule ptkrygiophore qui lui est propre. Trimmutom nanus n'a pas de series foncCes sur le dos. La rkpartition gkographique de celle espkce est beaucoup plus vaste qu'on ne l'avait cdi h ce jour, et elle recouvre, en plus de la localitk type dans les iles Chagos, les Philippines, la Papouasie-Nouvelle-Guinke, les iles Carolines, les iles Gilbert, les iles Fiji, les rkcifs de Minerve sud, le haut fond de Lord Howe, la mer de Corail, la partie occidentale de 1'Australie et les Maldives.

[Traduit par la revue]

Introduction Trimmatom was described by Winterbottom and Emery

(1981) for two species of highly specialized gobiids (T. nanus and T. oficius) from the Chagos Archipelago, central Indian Ocean. The genus was characterized by possessing unbranched fin rays in the second dorsal, anal, pectoral, and pelvic fins, a scaleless body, a gill opening extending anteroventrally to below the pupil, no head pores, and fusion of hypurals 1 -4 with each other and with the ural complex. Further collecting and examination of available material have revealed one new species that accords with the original definition of Trimmutom. In addition, two more undescribed species form a monophy- letic group (here called the Trimmatom nanus species group) with the three species mentioned above. Trimmu eviotops plus another six undescribed species (to be treated in a subsequent publication) form the sister group of the Trimmutom nanus

breast, and pectoral base scaleless; no head pores; and gill opening extending anteroventrally to below the vertical limb of the preopercle or below the pupil. The first ,three character states are here considered autapomorphies of Trimmutom, the last two are shared with Trimmu (which has not been shown to be monophyletic, but together with Trimmutom probably forms a monophyletic unit).

The Trimmutom nanus species complex is considered to form a monophyletic unit on the basis of the apomorphic con- dition of an unbranched fourth pelvic-fin ray. It is the purpose of this paper to provide descriptions and names for the three undescribed species in this complex to make them available for a study of the osteology, phylogeny, and biogeography of this group currently in progress.

Materials and methods species group. These two species groups are here placed in

In the genus Trimmutom the first element in the anal fin is bilater- Trimmutom, which is redefined as a genus of gobiids with the ally paired, and may be segmented. It is here counted as a fin ray characters: first of the fin is a rather than a spine (the normal condition in gobiids). The first ele-

segmented or unsegmented, bilaterally paired element (as ment of the second dorsal fin in some species may also be bilaterally opposed to a spine); fifth pelvic-fin ray ~nbranched and paired and segmented or unsegmented. Wherever specimen condition reduced to 15% or less of the length of the fourth ray (as allowed it, counts of pectoral-fin rays and of scales were made on opposed to 50% or more of the length of the fourth ray); head, both sides of the body. Lateral scales were counted anteriorly from

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2404 CAN. J. ZOOL. VOL. 67, 1989

the last midlateral scale overlapping the end of the hypurals to the first scale beneath the pectoral-fin axil without deviating from that scale row. Transverse scale row counts began at the scale adjacent to the anus and proceed diagonally anterodorsally (TRA) or posterodor- sally (TRP) to the dorsalmost scale in the series. The dorsal pterygio- phore formula follows Birdsong (1975). Meristic values for the holotype of the new species are underlined. Morphometrics have proved of little value in separating the species of Trimmatom, and are

not presented. Numbers of specimens, followed by the range of standard lengths for the sample in parentheses follow the catalogue numbers.

Abbreviations for repositories of material examined are as follows: AMS, Australian Museum, Sydney; ANSP, Academy of Natural Sciences, Philadelphia; BPBM, Bernice P. Bishop Museum, Honolulu; ROM, Royal Ontario Museum, Toronto; USNM, National Museum of Natural History, Washington.

