Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific

Transcription

1 aqua, Journal of Ichthyology and Aquatic Biology Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific Richard Winterbottom Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, 100 Queen s Park, Toronto, M5S 2C6; and Department of Zoology, University of Toronto, Toronto, Ontario M5S 3G5. rickw@rom.on.ca Accepted: Keywords Ichthyology, Systematics, Gobiidae, Trimma, new species, Western Pacific Ocean Abstract Three new species of the genus Trimma, all characterized by red or red brown bars on a pale background, are described. Trimma cana is characterized by eight well-defined red bars on the head and body on a white background, a naked nape, a well-developed interorbital trench, and a discreet dark bar across the dorsum just behind the eyes, with the melanophores lying on the medial surface of the frontal bone. Trimma sostra is distinguished by seven incomplete, diffusely-defined red bars on the head and body, a naked nape, a moderate interorbital trench, a dark spot on the lower pectoral fin base and another on the lower caudal peduncle. Trimma squamicana has a scaled nape, a moderate to deep interorbital trench with a poorly-developed or no postorbital trench, and eight red to reddish brown saddles over the dorsal midline, the posterior five of which have ventral counterparts. Zusammenfassung Beschrieben werden drei neue Arten der Gattung Trimma, die alle durch rote oder rotbraune Streifen auf blassem Untergrund gekennzeichnet sind. Trimma cana zeichnet sich durch acht gut erkennbare rote Streifen auf dem Kopf und auf dem Rumpf auf weißem Untergrund aus, außerdem durch einen unbeschuppten Nackenbereich, eine gut entwickelte Furche zwischen den Augen und einen schwachen dunklen Streifen quer über dem Rücken gleich hinter den Augen, wobei sich die Melanophoren auf der medialen Oberfläche des Frontalknochens befinden. Trimma sostra lässt sich durch sieben unvollständige, undeutlich begrenzte rote Streifen auf Kopf und Rumpf unterscheiden und ist weiterhin durch einen unbeschuppten Nackenbereich, mäßig deutliche Interorbitalfurche, einen dunklen Fleck an der Basis der unteren Brustflosse und einen zweiten auf dem unteren Schwanzzipfel gekennzeichnet. Trimma squamica zeigt einen beschuppten Nacken, eine mäßige bis tiefe Interorbitalfurche sowie eine schwach entwickelte oder ganz fehlende postorbitale Furche, außerdem acht rote bis rötlich braune Sattelflecken über der dorsalen Mittellinie, von denen die fünf hinteren ventrale Entsprechungen haben. Résumé On décrit ici trois nouvelles espèces du genre Trimma, toutes caractérisées par des barres rouges ou brun rouge sur fond pâle. Trimma cana se distingue par huit barres rouges bien nettes sur la tête et le corps, sur fond blanc, par une nuque sans écailles, un sillon interorbital bien développé et une barre foncée discrète juste derrière les yeux, avec les mélanophores sur la surface médiane de l'os frontal. Trimma sostra se distingue par sept barres rouges diffuses et incomplètes sur la tête et le corps, une nuque sans écailles, un sillon interorbital modéré, une tache noire sur la base inférieure de la pectorale et une autre sur le pédoncule caudal inférieur. Trimma squamicana a une nuque écaillée, un sillon interorbital modéré à profond avec un sillon postorbital peu développé ou pas du tout, et huit taches rouges à brun rouge en forme de selle sur la ligne médiane dorsale, dont les cinq postérieures ont des contreparties ventrales. Sommario Tre nuove specie del genere Trimma, tutte caratterizzate da barre rosse o rosso-brune su sfondo chiaro, sono qui descritte. Trimma cana è caratterizzata da otto ben definite barre rosse sul capo e sul corpo su fondo bianco, la nuca priva di scaglie, un solco interorbitale ben sviluppato e una distinta barra scura attraverso il dorso proprio dietro gli occhi, con i melanofori disposti sulla faccia mediale dell osso frontale. Trimma sostra si distingue per sette incomplete e sfumate barre rosse su capo e corpo, la nuca priva di scaglie, un solco interorbitale moderato, una macchia scura alla base inferiore della pettorale e un altra sulla parte inferiore del peduncolo caudale. Trimma squamicana ha la nuca ricoperta di scaglie, un solco interorbitale da moderato a profondo, con un solco postorbitale poco sviluppato, e otto bande a sella, variabili dal rosso al rosso-bruno disposte lungo tutta la linea mediana dorsale; di queste, le cinque posteriore hanno una controparte ventrale. Introduction Trimma contains some 80 species of small (less than 7 aqua vol. 9 no

