Lophotus cristatus, Bonelli, 1820

Angulo, Arturo & López-Sánchez, Myrna I., 2017, New records of lampriform fishes (Teleostei: Lampriformes) from the Pacific coast of lower Central America, with comments on the diversity, taxonomy and distribution of the Lampriformes in the eastern Pacific Ocean, Zootaxa 4236 (3), pp. 573-591 : 584-586

Zu cristatus (Bonelli, 1820) — TRACHIPTERIDAE

Scalloped ribbonfish (En); Listoncillo festón (Sp) ( Figure 4 , Tables 1 and 5 )

Material examined. 1 specimen ( UCR 2058.001 ); juvenile, 203 mm TL, 184 mm SL, collected 35 Km off of Punta Zapotal, Golfo de Papagayo, Guanacaste, Costa Rica, eastern Pacific Ocean , 10° 40' 15.91" N, 85° 58' 48.08" W, on 20 July 1988, by Frank Cedeño on board of the Nisshin Maru vessel, with bottom trawl, at a depth of 316– 322 m .

Diagnostic characters. A member of Trachipteridae in congruence with the diagnostic characters listed for the family in Heemstra & Kannemeyer (1984, 1986b), Bauchot (1995), Olney (2003d) and Nelson (2006). Generic and specific diagnostic characters are listed below, all in accordance with descriptions of specimens by Tortonese (1958), Fitch (1964), Roig & Demestre (1982), Heemstra & Kannemeyer (1984), Charter & Moser (1996a), Bianco et al. (2006), Psomadakis et al. (2007) and Kweon (2009).

Ventral portion of tail covered by spiny plates (vs. smooth, not covered by spiny plates in species of Desmodema ); caudal fin divided in two lobes (vs. not divided in two lobes in species of Desmodema ); dorsal-fin rays 121 (vs. usually 145–185 in species of Trachipterus ); lateral line as a zigzag series of elongate spiny plates (vs. straight, usually as a series of oval spiny plates in species of Trachipterus ); ventral edge of body scalloped (vs. straight in species of Trachipterus ) and without bony tubercles (with bony tubercles in species of Trachipterus ); eye length about 13% of snout-vent length (vs. 9–10% in Z. elongatus Heemstra & Kannemeyer, 1984 ); maximum body depth 19% of SL (vs. 9–10% in Z. elongatus ); lateral line plates about 100 (vs. 126–130 in Z. elongatus ).

Description. Measurements and counts, as well as comparative data, are presented in Table 5 . Body elongate, ribbon-like, compressed, covered with small, very deciduous, thin, cycloid scales (most body scales are missing, but the scale pockets are distinct; a few scales were left on the anterior portion of the body and the tail, mainly near the lateral line). Dorsal profile almost vertical on head and curved on back, becoming straight along the tail; ventral profile scalloped between the pelvic-fin bases and the beginning of the tail, being straight from there to the caudal fin; tail thin and relatively long. Maximum body depth just posterior to pelvic-fin base.

Head length about 36% of snout-vent length; snout length about equal to eye diameter; end of maxilla anterior to center of the orbit. Dorsal-fin origin posterior to middle of the orbit; first dorsal-fin rays short, not elongated, subsequent rays longer, with the maximum height of fin over and behind the anus; pectoral fins low, their origin anterior to pelvic-fin origin and their base horizontally oriented, allowing the fin to be nearly vertically oriented when addressed against the body; pelvic fins represented by six rudimentary spiny nubbins; caudal fin divided into two lobes, the upper lobe slightly upturned, with nine rays, the lower lobe represented by a single rudimentary spiny nubbin.

Color in live not recorded. Color in alcohol (see Figure 4 ) light brown, with the median and ventral portions of head, the nuchal region, around and below the pectoral-fin base and the abdomen darker; without well-defined spots or bars on body but a dark streak evident on back along the dorsal-fin base, running out to the caudal-fin base.

Remarks. Prior to Heemstra & Kannemeyer’s (1984) review of the Trachipteridae from South African waters, the genus Zu was considered monotypic. In their review, these authors described Z. elongatus and discussed characteristics regarding to the juvenile and adult life stages in the generic diagnosis for both Z. cristatus and Z. elongatus . Currently Z. elongatus is restricted to the southeastern Atlantic, western Indian and southwestern Pacific Oceans ( Heemstra & Kannemeyer 1984, Froese & Pauly 2016). As noted above, both species (Z. cristatus and Z. elongatus ) can be clearly separated by differences in several meristic and morphometric characters.

