Acestrocephalus sardina ( Fowler, 1913 ) Charax sardina Fowler, 1913: 566 Böhlke, 1984: 32 Eschmeyer, 1998: 1507 Acestrocephalus Cyrtocharax sardina Fowler, 1950: 312 A. sardina A. boehlkei A. pallidus A. nigrifasciatus A. acutus A. stigmatus A. maculosus Cynopotamus ( Acestrocephalus ) sardina Géry, 1972: 28 Acestrocephalus sardina Menezes, 1976: 39 Eschmeyer, 1998: 1507 Acestrocephalus ginesi Lasso & Taphorn, 2000: 443 Acestrocephalus cf. ginesi Lima et al ., 2005: 166 Description of five new species of Acestrocephalus Eigenmann and redescription of A. sardina and A. boehlkei (Characiformes: Characidae) Menezes, Naércio A. Neotropical Ichthyology 2006 2006-12-31 4 4 385 400     Acestrocephalus sardina( Fowler, 1913) Figs. 2-3     Charax sardina Fowler, 1913: 566, fig. 2 ( typelocality: Madeira River, about 200 mileseast of W. long. 60º20’W, Brazil);  Böhlke, 1984: 32(catalog);  Eschmeyer, 1998: 1507(catalog).   Table 1.Frequency distribution of scales above lateral line in the species of Acestrocephalus.    Cyrtocharax sardina;  Fowler, 1950: 312(listed).    Scales above lateral line 10 11 12 13 14 15    A. sardina 1 51 24    A. boehlkei 12 6 3    A. pallidus 48 12    A. nigrifasciatus 7 5    A. acutus 5 40 1    A. stigmatus 4 2    A. maculosus 6    Cynopotamus( Acestrocephalus) sardina;  Géry, 1972: 28(diagnosis in key).    Acestrocephalus sardina;  Menezes, 1976: 39(in part, only specimens from rioAripuanã, MZUSP 10423);  Eschmeyer, 1998: 1507(catalog); Lucena & Menezes, 2003: 200 (in check list; maximum length, distribution).   Acestrocephalus ginesi Lasso & Taphorn, 2000: 443(type locality: Venezuela, Apure State, Río Cinaruco, playa en frente de Laguna Larga, Distrito Muñoz( 06º33’45"N 67º24’W); holotypenot seen; topotypes examined); Lucena& Menezes, 2003: 200 (in check list; maximum length; distribution); Lasso, Lew, Taphorn, Nascimiento, Lasso-Alcalá& Machado-Allison, 2004: 148 (listed).    Acestrocephaluscf. ginesi;   Lima et al., 2005: 166(description; habitat; feeding habits; fisheries).   Material examined.  ANSP 39307, holotype, 31.4 mmSL, (data taken by H.A. Britski; digital image and radiographs examined), Brazil, Mato Grosso: rio Madeirasystem, by Edgar A. Smith, 1912;  MZUSP 10423, 1, 89 mmSL, Aripuanã: rio Aripuanã, 9º34’S 59º25’W;  MZUSP 60396, 1, 94 mmSL, rio Aripuanã, Porto de Balsaon the road between Colmiza and Panela, 10º09’S 67º27’W.  MZUSP 29237, 11, 49-65 mmSL, Amazonas: ilha de Tamaquaré, rio Negro;  MZUSP 29239and 29241, 36, 50-71 mmSL, Marauiá: rio Negro;  MZUSP 29240, 5, 51-66 mmSL, Massarabi: rio Negro;  MZUSP 31140, 1, 84 mmSL, Cachoeira de São Gabriel: rio Negro;  MZUSP 29238and 31036, 6, 47.5-86 mmSL, Paranádo Jacaré: rio Negro.  MZUSP 81209and 81259, 4, 81-94 mmSL, rio Tiquié, indian village of Cururu, 0º16’N 69º54’W.  MZUSP 56558, 2, 62and 65 mmSL, rio Jutaí, 2º57’S 67º0’W;  MZUSP 35498, 3, 52-69 mmSL, Venezuela, Apure: Río Orinocosystem, 1º55’N 67º04’W.  MZUSP 35499, 5, 53.7-82.6 mmSL, Rio Negro: Río Negro, near San Carlos do Rio Negro.   Diagnosis.  Acestrocephalus sardinais most similar to  A. nigrifasciatus, both having identical color patterns consisting of a triangular dark blotch on caudal-fin base, anteriorly continuous with a longitudinal dark stripe extending along lateral line ( Figs. 3and 12) not found in any other species of the genus. In addition, both have the eye diameter greater than their congeners ( Fig. 4).  Acestrocephalus sardinacan be distinguished from  A. nigrifasciatusby having fewer horizontal scale rows above lateral line (10-12 vs13-14) and below (10-12 vs12-13). See Tables 1and 2.  Acestrocephalus nigrifasciatusalso has the muscular hiatus over the anterior part of the swim bladder which is longer than and narrower than  A. sardinaand the fibers of the obliquus inferiorismuscle, visible in the latter are entirely covered by the obliquus superiorismuscle in the former (compare Figs. 5a and 5e).   