2 Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific 30 mm SL), often colourful gobiids, primarily associated with Indo-Pacific coral reefs. Members of the genus may be recognized by the lack of cephalic sensory canal pores, much reduced cephalic sensory papillae pattern, wide gill opening extending to below the vertical limb of the preopercle or anterior to this, lack of spicules on the outer gill rakers of the first gill arch, less than 12 dorsal and anal rays, and a fifth pelvic fin ray that is equal to or more than 40% the length of the fourth pelvic fin ray. There are 39 valid described species of Trimma and approximately 45 additional species which have yet to be described. A phenetically distinctive (and thus not necessarily monophyletic) subgroup of the genus contains three undescribed species which, in life, have a pale or white body colouration with several broad red or red-brown bars. The first of these to be described below, Trimma cana, has frequently been photographed on western Pacific reefs. Methods Methods follow Winterbottom (2002), except pectoral and pelvic fin ray branching is described from preserved material stained with a cyanine blue solution as outlined in Saruwatari et al. (1997). The term ray is used to designate a bilaterally-paired, segmented, and usually branched element of the fins; spine is used for elements that are unpaired, unsegmented and always unbranched. Values for holotype in bold where appropriate. All specimens were collected with rotenone or quinaldine. Abbreviations for repositories of material examined are: AMS Australian Museum, Sydney; BPBM Bernice P. Bishop Museum, Hawai i; CAS California Academy of Sciences, San Francisco; MCZ Museum of Comparative Zoology, Cambridge, Massachusetts; ROM Royal Ontario Museum, Toronto; and USNM Smithsonian Institution, Washington, DC. Trimma cana n. sp. Candycane pygmy goby (Figs. 1-4 A, B; 5 A) Trimma sp. Allen et al., 2003: 330, middle left figure (Indonesia, Palau and Papua New Guinea). Trimmatom sp. Lieske and Myers, 1994: 123, No. 15 (Indonesia, New Britain, Mariannas, Ryukyu and Izu Is., NW Australia). A total of 16 lots, 37 specimens, Holotype: ROM 73776, 22.3 mm SL male, Philippines, Mindanao Sea, Siquijor Is., Tonga Point, ( N, E), m, rotenone, by R. Winterbottom, G. D. Johnson and M. Burridge, 22 May 1987, ex-rom Paratypes: Fiji Islands: USNM , 1(18.5 mm SL), Matuku Island, just outside channel entrance, south side, ( S, E), m, V. G. Springer and co-collectors., 24 April 1982; Marshall Islands: Majuro Atoll, AMS I , 1 (20.6 mm SL), off SW end of airport outside reef, (07 05 N, E), J. Randall and A. Emery, 1 April 1970; Philippines: AMS I , 3 ( mm SL), Caban Island, Batangas, (13 35 N, E), April 1980; AMS I , 1 (17.6 mm SL), off San Carlos Research Station, (10 17 N, E), m, D. Hoese, 29 April 1980; ROM 49215, 2 ( mm SL), Bohol Strait, Mactan I., drop-off near point about 0.5 km south of Hudson Beach, (approximately 2 km south of Tambuli Beach resort), (10 15 N, E), m, R. Winterbottom and E. Murdy, 8 Aug. 1985; ROM 53070, 1 (21.5 mm SL), Mindanao Sea, Siquijor Is., Tonga Point, drop-off, ( N, E), m, R. Winterbottom, R. Mooi and P. Benjamin, 8 May 1987; ROM 53071, 1 (21.0 mm SL), Mindanao Sea, Siquijor Is., Tonga Point, west side about 1 km from tip of point, ( N, 123à27 16 E), m, G. D. Johnson, R. Mooi, E. Downar and P. Benjamin, 9 May 1987; ROM 53072, 7 ( mm SL, 3 removed to ROM 1148CS, mm SL), Mindanao Sea, Siquijor Is., Tonga Point, (09E12 16 N, 123E27 16 E), m, R. Winterbottom, G. D. Johnson, R. Mooi, E. Downar, 10 May 1987; ROM 53073, 5 ( mm SL), Mindanao Sea, Siquijor Is., Tonga Point, ( N, E), m, R. Winterbottom, R. Mooi, M. Burridge, 12 May 1987; ROM 53076, 3( mm SL, one removed to become the holotype), same as the holotype; USNM , 1(22.2 mm SL), Caceres reef near Huisan Point, east coast of Cebu, m., J. Libbey and co-collectors., 18 May 1979; USNM , 6 ( mm SL), NW side of Pescador Island, 2 km from Cebu mainland near resort town of Moalboal, ( N, E), m, J. Libbey and co-collectors., 7 May 1979; USNM , 4 ( mm SL), about 2 km west of town of Siquijor, ( N, E), m, J. Libbey and co-collectors., 14 May 1979; USNM , 1 (18.6 mm SL), Balicasag Island, west side at drop-off, ( N, E), m, V. G. Springer and co-collectors., 10 June 1978; USNM , 6 ( mm SL), Mactan Island, off east side, off Buyong Beach, ( N, E), m, V. G. Springer and co-collectors., 03 June Diagnosis Trimma cana has a white background with eight distinct red vertical bars on the head and body, and yellow spots on the medial fins; a well-defined dark bar across the postorbital region of the skull (may be partially obscured by the overlying anterior extension of the epaxialis body musculature in larger specimens); no scales on the head, opercle, cheek or nape; a second dorsal spine varying from slightly to very elongate (as far as the mid-peduncle); a well-developed interorbital trench; a variably-developed postorbital trench (usually developed); and a fifth pelvic fin ray which is unbranched and 50-85% of the fourth. aqua vol. 9 no

