Hyphessobrycon compressus ( Meek, 1904 )

Carvalho, Fernando R. & Malabarba, Luiz R., 2015, Redescription and osteology of Hyphessobrycon compressus (Meek) (Teleostei: Characidae), type species of the genus, Neotropical Ichthyology 13 (3), pp. 513-540 : 514-521

Hyphessobrycon compressus ( Meek, 1904) Figs. 1-6 ; 9-22

Hemigrammus compressus Meek, 1904: 87 , fig. 25 [original description, type locality: El Hule (Obispo), Oaxaca, río Papaloapan basin, Mexico].- Miller, 1907: 23 [listed].

Hyphessobrycon compressus milleri Durbin , in Eigenmann, 1908: 100 [original description, type locality: Los Amates, Guatemala]. NEW SYNONYM.

Hyphessobrycon compressus .-Durbin, in Eigenmann, 1908 [proposal of subgenus Hyphessobrycon and designation of Hemigrammus compressus Meek as type species].- Eigenmann, 1910: 436-437 [distribution].- Eigenmann, 1918: 172, 176, plate 24, fig. 1, plate 79, fig. 14 [redescription, analysis of types].- Géry, 1966: 223, 230, fig. 9, with legend in fig. 13 [analysis of holotype, figure of maxilla of one paratype and suggestion that genus could be restricted to its type species].- Géry, 1977: 478, 486 [image of jaws of one paratype; comments about genus Hyphessobrycon and its type species; H. milleri as possibly junior synonym of H. compressus ].- Zarske & Géry, 1997: 308, 310 [listed].-Weitzman & Palmer, 1997: 225-226 [comments about genus Hyphessobrycon and its type species; comparison with Hyphessobrycon milleri ].- Lucena, 2003: 93 [comments about relationships of H. compressus with other species of Hyphessobrycon ].- Miller, 2005: 157-158 [distribution and habitat].

Hyphessobrycon milleri .- Eigenmann, 1918: 177-178: (redescription, type designation).-Weitzman & Palmer, 1997: 226 (as possible synonym of H. compressus ).

Diagnosis. Hyphessobrycon compressus is distinguished from all congeners by the number of scales in the longitudinal series (41-48, mode 45, vs. less than 40 on other species); the number of scales rows between the dorsal-fin origin and the lateral line (7-9, mode 9, vs. 6 or less, rarely 7), and the absence of predorsal scales (vs. scales present). Furthermore, H. compressus can be recognized by the combination of a lack of humeral spots on body, presence of conspicuous bony hooks in anal fin (two large and several small), and hooks absent on pelvic fin.

Description. Morphometric data summarized in Table 1. Small size, maximum of 36.4 mm SL and 46.5 mm total length (AMNH 32275). Body compressed, moderately high, greatest body depth at vertical through dorsal-fin origin. Head profile triangular and rounded anteriorly from lateral view. Dorsal profile of head slightly convex anteriorly, nearly straight from posterior nostril to tip of supraoccipital spine. Dorsal profile of body slightly convex from posterior tip of supraoccipital to base of last dorsal-fin ray, then straight to adipose-fin origin. Ventral profile of body convex from tip of lower jaw to pelvic-fin origin, slightly convex from that point to anal-fin origin, and straight and posterodorsally slanted along of anal-fin base. Dorsal and ventral profile of caudal peduncle straight to slightly concave.

Mouth terminal, premaxillary and dentary approximately same length. Maxilla extending posteroventrally to anterior one-third of orbit almost to contact between second and third infraorbitals, and running approximately at 45 degree angle relative to longitudinal axis of body. Premaxilla short, approximately one-third size of maxilla ( Figs. 3b , 4 ). Nostrils close to each other, anterior opening small and circular, posterior opening twice as large. Nostrils separated by skin flap almost covering posterior nostril. Frontals not united anteriorly, with a triangular fontanel; parietal fontanel large, extending from epiphyseal bar to supraoccipital spine. Eyes moderate in size, without conspicuous adipose eyelid.