Description.Morphometrics of holotypeand additional specimens presented in Table 3. Meristic and morphometric data based on all lots for this species because no statistical 388 Description of five new species of  Acestrocephalusdifferences found among population samples studied, in spite of wide distribution of species. Body elongate, relatively large (SL= 31.4-90 mm), compressed and not very deep; greatest body depth between occiput and dorsal-fin origin near middle of pelvic-fin length. Dorsal body profile nearly straight, but inclined ventrally from snout tip to base of supraoccipital spine, slightly convex between that point and dorsal-fin origin, nearly straight along dorsal-fin base, and straight or nearly so from base of dorsal-fin termination to caudal peduncle. Ventral body profile convex from tip of lower jaw to anal-fin origin, nearly straight and dorsally inclined along anal-fin base and slightly concave from base of posterior most analfin ray to origin of procurrent caudal-fin rays. Snout pointed. Lower jaw included in upper jaw when mouth is fully closed. Mouth angled posteroventrally from anterior tip of snout to posterior part of mandibular joint. Maxilla extending slightly beyond vertical line passing through posterior border of orbit.   Fig. 3.  Acestrocephalus sardina, MZUSP81209, 93 mm SL, immature female, rio Tiquié, rio Negro drainage.   Table 2.Frequency distribution of scales below lateral line in the species of Acestrocephalus.    Scales below lateral line 10 11 12 13    A. sardina 58 16 2    A. boehlkei 18 3    A. pallidus 5 55    A. nigrifasciatus 5 7    A. acutus 1 22 23    A. stigmatus 3 3    A. maculosus 6   Table 3.Morphometrics of  Acestrocephalus sardina. Standard length is expressed in mm; measurements through head length are percentages of standard length; last four entries are percentages of head length. Specimens are from ANSP 39307 (holotype), MZUSP 29237-241, 31140, 31036, 81209, 35498, 35499, 60396, 10423, 56558.    Characters Holotype N Range Mean SD  Standard length 31.4 76 31.4-90.0  Body depth 26.1 66 24.9-30.8 28.0 1.2  Snout to dorsal-fin origin 49.0 76 48.2-50.3 50.1 0.9  Snout to pectoral-fin origin 31.2 76 28.6-33.4 30.4 1.2  Snout to pelvic-fin origin 42.0 76 40.4-45.6 43.0 1.2  Snout to anal-fin origin 57.3 76 56.1-62.7 58.9 1.5  Caudal peduncle depth 8.6 76 6.1-8.6 7.9 0.3  Caudal peduncle length 10.8 76 9.2-12.6 10.7 0.8  Pectoral-fin length 17.5 76 16.2-19.4 17.6 0.6  Pelvic-fin length 16.8 76 13.1-17.8 15.5 0.9  Dorsal-fin base length 11.1 76 11.0-14.3 12.7 0.6  Dorsal-fin height 27.4 76 22.7-28.0 25.1 1.1  Anal-fin base length 37.2 76 31.4-37.3 34.0 1.0  Anal-fin lobe length 20.0 76 16.3-21.8 18.3 1.1  Eye to dorsal-fin origin 35.0 76 31.7-36.0 33.2 0.8  Dorsal-fin origin to caudal-fin base 52.2 76 49.5-54.3 51.8 0.9  Head length 30.2 76 30.1-33.3 31.8 0.7  Horizontal eye diameter 31.5 76 31.3-37.4 34.4 1.2  Snout length 28.4 76 26.0-31.5 28.0 0.9  Least interorbital width 21.0 76 16.6-21.4 19.3 1.0  Upper jaw length 67.3 76 62.4-69.1 65.2 1.4   Fig. 4. Scatter plot of eye diameter on head length for specimens of  Acestrocephalus sardina,  A. boehlkei,  A. pallidus,  A. nigrifasciatusand  A. acutus. Acestrocephalus sardinaand  A. nigrifiasciatushave larger eye diameters than the other species suggesting the recognition of two species groups with respect to this character (see diagnoses of  A. sardinaand  A. nigrifasciatus).   