3 Richard Winterbottom Fig. 1. Trimma cana, live, Indonesia. Photo by G. Barrall. Fig. 2. Trimma cana, 18.1 mm SL male (paratype), freshly collected, Mactan I., Cebu, Philippines, ROM Photo by R. Winterbottom. Fig. 3. Trimma cana, 22.3 mm SL male (holotype), preserved, Siquijor I., Philippines, ROM Photo by R. Winterbottom. 9 aqua vol. 9 no

4 Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific Description The description is based on the holotype and up to 36 paratypes (values for the holotype in bold where appropriate). Dorsal fins VI I 9-10 (n = 37, 10 twice), second spine usually elongate in males, reaching to caudal peduncle, in females length of second spine is variable, all rays branched except occasionally in first and last; anal fin I (n = 37, 8 once, 10 once); pectoral fin (mean = 17.4, n = 34) with 4-11 branched rays at approximate centre of fin, reaching posteriorly to a vertical line with first few elements of anal fin; pelvic fin I 5, no frenum, basal membrane no more than 10% the length of the fifth pelvic fin ray, often vestigial, first four rays with one sequential branch, (twice individual fin rays branched sequentially two times), fifth ray unbranched and % the length of fourth, fourth ray reaching posteriorly to a vertical line with first few elements of anal fin. Lateral scales (mean = 23.5, n = 33), anterior transverse scales 6-7 A Narrow band of melanophores B C Broad band of chromatophores D Fig. 4A-D. Dorsal views of the heads of Trimma cana (A and B), 14.2 and 21.5 mm SL respectively, ROM 53073, T. sostra (C), 14.4 mm SL, ROM 73599, and T. squamicana (D), 18.3 mm SL, ROM Photos by R. Winterbottom (mean = 6.6, n = 33), posterior transverse scales 5-6-7, (mean = 5.8, n = 33; 7 twice); no predorsal scales; scales on breast cycloid, 3-4 rows of cycloid scales on pectoral base; cheek and opercle scaleless. Gill opening extending anteroventrally to below posterior margin of pupil to mid-pupil. Lower jaw with a short outer row of enlarged, curved, spaced canines near the symphysis, an inner row of somewhat smaller spaced canines, and one or two irregular rows of small conical teeth in between; teeth of upper jaw similar, but no inner row of canines. Tongue margin round, truncate or parenthesis shaped. Gill rakers on first arch = 14-21, (mean = 17.8, n = 25). Anterior nasal opening a tube; posterior nasal opening either a pore or a pore with a raised rim not adnate to eye. Bony interorbital 1/3 pupil width, a well-developed interorbital trench, and a postorbital trench that is usually well-developed or occasionally slightly developed. Colour in life: (based on colour slides of living speciaqua vol. 9 no

5 Richard Winterbottom mens from Indonesia, north-east Sulawesi and Palau, and freshly-collected specimens from the Philippines Figs. 1-2). Background colour white with eight vertical bars on the body. Bars vary in colour from yellow to red and are often a darker shade on the anterior half of the body. The first two bars cross the dorsal surface of the head as two separate bars and join together on the opercle to form a V shape. These bars do not extend to the ventral surface but end on the opercle. In slides of freshly-collected material, these two bars often blend together to create a single saddle with a slightly lighter patch in the centre, although the V shape is still evident ventrally. The third bar is centred on the first dorsal spine and extends ventrally on the body behind the pectoral fin base. The fourth bar begins behind the fifth spine of the first dorsal fin; the fifth from between the third and fifth element of the second dorsal fin. The sixth bar begins at the eighth element of the second dorsal; the seventh bar is at the middle of the caudal peduncle; and the eighth is just anterior to the end of the caudal peduncle. The width of the bars < than the white areas; the bars are clearly-defined and vertical; and bars three to eight extend from the dorsum to the ventral surface. The orbit is red with a thin yellow ring around the pupil, and occasional yellow blotches on its outer rim. Yellow spots are present in the first and second dorsal, anal, and caudal fins; a darker red spot is often present in the second dorsal fin between the first spine and the first fin ray. A reddish streak is present along the top of the pectoral fin base; the pectoral and pelvic fins appear hyaline. The slides of living specimens show the upper and lower lip orange red with a bright white median stripe from the tip of the snout along the interorbital region to mid-eye; the cheek is white with a small red bar extending from the eye to the corner of the