Leporinus apollo, Sidlauskas & Mol & Vari, 2011, Sidlauskas & Mol & Vari, 2011

Sidlauskas, Brian L, Mol, Jan H. & Vari, Richard P., 2011, Dealing with allometry in linear and geometric morphometrics: a taxonomic case study in the Leporinus cylindriformis group (Characiformes: Anostomidae) with description of a new species from Suriname, Zoological Journal of the Linnean Society 162 (1), pp. 103-130: 119-126

publication ID

http://doi.org/ 10.1111/j.1096-3642.2010.00677.x

persistent identifier

http://treatment.plazi.org/id/03B8FA36-495B-B22B-FC25-AAF0FBBAFE13

treatment provided by

Valdenar

scientific name

Leporinus apollo
status

SP. NOV.

LEPORINUS APOLLO   SP. NOV.

Leporinus cf. cylindriformis, Willink & Sidlauskas 2006: 106   (photograph, partial morphometrics and meristics of specimen designated herein as holotype, suggestion of undescribed status).

Leporinus  

Leporinus apollo cylindriformis   (holotype) L. eporinus apollo   (holotype)

Standard length 25.2–170.7 (64.9 ± 75.4) 91.5–148.3 (113.5 ± 18.5) 62.4–132.3 (83.1 ± 25.8)