Fig. 5.Schematic drawings of external view of muscles covering the anterior portion of the swim bladder in A –  Acestrocephalus sardina(MZUSP 29241); B –  A. boehlkei(MZUSP 38699); C –  A. maculosus(MNRJ 12657); D –  A. stigmatus(MZUSP 10422); E –  A. nigrifasciatus(MCP 30420); F –  A. acutus(MNRJ 17612); G –  A. pallidus(MZUSP 73471). Anterior towards left; 1 plr (first pleural rib); 2 plr (second pleural rib); os ( obliquus superioris); ls ( lateralis superficialis); oi ( obliquus inferioris). Not drawn to scale. Dorsal-fin rays ii, 9 inall specimens, n=76, including holotype. Posterior most ray unbranched, n=76. Adipose fin present. Anal-fin rays iv,32 (iv or v, usually iv unbranched, branched rays mean=30.3, range 28-33, n=76, posterior ray split to its base and counted as 1). Moderately developed anterior anal-fin lobe including anterior unbranched rays and first 7-8 branched rays. No hooks on anterior rays of males, but very few sexually mature males represented in examined sample. Pectoral-fin rays i,13 (anterior unbranched ray i, n=76) branched rays mean=13.6, range 12-15, n=76. Posterior tips of longest pectoral-fin rays reaching slightly beyond pelvic-fin origin. Pelvic-fin rays i,7, n=76. No hooks on pelvic-fin rays of sexually mature males. Distal tips of longest pelvic-fin rays extending to or slightly beyond anterior border of anus. Principal caudal-fin ray count 10/ 9 inall specimens, n=76.   Fig. 6.Scatter plot of number of maxillary teeth on standard length for specimens of  Acestrocephalus sardina,  A. boehlkei. Acestrocephalus nigrifasciatus,  A. pallidus, and  A. acutus. The figure is not intended to show species differences therefore regression lines were not drawn and regression analyses were not performed. The primary purpose is to express the tendencies of the number of teeth on the maxilla to increase according to an increase in standard length. For the species represented by large number of specimens the data points are widely scattered.   Fig. 7.Scatter plot of number of posterior dentary teeth for specimens of  Acestrocephalus sardina,  A. boehlkei,  A. pallidus,  A. nigrifasciatus, and  A. acutus. The figure is not intended to show species differences therefore regression lines are not drawn and regression analyses were not performed. The primary purpose is to express the tendencies of the number of teeth on the posterior row on the dentary to increase according to an increase in standard length. For the species represented by large number of specimens the data points are widely scattered. Lateral line complete, perforated scales 73 (mean=71.3, range 67-74, n=76). Scale rows above lateral line 12 (mean=11.3, range 10-12, n=76). Scale rows below lateral line 10 (mean=10.3, range 10-12, n=76). Scale rows around caudal peduncle 20 (mean=20.7, range 20-22, n=76).   Fig. 8. Map of northern and central South America showing the geographic distribution of the species of  Acestrocephalus. Some symbols may represent more than one locality. Premaxilla with two slightly enlarged inner conical teeth, an outer row with one anterior canine followed by row of small conical teeth and one posterior canine. Anterior canine outside anterior border of lower jaw when mouth closed. Outer row small conical teeth 8 (mean=7.7, range 7-9, n=75). Maxillary teeth 44 (mean=43.6, range 40-53, n=75). Maxillary teeth conical with tendency to increase in number according to increase in standard length ( Fig. 6). Dentary with outer row of conical teeth of which four anterior most spaced and first and third larger than third and fourth, these followed by posterior row of close-set smaller conical teeth that show tendency to increase in number with increase in standard length ( Fig. 7). Posterior dentary teeth 28 (mean=29.4, range 26-33, n=75). Teeth in inner row on dentary conical, very small, slightly inclined proximally to four anterior spaced larger conical teeth of outer row. Inner row dentary teeth 9 (mean=9.8, range 7-12, n=75). Vertebrae 38 (mean=39, range 38-40, n=35). Total number of gill-rakers on first gill-arch 7 (mean=7, range 6-8, n=76). Muscular hiatus of pseudotympanum ( Fig. 5a) relatively large, dorsally limited by lateralis superficialismuscle, posteriorly by large exposed portion of second pleural rib, anteriorly by small exposed portion of first pleural rib, anteroventrally by large portion of the obliquus superiorisand posteroventrally by small portion of obliquus inferiorismuscle. Small opening anterior to first pleural rib visible.  