Premaxillary teeth in two rows: outer row with 1(46), 2(78), or 3*(19), uni- to tricuspid teeth; inner row with 6(89), 7*(55), or 8(4) tricuspid teeth ( Figs. 3b , 4 ). Dentary with 4*(24), 5(96), or 6(30) large, tricuspid teeth, followed by 7(2), 8(3), 9(2), 10(2), or 11(1) smaller, conical teeth, gradually becoming smaller than largest anterior tooth ( Fig. 3c ). Dorsal border of maxilla relatively straight. Maxilla with 3(27), 4(54), 5(35), 6*(18) or 7(6) tricuspid teeth along anteroventral margin ( Fig. 3a ). Central cusp the longest on all teeth.

Scales cycloid, relatively small, with few radii (2-7). Circuli distinct anteriorly and marginally (dorsal and ventral). Lateral line incompletely pored, pored portion extending to vertical through pelvic-fin origin, nearly straight. Perforated lateral-line scales 5(10), 6(32), 7(46), 8*(26), or 9(8). Longitudinal scales series including pored scales 41(15), 42(15), 43(19), 44(8), 45(13), 46*(11), 47(4), or 48(1). Scales rows between dorsal-fin origin and lateral line 7(6), 8(48), or 9*(67). Scales rows between lateral line and pelvic-fin origin 6(32), 7*(80), or 8(7). Predorsal scales absent. Scale sheath along anal-fin base with 3(2), 4(11), 5*(18), or 6(12) scales in single row. Circumpeduncular scales 16(15), 17*(38), or 18(11). Axillary scale present, approximately same size as body scales.

Dorsal-fin rays ii,8(3), 9*(141), or 10(1); first unbranched ray approximately 45% of second ray. Dorsal-fin origin at midlength of body or posterior to that point, at vertical through anterior one-third of pelvic-fin base. Base of last dorsal-fin ray at or slightly posterior of vertical through tip of pelvic fin; posterior to anal-fin origin. Tip of longest ray of adpressed dorsal fin extends to adipose-fin origin. Adipose fin slightly semicircular distally, greatest dimension less than orbital diameter; adipose-fin origin between base of fourth and fifth posteriormost branched anal-fin rays; its posterior tip extending to vertical through branched anal-fin end. Pectoral fin with i,10(16), 11*(82), 12(45), or 13(12) rays. Tip of pectoral fin extending beyond to pelvic-fin origin; profile slightly pointed and greatest medially (its base from vertical through opercular bony to horizontal through end portion of third infraorbital). Pelvic fin with i,6(2), 7*(145), or 8(5) rays. Pelvic-fin origin located anterior to vertical through dorsal-fin origin; tip of pelvic fin extending to fourth branched anal-fin ray. Anal-fin rays iii*(71), iv(74), or v(7), 20(3), 21(2), 22*(45), 23(56), 24(35), or 25(13). Anal fin of males with large bony hooks; hooks absent in females. Anal-fin base nearly straight with first unbranched ray sometimes under muscles, but evident in cleared and stained specimens. Last unbranched ray and first two branched largest; remaining rays gradually decreasing in length to sixth branched ray; seventh through last rays approximately of same length. Caudal fin forked, lobes slightly rounded, similar in size, with i,9/8,i*(123) or i,10/8,i(1) rays. Caudal fin naked, other than for scales restricted to base. Basal scales same size as body scales. Dorsal procurrent caudal-fin rays 11(9) or 13(2). Ventral procurrent caudal-fin rays 8(4) or 9(6).

Branchiostegal rays 4(11). First gill arch with 8(1) or 9(1) gill rakers on epibranchial, 1(11) between epibranchial and ceratobranchial, 12(2) on ceratobranchial, and 2(7) or 3(1) on hypobranchial. Precaudal vertebrae 15(6) or 16(4). Caudal vertebrae 17(1), 18(9), or 19(1). Total vertebrae 33(7) or 34(3). Supraneurals 4(1) or 5(9), filiform, other than for some dorsal expansion.

Color in alcohol. Overall body color uniform greyish,yellowish to dusky, with scattered chromatophores uniformly distributed. Body without spots on longitudinal stripe. Inconspicuous, narrow longitudinal line along where epaxial and hypaxial muscles meet. Abdominal region usually less pigmented than remainder body.Iris black.Opercle,preopercle,and interopercle sometimes silvery. Dorsal fin with conspicuous black spot; spot more densely pigmented on proximal half of anterior rays. Spot extending to sixth branched ray and sometimes extending to distal tip of first branched rays. Dorsal and anal fins almost completely dark in mature males, with dense chromatophores concentration. Females with pigmentation less intense at half of anterior dorsal-fin rays and proximal length of anal-fin rays. Pectoral-, pelvic-, adipose-, and caudal fins normally dark gray or dark brown with scattered chromatophores on rays and interradial membrane. Some specimens with dark gray median caudal-fin rays ( Figs. 1-2 ).