mouth. Colour in alcohol: plain straw-coloured with very little pigment on the body (Fig. 3) or head (Fig. 5 A). A single, usually dumb bell shaped, band of melanophores is present on the head immediately behind the eyes (Fig. 4 A, B band may not be complete and may appear as two separate clusters of melanophores on head behind the eyes on either side of the nape). The pigment cells lie in the membrane on the medial surface of the frontal bones. If postorbital trenches are present melanophores are sometimes present in the trenches. No other bars are seen on the body (a single specimen had a single line of chromatophores on the body immediately behind the pectoral fin base). Melanophores are thickly-scattered in the membranes of the caudal fin and both dorsal fins, and even more so in the anal fin, particularly between the posterior few rays; paired fins hyaline. A few chromatophores may be present on the nape just above and posterior to the opercle, and along the top of the pectoral base. In a few specimens, four very small saddles (6-20 melanophores or chromatophores in each saddle) were present on the dorsal surface at the base of the fins. The cheek is immaculate. Comparisons There are three species of Trimma, T. cana, T. sostra, and T. squamicana which, when alive or freshly collected, share extensive red or red-brown vertical markings on a white background. Trimma squamicana is easily distinguished from the other two by its scaled nape and a colour pattern of red saddles over the dorsal and ventral surfaces rather than the bars seen on the lateral surfaces of T. sostra and T. cana. These saddles on T. squamicana are also present in preserved material. Trimma cana and T. sostra initially appear quite similar, sharing the evenly-spaced bands of red pigment along the sides of the body. However the bars on T. A B C Fig. 5A-C. Left lateral views of the heads of preserved specimens of: Trimma cana (A); T. sostra (B); and T. squamicana (C). Photos by R. Winterbottom. 11 aqua vol. 9 no

6 Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific sostra extend from just above the midlateral septum to the ventral surface, and consist of a poorly-defined soft rounded rectangles. In T. cana the bars are distinct, a consistent width from top to bottom, straight-sided, and run vertically from the dorsal to ventral surface even on very faded specimens. In preserved material, T. cana and T. sostra appear quite different. Both have a dark band on the nape immediately behind the eyes and often in the postorbital trench, but in T. sostra the band is broad and diffuse and consists primarily of chromatophores (Fig. 4 C); there is much more pigment on the upper half of the body; there is a dark spot on the pectoral base (Fig. 5 B) and another on the caudal peduncle (Fig. 7); in small specimens (< 15 mm) the bands on the body are similar to those on freshly-collected specimens; and there is often a sprinkling of melanophores and chromatophores on the cheek. In T. cana the cheek is immaculate and there is almost no pigment on the body except for an occasional small cluster of chromatophores just above the pectoral base and the band of pigment behind the eyes. In a few specimens 3 or 4 tiny saddles (6-20 melanophores or chromatophores per saddle) were present along the dorsum, but generally there is no evidence of the bands of pigment seen in living and freshly-collected specimens. There are four other species of Trimma which, when preserved, have a very plain colouration and which could be confused with Trimma cana. Trimma taylori and Trimma winchi can both be distinguished from T. cana by the broad (pupil width), flat interorbital space and the presence of predorsal scales. Trimma benjamini is also very plain and straw-coloured when preserved, but usually has two bars below the eye, a ring of melanophores around the dorsal half of the orbit, and has a very well developed postorbital trench. Trimma stobbsi has a dark spot above the opercle and is generally more dusky than yellow, with scale margins strongly outlined. Trimma taylori, T. benjamini, and T. stobbsi do not have a band of melanophores behind the eyes, but T. winchi does appear to have a sprinkling of melanophores in this region. In a closely-related genus, Trimmatom pharus has twelve very narrow red vertical bars on a white background, and an unbranched fifth pelvic fin ray that is at most 20% the length of the fourth ray. In the preserved state T. pharus has numerous dark bars on a straw yellow background. Trimma cana has informally been referred to as Trimma RW sp 30. Etymology The name cana is an arbitrary combination of letters embodying the first three letters of both the English words candy and cane. It is an allusion to the early 20 th Century innovation