Artificial key to the species of the Trimmatom nanus species complex 1. Scales present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Scales absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. All pelvic-fin rays unbranched. Trimmatom zapotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . First three pelvic-fin rays branched Trimmatom macropodus

3. Ten to 12 elements in second dorsal and anal fins (usually 11 or 12 and 10 or 11, respectively); pectoral-fin rays usually 17-21; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 8 small dark saddles over dorsum .4

Nine to 10 elements in second dorsal fin; 8 - 10 (usually 8 or 9) rays in anal fin; pectoral-fin rays 14 - 16; no dark saddles over dorsum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trimmatomnanus

4. Base of second dorsal fin crossed by two dark saddles; pectoral-fin rays 19-22 (usually 20); dorsal pterygiophore formula 3(22110) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trimmatom oficius Base of second dorsal fin crossed by a single dark saddle; pectoral-fin rays 16 - 19 (usually 17 - 18); dorsal pterygiophore formula 3(221100) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trimmatomsagma

Trimmatom macropodus n . sp. Figs. 1, 2, 7 mented but consisting of two hemitrichs; pectoral 13-14 (a =

Material examined Four lots, 4 specimens, 9.6-13.0 mm SL, 0-15 m, Tai-

wan, the Philippines, Coral Sea, and Great Barrier Reef. HOLOTYPE: AMS I. 19456-1 13, 12.5 mm SL (male), Aus-

tralia, Great Barrier Reef, Lizard Island, north end of Yonge Reef (14'35'S, 145'56'E), 5- 15 m. AMS Party, 30.1.1975.

PARATYPES: ROM 55289, 1 (9.6), Australia, Coral Sea, west side of Osprey Reef (13'54'S, 146'33'E), 1-15 m. AMS Party, XI. 1984. ROM 1179CS, 1 (12.7), the Philippines, Cuyo Islands, Tagauayan Island (10'57'48 "N, 12 1 " 13 '32 "E), 0-2.5 m. Smithsonian team, 25.V.1978 (now cleared and stained). USNM 293529, 1 (13.0), Taiwan, south end of rocky shore just south of Chin-Chiao-Wan (2 1 '55 ' 15 "N, 120'49'45 "E), 0 -6 m. V. G. Springer et d., 8.V. 1968.

Diagnosis Trimmutorn mcropodus differs from all other species in the

T. nanus species complex in having the first three rays of the pelvic fin branched (versus unbranched). It differs further from T. nanus, T. ojfkcius, and T. s a g m in possessing scales on the body (versus naked), a more restricted gill opening (extending anteroventrally to below the vertical limb of the preopercle versus to below pupil of the eye), and in having a very elongated fourth pelvic-fin ray (reaching posteriorly to or beyond the bases of the last anal-fin ray versus reaching no more posteriorly than the anterior one-third of the anal-fin base. It differs further from T. zapotes in having one scale fewer in the lateral series (23 vs. 24 -25), and from all four of the above species in details of colour pattern.

Description Dorsal VI + 8 -9 (x = 8.3), tip of depressed first dorsal

spine reaching base of first ray of second dorsal fin in three specimens, but elongate and reaching base of last ray of second dorsal fin in Taiwan specimen (USNM 293529), first element of second dorsal fin in spine (unsegmented and not bilaterally paired); anal 8 -9 (X = 8.3), first element unseg-

13. I), reaching posteriorly to vertical at origin of anal fin; pel- vic I 5, fifth ray unbranched and 15 % length of fourth, fourth ray unbranched and elongate, reaching posteriorly to or a little beyond base of last anal-fin ray, first three rays branched once, with lateral branch shorter than medial branch; fraenum absent; basal membrane vestigial. Lateral scales 23 (both sides of holotype, 23 scale pockets on left side of both USNM para- types); anterior and posterior transverse scales 6 (both sides, holotype only); anterior few rows of body scales cycloid, others ctenoid; no scales on cheek, opercle, predorsal, pec- toral base, or breast. Gill opening extending anteroventrally to below vertical limb of preopercle. Mouth terminal, inclined obliquely upwards; upper jaw with outer row of spaced, enlarged, curved canines, which are about twice the size of several irregular inner rows of small conical teeth; lower jaw teeth similar to upper but with innermost row of teeth enlarged and similar to outer row. Anterior nasal opening at the end of a tube, posterior nasal opening a pore with a raised rim sepa- rated from anterior margin of eye by a distance equal to 1.5 times pore diameter; nasal sac slightly elevated. Tongue broadly pointed. Bony interorbital width about one-quarter pupil diameter. First gill slit open, ossified gill rakers 1 + 6; dorsal pterygiophore formula 3(2,2,1,1,0). Cleared and stained paratype has a formula of 3(2,2,1,1,0,0), but proximal one-third of first pterygiophore of second dorsal fin bent sharply downwards and lies between neural spines of eighth and ninth vertebrae, whereas extension of main axis of ptery- giophore anteroventrally would enter seventh or eighth inter- space. Vertebrae 10 + 15 + ural complex = 26. Six dorsal and 5 ventral branched caudal-fin rays, with 8 dorsal and 7 ventral unbranched rays; 17 segmented caudal-fin rays. Cau- dal skeleton with hypurals l and 2 fused together and articulat- ing with fused ural complex plus hypurals 3 and 4; hypural 5 and parhypural both small, splint-like, and separated from ural centrum by a distance equal to their length; a single rod-like epural with a flange anteroventrally. No head pores; head papillae as in Fig. 2.

