Geophagus crocatus, Hauser, Frances E. & López-Fernández, Hernán, 2013

Hauser, Frances E. & López-Fernández, Hernán, 2013, Geophagus crocatus, a new species of geophagine cichlid from the Berbice River, Guyana, South America (Teleostei: Cichlidae), Zootaxa 3731 (2), pp. 279-286 : 280-284

Geophagus crocatus , new species

Fig. 1–5 , Table 1

Holotype. UG/CSBD 1656 (Ex ROM 87106), 1, 165.6 mm SL; Guyana: East Berbice: Berbice River, about 14 air km upstream of Kwakwani at Mappa Lagoon camp (5.17456°N 58.16336°W); H. López-Fernández, D. Taphorn, D. Bloom, J. Maldonado, C. Bernard and E. Holm, 20 March 2010.

Paratypes. All from Guyana: East Berbice: Berbice River: ROM 86834, 8, 50.8–76.5 mm SL (2 measured); Marlissa Falls in the rapids (4.90680°N 58.24471°W); D. Taphorn, D. Bloom, J. Maldonado and E. Holm, 24 March 2010.—ROM 86854, 26, 64.7–76.4 mm SL (5 measured); Berbice River, upstream of Kwakwani (4.90680°N 58.24471°W); D. Bloom, D. Taphorn, E. Holm and F. Gonzalez, 1 April 2010.—ROM 86918, 57, 47.6–109.3 mm SL (24 measured); Guyana: East Berbice: Berbice River, above and below Itabru Falls and in quiet lake-like expansions below the falls (4.85843°N 58.24087°W); H. López-Fernández, D. Taphorn, D. Bloom, J. Maldonado, C. Bernard and E. Holm, 23 March 2010.—ROM 86957, 48, 63.3–166.1 mm SL (10 measured); Guyana: East Berbice: Berbice River, downstream end of the town of Kwakwani near Hubert Gonzales property (5.27544°N 58.07370°W); E. Holm, D. Bloom and D Taphorn, 30 March 2010.—ROM 87290, 1, 103.0 mm SL; Guyana: East Berbice: Berbice River, just upstream of Kwakwani (5.24844°N 58.08754°W); D. Bloom, D. Taphorn, E. Holm and F. Gonzalez, 1 April 2010.

Diagnosis. Geophagus crocatus is distinguished from G. grammepareius Kullander & Taphorn, G. taeniopareius Kullander & Royero, G. argyrostictus Kullander, G. gottwaldi schindler & Staeck,and G. h ar re r i by the presence of an incomplete suborbital stripe (vs. complete). Geophagus crocatus can be further distinguished from G. abalios López-Fernández & Taphorn, G. brokopondo, G. surinamensis , G megasema Heckel, G camopiensis, G. altifrons (Heckel) , G. parnaibae Staeck & Schindler, G. sveni Lucinda, Lucena & Assis, and G. neambi Lucinda, Lucena & Assis , by the presence of an incomplete suborbital stripe formed by a preopercular black mark (vs. absent). Additionally, the lateral bar pattern of Geophagus crocatus distinguishes this species from all other species of Geophagus . The bar pattern is formed by 6 vertical bars on the flank, with bars 2 and 3 uniquely fused dorsally at the base of the spiny dorsal fin between spines 9 and 10 ( Fig. 1 ). Geophagus crocatus differs from all species in the G. surinamensis complex with incomplete suborbital markings by the presence of 6 lateral bars (vs. absent in G. proximus (Castelnau) and G. brachybranchus , 4 bars in G. winemilleri López-Fernández & Taphorn , and 7 bars in G. dicrozoster López-Fernández & Taphorn.

Description. Based on holotype (165.6 mm SL, Fig. 1 ) and 42 paratypes (47.5–166.1 mm SL), with notes on variation among smaller specimens. Measurements and counts are summarized in Table 1 . No apparent external sexual dimorphism.

Shape. Moderately elongate; dorsal outline more convex than ventral outline; head broader ventrally than dorsally, chest flat; specimens 65.0 mm SL and smaller more elongate. Dorsal head profile moderately convex, ascending to dorsal-fin origin, except in front of orbit where slightly concave, in specimens smaller than 65.4 mm SL, straight from orbit to dorsal-fin origin; dorsal-fin base descending, slightly convex to last ray, then forming a horizontal, moderately concave line to caudal-fin insertion. Ventral head profile straight, slightly descending to pelvic-fin insertion; straight, horizontal from pelvic-fin insertion to origin of anal fin; anal-fin base slightly convex, ascending; ventral caudal peduncle moderately concave, slightly ascending. Lips moderately wide, lower without caudally expanded fold (see Kullander et al., 1992, Fig. 3 ). Maxilla reaching 1/3–2/3 of the distance between nostril and orbit; ascending premaxillary process reaching slightly above midline of orbit. Opercle, preopercle, cleithrum, postcleithrum, and post-temporal lacking serration.