of adding red bands to a white candy formed in the shape of a shepherd s crook that is used as a consumable decoration at Christmas. Treated as a noun in apposition. Distribution Trimma cana has been found at the Philippines, Caroline Is., Fiji, Marshall Is. and Palau at depths of between 12 and 30.5 m. Trimma sostra n. sp. Sostra pygmy goby (Figs. 4 C; 5 B; 6-7) A total of 13 lots, 36 specimens. Holotype: ROM 74046, 18.1 mm SL male, Canton Atoll at overhang with rubble bottom, ( S, W), between 17 and 38 m., collected by G. Allen, S. Bailey and M. Adams, 22 June Paratypes: Caroline Islands: USNM , 12 ( mm SL, one removed to C&S, 18.6 mm SL), Senyavin Islands, west side of Ant Atoll, ( N, E), 0-24 m., V. G. Springer and co-collectors., 16 Sept.1980; USNM , 5 ( mm SL), Senyavin Islands, west side of Ant Atoll, ( N, E), 0-24 m., V. G. Springer and co-collectors., 16 Sept Fiji Islands: USNM , 1 (18.8 mm SL), Lau Group, Matuku Island, just outside channel entrance, south side, ( S, E), m., V. G. Springer and co-collectors., 24 April Kiribati, Gilbert and Ellice Islands: AMS I , 1 (20.0 mm SL), Abaiang Atoll, 90 m east of Teirio Island, D. Hoese, B. Goldman and L. Goldman, 07 Nov. 1973; Kiribati, Phoenix Islands: MCZ , 12 ( mm SL), collected with the holotype; ROM 73595, 1 (19.1 mm SL), Canton Atoll on slope just west of wreck of S.S. Taylor, ( S, W), 40 m, G. Allen, S. Bailey and M. Adams, 21 June 2002; ROM 73598, 2 ( mm SL), Canton Atoll on 70 degree slope with undercut ledges and sand on floor, ( S, W), 38 m., G. Allen, S. Bailey, M. Adams; ROM 73599, 5 ( mm SL), same as ROM 73595; ROM 73600, 2 ( mm SL), collected with the holotype; Marshall Islands: BPBM 22381, 2 ( mm SL), Enewetak Atoll, J. E. Randall and co-collectors., Apr-May Solomon Is: USNM , 5 ( mm SL), Stewart Is., reef face of outer reef off west side of Matuiloto Is., in a deep channel in the coral reef, ( S, E), 0-20 m, J. T. Williams and co-collectors, 03 Oct Diagnosis A species of Trimma with seven large regular orange red bars along the side of the body; a dark spot on the lower base of the pectoral fin, and another on the lower peduncle; internal pigmentation on the dorsal surface of the head just behind eyes well-developed but broadly diffuse, not forming a discreet bar; no predorsal scales; second dorsal spine slightly to very elongate; a moderate interorbital and variably-developed postorbital trench; and the fifth pelvic fin ray is unbranched and 50-70% of the length of the fourth. aqua vol. 9 no

7 Richard Winterbottom Description The description is based on the holotype and up to 35 additional specimens. Dorsal fins VI I 8-9, (8 once, n=36), second spine variable, reaching posteriorly to at least base of first element of second dorsal fin or as far as hypural plate, first ray of the second dorsal fin branched or unbranched, remaining fin rays branched; anal fin I 8-9, (8 twice, n = 32), first ray of anal fin usually unbranched, remaining rays branched (1 of 27 specimens with all rays unbranched); P , (mean = 18.6, n = 34, 16 and 21 once each), reaching posteriorly to between genital papilla and third element of anal fin, uppermost four to seven rays and ventralmost four to eleven rays unbranched, with one to eleven branched rays in between (in two specimens all rays were unbranched). V I 5, no frenum, basal membrane not more than 10% the length of the fifth pelvic fin ray, first four rays branched sequentially once; fifth ray unbranched, % the length of fourth ray; fourth ray reaching posteriorly to between first and fourth elements of anal fin. Lateral scales (mean = 24.1, n = 35), anterior transverse scales 5-6-8, (mean = 6.6, n = 33), posterior transverse scales (mean = 5.6, n = 33), opercle, cheek and midline of nape scaleless; 3-9 cycloid scales present on pectoral base, cycloid scales present on pelvic base. Gill opening extending anteroventrally to below posterior margin of eye to midpupil. Teeth in lower jaw consist of a short outer row of enlarged, widely spaced canines near the symphysis, irregular inner rows of smaller caniniform teeth and an innermost row of spaced, medium-sized canines; upper jaw teeth similar to those of the lower jaw but lacking innermost row. Tongue margin truncate or weakly bilobed with a central tip. Gill rakers on first arch = (mean = 20.6, n = 24). Anterior nasal opening a narrow tube, posterior nasal opening a wide pore with a raised rim, nasal openings of some specimens located on a raised oval sac (sac not obvious in all specimens); posterior nasal opening not adnate to eye. Bony interorbital 1/3 pupil width; a moderate interorbital trench; postorbital trench absent to welldeveloped. Colour in life: (from two colour slides from the Solomons and four digital images from Kiribati Republic Fig. 6): Background colour white with seven large orange red, roundish, rectangular blotches along the side of the body. The blotches are two to three scales wide (wider than the white areas that separate them) Fig. 6. Trimma sostra, 21.0 mm SL, freshly collected, Stewart I., Solomons. Photo by J. Williams. Fig. 7. Trimma sostra, 14.4 mm SL, preserved, ROM Photo by R. Winterbottom. 13 aqua vol. 9 no