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FIG. 1. Left lateral view of Trimmatom macropodus (holotype, AMS I . 19456-1 13, 12.5 mm SL male).

Colour pattern (freshly dead, based on 35-mrn transparency of holotype): head and body light yellow, liberally scattered with brown melanophores. Melanophores form diffuse dark bar beneath the eye and seven diffuse saddles over the dorsum: the first above pectoral-fin base, the second at base of spines 2 -4 of first dorsal fin, the third at base of spine 6, the fourth at bases of rays 2 -4 of second dorsal fin, the fifth at bases of rays 7 - 8 of second dorsal fin, the sixth just posterior to base of last ray of second dorsal fin, and the seventh at midpoint of caudal peduncle. Dorsal, anal, and caudal fins with prox- imal three-quarters bright yellow edged with grey; pectoral and pelvic fins hyaline. Margins of scales posterior to vertical at anal-fin origin lined with melanophores. Iris light yellow. Preserved (same specimen): pale straw yellow, saddles over 1 1 dorsum still present but bar under eye absent, all fins hyaline, dorsal half of peritoneum covered with melanophores. The specimens from Taiwan (USNM 293529) and the Philippines (ROM 1179CS) are more darkly pigmented, retain the bar under the eye, have an additional dark saddle over the dorsum between the two dorsal fins and another on the caudal peduncle midway between the seventh saddle and the first dorsal unbranched caudal-fin ray, and have irregular concentrations of melanophores along the vertical midline from the anal-fin origin to the end of the caudal peduncle (faintly visible in the holotype). The smallest specimen (AMS 1.251 12-039) is simi- lar to the holotype except that the distal one-third of the first dorsal fin is black.

Etymology FIG. 2. (a) Left lateral and (6) dorsal views of the head of Trimma- Named from the Greek makros9 meaning long9 and POus9 tom macropodus (holotype, AMS I . 19456- 1 13, 12.5 mm SL male) to

podos, a foot, in allusion to the extremely long fourth pelvic- show head papillae. Scale bar = 5 -. fin ray. To be treated as a noun in apposition.

Discussion This species is known from a total of four specimens from

Taiwan, northern Philippines, Coral Sea, and the Great Bar- rier Reef (Fig. 7), collected at a maximum depth of 15 m. Although there are some slight differences in colour pattern, these are probably due to preservation history rather than taxo- nomic distinction, and involve the lack of expression in the preserved material of three bars in the Barrier Reef - Coral Sea specimens that are diffuse at best in the northern speci- mens. Given that only four specimens have been collected, and that the depth range in which they have been taken has been rather extensively collected in the western Pacific,

Trimmatorn nanus Winterbottom and Emery Fig. 7

Synonymy Trimmatom nanus Winterbottom and Emery 1981, p. 143

(Chagos Archipelago) This species was described on the basis of 93 specimens col-

lected in the Chagos Archipelago, central Indian Ocean, in 1979. Since then, an additional 81 specimens have been col- lected or identified in museum collections. These specimens, listed below, considerably extend the range for this species eastward to the Gilbert Islands, southeastward to Fiji's South Minerva Reef and Middleton and Elizabeth reefs on the Lord

T. macropodus would appear to be a rare species. Howe Rise, northeastward to the Philippines, and north to the

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2406 CAN. J. ZOOL. VOL. 67, 1989

Maldives (Fig. 7). Counts of the second dorsal-, anal-, and pectoral-fin rays are given in Table 1, and compared with the original values for the Chagos Archipelago material. These meristics appear to be remarkably stable over a wide geo- graphic range.