Color in alcohol.Body pale to dark yellow, slightly darker dorsally than ventrally due to presence of dark chromatophores. Dark chromatophores on dorsal and lateral parts of trunk mostly concentrated along free border of scales. Dorsal part of head from tip of snout to supraoccipital region darker than remaining dorsal surface of body. Premaxilla, median part of maxilla and lower jaw densely pigmented with dark chromatophores. Scattered dark chromatophores on infraorbital and opercular bones. Lateral dark body stripe extending from upper opercle to caudal peduncle where fused with triangular dark blotch on caudal base, dark color extending to base of principal caudal rays. Lateral body stripe narrower anteriorly and posteriorly and sometimes obscured by guanine. Anterior part of lower jaw bordered with dark pigmentation. Mental area of lower jaw with diffuse dark blotch in some specimens. Dorsal-fin origin with black dot extending to base of first unbranched dorsal-fin ray. Pectoral, pelvic, dorsal, and caudal fins pale, with few scattered dark chromatophores.   Distribution.This species is known from tributaries of the rio Madeira, Mato Grosso, rio Jutaí and rio Negro, Amazonas, Braziland of the Orinoco Basin, Venezuela( Fig. 8).   Remarks.Menezes’ redescription of  A. sardina(1976)was based on the examination of two specimens, one of them from rio das Mortes near Xavantina, Mato Grosso. It was mentioned that no differences had been found among them and a small dark blotch at the humeral region was described for the species. Actually, this spot is present only in the specimen from rio das Mortes considered to belong to  A. stigmatusherein described. A dark humeral spot is never present in specimens of  A. sardina.At that time it was predicted that the taxonomic status of  A. sardinawould be cleared up only after a study based on a large series of specimens.   Acestrocephalus ginesiLasso & Taphornis herein considered a junior synonym of  A. sardina. Five paraypes from Río Negro, near San Carlos de Río Negro, Venezuela(MZUSP 53499) and three specimenscollected in the Apure State, near the typelocality were studied and proved to be morphologically indistinguishable from specimens of the population samples representing  A. sardina. [1099,1416,196,219] de Laguna Larga & Lucena & Menezes & Lasso & Lew & Taphorn & Nascimiento & Lasso-Alcala & Machado-Allison Venezuela 6.5625 Distrito Munoz 919 -67.4 Rio Cinaruco 2 387 1 Apure holotype ANSP H. A. Britski & Edgar A. Smith Brazil rio Madeira 2 387 ANSP 39307 1 Mato Grosso holotype MZUSP Aripuana Brazil -9.566667 rio Aripuana 1299 -59.416668 2 387 MZUSP 10423, 1 1 Mato Grosso holotype MZUSP Brazil -10.15 Porto de Balsa 1298 -67.45 rio Aripuana 2 387 MZUSP 60396, 1 1 Mato Grosso holotype MZUSP Brazil rio Negro ilha de Tamaquare 2 387 MZUSP 29237, 11 1 Amazonas holotype MZUSP Brazil rio Negro Marauia 2 387 MZUSP 29239 1 Amazonas holotype [944,1478,746,767] MZUSP Brazil rio Negro Massarabi 2 387 MZUSP 29240, 5 1 Amazonas holotype [839,1477,774,795] MZUSP Brazil rio Negro Cachoeira de Sao Gabriel 2 387 MZUSP 31140, 1 1 Amazonas holotype MZUSP Brazil rio Negro Jacare 2 387 MZUSP 29238 1 Parana holotype MZUSP Brazil 0.26666668 Cururu 1308 -69.9 rio Tiquie 2 387 MZUSP 81209 1 Parana holotype MZUSP Brazil -2.95 rio Jutai 1307 -67.0 2 387 MZUSP 56558, 2, 62 1 Parana holotype MZUSP Venezuela 1.9166667 Rio Orinoco 1307 -67.066666 2 387 MZUSP 35498, 3 1 Apure holotype MZUSP Venezuela Rio Negro San Carlos do Rio Negro Rio Negro 2 387 MZUSP 35499, 5 1 Apure holotype