1 Snout to dorsal-fin origin 46.4–51.6 (48.7 ± 2.6) 48.0–51.8 (49.6 ± 1.2) 48.6–50.1 (49.4 ± 0.6)

2 Snout to adipose-fin origin 85.5–87.5 (86.5 ± 1.0) 87.8–90.3 (88.6 ± 0.9) 85.6–87.5 (86.8 ± 0.8)

3 Snout to anal-fin origin 78.9–83.1 (80.7 ± 2.1) 83.4–87.1 (84.7 ± 1.2) 79.0–81.9 (80.8 ± 1.2)

4 Snout to pelvic-fin insertion 51.3–54.6 (52.6 ± 1.7) 52.3–56.1 (53.8 ± 1.1) 50.3–52.3 (51.2 ± 0.8)

5 Snout to pectoral-fin insertion 28.9–35.7 (32.0 ± 3.4) 27.5–30.3 (28.8 ± 0.9) 27.4–30.5 (28.6 ± 1.1)

6 Dorsal origin to pectoral-fin insertion 27.2–28.7 (27.8 ± 0.8) 30.5–33.2 (32.4 ± 0.8) 29.4–31.8 (30.5 ± 0.9)

7 Dorsal origin to pelvic-fin insertion 24.7–26.6 (25.6 ± 1.0) 29.1–33.6 (31.6 ± 1.4) 25.2–28.3 (26.5 ± 1.2)

8 Dorsal origin to anal-fin origin 39.2–43.6 (41.4 ± 2.2) 43.6–47.8 (46.3 ± 1.2) 40.0–42.6 (41.4 ± 1.0)

9 Dorsal origin to anal-fin insertion 48.8–51.4 (50.0 ± 1.3) 46.3–52.4 (50.6 ± 1.8) 45.9–48.0 (47.2 ± 0.8)

10 Dorsal origin to hypural joint 51.9–55.6 (54.3 ± 2.1) 53.3–56.5 (55.1 ± 1.2) 54.1–56.6 (55.3 ± 1.0)

11 Dorsal origin to adipose-fin origin 40.8–41.6 (41.3 ± 0.4) 41.0–44.0 (42.4 ± 1.0) 39.1–41.2 (40.4 ± 0.7)

12 Length of dorsal-fin base 14.9–17.0 (15.9 ± 1.1) 15.0–17.4 (16.0 ± 0.8) 14.6–15.9 (15.2 ± 0.5)

13 Dorsal-fin insertion to pelvic-fin origin 22.5–24.0 (23.3 ± 0.7) 27.1–30.9 (28.8 ± 1.2) 24.0–25.8 (25.0 ± 0.8)

Leporinus amazonicus   Leporinus friderici   Leporinus klausewitzi  

Standard length 48.9–95.3 (64.9 ± 21.2) 117.1–128.0 (122.5 ± 7.7) 33.6–158.9 (80.6 ± 44.8) 1 Snout to dorsal-fin origin 50.3–53.5 (52.3 ± 1.4) 44.6–46.1 (45.4 ± 1.0) 45.9–52.1 (48.5 ± 1.4) 2 Snout to adipose-fin origin 85.6–89.4 (87.2 ± 1.7) 84.4–86.7 (85.5 ± 1.7) 83.3–89.6 (86.4 ± 1.9) 3 Snout to anal-fin origin 82.2–84.1 (82.9 ± 0.9) 81.0–81.2 (81.1 ± 0.1) 78.0–86.3 (83.0 ± 2.1) 4 Snout to pelvic-fin insertion 53.0–54.8 (54.2 ± 0.8) 47.0–49.3 (48.1 ± 1.6) 49.2–53.3 (50.7 ± 1.1) 5 Snout to pectoral-fin insertion 30.5–32.5 (31.2 ± 0.9) 24.2–25.8 (25.0 ± 1.2) 25.0–32.1 (28.1 ± 2.5) 6 Dorsal origin to pectoral-fin insertion 32.1–33.9 (33.1 ± 0.9) 26.6–27.4 (27.0 ± 0.6) 23.9–30.5 (28.3 ± 1.8) 7 Dorsal origin to pelvic-fin insertion 31.1–33.7 (32.3 ± 1.2) 20.6–22.7 (21.6 ± 1.5) 22.0–26.6 (24.8 ± 1.1) 8 Dorsal origin to anal-fin origin 43.1–46.2 (44.5 ± 1.5) 42.0–43.6 (42.8 ± 1.2) 39.6–46.9 (43.6 ± 2.2) 9 Dorsal origin to anal-fin insertion 46.8–49.1 (48.4 ± 1.1) 49.1–51.7 (50.4 ± 1.9) 44.6–53.0 (49.5 ± 2.5) 10 Dorsal origin to hypural joint 53.4–54.4 (53.9 ± 0.4) 58.9–60.2 (59.6 ± 0.9) 50.9–59.2 (55.7 ± 2.1) 11 Dorsal origin to adipose-fin origin 36.0–39.9 (38.3 ± 1.7) 44.1–45.4 (44.7 ± 0.9) 36.3–45.1 (41.4 ± 2.6) 12 Length of dorsal-fin base 15.5–16.7 (16.4 ± 0.6) 14.7–14.8 (14.7 ± 0.0) 12.8–17.2 (15.2 ± 1.1) 13 Dorsal-fin insertion to pelvic-fin origin 28.2–30.2 (29.2 ± 0.9) 19.1–20.1 (19.6 ± 0.7) 20.0–25.7 (23.3 ± 1.3) 14 Dorsal-fin insertion to adipose-fin origin 20.4–23.5 (22.4 ± 1.4) 29.1–30.5 (29.8 ± 1.0) 21.4–30.2 (26.3 ± 2.4) 15 Dorsal-fin insertion to anal-fin origin 28.8–30.6 (29.9 ± 0.8) 29.7–29.9 (29.8 ± 0.2) 22.9–33.1 (28.9 ± 2.6) 16 Dorsal-fin insertion to anal-fin insertion 32.1–32.8 (32.4 ± 0.3) 34.1–35.8 (35.0 ± 1.2) 29.2–37.9 (34.2 ± 2.5) 17 Adipose-fin origin to anal-fin origin 19.6–20.8 (20.2 ± 0.5) 13.7–13.7 (13.7 ± 0.1) 13.3–16.8 (15.2 ± 0.9) 18 Adipose-fin origin to anal-fin insertion 15.0–15.6 (15.3 ± 0.3) 10.9–12.2 (11.5 ± 0.9) 10.1–13.4 (12.3 ± 0.8) 19 Adipose-fin origin to hypural joint 13.8–15.6 (14.8 ± 0.8) 17.3–18.0 (17.7 ± 0.5) 10.3–18.7 (13.7 ± 1.7) 20 Length of anal-fin base 8.7–10.9 (10.2 ± 1.0) 6.9–8.2 (7.6 ± 0.9) 7.7–11.7 (9.6 ± 1.1) 21 Anal-fin insertion to hypural joint 9.6–11.1 (10.3 ± 0.6) 10.3–10.9 (10.6 ± 0.4) 7.6–12.6 (9.5 ± 1.3) 22 Pelvic-fin insertion to anal-fin origin 28.2–29.8 (28.9 ± 0.8) 30.4–31.8 (31.1 ± 1.0) 29.5–36.6 (33.0 ± 2.6) 23 Pelvic-fin insertion to adipose-fin origin 38.9–42.9 (41.1 ± 1.8) 39.8–39.8 (39.8 ± 0.0) 46.0–44.0 (39.8 ± 2.3) 24 Pelvic-fin insertion to hypural joint 45.7–48.4 (47.0 ± 1.1) 49.3–52.9 (51.1 ± 2.5) 46.4–53.1 (49.8 ± 1.9) 25 Pelvic-fin insertion to pectoral-fin insertion 21.6–24.6 (23.4 ± 1.3) 23.3–25.2 (24.3 ± 1.3) 20.2–26.2 (24.1 ± 1.9) 26 Greatest body depth 31.9–33.9 (32.9 ± 1.0) 20.2–22.8 (21.5 ± 1.8) 23.3–27.3 (25.2 ± 1.1) 27 Greatest body width 13.6–14.9 (14.1 ± 0.6) 11.5–12.4 (11.9 ± 0.6) 11.6–15.9 (13.5 ± 1.1) 28 Caudal-peduncle depth 11.6–12.0 (11.8 ± 0.2) 8.1–8.8 (8.4 ± 0.5) 8.1–10.7 (9.5 ± 0.7) 29 Head length 27.2–31.7 (29.3 ± 1.8) 23.3–23.9 (23.6 ± 0.5) 23.6–30.4 (26.9 ± 2.4)