The colouration of the Chagos specimens when freshly dead was not recorded. Fresh colouration of a specimen from Fiji (ROM 45825, 10.0 mm SL, male): head and anterior body brick-red, grading to light orange posteriorly; fins light orange; a thin white bar on cheek below posterior margin of pupil; two thin white saddles over dorsum, the first above the pectoral-fin base and the second in the interspace between the two dorsal fins; an anterodorsal to posteroventral diagonal thin white bar across the opercular region just anterior to the pectoral-fin base.

The first element of the second dorsal and anal fins is an unsegmented paired ray.

Additional material examined CAROLINE ISLANDS: Senyavin Islands; USNM 223277, 4

(6.9 -7.7). FIJI: Great Astrolabe Reef; ROM 45824, 3 (6.7 - 9.0), ROM 45825, 1 (10.0), USNM 241715, 1 (9.8). Lau Islands; USNM 241731, 1 (8.2), USNM 243086, 1 (9.8). South Minerva Reef; USNM 258995, 4 (8.6-9.8). GILBERT ISLANDS: Abaiang Atoll; AMS I. 1805 1-058, 3 (8.6 -9.8). CORAL SEA: Osprey Reef; AMS 1.241 13-029, 2 (9.1 -9.6). LORD HOWE RISE: Elizabeth Reef; AMS 1.27149-039, 12 (7.4- 11.7), AMS 1.27152-035, 8 (7.5-11.2), AMS 1.27155- 017, 2 (9.6-10.3). Middleton Reef; AMS 1.27134-035, 4 (8.1 - 11.0), AMS 1.27138-060, 8 (8.0-1 1.7), AMS 1.27139- 031, 7 (7.7- 11.4), ROM 54980, 7 (7.4- 10.0). MALDIVES: Male Atoll; ROM 54989, 1 (8.5). PAPUA NEW GUINEA: Ninigo Islands; USNM 243925, 2 (8.7 -9.4). PHILIPPINES: Batangas; AMS 1.21907-002, 1 (10.0), AMS 1.21918-043, 2 (7.2-8.9). Negros; ROM 48789, 1 (8.9). WESTERN Am- TRALIA: Scott Reef; AMS 1.21318-044, 3 (7.9 -9.2).

Trimmatom oficius Winterbottom and Emery Fig. 7

Synonymy Trimmatom ofucius Winterbottom and Emery 1981, p. 146

(Chagos Archipelago) No further material of this species has been found, and it

may well prove to be endemic to the Chagos Archipelago (Fig. 7). The first element of the second dorsal and anal fins is an unsegmented paired fin ray.

Trimmatom sagma n.sp. Figs. 3, 4, 7

Material examined Nine lots, 25 specimens, 8.1-17.6 mm SL, 9-58 m,

Cocos-Keeling Islands, Moluccas, and Philippines. HOLOTYPE: ROM 531 18, 12.2 mm SL (female), Philip-

pines, Negros, off mouth of Bais Bay, 24 - 36 m. R. Winter- bottom et al., 15.V. 1987.

PARATYPES: ANSP 162542, 2 (10.2 - 1 1.0), Cocos-Keeling Islands, N side of Turk Reef on drop-off (12"06'30"S, 96"49'35"E), 51 -58 m. W. F. Smith-Vaniz et al., 25.m. 1974. ROM 53 1 17, 1 (12.2), Philippines, Siquijor Island, Tonga Point, drop-off wall and cave, 15 -21 m. R. Winterbottom et al., 12.V.1987. USNM 243908, 1 (15.1), Philippines, SE side of Apo Island (9"4'35"N, 123"16'44"E), 0-30 m. V. G. Springer et al., 6.VI.1978. USNM 244182, 4 (9.5-12.8), Indonesia, Kepulauan Banda, Roen Island (4" 32 '36 "S, 129"40'36"E), 9-15 m. B. B. Collette et al., 8.V11.1979.

USNM 263486, 2 (8.8 - 12. I), Philippines, Pescador Island, 2 km off Cebu (9"55'30"N, 123"20'30"E), 30 m. J. Libby et al., 8.V. 1979. USNM 263498, 1 (10.2), E coast of Cebu, Caceres Reef near Huisan Point, 24-30 m. J. Libby et al., 18.V.79. USNM 2635 13, 1 (13.3), Philippines, W side of Balicasag Island (9'3 1 '14 "N, 123"40 '00 "E), drop-off, 0 - 24 m. V. G. Springer et al., 10.VI. 1978. USNM 264737, 12 (8.1 - 17.6), Philippines, Pescador Island, 2 km off Cebu (9"55'30"N, 123"20'30"E), 18-24 m. J. Libby et al., 7 .V. 1979 (3 specimens cleared and stained).