Although Z. cristatus has, possibly, a global distribution ( Gaither et al. 2015), in the eastern Pacific Ocean there are no published records between the USA-northern Mexico coasts ( Miller & Lea 1972, Eschmeyer & Herald 1983, Charter & Moser 1996a, d), including the Gulf of California ( Aceves-Medina et al. 2003, Avendaño-Ibarra et al. 2014), and the Peru-Chile coasts ( Pequeño 1989, 2011, Chirichigno & Vélez 1998, Kweon 2009), with the exception of a single report for the Galapagos Islands ( McCosker & Rosenblatt 2010). Our specimen represents, on the basis of Bussing & López (1994, 2005, 2009, 2011), the first documented record of the species in lower Central American (Costa Rican) Pacific waters.

Figures

FIGURE 4. Zu cristatus (Bonelli, 1820), UCR 2058.001, juvenile, 203 mm TL, 184 mm SL, collected off Costa Rica, eastern Pacific Ocean. Scale bar = 10 mm.

Tables

TABLE 5. Measurements anđ counts of Zu cristatus from Costa Rica (UCR 2058.001) anđ comparative literature đata. Measurements not attainable (i. e. structure absent, broken or inconspicuous) or unavailable are representeđ with an en-đash (Q).

Character	UCR 2058.001	Tortonese (1958)	Roig & Demestre (1982)	Heemstra & Kannemeye r (1984)	Charter & Moser (1996a)	Bianco et al. (2006)	Psomadakis et al. (2007)	Kweon (2009)
Morphometrics Total length (mm) Stanđarđ length (mm) Heađ length (mm)	203 184 29	1105 980 160	1115 1000 165	Q 173Q950 Q	Q Q Q	Q 180.0 38.0	1031Q1219 926Q1105 153Q191	Q 645 Q
Heađ length (%SL) Heađ đepth (%SL)	15.8 16.7	16.3 Q	16.5 Q	14.5Q16.9 Q	15.0Q25.0 Q	21.1 22.8	16.5Q17.3 Q	Q Q
Greatest bođy đepth (%SL) Bođy đepth at anus (%SL) Snout to đorsal-fin origin length (%SL)	19.0 12.7 10.2	21.4 Q Q	20.5 Q Q	20.2Q25.8 9.1Q12.9 Q	19.0Q33.0 Q Q	22.8 Q Q	19.7Q21.3 11.7Q12.9 Q	23.8 13.4 Q
Snout to pectoral-fin origin length (%SL) Pectoral fin length (%SL)	14.2 5.6	Q 6.6	Q 7	Q Q	Q 3.0Q13.0	Q Q	Q 6.1Q6.5	Q Q
Pectoral fin base (%SL) Snout to pelvic-fin origin length (%SL) Pelvic fin length (%SL)	1.7 15.8 0.7	Q Q Q	Q Q Q	Q Q Q	Q Q 14.0Q629.0	Q Q Q	Q Q Q	Q Q Q
Pelvic fin base (%SL) Snout to vent length (%SL)	1.7 44.3	Q 47.4	Q 45	Q 41.0Q47.5	Q 47.0Q62.0	Q Q	Q 44.8Q50.1	Q 41.2
Snout length (%HL) Maxillary length (%HL) Maxillary đepth (%HL)	35.3 36.9 23.2	34.4 Q Q	33.3 Q Q	Q Q 19.9Q24.3	15.0Q31.0 Q Q	Q Q Q	29.4Q32.5 Q 21.5Q24.1	Q Q Q
Orbit điameter (%HL) Post-orbital heađ length (%HL)	35.8 47.4	35.6 Q	Q Q	35.0Q42.9 Q	27.0Q46.0 Q	5.6	34.6Q35.6 Q	Q Q
Meristics Dorsal-fin elements Pectoral-fin elements	121 10	125 10	117 11	120Q150 10Q12	120Q150 10Q12	120 12	125Q130 10Q11	130 11
Pelvic-fin elements Cauđal-fin elements (upper+lower lobes) Gill-rakers on first gill arch (epibranchial+ceratobranchial)	6 9+1 3+9	Q 9+1 2+9	Q 9+4 2+8	5Q7 6Q12+1Q5 2Q3+8Q9	3Q7 Q 2Q3+8Q9	9 Q 3+8	Q 9 3+7Q8	6 9+2 3+8