Albula gilberti Pfeiler

Pfeiler, Edward, Van, Albert M., Heiden, Der, Ruboyianes, Ryan S. & Watts, Tom, 2011, Albula gilberti, a new species of bonefish (Albuliformes: Albulidae) from the eastern Pacific, and a description of adults of the parapatric A. esuncula, Zootaxa 3088, pp. 1-14 : 6-8

Albula gilberti Pfeiler & van der Heiden, new species

Cortez Bonefish

Figure 1 A, Tables 2, 3

Albula vulpes (not of Linnaeus): Jordan, 1905:147 (fig. 112); Gill, 1907 (same figure as in Jordan, 1905); Thompson, 1919; Delsman, 1926; Fitch, 1950; Frizzell, 1965; Lavenberg and Fitch, 1966:98; Castro-Aguirre et al., 1970; Fitch and Lavenberg, 1971; Miller and Lea, 1972:52; Goodson, 1988:144; Morales-Nin, 1994:213; Lea and Rosenblatt, 2000:119.

Albula neoguinaica (not of Valenciennes): Allen and Robertson, 1994:41; Castro-Aguirre et al., 1999:93.

Albula esuncula (not of Garman): Robertson and Allen, 2008.

Albula sp.: Pfeiler, 1981, 1987; Pfeiler et al., 1988; van der Heiden and Findley, 1990:213; Pfeiler, 1996, 1997; Pfeiler et al., 1998, 2000.

Albula sp. A: Colborn et al., 2001; Pfeiler et al., 2002; Bowen et al., 2008; Pfeiler et al., 2008a,b( Fig. 1 a).

The above studies examined specimens, either in whole or in part, of different life history stages of what we recognize here as A. gilberti based on sampling locations (Gulf of California, outer Pacific coast of the Baja California peninsula, and coastal southern California) and mitochondrial DNA sequence data ( Albula sp. A, only). In the studies of van der Heiden and Findley (1990) and Morales-Nin (1994), both A. gilberti and A. esuncula (see below) may have been examined given that samples were taken where the two species are sympatric; both citations are included under each species.

Holotype. CNPE-IBUNAM 16880 (ex CIAD 10–03/TB 03.ALG– 36, 194 mm SL), Isla Venados (exposed side) El Playón, Mazatlán, Sinaloa, Mexico, marine, cast net, obtained from local fisherman Hipólito Olague Sifuentes, 31 January 2009.

Paratypes. CNPE-IBUNAM 16881 (ex CIAD 10–03/TB 03.ALG–33, –37, 2[184–187 mm]), same collection data as holotype; CIAD 10–01/TB 01.ALG–29, –30, 2(182–189 mm), Estero de Urías, Mazatlán, Sinaloa, Mexico, cast net, Hipólito Olague Sifuentes, 24 October 2008; CIAD 10–02/TB 02.ALG–31, –32, 2(165–175 mm), nearshore, coast of Mazatlán, Sinaloa, Mexico, marine, cast net, Hipólito Olague Sifuentes, 25–26 October 2008; CIAD 05–3/TB 02.ALG–07 to –11, –13, –16, –18, –20, –21, –23 to –27, 15(185–257 mm), Isla Venados (exposed side) El Playón, Mazatlán, Sinaloa, Mexico, marine, cast net, depth 2 m, Hipólito Olague Sifuentes, 3 July 2005.

Other material examined. CIAD 99–03/TB 03.ALG–1, –3, –5, 3(224–253 mm), Bahía Kino, Sonora, Mexico, marine, shrimp trawler, depth 22–27 m, 18 March 1999; CIAD TB 99–03.ALG–2, –4, –6, same collection data as previous lot; Guaymas, Sonora, Mexico, 5 (193–279 mm), beach seine and trawl, 24 November 1993 and 26 March 1994, no vouchers.

Diagnosis. Distinguished from A. esuncula by diagnostic nucleotide substitutions at 17 different sites in the 544 bp cyt b gene segment ( Table 4 ). The cyt b segment corresponds to nucleotide positions 14502–15045 in the complete mitochondrial genome of Albula glossodonta [GenBank accession no. AP002973 ; phylogenetic evidence suggests that the genome sequenced was actually from A. argentea (= A. forsteri ) and not A. glossodonta ( Pfeiler et al. 2006) ]. In A. gilberti , the pelvic-fin tip may reach the posterior edge of the anus whereas in A. esuncula the tip does not surpass the anterior edge. In A. gilberti , the number of pelvic-fin rays varies from 9 to 12 whereas it is always ten in A. esuncula . Lateral-line scale counts and numbers of rakers on the first gill arch are higher in A. gilberti (68–73 vs. 68–71 and 4–10 vs. 3–8, respectively). Since we examined only four or nine specimens of A. esuncula , according to the characteristic, the diagnostic value of the meristic differences between both species and the position of the pelvic-fin tip should not be considered validated yet and be used with caution.

