Elacatinus lobeli, Randall, John E. & Colin, Patrick L., 2009

Randall, John E. & Colin, Patrick L., 2009, Elacatinus lobeli, a new cleaning goby from Belize and Honduras, Zootaxa 2173, pp. 31-40 : 32-40

Elacatinus lobeli , new species

( Figs. 1–8 ; Tables 1–3)

Gobiosoma oceanops (in part) Böhlke & Robins, 1968: 101 -102 ( British Honduras).

Gobiosoma oceanops (in part) Colin, 1975: 24, fig. E ( Belize).

Gobiosoma oceanops (non Jordan) Randall, 1996: 312, fig. 388 ( Belize).

Gobiosoma (Elacatinus) evelynae (non Böhlke & Robins) Greenfield & Johnson, 1999: 254 ( Belize and Honduras).

Gobiosoma oceanops (non Jordan) Humann & Deloach, 2002: 263, upper fig. (Key Largo, Florida locality corrected to Roatan, Honduras).

Type series: Holotype: USNM 365030, male, 31.0 mm, Belize, Pelican Cays, North Elbow Cay, 16°42’N, 88°10’W, east side, patch reefs on sand bottom, coral heads nearly to surface, 2.4 m, rotenone, J.C. Tyler & W.P. Davis, 31 January 2001. Paratypes: UF 209469, 4: 10.0- 18.6 mm, Belize, Lighthouse Reef, 0.25 miles west of Halfmoon Cay, W.A. Starck, 1 July 1961; UF 231141, 28.9 mm, Belize, Queen’s Cay, P.L. Colin, 26 October 1972; UF 231403, 18.2 mm, Belize, Tobacco Reef, P.L. Colin, 28 October 1972; USNM 274918, 21.6 mm, Belize, Carrie Bow Cay, spur and groove buttress, 6.5–7.5 m, B. Kensley and P. Hutchings, 10 June 1981; USNM 276146, 18.5 mm, Belize, Carrie Bow Cay, east side, coral reef, spur and groove with coral heads, 10–12 m, 10 November 1984; BPBM 40975, 12: 9.5–20.5 mm, Honduras, Islas de la Bahía, Roatan, south coast, off CocoView Resort, coral heads, 10 m, quinaldine, P.L. Colin, 5 April 1989; USNM 336451, 2: 21.4–23.3 mm, Belize, Carrie Bow Cay, southwest side, patch reef, mainly sponges and dead coral, 10 m, quinaldine, J.C. Tyler and D. Tyler, 6 March 1995; USNM 347400, 21.5 mm, Belize, Pelican Cays, Cat Cay, southwest end, Agaricia slope and boulder corals, 9–13.5 m, J.C. Tyler, M. Tyler, W. P. Davis & C. L. Smith, 14 October 1997; USNM 365028, 4: 15.3–23.7 mm, Belize, Pelican Cays, Cat Cay, west side, outside of coral wall at entrance to lagoon, 13.5–17 m, rotenone, J.C. Tyler & W.P. Davis, 29 January 2001; USNM 360468 6: 13.5–25.5 mm, Belize, Pelican Cays, Peter Douglas Cay, patch reef, 3 m, rotenone, J.C. Tyler & W.P. Davis, 1 February 2000; USNM 360469, 2: 18.0– 23.3 mm, Belize, Pelican Cays, Lagoon Cays, smaller of the two, southeast side, patch reef on sand bottom, 2.5 m, rotenone, J.C. Tyler & W.P. Davis, 3 February 2000; USNM 360470, 10: 9.5– 25.3 mm, Belize, Pelican Cays, Little Cat Cay, south end, reef slope with coral patches, 13.5–17 m, rotenone, J.C. Tyler & W.P. Davis, 4 February 2000; USNM 365029, 3: 10.5–24.5 mm, Belize, Pelican Cays, Manatee Cay, west side, outside coral wall at entrance to lagoon, 12–17 m, rotenone, J.C. Tyler and W.P. Davis, 29 January 2001; USNM 395055, 22.5 mm, same data as holotype; MNHN 2009-0019, 2: 21.5–21.8 mm, Belize, Wee-Wee Cay, 16°45.860’N, 88°8.631’W, patch reef of mixed coral and sponge on sloping sand substratum, 5 m, hand net, P.S. Lobel, 5 December 2008; BPBM 40974, 2: 18.0– 21.6 mm, same data as preceding.

