Hyphessobrycon panamensis Durbin, 1908

Ota, Renata R., Carvalho, Fernando R. & Pavanelli, Carla S., 2020, Taxonomic review of the Hyphessobrycon panamensis species-group (Characiformes: Characidae), Zootaxa 4751 (3), pp. 401-436 : 422-426

Hyphessobrycon panamensis Durbin, 1908

( Figs. 15–18 , Tab. 5)

Hyphessobrycon panamensis Durbin, in Eigenmann, 1908: 101 [original description, type locality: “Boqueron River, Panama ”]—. Eigenmann, 1910: 436 [ Panama; listed]—. Meek & Hildebrand, 1916: 287 [ Panama, río Chagres basin; synonymic list; description; distribution]—. Eigenmann, 1918: 186, plate 26 (fig. 1), plate 33 (fig. 4) [in part; specimens from Panama, río Boqueron basin; synonymic list; description; distribution]—. Eigenmann, 1920a: 17 [in part; specimens from Panama, río Chagres basin; distribution]—. Eigenmann, 1920b: 15 [in part; specimens from Panama, río Chagres; distribution]—. Eigenmann, 1922: 141 [synonymic list; in part; specimens from Panama, río Chagres; distribution]—. Jordan et al., 1930 [ Panama, río Chagres basin; synonymic list; distribution]—. Hildebrand, 1938: 269 [ Panama, río Chagres basin; short description]—. Vari & Howe, 1991: 27 [type catalog]—. Weitzman & Palmer, 1997: 227–229 [in part; specimens from Panama: canal Zone, río Chagres, río Tocué, “Largateria creek”, upper Trinidad, Reservois Creek; comments on color in life and distribution]—. Zarske & Géry, 2002: 22-30 [diagnosis from H. columbianus ; comments on cryptic species; diagnosis in key, photo]—.Lima et al., 2003: 139 [listed; distribution]—. Maldonado-Ocampo et al., 2008: 169 [listed, Colombia; Pacific slope rivers; distribution]—. García-Alzate et al., 2010: 55 [recorded from Colombia; comparison with H. sebastiani ]—. García-Alzate et al., 2013: 182 [restriction of the distribution to Panama and Costa Rica; in part; specimens from Panama: río Boqueron, and zona del Canal del Panama].

Hemigrammus minutus Meek & Hildebrand, 1912: 67 [original description, type locality: “río Agua Clara, Canal Zone, Panama ”]—. Eigenmann, 1913: 31 [synonymization with Hyphessobrycon panamensis ]—. Meek & Hildebrand, 1916: 287 [as a synonym of H. panamensis ]—. Eigenmann, 1918: 186 [as a synonym of H. panamensis ]—. Ibarra & Stewart, 1987: 45 [type catalog]—. Weitzman & Palmer, 1997: 227 [as a synonym of H. panamensis ]—. Zarske & Géry, 2002: 26–28 [as a synonym H. panamensis ;]—.Lima et al., 2003: 139 [listed; as a synonym of H. panamensis ].