8 Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific and the edges of the blotches are diffuse and poorlydefined. The first blotch covers the operculum and sometimes extends over the dorsal surface to form a large saddle across the body. Subsequent blotches extend from just above the midlateral septum and continue down to or almost to the ventral surface. A dark thumbprint shape is present on the pectoral base. This thumbprint spot either becomes part of the second blotch or is situated just anterior to it. The final blotch is just anterior to the caudal fin and is sometimes a distinct chevron shape (pointing anteriorly). The upper half of the chevron extends to the dorsal surface and is yellow. Scales are outlined on the upper half of the body. Some specimens have small orange or yellow spots around the base of the two dorsal fins. Rows of yellow spots are present on dorsal and caudal fins. Some yellow pigment also appears to be present in the pelvic and anal fins, but any pattern is difficult to discern from the available images. The pectoral fins are hyaline. The orbit is red with a yellow ring surrounding the pupil. The area above the upper lip is orange red, the lips and the area adjacent and below the mouth is yellowish with a scattering of orange pigment. No spots or pigment are visible on cheek. Colour in alcohol: Background colour is straw yellow, with a few melanophores and chromatophores scattered on the body, particularly the dorsal half (Fig. 7). A large dark oval spot is present on the upper half and extends to the posterior edge of the pectoral base (Fig. 5 B), and another dark spot is present on the ventral half of the caudal peduncle just anterior to the caudal fin. The area across the top of the head immediately behind the eyes is heavily sprinkled with chromatophores (Fig. 4C), which lie in the membrane covering the medial surface of the frontal bones. In some specimens the chromatophores form a band behind the eye to the two o clock position in the postorbital trench and the adjacent area lacks pigmentation. The cheek is either plain or lightly-sprinkled with melanophores. In heavily-pigmented specimens (generally <15 mm SL) scale pockets are outlined with melanophores on the upper half of the body and there are two broad diagonal bands of chromatophores on the sides of the body immediately posterior to the pectoral fin base, beneath the pectoral fin. Additional bands may continue at regular intervals but are internal. These subsequent bands appear less diagonal and more vertical. Chromatophores are usually present on the fin rays and interradial membranes of the median fins. On well-pigmented specimens there is a sprinkling of melanophores in the paired fins, but in specimens with little pigment all fins may be hyaline. Comparisons Preserved specimens of Trimma sostra are identified by their plain straw yellow colour, naked nape, a single dark oval spot on the pectoral base and another dark spot on the ventral half of the caudal peduncle. Trimma griffithsi is the only plain yellow Trimma (when preserved) with a similar caudal spot. Trimma griffithsi differs significantly in having no pectoral spot, a scaled nape, no trenches, and no melanophores behind the eyes. When alive or freshly-collected, Trimma sostra can be distinguished from Trimma cana by the shape and extent of the orange-red bars on the body. This species has been informally referred to as Trimma RW sp 42. Etymology Sostra is a derivation of Sostratus, the Cnidian designer and builder of the Lighthouse of Alexandria, one of the seven wonders of the ancient world. built about 350BC on the then island of Pharos, near the modern city of Alexandria in Egypt. The name an allusion to the creator of that most famous lighthouse, and to the red and white bars of the new species which are reminiscent of the colours of many 20 th Century lighthouses. Treated as a noun in apposition. Distribution Trimma sostra has been found at the Caroline Is., Fiji, Kiribati Republic, Marshall Is., Solomon Is., and Ponape. Collection depths varied from 0-40 m. Trimma squamicana n. sp. Candy scale pygmy goby (Figs. 4 D; 5 C; 8-9) A total of 10 lots, 44 specimens; all specimens from Kiribati Republic, Phoenix Is. Holotype: ROM 73761, 20.8 mm SL female, Canton Atoll on steep slope just W of wreck of S. S. Taylor, ( S, W), collected at a