Leporinus aff. cylindriformis, Mol et al. 2007: 365   (historic presence in region now spanned by Brokopondo reservoir, Suriname River drainage, Suriname).

Holotype: SURINAME: Saramacca: FMNH 116827, 111.1 mm, Coppename River, Sidonkrutu , sand island and channel (04°31′51″N, 56°30′56″W) J. Mol, B. Chernoff, P. Willink & M. Cooperman, 9.iii.2004. GoogleMaps  

Paratypes: SURINAME: Nickerie: USNM 225993 View Materials , 7 specimens, 68.8–93.6 mm (2 CS, 75.1–89.9 mm)   ; NZCS F-7067 (out of USNM 225993 View Materials ), 1 specimen, 82.3 mm, Corantijn River drainage, Matappi Creek (05°01′N, 57°17.5′W), H. M. Madarie, 17.v.1980 GoogleMaps   . Sipaliwini: MHNG 2672.085 View Materials , 1 specimen, 113.8 mm   ; NZCS F-7068 (out of MHNG 2672.085 View Materials ), 1 specimen, 110.8 mm, Corantijn River at Wonotobo Falls , around camp (4°11′0.5″N, 57°57′25.1″W), J. I. Montoya-Burgos GoogleMaps   , R. Covain & P. Hollanda Carvallo   . MHNG 2673.002 View Materials , 3 specimens, 48.6–127.7 mm, Corantijn River, Kaw Falls (04°59′48.3″N, 57°37′49.5″W), J. I. Montoya-Burgos GoogleMaps   , R. Covain & P. Hollanda Carvallo   . MHNG 2673.083 View Materials , 1 specimen, 118.0 mm, Gran Rio, Suriname River drainage, at Assigon (3°57′3.9″N, 55°32′1.6″W), J. I. Montoya-Burgos GoogleMaps   , R. Covain & P. Hollanda Carvallo   . MHNG 2673.098 View Materials , 1 specimen, 133.9 mm, Gran Rio, Suriname River drainage, at Kossindo in front of Cajana village (3°54′5.4″N, 55°34′26.5″W) J. I. Montoya-Burgos GoogleMaps   , R. Covain & P. Hollanda Carvallo   .