Color in life. Overall body color dark silvery to dusky (in reproductive males) dependent on conditions (stress, reproductive condition) (Greenfield & Thomerson, 1997) or light olivaceous ( Meek, 1904). Caudal fin yellowish to reddish. Caudal peduncle without spot. Dorsal fin black, chromatophores more densely concentrated along proximal half of anterior dorsal rays. This pattern sometimes observed on all fins. Pelvic fin darkish gray. Anal fin with brown or black stripe along midlength of rays; stripe extending along all of anal fin in mature males (Greenfield & Thomerson, 1997) ( Fig. 5 ).

Sexual dimorphism. Mature males can be distinguished from females by the presence of bony hooks on anal fin and by the slightly less concave anterior distal margin of anal fin. Males over 28.0 mm SL have small, slightly developed bony hooks. Males larger than 32.0 mm SL have two pairs of large bony hooks. The first pair is larger, retrorse, fishhooklike and normally located at midlength of last unbranched ray. Length of hook larger than that of ray segment, with posterior tip of hook extending to adjacent ray. Second pair of large bony hooks slightly smaller than first and located immediately before first ramification of branched anal-fin ray. Small bony hooks (size smallest that ray segment) present on unbranched ray and anterior six branched rays of anal fin. Hooks located on distal portion of ray after ray ramification with one pair of bony hooks by ray segment. Tissue developed around large bony hooks of anal fin ( Fig. 6 ). Gill glands (sensu Burns & Weitzman, 1996) on first gill arch in males and females were not macroscopically evident.

Distribution. Hyphessobrycon compressus is distributed in many independent Atlantic slope rivers and streams of southern of Mexico, Belize, and Guatemala, an area known as Middle America (sensu Winker, 2011), in the Usumacinta Province (sensu Miller, 1966, fig. 3) ( Fig. 7 ). It is the most northerly distributed species of Hyphessobrycon . Although there are numerous isolated populations within this range, our analysis revealed they together constitute an unique species without detected variations in meristic and morphometric data among these populations.

Common names. The species is commonly known as billium, Mayan tetra ( Belize), Maya tetra, sardinita plateada ( Mexico), vihersulkatetra ( Finland), pepesca, sardine ( Alvarado et al., 2005; Froese & Pauly, 2014).

Ecological notes. Hyphessobrycon compressus seems to be most frequently found in wetlands, where it is associated with macrophytes, over sandy and muddy substrates (Greenfield & Thomerson, 1997). It is rather sensitive to stress and dies quickly after capture ( Endruweit, 2013). In a pool on right side of the road MEX 307, Nuevo Orizaba - Nuevo Reforma, río Usumacinta basin, Mexico, it was abundant in lentic water, with plenty of shade along the margin due to overhanging branches. The water was two meters maximum depth, without aquatic macrophytes, but with terrestrial vegetation hanging into the pool. The bottom was gravel 5 mm, loam and the water highly turbid and greenish ( Endruweit, 2013). Mature males have an intense black color to the fins, especially the dorsal and anal fins, but it rapidly loose the coloration after removal of the water, becoming pale as females ( Endruweit, 2013) ( Fig. 5c ). The species is commercialized in the aquarium trade ( Alvarado et al., 2005).

Remarks. In the original description of Hemigrammus compressus, Meek (1904) mentioned only the type (F.C.M. 4641, now FMNH 4641), though there is a range of values for some measurement and meristic data in the description, e.g., “(…) A. 25 to 27; scales 45 to 48; (…) the lateral line incomplete, on the 4 to 10 anterior scales (…) [sic]”. Eigenmann (1918), in the brief redescription of this species, examined eight specimens in three lots: IU 10798 and IU 11126 (now combined in CAS 70114, with five specimens and MCZ 29911, with two specimens), and IU 10929 (now CAS 70116, with one specimen, and with doubts about the locality of collection of this lot and collector), all from Mexico, collected by S. E. Meek. There are, however, no records for these specimens (CAS 70114, CAS 70116, and MCZ 29911) as types.