Description. Meristic and morphometric data are given in Tables 2 and 3. Body fusiform, moderately elongate, slightly compressed; dorsal profile more strongly convex than ventral. Caudal peduncle depth 6.6–8.7% SL, mean 7.5%. Head conical, subquadrangular (26.4–34.5% SL, mean 30.9%); snout bluntly conical, projecting far in advance of mouth (39.6–45.6% HL, mean 42.3%). Eyes with prominent, annular, adipose eyelid (14.9–25.2% HL, mean 19.3%). Interorbital space 20.0–26.6% HL, mean 22.3%. Mouth small, inferior and horizontal; maxilla failing to reach eye by about 50% of horizontal eye diameter. Teeth on premaxillary, anterior portion of maxillary, lower jaw, vomer and palatines villiform. Tooth patches on parasphenoid, mesopterygoids and tongue composed of enlarged, rounded, molariform teeth; patch on parasphenoid elongate, pear-shaped, flanked by curved patches on mesopterygoids noticeably surpassing the parasphenoid patch anteriorly ( Fig. 2 A). Gill rakers on first arch rudimentary, tubercle-like, covered with tiny spines 4–10 + 10–12 (mode on upper limb = 9 [33.3%], 7–9 in 76.7% of specimens; mode on lower limb = 11 [46.7%]; total number of gill rakers on first arch 15–21 (mode = 21 [23.3%], 19–21 in 63.3% of specimens). Fins without spines. Dorsal-fin rays 17–18 (mode = 18 [90.0%]). Anal-fin rays 8–9 (mode = 8 [73.3%]). Dorsal- and anal-fin rays with conspicuous membranous lateral extensions creating a plumelike appearance. Pectoral-fin rays 18–20 (mode = 18 [63.3%], only one with 20 rays). Pelvic-fin rays 9–12 (mode = 10 [80%], only one with 9 and one with 12 rays); tip of pelvic fin not reaching or just reaching anterior edge of vent in 37.5% and 12.5% of specimens, respectively, however, reaching beyond anterior edge in most specimens (50.0%; very rarely to posterior edge in 4.2%). Caudal fin broadly forked, upper lobe slightly longer than lower. Scales on body medium-sized, with frilled membranous border; head naked; back with central row of elongate, membranaceous scales, frilled at posterior edge. Lateral line scales pored (68–73; mode = 71 [32.0%], only one specimen extends lower limit to 68; no specimens with 69 scales).

1 Nucleotide site no. 441 is a first codon position which results in a diagnostic amino acid difference between A. gilberti (leucine) and A. esuncula (isoleucine). The remaining sites are all at third codon positions and the substitutions are synonymous. An additional site (no. 341) is diagnostic for the Gulf of California population of A. gilberti (T) and A. esuncula (C) (Pfeiler et al. 2008a), but is not diagnostic when the southern California population of A. gilberti is included.

Coloration. Color of thawed specimens from Mazatlán, Sinaloa: brilliantly silvery, blue-green to blue-gray above, back and sides with 8 to 11 thin, dark lines between the rows of scales; 7–9 above and 1–3 below the lateral line; in addition, back of smaller specimens with up to 9 dark bands; very thin, black line along lateral line canal. Outer face of basal portion of paired fins, triangular space between lower jaws, gill membrane, and ventral border of operculum lemon-yellow; branchiostegal rays pale. Belly, lower half of dorsal fin, caudal fin, and base of anal fin faint yellowish. Paired fins often with scattered melanophores on inner face, inner face of basal portion lemonyellow to bright orange, most obvious in pectoral fin.

In fresh individuals from Guaymas, Sonora, inner face of basal portion of paired fins also yellowish-orange, with numerous orange spots extending distally along most of the fin rays (the last 3 or 4 posterior rays usually lack these spots). Yellowish color also was noted at the bases of the paired fins in California specimens of A. gilberti ( Fitch & Lavenberg 1971; Miller & Lea 1972).

Color of preserved specimens (alcohol): silvery aspect lost; orange color on inner face of basal portions of paired fins changed to dark brown; lines over back and sides gray to brown; larger specimens with 6 to 8 thin, faint dark lines below lateral line, changing ventralward from between to along rows of scales and most pronounced on posterior half of body; upper margin of dorsal and caudal fins dark, remainder grayish to pale; all other fins grayish to pale.

Remarks. Maximum size in A. gilberti is probably <36 cm SL ( Pfeiler et al. 2000, 2002). The common name, Cortez Bonefish, follows Nelson et al. (2004).

Distribution. Presently known from Mazatlán, Sinaloa throughout the Gulf of California and outer coast of the Baja California peninsula, Mexico to California, USA.

Etymology. Named for the pioneer ichthyologist Charles Henry Gilbert who, in 1889, first recorded the metamorphosis of bonefish leptocephali (see Jordan 1905, and Gill 1907) based on specimens collected in the Gulf of California. Given that Gilbert's fish collections were conducted mainly along the shore and coastal waters of the northern Gulf of California ( Gilbert 1890) it is highly probable that he collected what we recognize here as A. gilberti .

Figures

FIGURE 1. (A) Albula gilberti n. sp., holotype, 194 mm SL, 248 mm TL, CIAD 10 – 03 / TB 03. ALG – 36; (B) Albula esuncula, 194 mm SL, 249 mm TL, CIAD 10 – 03 / TB 03. ALE – 34.

FIGURE 2. Tooth patches in roof of mouth: (A) Albula gilberti n. sp., paratype CIAD 10 – 01 / TB 01. ALG – 30; (B) Albula esuncula, CIAD 10 – 03 / TB 03. ALE – 35. PS, parasphenoid; MP, mesopterygoids. Scale bars = 5 mm.

Tables

TABLE 4. Diagnostic nucleotide sites in the mitochondrial cytochrome b gene fragment in Albula gilberti n. sp. and A. esuncula (from Pfeiler et al. 2008 a).

Cyt b Position1 77 83 110 122	A. gilberti C C C T	A. esuncula T T T C
194 197 224 239 275 293	T C or A G G C T	C T A A T C
311 413 416 431	C T C G	T C T A
441 461 467	C T G	A C A