Diagnosis: Leporinus apollo   can be distinguished from all other members of Leporinus   except L. cylindriformis   , L. niceforoi   , L. cf. niceforoi   , L. ortomaculatus   , and a possibly undescribed species from the Amazon drainage ( Leporinus sp.   , see discussion below) by the combination of an extremely dorsoventrally slender body (percentage of body depth immediately anterior to the dorsal-fin origin in standard length in range of 18–23%) and a pigmentation pattern including three or four large, black spots centred along the lateral-line-scale row. Leporinus apollo   can be distinguished from L. niceforoi   , L. ortomaculatus   , and Leporinus sp.   by the possession of six scales in a transverse series above the lateral line (in all but one examined specimen, which has five scales in that series) versus five scales in that series in all examined specimens of L. niceforoi   , L. ortomaculatus   , and Leporinus sp.   It can be distinguished from L. cf. niceforoi   by the percentage of body depth in standard length of 18.3–22.9% versus 23.3– 27.3% and by the typical transverse scale count at the dorsal and pelvic fin origins of 6/5 (5/5 and 6/4 each occur once) versus a typical count of 5/4 (occasionally 5/5, once 6/4, never 6/5). Leporinus apollo   can be distinguished from L. cylindriformis   and L. niceforoi   by the presence of a small, dark spot on the body immediately ventral to the seventh, eighth, or ninth scale of the lateral line, versus the absence of such a spot in those two species. Leporinus apollo   can be further distinguished from L. cylindriformis   by the possession of a dark spot centred immediately posterior to the opercle and slightly ventral to the lateralline-scale row (versus the lack of such a spot), the presence of a series of nine to 14 dark bars across the dorsal surface of the body that terminate ventrally in darker areas that form an irregular stripe situated dorsal and parallel to the lateral line scale row (versus the lack of well-developed transverse bars and absence of such dark areas), and by the percentage of body width in standard length in the range of 9.7– 14.0% (versus 15.2%).

Description: Meristic counts for holotype and paratypes in Table 5, morphometrics in Table 6. Body fusiform and very slender, with body depth 18.3– 22.9% of SL. Head elongate and roughly triangular in lateral profile, with depth measured at posterior terminus of opercle 62.7–72.3% of head length. Greatest depth and width of body located at vertical through dorsal-fin origin. Profile of predorsal region of body nearly straight, with only slight convexity. Dorsal fin-base and profile of body from base of last dorsal-fin ray to adipose fin straight and posteroventrally slanted. Body with distinct vertical constriction in region posterior of adipose fin and anterior of hypural plate. Adipose-fin origin located on vertical through base of fourth branched anal-fin ray. Ventral margin of head and body straight and posteroventrally inclined from tip of lower jaw to inflection point directly ventral to dorsal-fin origin. Ventral profile of body posterodorsally angled posterior to that point. Pelvic-fin insertion located at vertical through base of second branched dorsal-fin ray.

Mouth small and slightly subterminal; upper and lower jaws meet along horizontal tangent to ventral margin of eye. Ventral margin of upper jaw sinusoidal, reflecting oblique angle between ventral margin of premaxilla and maxilla. Margins of upper and lower lips with slight ridges. Premaxilla and maxilla each typically bear four teeth. Teeth on each jaw graded in size with symphyseal teeth largest and terminal tooth of series distinctly smaller. Single row of replacement teeth present in crypt within dentary. Dentary teeth fit far behind teeth of upper jaw in closed mouth, resulting in pronounced overbite.