Scales. E1 32(33), 33(10); scales between upper lateral line and dorsal fin 6.5–7.5 anteriorly, 2.5–3.5 posteriorly. Two scale rows between lateral lines. Scales on upper lateral line 20(2), 21(5), 22(20), 23(15), 24(1) and lower lateral line 10(1), 12(2), 13(5), 14(7), 15(23), 16(3), 17(2). Scales between upper lateral line and dorsal fin 5.5–7.5 anteriorly, 2.5 posteriorly. Anterior half of cheek naked, remainder with ctenoid scales; cheek scale rows 8–9. Operculum and sub-operculum covered with ctenoid scales. Interopercle with cycloid scales caudally.

Single postorbital column of ctenoid scales. Occipital and flank scales ctenoid. Circumpeduncular scale rows 7 above upper, 7 below lower lateral line, ctenoid.

Fin scales. Anal, pectoral and pelvic fins naked. Dorsal fin scaled on spinous and soft portions, scales ctenoid, and arranged in double or triple columns along interradial membranes up to one third to one half of fin height. Scaly pad at base of dorsal fin formed by irregularly arranged small, ctenoid scales extending from first spine to fifth to seventh soft ray. Anal fin scaled on anterior section of soft portion, scales ctenoid, arranged in a single column along interradial membranes to one quarter to one third of fin height. Caudal fin scaled along its entire surface, except for the tip of rays, and part of membranes between D3 and V3, scales ctenoid. Accessory caudal fin extension of lateral line between V4 and V5, absent on dorsal lobe.

Fins. Dorsal XVII,11(7), XVII,12(36); anal III,7(41), III-8 (2). Dorsal-fin spines increasing in length from first to sixth, equal in length to ninth, then slightly shorter; loose membranes behind spine tips pointed, up to 1/3 length of spines. Soft portion expanded and pointed, reaching 1/3 of caudal-fin length, rays 4–6 longest but not produced into filaments; in specimens 62.4 mm SL and smaller dorsal fin not reaching caudal-fin insertion. Anal fin round, moderately pointed in largest specimens, with rays 2–5 longest, not reaching caudal fin or barely beyond its base in largest specimens. Caudal fin emarginate with lobes of approximately the same length and without filaments; specimens 55.6 mm SL or less with slightly or not produced rays, reaching at most 1st anal-fin spine.

Teeth. Outer row of upper jaw with 12–26 approximately cylindrical, frequently blunt, slightly recurved, unicuspid teeth; larger than in inner rows, extending along most of premaxillary length; 3–4 inner rows, separated by a clear gap from outer row; teeth on inner row thin, slightly recurved, unicuspid. Outer row of lower jaw with 6–23 blunt, slightly recurved, unicuspid teeth; inner rows 6, separated from outer row by distinct gap; teeth thin, slightly recurved, unicuspid.

Gills. External rakers on first gill arch: 7(2), 8(10), 9(27), 10(4) on epibranchial lobe, 1 in angle and 10(3), 11(35), 12(5) on ceratobranchial, none on hypobranchial. Gill filaments with narrow basal skin cover.

Tooth plates. Lower pharyngeal tooth plate elongate ( Fig. 2 ); width of bone 83% of length; dentigerious area 83% of width; 28 teeth in posterior row, 10 in median row. Anteriormost teeth subconical, laterally compressed and erect, teeth thinner and more laterally compressed towards caudal edge of plate, posteromedial teeth much larger, almost cylindrical, cusps posterior, almost blunt. Ceratobranchial 4 with 6 toothplates with between 3 and 11 unicuspid teeth.

Vertebrae. 14+18=32(6), 15+18=33(2), 15+17=32(1); 9–11 epihemal ribs.

Color pattern in alcohol (Figs. 1,3). Background colour grayish yellow; nape, snout and upper lip darker gray, scaled portion of cheek lighter; lower lip yellowish white. Opercle darker on dorsal third, with faint, black to dark gray, vertical preopercular mark; lower half of opercle and subopercle dusky yellow. Ventrally, gill cover dusky yellow or yellowish white in some specimens; branchiostegal membrane also grayish-white. Chest yellow laterally and ventrally, white in specimens less than 55.4 mm SL. Juveniles with silvery-white chest region. chest region. A broad, faint supraorbital bar extends dorsally above the posterior half of orbit. Flanks with 6, dorsoventrally directed, dark-gray bars fading or disappearing ventrally ( Fig. 3 ). Bar 1 expands from the 7th–8th predorsal scale to the base of the 5th dorsal-fin spine forming an inverted triangle, anterior edge roughly delimited by the extrascapular and posterior edge descending ventrally to pectoral-fin insertion. Bar 2 extends between base of dorsal-fin spines 6–7 and 9 and runs vertically to H4–5. Bar 3 slightly caudally oriented, originates between the base of dorsal fin spines 11–12 and 12–13, descends ventrally and fades progressively to H5–6. Bar 3 appears to fuse dorsally with bar 2, forming a bridge with a thickness of 1–1.5 scale widths from E5–E6 (Figs. 3,4). A welldemarked, black medial spot is located on bar 3, extending rostro-caudally between scales 11 and 14–15 of E3 and dorsoventrally between the lower half of E4 and E2, such that the upper lateral line traverses the dorsal 1/4 –1/3 of the spot. Bar 4 extends between the bases of dorsal-fin spines 14–15 to 16, and descends ventro-caudally to H1. Bar 5 extends between the base of dorsal-fin spine 16 and ray 1 or rays 1–2 and rays 4–5, descends vertically fading at H1. Bar 6 extends caudally from the third postdorsal scale to just anterior to caudal peduncle edge, descends vertically and fades at H1–2.