Géry (1966) presented some data for the holotype of Hemigrammus compressus and mentioned the existence of paratypes, but did not list them (one is MHNG 2181.076; this specimen is cited and jaws illustrated in Géry, 1966: 223, but figure legend is mislabeled as Ceratobranchia binghami ; the same figure is presented in Géry, 1977: 486 and labelled as a paratype of Hyphessobrycon compressus ). In the catalog of FMNH fish types, Henn (1928) did not cite any types to H. compressus . Grey (1947), in turn, listed the holotype and 34 paratypes (23 from El Hule and 11 from Obispo). Ibarra & Stewart (1987) mentioned the holotype and 28 paratypes, from two localities (río Papaloapan and río Obispo). Both, Grey (1947) and Ibarra & Stewart (1987) did not mention the catalog number (with respective specimens number) for these types.

Information added to jar FMNH 105930 by Géry (November 1965) suggested that these specimens could be members of Astyanax . Marilyn Weitzman, in a subsequent analysis, confirmed Géry’s information and inserted an undated note identifying the specimens as Astyanax sp. We identify these specimens as Astyanax cf. mexicanus . Vari & Howe (1991) commented that the two specimens in USNM 55728 (probably ex FMNH 4662, now missing – S. Raredon, pers. comm.) are two paratypes of Hemigrammus compressus (26.0- 29.5 mm SL). Eschmeyer (2014) listed the holotype and 36 paratypes of Hemigrammus compressus as: BMNH 1905.12.6.4-5 (2); FMNH 4642 (17), FMNH 4662 (11); FMNH 105930 (ex FMNH 4642 - 2); MCZ 29911 (ex IU 11126 - 2), and USNM 55728 (2, missing). All these lots were collected by Meek in March and April 1903. According to ICZN (1999), Articles 72.4.1 and 72.4.1.1., all these specimens may be, in fact, paratypes of Hemigrammus compressus . Furthermore, we add also for type series two lots of California Academy of Science (CAS 70114 and 70116) and one lot at the National Museum of Natural History, Smithsonian Institution (USNM 204387). These were collected by Meek during March-April 1903, as described by Meek (1904), and should therefore be also considered paratypes of H. compressus .

Lima et al. (2003) mentioned the holotype of Hyphessobrycon compressus milleri as “whereabouts unknown”. The specimen is housed in the California Academy of Sciences (CAS) and it was with an old identification label of Hemigrammus compressus ( Fig. 8 ). The old collection number in the jar (IU 11255) was metallic and oxidized over time, impregnating the entire specimen with a ferrous color. After careful examination, we found that the holotype of Hyphessobrycon compressus milleri is, indeed, a mature male of H. compressus , with two large bony hooks and black anal fin along its entire length ( Fig. 8 ). The dense chromatophore concentration in this specimen proposed by Durbin, in Eigenmann (1908), as diagnostic for the species, is rather one of the characteristics of mature males of Hyphessobrycon compressus . Furthermore, the jaw length of the holotype of Hyphessobrycon compressus milleri (“maxillary considerably less than the length of the eye” [sic]), is also observed in H. compressus , as is the form of the third infraorbital (“second suborbital covering two-thirds of cheek, otherwise as in H. compressus ” [sic]) (compare Figs. 1 and 8 ). Eigenmann (1918) suggested also that Hyphessobrycon milleri is very close to H. compressus , but deferred in having the dorsal-fin spot extending for entire fin.

Meristic data of the holotype of Hyphessobrycon compressus milleri are: ii,9 dorsal fin rays; caudal fin broken; iv,22 anal-fin rays, broken in some parts; i,7 pelvic-fin rays; i,11 pectoral-fin rays; 9 perforated lateral line scales; 46 scales in longitudinal series; 18 circumpeduncular scales; 9 scales rows between dorsal-fin origin and lateral line; 7 scales rows between lateral line and pelvic-fin-origin; 4 scales in sheath along anal-fin base; predorsal scales absent in distinct series; 4 maxillary teeth; 2 premaxillary teeth in outer series; 7 premaxillary teeth in inner series; 6 dentary teeth; all tricuspid teeth. Second specimen of Hyphessobrycon milleri (= H. compressus ), collected with the holotype but not cited in the original description, was also analyzed and is listed as non-type material of Hyphessobrycon compressus (CAS 70113).