Anterior nare tubular and anteriorly directed. Posterior nare rhomboidal or in shape of figure of eight, with approximately ten olfactory ridges visible externally. Nares situated on horizontal bisecting ventral hemisphere of pupil. Antorbital, infraorbitals, and supraorbital with general forms comparable to that illustrated for L. fasciatus   in Sidlauskas & Vari (2008: fig. 9) other than for a wider nasal and for the fusion of the fourth and fifth infraorbitals into a single element with posteriorly directed branch of laterosensory canal midway along its vertical extent.

Four branchiostegal rays with medial ray smallest. Fleshy opercular membrane fused to isthmus.

Anal fin preceded by single very small additional unbranched ray, visible in radiographs but not externally and not included in counts. First externally visible unbranched ray of anal fin one-half or less length of second unbranched ray. Branched rays of anal fin articulated to second to ninth proximal and distal pterygiophores. Dorsal fin preceded by single very small additional unbranched ray, visible in radiographs but not externally and not included in counts. First externally visible unbranched ray of dorsal fin slightly more than one-half length of second unbranched dorsal-fin ray. Branched rays of dorsal fin articulated to second through 11th proximal and distal pterygiophores. First dorsal pterygiophore typically lies between neural processes of 11th and 12th or tenth and 11th vertebrae, but in one individual between neural processes of ninth and tenth vertebrae.

Pectoral fin elongate, with second and third unbranched rays longest. Adipose fin elongate with convex upper margin and straight or concave ventral margin. Caudal-fin lobes distinctly pointed, with longest rays those immediately ventral to dorsalmost rays and immediately dorsal to ventralmost rays.

Body fully scaled. Fins not scaled except for row of small scales at base of anal fin and overlaying basal portion of middle caudal-fin rays.

Coloration in alcohol: Overall ground colour pale yellow to light brown, darkest dorsal to lateral line and palest on ventral surface of head, gular region and portion of body ventral to third scale row below lateral-line scale row. Dorsal surface of head, upper jaw, and area lateral to infraorbital series dusky. Skin covering upper margin of maxilla distinctly darker than skin covering remainder of maxilla, resulting in pigmentation in the form of thin moustache.

Four large dark spots ranging in shape from circular to horizontally elongate ellipses located along lateral surface of body. Anterior spot centred on first scale row ventral to lateral-line-scale row and posterior three spots centred on lateral-line scale row. First large spot begins just posterior to fleshy flap of opercle and extends posteriorly across approximately three scales. Anterior limit of second large spot situated at vertical through base of second branched dorsal-fin ray, with spot extending posteriorly across six or seven scales. Anterior limit of third large spot located immediately posterior to vertical through posterior limit of anus, with spot extending posteriorly across approximately five scales. Fourth large spot centred over caudal peduncle, spanning approximately five scales.

Variable number of small accessory spots positioned along second or third horizontal scale row ventral to lateral-line scale row. All examined specimens with at least one such small spot centred on second horizontal scale row below lateral-line scale row and located ventral to seventh, eighth, or ninth lateral line scale. Most specimens with additional small spot located midway between and slightly ventral to second and third large spots (this spot absent in all three specimens in MHNG 2673.002, see Fig. 2 View Figure 2 ). Some specimens ( MHNG 2673.083, MHNG 2673.098) with as many as seven additional small spots arranged in irregular horizontal line across ventrolateral portion of body.

Nine to 14 (typically 13 or 14) dark transverse bars extending across dorsal surface of body, each terminating on left and right side in area of more intense dark pigmentation positioned over third (anteriorly) or second (posteriorly) horizontal scale row dorsal to lateral-line-scale row. Contrast between transverse dorsal bars and ground coloration typically pronounced, but some specimens ( MHNG 2672.085, NZCS F-7068) with pigmentation of dorsal transverse bars muted and less intense. Rayed fins hyaline except for widely dispersed melanophores outlining caudal-fin rays. Adipose fin pale overall, but occasionally with dusky border.