Diagnosis. Hyphessobrycon panamensis differs from all congeners, except from H. compressus , H. diancistrus , H. otrynus , and those belonging to the H. panamensis species-group, by the presence of one large bony hook per fin ray, antero-dorsally oriented and surrounded by a fleshy area, on last unbranched and first branched anal-fin rays of mature males (vs. absence of hooks, or presence of small and numerous hooks on anteriormost anal-fin rays). Hyphessobrycon panamensis can be distinguished from H. compressus by the absence of a dark blotch on the dorsal fin (vs. presence), by the presence of predorsal series (vs. absence), and by presenting 33–35 scales in longitudinal series (vs. 41–48). It can be distinguished from H. diancistrus and H. otrynus by presenting the caudal fin hyaline (vs. presence of dark blotches on caudal-fin lobes in H. diancistrus ; distal third of caudal fin darkened in H. otrynus ). It differs from H. columbianus by the absence of a silvery-blue iridescent coloration on dorsal region of flank in life (vs. presence), and by the lower body depth (36.1–45.7% SL vs. 46.0–50.3% SL in H. columbianus ). It can be distinguished from H. savagei by presenting the second humeral blotch less conspicuous than the first, extending one or two longitudinal scale rows below lateral line, with posterior margin as a concentration of melanophores dispersing towards longitudinal midlateral stripe (vs. humeral blotches equally pigmented, extending two to four longitudinal scale rows below lateral line, with contours and margins always well-defined). Hyphessobrycon panamensis differs from H. bussingi , H. condotensis and H. daguae by the lower number of branched anal-fin rays (19–23, modes = 21 and 22; vs. 23–27, rarely 22, mode = 24 in H. condotensis and H. daguae , and mode = 25 in H. bussingi ). It can be further distinguished from H. bussingi and H. condotensis by presenting 6, rarely 5½ (mode = 6), scale rows between lateral line and pelvic-fin insertion (vs. 4–5½, mode = 5 in H. bussingi ; and 4½–6, mode = 5 in H. condotensis ). It also differs from H. condotensis , by presenting 7–8 (mode = 7) scale rows between lateral line and dorsal-fin insertion (vs. 5–7, mode = 6). Additionally, it can be distinguished from H. daguae by presenting a well-defined first humeral blotch (vs. only one diffuse humeral blotch).

Description. Morphometric data in Table 5. Body compressed, greatest depth at vertical through dorsal-fin origin. Dorsal profile of body convex from upper lip to vertical through anterior nostril; straight or slightly concave from this point to distal tip of supraoccipital process. Slightly convex from tip of supraoccipital process to dorsal-fin origin; straight or slightly convex from this point to adipose-fin origin; and straight along caudal peduncle. Ventral profile of body convex from lower lip to pelvic-fin origin; straight or slightly convex from this point to anal-fin origin; straight along anal-fin base; and straight or slightly concave along caudal peduncle.

Jaws equal, mouth terminal. Premaxillary teeth in two rows; outer row with 2(1), 3*(9), 4(2), or 5(1) tri- to pentacuspid teeth; inner row with 5*(15) tri- to pentacuspid teeth. Posterior margin of maxilla at vertical through anterior margin of pupil. Maxilla with 2(6), 3*(6), 4(1), or 5(2) tri- to pentacuspid teeth. Dentary with 4*(8), 5(6) large penta- and tricuspid teeth, gradually decreasing in size, followed by conical and abruptly smaller teeth. Central cusp more developed than lateral ones.

Scales cycloid. Lateral line incompletely pored with 7(1), 8(2), 9(2), 10(6), 11*(6), 12(4), 13(2), 15(1), 16(1), or completely pored with 33(1) perforate scales. Longitudinal series, including perforate scales, with 33*(6), 34(3), or 35(3). Scale rows between dorsal-fin origin and lateral line 7(19), 7½*(1), or 8(3). Scale rows between lateral line and pelvic-fin insertion 5½*(2) or 6(20). Predorsal series with 11*(4), 12(5), or 13(2) scales. Single row of six scales covering base of anteriormost anal-fin rays. Circumpeduncular scales 13(1), 14*(7), or 15(2).

Dorsal-fin rays ii,8(1) or ii,9*(14). First dorsal-fin pterygiophore located between neural spines of ninth and 10 th (3) vertebrae. Adipose fin present. Pectoral-fin rays i,10*(3), 11(7), or 12(2), distal tip of rays reaching pelvic-fin origin. Pelvic-fin rays i,7*(13), distal tip reaching anal-fin origin. Anal-fin rays iii*(17), iv(6), 19(1), 20(2), 21(8), 22*(8), or 23(4). Anal fin of mature males with large bony hooks. Caudal fin bifurcate, lobes approximately of same size, i,9/8,i(1) rays.

First gill arch with 7(7) or 8(2) rakers on epibranchial, 1(9) on intermediate cartilage, 10(1), 11(6), 12(1), or 13(1) on cerato+hipobranchial. Branchiostegal rays 4. Total vertebrae 33*(3), supraneurals 4*(2) or 5(1) ( Fig. 17 ).

