urn:lsid:zoobank.org:act:5D3D9820-B201-42B3-877D-1559F5394CF0

(Figs. 1-2; Tab. 1)

Bryconops caudomaculatus. -Planquette et al., 1996:266-67 [photos; in part, specimens from Maroni, Mana and Sinnamary rivers, French Guiana]. -Papa et al., 2021:09 [mentioned in fig. 3; photo in BOLD data base].

Holotype. ANSP 207355, 94.5 mm SL. Suriname, Sipalawini, Litanie River at mouth and confluence with Maroni River, just upstream from settlement of Konya Kondre, 03^o17’24”N 54^o04’38”W, 21 Apr 2007, J. Lundberg, M. Sabaj, P. Willink, K. Wan & J. Mol.

Paratypes. All from Suriname. ANSP 188700, 33, 80.7-94.7 mm SL; INPA 59652, 9, 79.5-90.2 mm SL, 1 c&s; NZCS 7099, 5, 80.9-93.5 mm SL; collected with the holotype. ANSP 189282, 1, 37.5 mm SL, Sipalawini, Lawa River, large cataract complex, ca. 8 km south-southwest of Anapaike, 03°19’52”N 54°4’20” W, 21-24 Apr 2007, J. Lundberg, M. Sabaj, P. Willink, K. Wan & J. Mol.

Diagnosis. Bryconops florenceae differs from all congeners by having its caudal-fin coloration dominated by an isolated, dark blotch occupying the sub-basal portion of the dorsal lobe, leaving the distal portion comparatively pale (vs. isolated blotch absent or restricted to the distal portion of dorsal lobe in B. rheoruber). The new species is further distinguished from its congeners, except Bryconops alburnoides Kner, 1858, B. allisoni, B. caudomaculatus (Günther, 1864), B. chernoffi, B. collettei, B. disruptus Machado-Allison & Chernoff, 1997, B. durbinae (Eigenmann, 1908), B. gracilis (Eigenmann, 1908), B. magoi, B. hexalepis, B. imitator, B. marabaixo, B. piracolina, B. rheoruber, and B. tocantinensis by having the posterior extension of the maxilla not reaching the junction of the second and third infraorbital bones (vs. reaching that junction). Bryconops florenceae can be diagnosed from the aforementioned species, except B. alburnoides, B. collettei, B. gracilis, and B. magoi, by having 29-32 branched anal-fin rays (vs. 18-28). Finally, Bryconops florenceae differs from B. alburnoides, B. gracilis, B. collettei, and B. magoi by having a deeper body, 30.3-31.7% SL (vs. 18.4-25.7% SL). Additionally, it can be distinguished from B. alburnoides and B. gracilis by possessing 44-47 perforated scales in the lateral line (vs. 54-62), and from B. collettei and B. magoi by having six (rarely 7) series of scales above the lateral line (vs. 7-, rarely 8).

FIGURE 1

Description. Morphometric data presented in Tab. 1. Body compressed, greatest body depth located just anterior to dorsal-fin origin. Dorsal body profile slightly convex from margin of upper lip to end of supraoccipital spine, then slanted posterodorsally to dorsal-fin origin; straight and posteroventrally inclined along dorsal-fin base, slightly convex from end of dorsal-fin base to adipose-fin base, and slightly concave from latter point to anterior dorsal procurrent caudal-fin rays. Ventral profile of head and body convex from lower lip to pelvic-fin origin, then straight to slightly convex from latter point to anal-fin origin and straight, rising more sharply along anal-fin base. Ventral profile of caudal peduncle slightly concave.