Coloration in juveniles (two smallest specimens in MHNG 2673.002, both measuring approximately 49 mm SL) similar overall to pigmentation in adults, with four large lateral spots, transverse dorsal bars, and horizontal series of smaller spots dorsal and ventral to lateral-line-scale row all in evidence. Second and third large lateral spots extend further ventrally in juveniles than in adults, with dark pigmentation in juveniles approaching, but not contacting, bases of pectoral and anal fins.

Coloration in life: Based upon two photographs taken immediately after capture and kindly provided by R. Covain: ground colour pale yellow, with pectoral and pelvic fins and exposed portions of interopercle and subopercle displaying more intensely yellow coloration. Margin of adipose fin orange or red. Pigmentation otherwise as described for preserved material.

Growth and ontogeny: Small to moderate sized species of Leporinus   , with maximum known body size of 133.9 mm SL. Juveniles with proportionally larger heads than adults, with percentage of head length in SL about 23% in smallest specimens (~ 49 mm SL) and about 26% in largest specimens. Slightly subterminal mouth position invariant amongst examined specimens, although an ontogenetic shift in mouth position may occur in very small juveniles as it does in many other members of the Anostomidae   ( Santos, 1980; Sidlauskas et al., 2007).

Geography: Known only from the Coppename, Corantijn, and Suriname rivers of western and central Suriname ( Fig. 12 View Figure 12 ), which flow from the Guyana Shield into the Atlantic Ocean. The historic distribution included the region of the Suriname river currently spanned by the Brokopondo reservoir, as two specimens were collected there in 1963–64 prior to the closure of the dam and the creation of the reservoir ( Mol et al., 2007, listed as L. aff. cylindriformis   in their appendix 1) Extensive subsequent collections in Brokopondo have yielded no additional specimens of L. apollo   , suggesting that it is now extirpated from the reservoir ( Mol et al., 2007).

Phylogenetic placement: Dissection of the CS specimens of L. apollo   reveals the species to lack the synapomorphies of Hypomasticus   (clade 4 of Sidlauskas & Vari, 2008), but to possess instead a character distribution that would nest the species within clade 8 of the phylogeny advanced in that publication. As L. apollo   also lacks the synapomorphies of Sidlauskas & Vari’s (2008) clade 12 (which contains the majority of genera within the Anostomidae   that nest within clade 8) it clearly fits within the current concept of Leporinus   .

Etymology: We name the species ‘ apollo   ’ after the god of the sun, music and healing in Greek and Roman mythology. The extremely slender form of the new species is reminiscent of the arrow that was Apollo’s favoured weapon and predominant symbol, and the yellow cast of the body and fins and the rounded shape of the lateral markings evoke the sun that was one of Apollo’s primary aspects.

Comparison with Leporinus gossei: As   noted by Willink & Sidlauskas (2006), L. apollo   has a very similar colour pattern to that of L. gossei   , a rare species known solely from French Guiana (see photograph in Planquette, Keith & Le Bail, 1996: 155). Although no specimens of L. gossei   were available for study, L. gossei   is clearly a much deeper bodied species than is L. apollo   . The meristics reported for the two species are also highly dissimilar, with six scales in the upper transverse series and 40–43 total lateral-line scales in L. apollo   versus four (rarely five) upper transverse scales and 36–37 (rarely 38–39) lateral-line scales in L. gossei   . Notwithstanding the geographical proximity of the two species, there is no question that L. gossei   belongs to the assemblage of species centred on L. friderici   and that L. gossei   and L. apollo   are distinct.