depth of 40 m., G. Allen, S. Bailey and M. Adams, 21 June Paratypes: CAS 60283, 1 (18.1 mm SL), Canton Atoll, Shark Alley, 33 m, J. E. McCosker and S. McCosker, 15 Aug. 1978; MCZ , 10 ( mm SL), Canton Atoll at overhangs and rubble bottoms, ( S, W), m, G. Allen, S. Bailey, M. Adams, 22 June 2002; MCZ , 2 ( mm SL), Canton Atoll on 75 degree slope, ( S, W), 48 m, G. Allen, S. Bailey and M. Adams, 23 June 2002; MCZ , 2 ( mm SL), Canton Atoll on 70 degree slope with undercut edges and sand on floor, ( S, W), 38 m, G. Allen, S. Bailey and M. Adams, 21 June 2002; ROM 73592, 3 ( mm SL), Manra Atoll, sandy bottom surrounded by coral and ledges, ( S, 171E54 54 W), 11 m, G. Allen and S. Bailey, 15 June 2002; ROM 73593, 5 ( mm SL), Bikini Atoll, ( S, W), 34 m, G. Allen and S. Bailey, 29 June 2002; ROM 73594, 11 ( mm SL, one removed to become the holotype), same data as holotype; ROM 73596, 6 ( mm SL), Canton Atoll in front of sheer wall with overhangs and grottos, ( S, W), 14 m, G. Allen, 24 June 2002; ROM 73597, ex-mcz , 3 ( mm SL), Canton Atoll lagoon, 17 m, G. Allen and S. Bailey, 26 June aqua vol. 9 no

9 Richard Winterbottom Diagnosis Trimma squamicana has eight red to reddish brown saddles over the dorsal midline and five similar saddles on the ventral midline on a white background; the second dorsal spine is variably elongate; the fifth pelvic fin ray is unbranched; the interorbital trench is moderate to deep, the postorbital trench is generally poorly-developed or absent; and the nape is scaled. Description The description is based on the holotype and up to 42 additional specimens. Dorsal fins VI I 8-9 (8 once, n = 24), second spine variably elongate, from slight to reaching posteriorly as far as middle of second dorsal fin, first and/or last rays of second dorsal fin may be branched or unbranched, all remaining rays branched; anal fin I 8-9, (mean = 8.7, n = 22), first ray unbranched, second, third and last rays branched or unbranched, remaining rays branched; P , (mean = 18.3, n = 22), reaching posteriorly to a vertical in line from between genital papillae and third element of anal fin, four to ten branched rays in mid region of fin; V I 5, no frenum, basal membrane vestigial, first four rays branched sequentially once, fifth ray unbranched, 50-75% of fourth ray, fourth ray reaching posteriorly to between first to fifth element of anal fin. Lateral scales (mean = 23.9, n = 24), anterior transverse scales (mean = 8, n = 23), posterior transverse scales 6-8 (mean = 7.5, n = 23). Cheek and opercle scaleless, pelvic and pectoral fin bases scaled; predorsal scales (smaller specimens with few or no predorsal scales). Gill opening extending anteroventrally to below posterior margin of pupil to mid-pupil. Teeth in lower jaw consist of an enlarged, outer row of widelyspaced, curved canines near the symphysis, irregular inner rows of smaller, caniniform teeth which extend to dorsal flange of dentary, and an innermost row of moderately-developed, spaced canines; upper jaw teeth similar to those in lower jaw, extending almost to distal tip of premaxilla, irregular inner rows of small caniniform teeth but no inner enlarged row. Tongue margin round or truncate, gill rakers on first arch = (mean = 17.5, n = 6, gill rakers of holotype damaged, no value included). Anterior nasal opening a medium narrow tube, posterior nasal opening a large pore with a raised rim; nasal openings may or may not be located on a raised oval sac. Bony interorbital width 1/4 1/3 pupil width, with a moderate to deep (steep-sided) interorbital trench; postorbital trench generally absent or slightly-developed (occasionally moderate to welldeveloped). Colour in life: (from two digital images of freshly-collected material from Canton Is. Phoenix Group Fig. 8). Freshly-collected specimens have a ground colour of white with eight reddish brown, evenly-spaced saddles of similar size over the dorsal midline. The first saddle is anterior to the dorsal fin, saddles 2-4 occur at the bases of the first and second dorsal fins, and saddles 5-7 occur over the caudal peduncle (with the seventh saddle being at the very posterior portion of the peduncle Fig. 8. Trimma squamicana, freshly collected, Canton I., Phoenix Group. Photo by G. Allen. Fig. 9.Trimma squamicana, 18.3 mm SL, preserved, Canton I., Phoenix Group, ROM Photo by R. Winterbottom. 15 aqua vol. 9 no