Diagnosis Trimmatom sagma differs from all other species of the genus

in possessing a 3(2,2,1,1,0,0) dorsal pterygiophore formula and in having a single dark saddle crossing the base of the second dorsal fin. It can be separated from T. macropodus by the unbranched nature of the first three pelvic-fin rays, and from that species and T. zapotes in lacking scales on the body, having 15 or more pectoral-fin rays (vs. 14 or fewer). It differs from the above two species and from T. nanus in having 11 or more rays in the second dorsal fin (vs. 10 or fewer), and 10 or more anal-fin rays (vs. 9 or fewer; two specimens of 106 T. nanus with 10 rays). Trimmatom sagma usually has fewer pectoral-fin rays than T. ofucius ( 1 = 17.7 vs. 20. I), although the ranges overlap.

Description Dorsal VI + 11 -12 (f = 11.6), depressed tips of spines of

first dorsal fin not reaching posteriorly beyond first ray of second dorsal fin, first ray of second dorsal fin bilaterally paired but unsegmented; anal 10,lJ, 12 ( 1 = 10.6), first ray bilaterally paired and may be segmented; pectoral 15, 16, 17, 18, 19 (f = 17.7), not quite reaching vertical at anus; pelvic - I 5, no rays branched, fifth ray 10% length of fourth ray, which reaches posteriorly to between urogenital papilla and first ray of anal fin; fraenum absent; vestigial basal mem- brane. No scales on head or body. Gill opening extending anteroventrally to below midpupil. Mouth terminal, inclined obliquely upwards; outer row of teeth in both jaws much enlarged, curved, spaced canines from symphysis to bend in jaw, with several inner rows of small conical teeth medially grading into a single row posterolaterally on jaws. Nasal sac elevated, anterior nasal opening just above upper lip at end of a tube, posterior nasal opening with raised rim separated from anterior margin of eye by a distance equal to opening's diameter. Tongue slim and rounded at tip. Bony interorbital width about one-third pupil diameter. First gill slit open. Ossi- fied gill rakers 2-3 + 14- 15 (X = 2.3 + 14.3); dorsal pterygiophore formula 3(2,2,1,1,0,0); vertebrae 10 + 15 + ural complex = 26; 6 dorsal and 5 ventral branched caudal-fin rays (one specimen with 4 ventral rays, one of which has a double base), with 10- 1 1 dorsal and ventral unbranched rays; 15 or 16 segmented caudal-fin rays (n = 3 for all characters in this sentence). Caudal skeleton with hypurals 1 and 2 fused together and to ural complex. No head pores, papillae as in Fig. 4.

Colour pattern (freshly dead, based on 35-mm transparency of holotype): head, body, and fins pale orange, becoming lighter posteriorly, sprinkled with brown melanophores , which are most concentrated anteriorly on head, gradually dwindling in number posteriorly, with only a few present on caudal peduncle. Five small dark saddles visible over dorsum of photographed specimen: first just anterior to first dorsal fin, second between bases of fifth and sixth dorsal spines, third at

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TABLE 1. Selected meristics for additional specimens of Trimmatom nanus

No. of dorsal rays No. of anal rays No. of pectoral rays

9 1 0 n x 8 9 1 0 n 1 1 4 1 5 1 6 n x n

Fiji Lau Island South Minerva Reef Viti Levu

Gilbert Islands, Abaiang Atoll Caroline Islands, Ant Atoll Lord Howe Rise

Elizabeth Reef Middleton Reef

GBR, Osprey Reef PNG, Ninigo Islands Philippines

Negros Batangas

Northwest Australia, Scott Reef Indonesia, Saparua Maldive Islands, Male Atoll

Totals Chagos Archipelago

NOTE: GBR, Great Barrier Reef; PNG, Papua New Guinea; n, sample size.