Color in alcohol. Background coloration beige to light brown. Dorsal region of head and middorsal region of body with dense concentration of melanophores. Region above pupil darkened. Infraorbitals beige, with few scattered melanophores. Opercle retaining guanine pigmentation, without melanophores. Inferior portion of maxilla and gular region with few scattered melanophores, slightly more concentrated on anterior half. Two dark-brown humeral blotches, vertically elongated, separated by light-beige area. First humeral blotch conspicuous, with melanophores equally distributed, extending four to five longitudinal scale rows above and two below lateral line. Second humeral blotch usually inconspicuous, extending four to five longitudinal scale rows above and one below lateral line; posterior margin with concentration of melanophores concentrated along longitudinal midlateral stripe. Body sides with melanophores regularly distributed, except on antero-ventral half, with few or without melanophores. Posterior margin of scales on superior third of body sides with concentration of melanophores. Brownish to silvery longitudinal midlateral stripe, from second humeral blotch to caudal peduncle, more conspicuous on posterior region. Fins hyaline, with slight concentration of melanophores on distal half of dorsal fin, distal third of anal fin, and median caudal-fin rays. Abdominal region, from pectoral-fin origin to pelvic-fin end, without melanophores ( Fig. 18 ).

Distribution. Hyphessobrycon panamensis is known from the río Bejuco, río Boquerón, río Calovébora, río Chagres and río Lllano Succio basins, and in the Canal Zone, in Panama (both Atlantic and Pacific versants) (Figs. 4, 8 and 21).

Sexual dimorphism. Mature males with one large bony hook per fin ray, anterodorsally oriented and surround- ed by fleshy area, from the last unbranched (on fourth segment) to the third branched (varying on fifth to seventh segments) anal-fin rays of mature males ( Figs. 5b and 6b ). Very small hooks, difficult to discern, can be present on distal segments of most anterior anal-fin rays. Dorsal-fin length of males slightly longer than in females.

Ecology and habitat. Hyphessobrycon panamensis feeds on aquatic and terrestrial insects. The oocytes diameter varies between 0.7 to 0.8 mm ( Kramer, 1978; Kramer & Bryant, 1995).

Remarks. Eigenmann (1913) proposed Hemigrammus minutus Meek & Hildebrand as a junior synonym of Hyphessobrycon panamensis . The examination of the paratypes of He. minutus conducted during the present study showed that the purported diagnostic characters from the latter taxon overlap with H. panamensis and, therefore, the proposed synonymy is herein confirmed.

Hyphessobrycon panamensis has its diagnosis from similar species redefined herein based mainly in the low number of branched anal-fin rays. The geographical distribution of the species is restricted herein to the central provinces of Panama, draining both Atlantic and Pacific versants. There is no record indicating the syntopy with other species of the group.

In the literature, Hyphessobrycon panamensis has been recorded in Costa Rica (e.g. Bussing, 1987, 1998) and Colombia (e.g. Eigenmann, 1920a, b, c, d; Dahl, 1971; Weitzman & Palmer, 1997; Zarske & Géry, 2002; García-Alzate et al., 2010). However, specimens identified as H. panamensis from Colombia belong either to H. columbianus , H. condotensis or H. daguae (the latter species herein revalidated and considered as senior synonym of H. chocoensis ; see remarks on this species, above). In addition, specimens identified as H. panamensis from the province of San Blas, southeast Panama actually correspond to H. columbianus . On the other hand, specimens previously identified as Hyphessobrycon panamensis from Costa Rica and in the province of Bocas del Toro, Panama (at the border with Costa Rica), belong rather to H. bussingi , new species, described herein.

The type series of Hyphessobrycon panamensis is composed of six syntypes (MCZ 20688 and USNM 120416). The lectotype herein designated is a male specimen with large hooks on the anal-fin ray (USNM 120416, fig. 15a), and all the remaining specimens consequently become paralectotypes, as ruled by the article 74 of ICZN (1999).