TABLE 1

	H	Range	Mean	SD
Standard length (mm)	94.5	79.5-94.5	85.2	-
Percents of standard length
Snout to dorsal-fin origin	48.1	45.7-48.1	46.8	0.8
Snout to anal-fin origin	64.7	61.4-65.1	63.1	1.4
Snout to pelvic-fin origin	49.8	46.0-49.8	47.8	1.3
Pelvic-fin length	12.2	12.2-16.1	14.8	1.3
Snout to pectoral-fin origin	25.7	24.0-26.0	24.9	0.7
Pectoral-fin length	20.5	19.4-21.7	20.5	0.7
Dorsal-fin base length	15.0	13.4-15.0	14.2	0.6
Depth at dorsal-fin origin	31.7	30.3-31.7	31.1	0.4
Dorsal-fin terminus- adipose origin	27.3	26.2-28.6	27.5	0.8
Dorsal-fin origin- adipose origin	41.3	40.3-42.5	41.3	0.8
Adipose terminus to hypural plate	13.1	12.6-14.3	13.6	0.6
Anal-fin base length	34.0	32.3-34.5	33.3	0.8
Caudal-peduncle length	9.6	9.6-12.8	11.1	1.1
Caudal-peduncle depth	9.2	8.7-9.3	9.1	0.2
Head length	24.3	22.3-24.3	23.5	0.7
Maxillary length	12.1	11.3-12.2	11.5	0.3
Snout length	6.6	5.7-6.6	6.0	0.3
Horizontal orbit diameter	10.6	9.7-10.8	10.4	0.3
Percents of head length
Maxillary length	50.0	47.2-50.5	48.9	1.2
Snout length	26.9	23.8-28.0	25.7	1.7
Horizontal orbit diameter	43.4	43.4-45.0	44.3	0.7
Tip of snout to tip of supraoccipital	94.7	94.0-96.9	94.9	1.0
Posterior margin of orbit to end of opercle	32.6	30.2-32.6	31.5	0.9

Mouth terminal. Posterior extension of maxilla not reaching junction between second and third infraorbital bones, with distal tip finishing near vertical through anterior margin of pupil. Supraorbital bone present, not reaching sixth infraorbital posteriorly. Premaxillary teeth in two rows (Fig. 2), with central cusp more developed than lateral cusps. Outer tooth row not aligned, with 4(1) or 5(9) tri- to pentacuspid teeth; inner tooth row with 5(10) penta- to heptacuspid teeth. Maxilla edentulous (10). Dentary with 5*(7) or 6(4) tri-, penta-, or heptacuspid teeth, followed by 7-10 smaller, conical teeth (Fig. 2).

FIGURE 2

Dorsal-fin rays ii,9*(10); first unbranched ray about one-half length of second unbranched ray. Dorsal-fin origin situated on vertical through pelvic-fin origin, near middle of body. Posterior margin of dorsal fin straight to slightly concave. Adipose-fin origin approximately at vertical through base of 25^th or 26^th branched anal-fin ray. Pectoral-fin tip nearly reaching vertical through dorsal-fin origin. Pelvic-fin rays i,7(10). Pelvic-fin origin aligned with dorsal-fin origin. Pelvic-fin tip not reaching anal-fin origin. Anal-fin rays iv, 29(1), 30*(5), 31(3) or 32(1). Anal-fin origin posterior to vertical through base of last dorsal-fin ray. Distal margin of anal fin gently concave with last simple ray and second and third branched rays slightly longer than others. Principal caudal-fin rays 8+9*(10). Caudal fin forked; ventral lobe scarcely longer than dorsal. Dorsal procurrent caudal-fin rays 11(2) or 12*(3); ventral procurrent caudal-fin rays 11(2) or 12*(3).

Scales cycloid, with few (5-7) well-marked radii; circuli only present anteriorly. Total number of scales in longitudinal series containing lateral-line scales 44(1), 45*(2), 46(6) or 47(1). Scale rows between lateral line and dorsal-fin origin 6*(9) or 7(1); scale rows between lateral line and pelvic-fin origin 3*(9) or 4(1). Predorsal scales 11*(8) or 12(2) in a regular series. Scale rows around caudal peduncle 14(9) or 15(1). Precaudal vertebrae 17*(2) or 18(3); caudal vertebrae 23(3) or 24*(2); total vertebrae 41*(5). Supraneurals 6*(5). First dorsal-fin pterygiophore located between 10^th and 11^th or 11^th and 12^th vertebrae.