Comparative material: Elacatinus oceanops: Gulf of Mexico, Florida Middle Ground, south of Apalachee Bay, 28°35’N, 84°16’W, UF 150487, 21 mm; 28°32’N, 84°16’W, UF 73225, 3: 25–37 mm. Dry Tortugas, Loggerhead Key, UF 11837, 11: 14–34 mm. Atlantic Ocean, Florida, Pompano Beach, UF 170924, 4: 26–36 mm; UF 170925, 9: 21–37 mm. Ft. Lauderdale, UF 147297, 4: 30–39 mm. Bache Shoal, 25°28’3”N, 80°9’6”W, UF 228488, 3: 19–36 mm. Margot Fish Shoal, BPBM 15527, 2: 30–41 mm. Florida Keys, Lower Matecumbe Key, UF 203650, 6: 22–31.5 mm. Alligator Reef, 24°50’48”N, 80°37’15”W, UF 219901, 9: 23–29 mm; 24°50’33”N, 80°37’9”W, UF 219392, 7: 17–33 mm. Sombrero Reef, 24°37’39”N, 81°6’42”W, UF 70656, 2: 28–31 mm.

Diagnosis: Dorsal rays VII + I, 10–12 (usually 11); anal rays I,10 (10–11, rarely 11); pectoral rays 15–17 (usually 16); branched caudal rays 10–12 (usually 11); mouth ventral, the snout overhanging; tongue truncate; rostral frenum present; color in alcohol pale yellowish with a black stripe from front of snout, through lower half of eye, across upper part of operculum and dorsal third of pectoral-fin base, broadening along lower side of body, to posterior end of caudal fin; a broad black middorsal stripe on snout, continuing onto postorbital head (where often divided medially), then along base of dorsal fin, joining to a single narrow stripe dorsally on caudal peduncle, and extending submarginally to end of caudal fin; color in life pale gray to white, with black stripes as described; a narrow, pale blue, pale yellow, or white stripe from anterior nostril through dorsal part of eye, continuing as a narrow bright blue stripe within lower part of pale gray stripe on upper side of body, and extending as a narrow blue band into caudal fin.

Description: Dorsal rays VII + I,10 (10–12, usually 11); anal rays I,10–11 (usually 10); dorsal and anal soft rays branched, the last to base; pectoral rays 15 (15–17, usually 16), the uppermost and lowermost unbranched; pelvic rays I,5; pelvic frenum well developed; branched caudal rays 10 (10–12, usually 11); upper and lower procurrent caudal rays 9 (9-10), the posterior three segmented: head and body entirely naked,; gill rakers 1 + 7; vertebrae 28.

The following morphometrics are given as percentages of the standard length: body depth 17.8 (16.6–17.7); body compressed, the width 12.5 (11.0–12.1); head length 27.1 (27.0–27.8); snout length 8.3 (7.6–8.4); orbit diameter 6.5 (6.6–7.7); interorbital width 5.9 (5.5–6.2); caudal-peduncle depth 12.5 (10.4–12.5); caudal-peduncle length 21.2 (21.3–22.7).

Mouth ventral and very slightly oblique, forming an angle of about 5° to horizontal axis of body; maxilla reaching to or slightly posterior to posterior edge of pupil, the upper-jaw length 12.4 (10.9–12.1) %SL; each side of jaws of male holotype with a row of about 15 well-spaced, conical, incurved and retrorse teeth, the sixth tooth from front of jaw twice as large as preceding tooth and more strongly curved; remaining teeth in jars progressively shorter; a strongly recurved canine tooth of about pupil length medial to fifth and sixth teeth of lower jaw; teeth of females smaller and more numerous. close-set, and without the huge canine; tongue broadly bilobed; no rostral frenum, and no mental flap; gill opening short, extending slightly ventral to level of lower edge of pectoral-fin base; gill membranes attached anteriorly to isthmus; gill rakers short, the longest at angle about one-half length of longest gill filaments.

Anterior nostril tubular, at edge of snout above upper lip, in line with ventral edge of orbit; posterior nostril an elliptical aperture with a fleshy rim, a nostril diameter anterior to eye at level of ventral edge of pupil; eight cephalic sensory pores as diagrammed by Lachner & Karnella (1980: fig. 4a); cephalic sensory papillae essentially the same as described for Elacatinus colini by Randall & Lobel (2009), but more obscure.