Figures

Fig. 1. Hyphessobrycon compressus, holotype, FMNH 4641, 31.2 mm SL, male, río Papaloapan, Oaxaca, Mexico. © FMNH Division of Fishes.

Fig. 2. Hyphessobrycon compressus, paratypes: (a) BMNH 1905.12.6.4-5, male, 31.5 mm SL; (b) MHNG 2181.076, male, 29.2 mm SL; (c) USNM 204387, male, 31.3 mm SL. Photos by James Maclaine (BMNH), Phillipe Wagneur (MHNG), and Sandra Raredon (USNM).

Fig. 3. Hyphessobrycon compressus, UFRGS 9683, female, 32.2 mm SL, right lateral view of (a) maxilla, (b) premaxilla, and (c) dentary. AAR = anguloarticular; DEN = dentary; MAX= maxilla; PMX = premaxilla; RAR = retroarticular. Scale bars of (a, c) = 0.5 mm and (b) = 0.2 mm.

Fig.4. Hyphessobrycon compressus, UFRGS 9683, female, 30.9 mm SL, ventrolateral view of premaxillary teeth in left premaxilla. (a) inner and outer row of premaxillary teeth, (b) detail of tooth form and alignment. Scale bars of (a) = 0.2 mm and (b) = 0.1 mm.

Fig. 5. Hyphessobrycon compressus just after collection, not preserved, left view: (a) nuptial male individual displaying darker color pattern, collected in drainage of río Coatzacoalcos basin, Veracruz Province, Mexico; (b) female from río Usumacinta basin, Chiapas Province, southern Mexico. (c) female from river near Teapa, Tabasco, Mexico. Background of images were edited and differences in fins color are due to back ground color of original images, normally made on hand. © Photos (a-b) by Marco Endruweit and (c) by Michael Tobler.

Fig. 6. Hyphessobrycon compressus, UFRGS 9683, male, 31.2 mm SL, anal fin and detail of bony hooks, left lateral view. DRA = distal radial; MRA = medial radial, and PRA = proximal radial. Scale bar = 1 mm.

Fig. 9. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, neurocranium in dorsal view, anterior to left. EPO = epioccipital; EXO = exoccipital; FRF = frontal fontanel; FRO = frontal; LET = lateral ethmoid; MES = mesethmoid; NAS = nasal; PAR = parietal; PTF = posttemporal fossa; PTO = pterotic; SOC = supraoccipital; SPH = sphenotic. Scale bar = 1 mm.

Fig. 10. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, neurocranium in left lateral view, anterior to left. AUF = auditory foramen; BOC = basioccipital; EPO = epioccipital; EXO = exoccipital; FRO = frontal; LET = lateral ethmoid; MES = mesethmoid; OSP = orbitosphenoid; PAR = parietal; PRO = prootic; PSP = parasphenoid; PTF = posttemporal fossa; PTO = pterotic; PTS = pterosphenoid; RSP = rhinosphenoid; SOC = supraoccipital; SPH = sphenotic; VOM = vomer. Scale bar = 1 mm.

Fig. 11. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, neurocranium in ventral view, anterior to left. BOC = basioccipital; EXO = exoccipital; FRO = frontal; INC = intercalar; LET = lateral ethmoid; MES = mesethmoid; OSP = orbitosphenoid; PRO = prootic; PSP = parasphenoid; PTO = pterotic; PTS = pterosphenoid; SPH = sphenotic; VOM = vomer. Scale bar = 1 mm.

Fig. 12. Hyphessobrycon compressus, UFRGS 9683, 30.7 mm SL, female, asteriscus otolith, (a) left, ventral view and (b) right, dorsal view. Scale bar = 0.5 mm.

Fig. 13. Hyphessobrycon compressus, UFRGS 9683, 31.1 mm SL, female, antorbital and infraorbital series, left lateral view, anterior to left. AOR = antorbital; IO (1 to 6) = infraorbitals. Scale bar = 1 mm.