Gill rakers on first gill arch 18(1): 2(1) on hypobranchial, 8(1) on ceratobranchial, 1(1) on cartilage between ceratobranchial and epibranchial, and 7(1) on epibranchial. Gill rakers setiform. Branchiostegal rays 4(1): 3(1) on anterior ceratohyal and 1(1) on posterior ceratohyal.

Coloration in alcohol. Overall color of body yellowish tan. Snout, dorsal region of head, anterior portions of dentary, maxillary, and sixth infraorbital bone dusky with scattered melanophores. Infraorbital bones 1-5, posteromedial portion of maxillary, opercle and gular region whitish to yellowish, with few scattered melanophores. Humeral blotch absent. Dusky midlateral stripe evident from immediately posterior to dorsal portion of opercle to caudal-fin base; stripe overlaid with silvery iridescence that becomes slightly more conspicuous posteriorly from vertical through dorsal fin. Scales on dorsal and dorsolateral portions of body with melanophores concentrated along posterior margin, forming a slightly reticulate pattern overall. Ventrolateral scales with scattered melanophores, not forming reticulate pattern. Dorsal, adipose, pectoral, pelvic and anal fins hyaline with few scattered melanophores. Caudal fin with dark melanophores outlining rays and their branches; dorsal lobe conspicuously darker with higher concentration of melanophores forming a black, sub-basal blotch on dorsalmost rays (Fig. 1).

Coloration in life. Based on photo presented in Planquette et al. (1996:267), body silvery, becoming tan dorsally. Opercle, infraorbital bones, eye, posteromedial region of maxilla and ventral region of head silvery. Dorsal and adipose fins tinted with reddish orange. Pectoral, pelvic and anal fins pale. Caudal fin with small, reddish-orange patch at base of dorsal lobe, proximal to black blotch; both lobes with narrow dark distal margin.

Sexual dimorphism. Mature males of Bryconops florenceae possess bony hooks on pelvic- and anal-fin rays. Pelvic-fin rays with 3-4 small hooks. Anal-fin hooks larger and more numerous (4-8 per ray), present from 3^rd unbranched ray to 15^th branched ray and gradually decreasing in size and number from anterior to posterior. Planquette et al. (1996:266) similarly noted the presence of numerous anal-fin ray hooks in males. The specimens we examined were collected in April, which may represent the breeding season for this species in the upper Maroni Basin. It is unknown whether the hooks are permanent or regress after this period.

Etymology. The species is named in honor of Florence de Rapleye Foerderer (1926-1999) whose will granted $7 million each to The Academy of Natural Sciences of Philadelphia, The Philadelphia Zoo and Gallaudet University, a liberal arts college for deaf and hard-of-hearing students. Florence held a great love for animals and her generous bequest continued the Foerderer family’s long history of civic involvement and philanthropy in the Philadelphia area (Schmidt, 2001). A patronym.

Conservation status. Bryconops florenceae is a widely distributed species in the Maroni, Mana and Sinnamary river basins (see Planquette et al., 1996), with an Extent of Occurrence (EOO) of approximately 25,000 km², based on the distribution map provided by Planquete et al. (1996) and the sampling sites of the type-series. Furthermore, no threats were found that would put it at risk in the near future. Thus, we suggest that Bryconops florenceae be classified as Least Concern (LC), according to the International Union for Conservation of Nature (IUCN) categories and criteria (IUCN Standards and Petitions Subcommittee, 2019).

Geographical distribution. Bryconops florenceae is known from the Maroni River basin in Suriname and French Guiana (Fig. 3). Planquette et al. (1996:266-67) also noted its presence in the Mana and Sinnamary rivers. They commented that the species frequents areas of rapid current with rocky bottoms in the main channel of the river, such as the collection locality depicted in Fig. 4.

FIGURE 3

FIGURE 4