FIG. 3. Left lateral view of Trimmatom sagma (holotype, ROM 53 1 18, 12.2 rnrn SL female).

base of first dorsal ray, fourth at base of sixth ray, fifth at base of last dorsal-fin ray. Iris black and gold. Preserved: pale straw coloured with melanophores. Most specimens with addi- tional small dark saddle over base of first unbranched dorsal caudal-fin rays. A few specimens very pale, with little trace of dorsal saddles, others with diffuse bar of brown melano- phores on cheek below posterior edge of pupil.

Etymology Named from the Greek sagma, a saddle, in reference to the

pattern of small dark saddles across the dorsum that is charac- teristic of the new species. To be treated as a noun in appo- sition.

has been taken in the same rotenone collection as T. nanus in the latter area. One specimen from Banda had 15 pectoral-fin rays on both sides, another from the Philippines had 16 rays on each side. The remaining specimens had 17 or more pec- toral rays. Normally, the medial gill rakers on the first gill arch consist of a clump of spinules arising from a common base. In one of the cleared and stained specimens, however, the second to sixth dorsalmost inner rakers of the cerato- branchial are flat and blade-like, similar to the lateral rakers. The dorsalmost of these rakers is directed anteromedially, the following 4 rakers are directed posteromedially. The rakers below this are spinulose.

Discussion Trimmatom zapotes n. sp. Figs. 5, 6, 7

Of the 25 known specimens of 7'. sagma, two are from the Material examined Cocos-Keeling Islands, four are from Banda in the Moluccas, Eleven lots, 17 specimens, 7.4-15.5 mm SL, 0-25 m, and the remainder from the Philippines (Fig. 7). The species Caroline Islands, Gilbert Islands, Great Barrier Reef.

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2408 CAN. J. ZOOL. VOL. 67, 1989

FIG. 4. (a) Left lateral and (b) dorsal views of the head of Trimmu- tom sagmu (composite) to show head papillae. Scale = 1 rnm.

HOLOTYPE: AMS I. 18739-103, 15.5 mm SL, male, Aus- tralia, Great Barrier Reef, Lizard Island, S side of Palfry Island (14"43'S, 145"27'E), 3-10 m. J. Paxton et al., XI. 1975.

PARATYPES: AMS I. 18044-053, 1 (1 3.0), Gilbert Islands, Abaiang Atoll, 100 m E of Teirio Island, 5 - 10 m. D. F. Hoese et al., 7 .XI. 1973. AMS I. 18047, 2 (7.4 - 14.9), Gilbert Islands, Abaiang Atoll, N end of lagoon, 3 km E of Ribbon Island, 5 m. D. F. Hoese, 8.XI. 1973 (specimen now cleared and stained). AMS 1.20757-070, 1 (1 1.2), Australia, Great Barrier Reef, W end of Raine Island (1 1 "36'S, 144'01 'E), 0-20 m. AMS Party, 11.1979. AMS 1.20779-158, 3 (9.0- 11. l), Australia, Great Barrier Reef, Cape York, N end of Tijou Reef, lagoon (13"05'S, 143"57'E), 0-25 m. AMS Party, 11.1979. AMS 1.20956-03 1, 1 (1 1.2), Australia, Great Barrier Reef, Cape York, Tijou Reef (13 "04'S, 143 "57'E), 3-12 m. AMS Party, 11.1979. AMS 1.22611-057, 1 (9.6), Australia, Great Barrier Reef, Escape Reef North, coral garden (15"49'S, 145"501E), 3 - 11 m. AMS Party, X.1981. AMS 1.22633-094, 2 (8.2 - 8.7), Australia, Great Barrier Reef, Escape Reef North, bornrnie in lagoon (15"49'S, 145"501E), 2-11 m. AMS Party, XI.1981. ROM 55290, 1 (12.2), Caroline Islands, Ponape, lagoon reef on W side of Ponape Passage, 13 m. J. E. Randall et al., 3.IV. 1970. ROM 55291, 3 (9.5 - 11.8), Australia, Great Barrier Reef, W tip of Raine Island (11°36'S, 144"01'E), 0-20 m. AMS Party, 11.1979. ROM 1180CS, 1 (11.0), Australia, Great Barrier Reef, Lizard Island, North Point Reef, 5 - 7 m. AMS Party, 30.1.1975 (specimen now cleared and stained).

genus in having the combination of a scaled body and all pelvic-fin rays unbranched. It differs further from T. nanus, T. o&cius, and T. sagma in possessing a more restricted gill opening (extending anteroventrally to below the vertical limb of the preopercle versus to below pupil of eye), and in having a much elongated fourth pelvic-fin ray (reaching posteriorly to or beyond the posterior region of the anal fin versus no farther posteriorly than the bases of the anterior few anal-fin rays). It differs from T. macropodus in having one or two more scales in the lateral series (24-25 vs. 23), and from all four of the above species in details of colour pattern.