10 Three new species of Trimma (Pisces; Gobiidae) from the central, western and south Pacific and sometimes a little lighter in colour). The posterior five saddles have mirror images on the ventral surface. Scale pockets outlined on the dorsal half of the body. There is a diffuse, rounded, spot on the pectoral base; a diffuse mark on the anterodorsal region of the opercle, and a somewhat elongate, horizontal blotch on the shoulder above the opercle these markings are dark reddish brown in colour. Median fins appear to be hyaline but the low resolution of the images may obscure any colour pattern in paired fins Colour in alcohol: background colour straw yellow with a sprinkling of chromatophores (Fig. 9). A diffuse band of chromatophores (orbit width) crosses the dorsum just behind the eyes in the epidermis, and another such band beneath it on the medial surface of the frontal bones. A diffuse, 1/3 pupil-sized, dark, elongate spot is present just at and above the upper posterior corner of the opercle and there is a large, dark, very diffuse spot ( 1 / 2 to pupil size) on the pectoral base (Fig. 5 B). Seven pupil-sized saddles are present over the dorsal midline. The first saddle is found anterior to the first dorsal fin, vertically in line with the spot above the operculum. The second saddle is centred between the second and fourth fin spines and the third saddle is centred on the sixth spines of the first dorsal fin. The fourth and fifth saddles are centred on the second and sixth elements of the second dorsal fin respectively. The sixth and seventh saddles cross the caudal peduncle. The location of each saddle may vary by one or two fin elements. Saddles are generally similar in size and evenly-spaced. Smaller specimens (less than 20 mm SL) have a more distinct and complex pattern, with two additional spots, one on the anterior portion of the opercle and one just above the upper anterior corner of the opercle. An additional saddle or band may be present at the top of the head, one pupil width behind the eye or this feature may appear as two separate spots on either side of the dorsal midline. Saddles may also occasionally be present on the ventral surface on the posterior half of the fish, mirroring the last four saddles on the dorsal surface, or a well-developed line of chromatophores may be present along the ventral midline. Numerous melanophores are present in the interradial membranes of the dorsal, caudal and anal fins. A few melanophores are present at the tips of the pelvic fin rays; the pectoral fins are hyaline. Scattered melanophores and chromatophores are present on the cheek. Comparisons Dark saddles on a straw yellow background, a moderately-developed interorbital trench and a scaled nape distinguish Trimma squamicana from other species of the genus when preserved. Trimma anaima is a small straw-coloured species with tiny dark saddles across the dorsum, has no scales on the nape, and no interorbital trench. If there is very little colouration on the specimen of Trimma squamicana, it can be distinguished from T. taylori and T. winchi by the narrower interorbital width and moderately-developed interorbital trench. This species has been informally referred to as Trimma RW sp 43. Etymology A compound name derived from squamus, a scale, and the specific name of candy cane pygmy goby described above, in allusion to the red and white body and scaled nape of the new species. Treated as a noun in apposition. Distribution Trimma squamicana has been found only at the Kiribati Republic, Phoenix Is., and was collected at depths of m. Acknowledgements As always, it is my pleasure to thank my research assistant, Margaret Zur, for the data gathering and preliminary draft of the material presented in this paper. Many thanks, too, to my many companions and co-collectors of the extensive ROM Trimma material. Special appreciation to Gerry Allen for alerting me to the Phoenix Islands collections and sending me his images of the local Trimma species, and to Karsten Hartel (MCZ) for his generosity in making those specimens so freely available to me and to the ROM collections. Bill Eschmeyer (CAS) offered much- appreciated advice on the formation of the specific names. Fieldwork was facilitated through grants from the ROM Foundation and Department of Museum Volunteers, the CBCB, and a National Science and Engineering Research Council of Canada Grant OGP to the author. This paper represents Contribution No. 319 of the Centre for Biodiversity and Conservation Biology of the Royal Ontario Museum (ROM) to the biological sciences. References Allen, G., Steene, R., Humann, P. & N. DeLoach Reef Fish Identification. Tropical Pacific. New World Publs., Jacksonville, Fla. 457 pp. Lieske, E. & R. Myers Collins Pocket Guide. Coral Reef Fishes. Indo-Pacific & Caribbean. Harper Collins Publ., New York. 400 pp. Saruwatari, T., Lopez, J. A. & T. W. Pietsch Cyanine blue: a versatile and harmless stain for specimen observation. Copeia, 1997 (4): Winterbottom, R Two new species of Trimma (Gobiidae) from the central, western and south Pacific. aqua, Journal of Ichthyology and Aquatic Biology, 5 (2): aqua vol. 9 no