Origin of first dorsal fin above rear base of pelvic fins, the predorsal length 34.8 (33.4–34.5) %SL; dorsal and anal spines slender and flexible; third or fourth dorsal spines longest, 16.2 (l5.8–16.6); last membrane of first dorsal fin reaching origin of second dorsal fin (not in holotype due to apparent healed injury); spine of second dorsal fin 11.3 (11.1–12.6); middle to penultimate dorsal soft rays subequal, the longest, 17.9 (17.8–18.5); origin of anal fin slightly posterior to base of first dorsal soft ray, the preanal length 54.8 (54.3–58.7); anal spine 11.3 (10.0–11.1); penultimate anal soft ray usually longest 16.2 (15.8–16.7); caudal fin rounded, 21.5 (20.8–23.1); base of pectoral fins directly posterior to and slightly shorter than gill opening; eighth pectoral ray usually longest, nearly reaching a verticals at anus, 22.8 (22.7–25.3); origin of pelvic fins slightly posterior to rear base of pectoral fins, the prepelvic length 28.6 (26.8–28.7); pelvic fins joined to a near-circular disk, the disk length, 16.4 (16.6–17.6); genital papilla of male, narrowly triangular in ventral view, equal to pupil diameter in holotype.

Color of holotype in alcohol: pale yellowish with a black stripe from front of snout, through lower half of eye, across upper part of operculum and dorsal third of pectoral-fin base, broadening along lower side of body and extending to posterior end of caudal fin; a broad black middorsal stripe on snout, continuing onto postorbital head (where often divided medially), then along base of dorsal fin, joining to a single narrow stripe dorsally on caudal peduncle, and extending submarginally to end of caudal fin.

Color in life of holotype not recorded. Color of the species in life as shown in Figs. 2–8 .

Etymology: We are pleased to name this goby in honor of Dr. Phillip S. Lobel of Boston University, who provided specimens, photographs, and biological data.

Remarks: As mentioned, Elacatinus lobeli has long been identified as E. oceanops Jordan. The genetic difference published by Taylor & Hellberg (2006: 705) prompted us to make a more careful comparison of specimens from the two populations. The most obvious difference is the larger average and maximum size of E. oceanops . Of 50 lots of this species from Florida waters listed by Böhlke & Robins (1968: 102), 19 contain specimens longer than 30 mm SL. The largest specimen, BPBM 15527, 41.0 mm SL, was collected in the Florida Keys. Of 25 lots of specimens of E. lobeli examined, only the holotype, 31 mm SL, is over 30 mm. The next-largest specimen measures 28.9 mm SL. The specimens of nine USNM lots of E. lobeli are too small for accurate meristic and morphometric data. They are not included as types.

Two meristic differences were found. E. lobeli has 15–17 pectoral rays, with a strong mode at 16, compared to 16–18, modally 17, for E. oceanops (Table 2). Better separation was obtained from counts of the branched caudal rays, 10–12 for E. lobeli , compared to 12–14 for E. oceanops ( Table 3). Note the few individuals with the shared count of 12 branched rays.

TABLE 2. Pectoral-ray counts1 of two species of Elacatinus .

Number of rays 15 16 17 18 E. lobeli 14 31 13

E. oceanops 38 48 2

1Counts of pectoral rays were made on both sides of specimens, including types and nontypes.

Number of rays 10 11 12 13 14 E . lobeli 3 27 2

E. oceanops 4 43 3 We also found a difference in the length of the pelvic disk. The pelvic-disk length of 12 specimens of E. lobeli , 21.0–31.0 mm in SL, ranged from 16.4–17.8% SL (=17.1%), compared to 15.1–16.0 % SL (=15.6%) for 12 specimens of E. oceanops , 21.6–32.0 mm SL.

Elacatinus lobeli is presently known only from Belize and the islands of Utila ( Fig. 6 ), and Roatan (BPBM 40975), Islas de la Bahía, Honduras, hence well-separated from E. oceanops , which appears to be restricted to Florida ( Fig. 8 ). The record of E. oceanops from Yucatan by Böhlke & Robins (1968: 103) is an error: UMML 9271, now UF 239271, 16.5 mm, was collected at Long Cay, Lighthouse Reef, Belize by Walter A. Starck on 3 July 1961.