Material examined. 54 specimens (20.6–48.6 mm SL). All from Panama. Type material. USNM 120416 , lectotype of Hyphessobrycon panamensis (by present designation), 25.4 mm SL (rd): río Boqueron , Atlantic slope; Hassler Expedition, 31 Jul 1872 . USNM 443817 , paralectotype of Hyphessobrycon panamensis , 25.7 mm SL (rd) , same data as lectotype. MCZ 20688, paralectotypes of Hyphessobrycon panamensis , 5, 20.6–23.5 mm SL (dry specimens) , same data as lectotype; FMNH 12770 , paratypes of Hemigrammus minutus , 2, 25.3–30.5 mm SL: Panama, Cana Zone, Agua Clara; S. F. Hildebrand & S. E. Meek, 10 Mar 1911 ; FMNH 12771 , paratype of Hemigrammus minutus , 35.9 mm SL: Panama, Canal Zone, río Mandingo , Bas Obispo; S.F. Hildebrand & S.E. Meek, 02 Feb 1911 . USNM 78628 , paratypes of Hemigrammus minutus , 31 (20, 22.9–31.3 mm SL): Canal Zone, río Agua Clara ; S.E. Meek & S.F. Hildebrand, 10 Mar 1911 . Non-types. Bocas del Toro, río Calovébora basin: UCR 1463006, 2 (1, 34.6 mm SL), río Calouébora , next to mouth, 08°33ʼN 81°11ʼW; T. Thomson, 01 Apr 1983 . Cólon, río Llano Sucio basin: AMNH 37802 , 24 (4, 25.5–31.4 mm SL): Canal Zone, quebrada Juan Grande near Gamboa , 09°07’N 79°43’W; P.C. Rosen et al., 04 Jan 1978 . LBP 2759, 7, 26.6–35.0 mm SL (1 rd, 34.8 mm SL): Santa Rita de Arriba, río Llano Sucio , 09°19’26.2’’N 79°46’08.2’’W; C. Oliveira, R. G. Reina, C. Veja & S. Perez, 14 Jul 2005 . Veraguas, río Bejuco basin: MCP 39195, 5 , 36.0 – 48.6 mm CP: río Bejuco , 08°48’N 81°01’W; P. Rham, 12 Aug 1998 . West Panama, Canal Zone : ANSP 99866 , 16 (5, 31.9–35.5 mm SL), creek 2 mi E of Nuevo Emperador road, 9°02’N 79°47’W; H.G. Loftin & E.L. Tyson, 17 Aug 1962 . ANSP 146800 , 14 (5, 24.7–30.5 mm SL), brook 1.1 km E of Nuevo Emperador on Nuevo Emperador-Arraijan road, 9°02’N 79°47’W; D. Fromm & P. Fromm, 13 Mar 1981 .

Figures

FIGURE 5. Radiograph of anterior portion of anal fin of mature males, showing large bony hooks of: a) Hyphessobrycon bussingi (NUP 22294, 33.7 mm SL), b) H. panamensis (LBP 2759, 34.8 mm SL), c) H. savagei (UCR 4201, 24.7 mm SL). Very small hooks can be present on distal segments of most anterior anal-fin rays (white traces on a and b).

FIGURE 6. Large bony hooks on the anal fin of mature males, surrounded by fleshy area: a) Hyphessobrycon bussingi (NUP 22294, 33.7 mm SL), b) H. panamensis (LBP 2759, 34.8 mm SL), c) H. savagei (UCR 4201, 24.7 mm SL).

FIGURE 15. Hyphessobrycon panamensis, a) USNM 120416, lectotype, 25.4 mm SL; Panama, río Boqueron, Atlantic slope; b) USNM 443817, paralectotype, 25.7 mm SL, same data as lectotype.

FIGURE 16. Hyphessobrycon panamensis, MCZ 20688, paralectotype, 20.6 mm SL; Panama, río Boqueron, Atlantic slope.

FIGURE 17. Radiograph of Hyphessobrycon panamensis, USNM 120416, lectotype, 25.4 mm SL; Panama, río Boqueron, Atlantic slope.

FIGURE 18. Hyphessobrycon panamensis, LBP 2759; Panama, Cólon, Santa Rita de Arriba, río Llano Sucio, (a) 33.9 mm SL, male, (b) 34.7 mm SL, female.