Fig. 14. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, suspensorium in left lateral view, anterior to left. APL = autopalatine; ECP = ectopterygoid; HYO= hyomandibula; IHY = interhyal; IOP = interopercle; OPE = opercle; POP = preopercle; QUA = quadrate; SOP = subopercle; SYM = symplectic; MSP = mesopterygoid; MTP = metapterygoid. Scale bar = 1 mm.

Fig. 15. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, (a) left hyoid skeleton in dorsal view, and (b) left lateral and dorsal views of urohyal. ACH = anterior ceratohyal; BRR = branchiostegal ray; DHY = dorsal hypohyal; IHY = interhyal; PCH = posterior ceratohyal; URY = urohyal; VHY = ventral hypohyal. Scale bar = 1 mm.

Fig. 16. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, (a) branchial skeleton in dorsal view, and (b) detail of second branchial raker of epibranchial 1. BB1-4 = basibranchials 1-4; BHY = basihyal; CBR = ceratobranchial (1-5); EBR = epibranchials (1-4); HBR = hypobranchials; PBR = pharyngobranchials (1-4). Scale bar = 1 mm.

Fig.17.Hyphessobrycon compressus,UFRGS 9683, 31.2 mm SL, male, Weberian apparatus in left lateral view, anterior to left. CLT = claustrum; ITL = intercalarium; NAR = neural arch; NCO = neural complex of Weberian apparatus; NSP = neural spine of fourth and fifth vertebrae; PRB = pleural rib; SCP = scaphium; TP3 = transverse process of third vertebra; TRP = tripus; VCN = vertebral centrum. Scale bar = 1 mm.

Fig. 18. Hyphessobrycon compressus, UFRGS 9683, 31.1 mm SL, female, posterior precaudal and anterior caudal vertebrae in left lateral view, (a) precaudal vertebrae and (b) caudal vertebrae.; EPN = epineural; EPP = epipleural; HPZ = haemal postzygapophysis; HSP = haemal spine; NPZ = neural postzygapophysis; NSP = neural spine; PRB = pleural rib; VCN = vertebral centrum. Scale bar = 1 mm.

Fig. 19. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, pectoral girdle in (a) medial view, anterior to right, and (b) lateral view, anterior to left. CLE = cleithrum; COR = coracoid; EXP = extrascapular; MCO = mesocoracoid; PC1 = postcleithrum 1; PC2 = postcleithrum 2; PC3 = postcleithrum 3; SCA = scapulum; SCL = supracleithrum; PRA = proximal radial; PTR = pectoral-fin rays; PTT = posttemporal. Scale bar = 1 mm.

Fig. 20. Hyphessobrycon compressus, UFRGS 9683, 31.1 mm SL, female, pelvic girdle in (a) ventral view of right pelvic fin and (b) dorsal view of left pelvic fin, anterior to left. ISP = ischiatic process; PVB = pelvic bone; PVR = pelvic-fin rays. Scale bar = 1 mm.

Fig. 21. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, dorsal fin in left lateral view. DOR = dorsalfin rays; DRA = distal radial; MRA = medial radial; PRA = proximal radial. Scale bar = 1 mm.

Fig. 22. Hyphessobrycon compressus, UFRGS 9683, 31.2 mm SL, male, caudal skeleton in left lateral view. EPU = epurals; CRA = caudal-fin rays; DPR = dorsal procurrent caudal-fin rays; HSP = haemal spine; HYP = hypurals; NSP = neural spine; PAP = parhypural; SNP = specialized neural process; URN = uroneural; URT = urostyle; VPR = ventral procurrent caudal-fin rays. Scale bar = 1 mm.

Fig. 7. Geographic distribution of Hyphessobrycon compressus. Green light square represent approximate locality of Hemigrammus compressus holotype and dark green triangle represent approximate locality of Hyphessobrycon compressus milleri holotype. Some symbols can represent more than one lot or locality. 1) Mexico, 2) Belize, 3) Guatemala, 4) Nicaragua, and 5) El Salvador.

Fig. 8. Hyphessobrycon compressus milleri, holotype, CAS 70115, 31.3 mm SL, male, Los Amates, Guatemala. Views (a) left lateral, (b) dorsal, (c) ventral, and (d) radiograph of holotype. Photos by © California Academy of Sciences.