Greenfield & Johnson (1999: 254) reported the cleaning goby Gobiosoma (Elacatinus) evelynae (Böhlke & Robins) as the tenth most common goby on patch reefs and the spur-and-groove habitat in Belize and Honduras. They gave the depth range as 1.2–27.1 m. The second author examined their specimens at the Field Museum of Natural History and re-identified them as Elacatinus lobeli . We have not collected or observed Elacatinus evelynae in Belize or Honduras.

Elacatinus lobeli is often seen at rest on live coral. Figs. 2–5 portray individuals on four different corals. We selected these images also to show the variation of the color of the narrow pale stripe on the snout and upper part of the eye.

Like Elacatinus oceanops , E. lobeli may be observed in symbiotic association with other fishes by removing ectoparasites. Phillip S. Lobel provided us with a list of 39 species of fishes, representing 14 families, that have been observed to receive the services of E. lobeli in Belize. We illustrate this goby in action on the grouper Epinephelus striatus ( Fig. 7 ) and the moray eel Gymnothorax funebris ( Fig. 8 ). The digestive tracts of four paratypes of E. lobeli were dissected for food material. One fish had eaten 11 larval gnathiid isopods up to 1.5 mm in length, one contained a single larval isopod, and the other two were essentially empty.

In addition to the four corals shown in our illustrations, we found the following species that served as sites for the goby cleaning stations: Diploria strigosa , D. labyrinthiformis , Siderastrea sidera , and Stephanocenia michilini. Usually there was more than a single goby at a cleaning station, generally two or three, but one colony of Diplora strigosa had six.

The frequency of visitation by different reef fishes to a cleaning station was the objective of a student project supervised by Lobel at Wee Wee Cay, Belize. Of the 15 species recorded, the most frequent visitor was Lutjanus apodus with 20 visits, followed by Haemulon carbonarium with 17, Acanthurus bahianus with 10, Haemulon chrysargyreum with eight, Sparisoma rubripinne with six, Mycteroperca venenosa with four, and Ocyurus chrysurus with two.

Sazima et al. (2000) found a total of 34 client fish species of the barber goby Elacatinus figaro off southeastern Brazil, representing 16 families. In contrast to the clients of E. lobeli , the most frequent visitors of E. figaro stations were pomacentrids (37.9% of the cleaning events), followed by haemulids.

Another student project in Belize recorded the time of visitation by client fishes. As might be expected from its much larger size, Mycteroperca venenosa had the longest visit, 4 minutes, 10 seconds; the nextlongest was Sparisoma rubripinne with 39 seconds.

A third study determined that visits to a cleaning station were 2.2 times more frequent at dawn than midday, and 2.9 times more frequent at dusk than midday.

The holotype and largest specimen is a male. The ovary of a 24-mm female paratype contained 186 ova, 0.7 mm in greatest dimension. The ova had slightly flattened surfaces from being juxtaposed in the ovary.

Elacatinus lobeli has a bitter-tasting skin mucus, as has been detected for other species of the genus, but it is not as repelling as the mucus of the sympatric sponge-dwelling species, E. colini ( Randall & Lobel, 2009) .

Figures

FIGURE 1. Holotype of Elacatinus lobeli, USNM 364030, male, 31 mm, Pelican Cays, Belize (photograph by J. E. Randall).

FIGURE 2. A pair of Elacatinus lobeli on the coral Agaricia sp., Belize (photograph by J. E. Randall).

FIGURE 3. Elacatinus lobeli on the coral Monastrea annularis, Belize (photograph by P. S. Lobel).

FIGURE 4. A juvenile of Elacatinus lobeli on the coral Monastrea cavernosa, Turneffe Reef, Belize (photograph by J. E. Randall).

FIGURE 5. Elacatinus lobeli on the coral Colpophyllia natans, Belize (photograph by J. E. Randall).

FIGURE 6. Elacatinus lobeli on the coral Monastrea cavernosa, Isla Utila, Honduras (photograph by R. F. Myers).

FIGURE 7. Five individuals of Elacatinus lobeli cleaning Epinephelus striatus, Belize (photograph by J. E. Randall).

FIGURE 8. Three individuals of Elacatins lobeli cleaning Gymnothorax funebris, Belize (photograph by J. E. Randall).