Description Dorsal VI + I 8 - 9 (X = 8.1, n = 15), one specimen (AMS

1.20775-062) abnormal with VII + 8, excluded from count, first element of second dorsal fin a spine, dorsal spines usually short and reaching to first element of second dorsal fin when depressed, except in two male specimens from Escape Reef (AMS 1.22633-094, 8.2-8.7 mm SL), in which first dorsal spine is elongate and reaches posteriorly to base of seventh or eighth ray of second dorsal fin; anal 8 -9 (X = 8.1, n = 16), first ray bilaterally paired and segmented; pectoral 12-13 (X = 12.4, n = 29), reaching posteriorly to vertical at origin of anal fin; pelvic I 5, no rays branched, fifth ray less than 10% length of fourth, fourth elongate, reaching posteriorly to between bases of posterior anal-fin rays and caudal peduncle; fraenum absent, basal membrane vestigial. No scales on head, pectoral base, or breast; lateral scales 24 - 25 (X = 24.2, n = 11); anterior transverse scales 6 (n = 10); posterior transverse scales 6 (n = 10); scales cycloid anteriorly, becoming ctenoid below fourth to fifth spines of first dorsal fin. Gill opening extending anteroventrally to below vertical limb of preopercle. Mouth terminal, inclined obliquely upward, outer row of teeth in both jaws spaced, enlarged, curved canines, several irregu- lar rows of small conical teeth medial to this, innermost row of lower jaw teeth similar to outermost row. Nasal sac slightly elevated, anterior nasal opening at end of tube above upper lip, posterior nasal opening pore-like, with raised rim separated from orbit by a distance equal to 3 times its diameter. Tongue slim, rounded at tip. Bony interorbital width about one-quarter pupil diameter. First gill slit open, ossified gill rakers 1 + 5 - 6. Dorsal pterygiophore formula 3(2,2,1,1,0); vertebrae - 10 + 14 + ural complex = 25 in the single cleared and stained specimen; 6 dorsal and 5 ventral branched caudal-fin rays, with 8 dorsal and 8 ventral unbranched rays; 17 segmented caudal-fin rays. No head pores, papillae as in Fig. 6.

Colour pattern (freshly dead, based on 35-rnrn transparency of specimen from Escape Reef): cheek and posterior half of body light yellow -green, remainder translucent; five internal darkish body bars, first below second spine of first dorsal fin, second below fifth spine, third below rays 2 or 3 of second dorsal fin, fourth below last ray of second dorsal fin, and fifth on peduncle just anterior to ural complex; anterior nasal tube red; bar on cheek below pupil and eight diffuse saddles over dorsum pink; bases of caudal-fin rays pink; both dorsal fins yellow; margins of scales on posterior half of body outlined with melanophores; iris off-white. Preserved (based on holo- type): ground colour straw-yellow with scattered melano- phores and chromatophores; diffuse bar on cheek below pupil; eight diffuse saddles over dorsum, first above opercle, second

Diagnosis above and just posterior to pectoral base, third at bases of Trimmatom zapotes differs from all other species in the spines 2-4 of first dorsal fin, fourth at base of spine 6; fifth

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WINTERBOTTOM

FIG. 5. Left lateral view of Trimmatom zapotes (holotype, AMS I. 18739- 103, 15.5 mm SL male).

surface of peritoneum; thin subcutaneous line of melanophores along midlateral septum.

Etymology Named from the Greek zapotes, a hard drinker, in allusion

to the red anterior nasal tube of the new species. To be treated as a noun in apposition.

Discussion The new species has been taken at the Caroline and Gilbert

islands, and at the northern half of the Great Barrier Reef (Fig. 7).