Remarks on differentiation from Leporinus cylindriformis: Despite   their similarity in meristics and most morphometrics, the coloration of L. apollo   differs substantially from the current pigmentation of the L. cylindriformis   holotype and from the original illustration of that specimen, which was prepared around 1870 on behalf of Agassiz and reproduced by Borodin (1929). In particular, the Suriname material possesses a dark mark behind the opercle, another mark ventral to approximately the eighth scale of the lateral line, and many dark bands across the dorsal surface of the body that terminate ventrally in yet darker areas. None of those dark marks appear in the original drawing of the holotype. Comparison of the coloration in the Suriname material with the holotype itself is complicated by the 150 + years since the preservation of the specimen, which is now rather faded. Although the three horizontally elongate spots along the lateral line scale row that appear in Borodin (1929) can still be seen clearly on the holotype ( Fig. 1 View Figure 1 ), these are less extensive than the marks in comparable locations in L. apollo   . More significantly, the L. cylindriformis   holotype ( Fig. 1 View Figure 1 ) and the original illustration ( Borodin, 1929: pl. 10) lack several of the other prominent dark marks present in L. apollo   . Most notably, there is definitely no dark spot below the eighth scale of the lateral line in the L. cylindriformis   holotype, and this spot represents the most diagnostic aspect of coloration separating the holotype from the Suriname specimens.

Although the holotype definitely does not currently have the prominent markings that characterize L. apollo   , the possibility exists that it did at an earlier point in ontogeny. The L. cylindriformis   holotype at 188.0 mm SL is approximately 45 mm longer than the largest known specimen of L. apollo   (133.9 mm SL), and thus the apparent differences in coloration might diagnose different developmental stages of the same species, not separate species. Such a scenario would require the loss of a very considerable amount of pigment over a fairly short interval of growth. Given that the largest examined specimens of L. apollo   are as darkly pigmented as the smallest, we consider this scenario to be highly unlikely. Unfortunately, a search of several museums has revealed no additional material of L. cylindriformis   that could clarify the issue.

Identification of the material described herein as L. apollo   as L. cylindriformis   would also require explanation of the disjunct distribution of the species in the Amazon and in three of the coastal drainages of Suriname, without that species also occurring in Brazil’s Amapá state or in French Guiana. Such a geographical distribution is not entirely implausible and could result from vicariance, dispersal via the Amazonian freshwater plume ( Muller-Karger, McClain & Richardson, 1988; Hu et al., 2004), or local extinction in the intermediate drainages. Although such a distribution is not impossible, this would be a novel biogeographical pattern; amongst the fish species that have been critically reviewed in recent years we are not aware of any that are distributed in Suriname and the central Amazon without intervening populations. Taken as a whole, the scenario of synonymy is significantly more convoluted than the alternative that L. apollo   represents a new species closely allied to L. cylindriformis   .

As a final enigma, the absence of additional specimens of L. cylindriformis   begs explanation. Is the species naturally rare or an inhabitant of rarely sampled habitats such as rapids? Does the specimen represent a species that is now extirpated in the vicinity of Porto de Moz? If so, might a population still exist elsewhere, perhaps further upriver along the Rio Xingu? The possibilities are numerous, but any answers must remain speculative unless new specimens are discovered in a museum collection or in the vastness of the Amazon.

FMNH

Field Museum of Natural History

CS

Musee des Dinosaures d'Esperaza (Aude)

NZCS

University, National Zoological Collection of Suriname

R

Departamento de Geologia, Universidad de Chile

MHNG

Museum d'Histoire Naturelle

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Characiformes

Family

Anostomidae

Genus

Leporinus

Loc

Leporinus apollo

Sidlauskas, Brian L, Mol, Jan H. & Vari, Richard P. 2011
2011
Loc

Leporinus aff. cylindriformis

Mol JH & Merona B & Ouboter PE & Sahdew S 2007: 365
2007
Loc

Leporinus cf. cylindriformis

Willink PW & Sidlauskas B 2006: 106
2006