Dorsal fin dusky, lappets dark gray or blackish, forming a dark edge along fin; soft portion white-spotted on inter-radial membranes; in specimens 44.0 mm SL or smaller three dusky longitudinal, parallel stripes alternate with light stripes along soft portion of dorsal fin. Anal fin hyaline to slightly dusky; largest specimen with dark gray lappets. Caudal fin gray-brown, with whitish longitudinal bands of variable length and elongate spots, forming no evident pattern; specimens up to 65.0 mm SL with 4 dark, vertical bands that gradually turn into the pattern described above with increasing size. Pectoral fin immaculate. Pelvic fin dusky, darker distally.

Live colors (Figs. 3,4). Melanic markings as in alcohol specimens. Background color yellowish grey. Five to seven faint, iridescent blue bands alternating with olive green along body, but not always distinct. Head without markings except for iridescent blue on ventral portion of preopercule; gill cover yellow. Dorsal fin reddish with faint iridescent blue spots, especially on soft portion; some specimens with tips of spiny portion black; pelvic fin dusky except for white distal portion of first ray; in smaller specimens bright yellow; anal fin reddish with three iridescent blue stripes; caudal fin reddish with a variable pattern of iridescent blue stripes and spots.

Distribution and habitat ( Fig. 5 ). Geophagus crocatus was collected in the Berbice River, above and below the rapids at Itabru Falls. The Berbice is a black water river running through thick gallery forests. Geophagus crocatus was most abundant in areas of sluggish water with sandy bottoms with relatively little forest cover. Geophagus crocatus was collected in waters with low conductivity (2–39 µS), temperature 25–33°C, and low to neutral pH (4.1–7.1). Secchi depth was 0.7–1 m, velocity 0.1–0.3 m /s, and dissolved oxygen 5.1–6.7 mg /l.

Etymology. From the Latin adjective crocatus , saffron yellow. Given in reference to the yellow operculum on live specimens.

Figures

FIGURE 1. Geophagus crocatus. Holotype. UG / CSBD 1656 (Ex ROM 87106), 165.6 mm SL; Guyana: East Berbice: Berbice River (5.17456 ° N 58.16336 ° W).

FIGURE 2. Lower pharyngeal toothplate; from ROM 86918 117.0 mm SL.

FIGURE 3. Diagrammatic representation of the lateral bars distinguishing Geophagus crocatus.

FIGURE 4. Geophagus crocatus, ROM 86918, 91.2 mm SL, Berbice River, above and below Itabru falls and in quiet lake-like expansions below the falls.

FIGURE 5. Collecting sites of Geophagus crocatus in the Berbice drainage in Guyana. One dot may represent more than one collection locality. The open circle represents the type locality.

Tables

TABLE 1. Morphometrics of Geophagus crocatus.

	Holotype	n Mean	Min	Max	Stdev
SL (mm)	165.6	42 80.6	47.6	166.1	26.8
Percent SL
Head length	35.2	42 34.2	28.9	37.3	1.8
Body depth	41.9	42 37.8	33.0	43.9	2.4
Caudal peduncle depth	12.4	42 11.7	10.5	12.8	0.6
Caudal peduncle length	14.1	42 17.0	13.7	20.0	1.4
Pectoral fin length	33.9	42 32.5	28.1	38.0	2.3
Pelvic fin length	49.5	42 33.4	15.4	51.3	6.8
Last dorsal spine length	16.5	42 14.6	11.6	18.9	1.6
Snouth length	20.8	42 17.1	11.9	20.8	2.2
Orbital diameter	8.2	42 9.5	8.2	11.1	0.7
Head width	12.6	42 11.9	9.8	13.7	1.1
Interorbital width	9.5	42 7.8	6.5	11.6	1.0
Preorbital depth	14.1	42 11.1	8.7	15.6	1.6
Percent HL
Snout length	59.1	42 50.1	36.9	64.4	6.2
Orbital diameter	23.2	42 27.9	23.2	35.0	2.4
Head width	35.8	42 35.0	27.3	43.7	3.9
Interorbital width	27.1	42 22.9	19.0	33.6	3.1
Preorbital depth	40.1	42 32.5	23.6	46.7	4.6