In 12 of the 14 specimens with the first dorsal spine undamaged, the tip of the depressed spine reaches posteriorly to the dorsal fin interspace or the base of the first ray of the second dorsal fin (7.4 - 14.9 mm SL, males and females). The

I spine is elongate and reaches to the bases of the 7th or 8th rays of the second dorsal fin in two specimens from Escape Reef (8.2-8.7 mm SL, both males). The colour transparency, provided by D. F. Hoese, is of a specimen with the same cata- logue number as these last two specimens, but the first spine of the dorsal, fin is clearly not elongated, and the specimen appears to be missing. The only other specimen from Escape Reef (a 9.6 mm SL male) has a very slightly elongated first dorsal spine, reaching to the base of the 1st ray of the second dorsal fin. It seems therefore that the elongated first spine is not linked to geographic locality, as it appears to be in some other gobies (e.g., Sueviota lachneri, see Winterbottom and Hoese 1988). There would appear to be at least three explana- tions for the elongation: it could be an ontogenetic transforma- tion, individual variation, or a temporal phenomenon. The

FIG. 6. (a) Left lateral and (b) dorsal views of the head of Trimma- tom zapotes (holotype, AMS I. 18739-1703, 15.5 mm SL male) to show head papillae. Scale = 5 mm.

at bases of rays 2 -4 of second dorsal fin, sixth at bases of rays 7 or 8; seventh just posterior to base of last ray, and eighth two-thirds of the distance along caudal peduncle; margins of scales with chromatophores, especially posteriorly; spines of first dorsal fin margined with chromatophores, present but less well developed on rays of second dorsal and caudal fins; chro- matophores present in interradial membrane of anal fin, at bases of proximal pterygiophores of anal fin, and over dorsal

first hypothesis appears to be refuted by the short spine present in a 7.4 mm SL immature specimen from Abaiang Atoll and in a 9.0 mm SL female from Cape York. The second explana- tion seems unlikely if such variation is random, since the two specimens with elongated spines were taken in the same sta- tion. The last explanation is consistent with the fact that all the remaining males, which are larger than the two Escape Reef specimens, lack elongate dorsal spines. Thus, spine elongation may be associated with reproductive activity, with the spine being resorbed at the end of the breeding season. The holotype is the only other specimen collected during the same month (November) as the two Escape Reef specimens, but the first dorsal spine is broken.

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2410 CAN. J. ZOOL. VOL. 67, 1989

FIG. 7. Distribution map for the Trimmatom nanus species complex. A , T. macropodus; a, T. nanus; r , T. oficius; +, T. sagma; m, T. zapotes.

NOTE ADDED IN PROOF: A fifth specimen of T. macropodus was recently collected in the Comores islands off northwest Madagascar in the western Indian Ocean. It is excluded from the type series. ROM 56563, 11.3 mm SL, Federal Islamic Republic of Comores, Moheli Island, bay at SW tip about 3 naut. mi. W of Nioumachoua (12"21t15"S, 43"40t00"E), vertical wall with numerous caves, fine sand - silt substrate with some algae, hard and soft corals, 9 - 17 m, rotenone, 09: 15 - 10:20. Collected by R. Winterbottom and W. Holle- man, 27 November 1988.

Acknowledgments

I would like to thank the following for the loan of the speci- mens on which this paper is based: D. F. Hoese (AMS); S. Jewett (USNM); J. E. Randall (BPBM); and W. F. Smith- Vaniz (ANSP). Special thanks are extended to D. F. Hoese for loaning the colour transparencies of two of the new species,

and for abandoning his plans to describe them. Victor G. Springer (USNM) reviewed the manuscript and made numer- ous useful suggestions for its improvement. The research leading to this paper was supported by Benjamin Film Labora- tories Ltd. of Toronto and the Royal Ontario Museum, and by Natural Sciences and Engineering Research Council of Canada grant No. A7619 to the author.

BIRDSONG, R. S. 1975. The osteology of Microgobius signatus Poey (Pisces: Gobiidae), with comments on other gobiid fishes. Bull. Florida St. Mus., Biol. Sci. 19(3): 135 - 187.

WINTERBOTTOM, R., and EMERY, A. R. 1981. A new genus and two new species of gobiid fishes (Perciformes) from the Chagos Archi- pelago, central Indian Ocean. Environ. Biol. Fish. 6(2) : 13 1 - 149.

WINTERBOTTOM, R., and HOESE, D. F. 1988. A new genus and four new species of fishes from the Indo-west Pacific (Pisces; Perci- formes; Gobiidae), with comments on relationships. R. Ont. Mus. Life Sci. Occas. Pap. No. 37.

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