taxonID	type	description	language	source
D320B92EFFDCF42DEAF78B3CFAE27D6D.taxon	diagnosis	Diagnosis. Amazonspinther is diagnosed among all characid species by the autapomorphic presence of three conspicuous black blotches on the base of the dorsal, anal, and caudal fins (ch. 43; Fig. 1). Amazonspinther is diagnosed among all genera of the Cheirodontinae by two uniquely derived characters, the anteriormost proximal radial of the anal fin with an anteriorly extended lamina entering the abdominal cavity, between the distal portions of the 12 th to 14 th pleural ribs (ch. 44; Fig. 2) (vs. short anteriorly extended lamina, not entering the abdominal cavity and not between pleural ribs), and by the extremely elongate caudal peduncle, corresponding to 27.3 - 30.2 % of SL. Caudal peduncle length is comparatively short in cheirodontines, ranging from 11.0 to 19.6 % of SL. Spintherobolus papilliferus has an elongate caudal peduncle (21.3 - 27.0 % of SL), but shorter than that observed for Amazonspinther. Among all genera of the tribe Cheirodontini, Amazonspinther is diagnosed by two features: a small number of ventral procurrent caudal-fin rays (7 - 9 vs. 11 - 28; Malabarba, 1998: 205 - 207, 209, ch. 42; Weitzman & Malabarba, 1999: 8 - 9, ch. 5; 11 - 16 in Spintherobolus species) (Fig. 3); and hemal spines of one, two, or sometimes three posterior caudal vertebrae directly articulating with the ventral procurrent caudal-fin rays (Fig. 3; vs. hemal spines of at least the four posterior caudal vertebrae directly articulating with the ventral procurrent caudal-fin rays).	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDCF42DEAF78B3CFAE27D6D.taxon	etymology	Etymology. Amazon, in reference to the Amazon basin, and spinther from the Greek spinther, masculine, meaning sparks, fire, in reference to both the closely related genus Spintherobolus and to the appearance of the yellow neuromasts of the head, also observed in Spintherobolus (Fig. 4).	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDFF42AEAB98E3EFB8B7F90.taxon	description	Fig. 1	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDFF42AEAB98E3EFB8B7F90.taxon	materials_examined	Holotype. MCP 38623 (1 unsexed 19.63 mm SL), Brazil, Amazonas, Humaitá-Canutama, stream crossing road Transamazônica about 12 km west of Humaitá to Lábrea, rio Madeira basin, 07 ° 34 ’ 25 ” S 63 ° 06 ’ 39 ” W, 27 July 2004, P. Lehman, F. T. Lima, P. A. Buckup, V. A. Bertaco & J. Pezzi da Silva. Paratypes. All from Brazil, Amazonas: ANSP 187154 (1 unsexed 13.68 mm SL), INPA 28199 (1 unsexed 13.93 mm SL), MCP 37571 (1 female 14.05 mm SL c & s), MNRJ 31096 (2 unsexed 12.79 - 13.56 mm SL), collected with holotype. INPA 28659 (2 unsexed 14.49 mm SL & 14.74 mm SL), Autazes, stream of rio Tupana, rio Madeira basin, around 48 km southeast to the municipality of Careiro, 04 ° 09 ’ 24 ” S 60 ° 08 ’ 40 ” W, 3 July 2007, H. M. V. Espírito Santo, A. V. Galuch & D. Barros. INPA 28660 (2 unsexed 16.32 mm SL & 16.73 mm SL), same locality and collectors as INPA 28659, 5 July 2007. INPA 28661 (3 unsexed 14.72 - 15.41 mm SL), same locality and collectors as INPA 28659, 7 July 2007. INPA 28662 (1 female 19.68 mm SL, 2 unsexed 11.02 mm SL & 12.14 mm SL), Canutama, stream of upper rio Mucuim, about 50 km west of Porto Velho, 08 ° 39 ’ 16 ” S 64 ° 22 ’ 02 ” W, 25 April 2007, F. P. Mendonça & D. Barros. INPA 28663 (1 unsexed 13.86 mm SL), same locality and collectors as INPA 28662, 2 May 2007. INPA 28664 (7 unsexed 11.28 - 19.79 mm SL), same locality and collectors as INPA 28662, 3 May 2007. INPA 28665 (1 female 15.39 mm, 37 unsexed 12.18 - 15.77 mm SL), MCP 42017 (1 female 15.73 mm SL, 9 unsexed 12.24 - 15.82 mm SL), same locality and collectors as INPA 28662, 29 April 2007. MCP 37572, 2 (1 unsexed 14.98 mm SL c & s, 1 unsexed 14.85 mm SL), Canutama, stream of rio Açuá, rio Mucuim drainage, about 136 km southwest of Humaitá on road BR- 319, rio Purus basin, 08 ° 12 ’ 13 ” S 63 ° 53 ’ 01 ” W, 28 July 2004, R. Reis, E. Pereira, F. Langeani & A. Cardoso.	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDFF42AEAB98E3EFB8B7F90.taxon	diagnosis	Diagnosis. The same as for the genus.	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDFF42AEAB98E3EFB8B7F90.taxon	description	Description. Morphometric and meristic data given in Table 1. Largest specimen 19.79 mm SL, possibly a female. General body shape relatively elongate. Greatest body depth at dorsal-fin origin corresponding to most elevated point in dorsal profile; greatest body depth slightly ahead of dorsal fin in females. Dorsal body profile slightly convex from snout to dorsal-fin origin, slightly concave to caudal peduncle. Ventral profile almost straight from isthmus to anal-fin origin. Anal-fin base slightly concave. Caudal peduncle very long, not deep. Two pseudotympanums, one anterior to first pleural rib and another between first and second pleural ribs (Fig. 1). Head short, snout blunt, mouth subterminal. Posterior margin of opercle sinusoidal, with upper portion concave and lower portion convex. Obliquely positioned maxilla; posterior tip at vertical through anterior eye border and below projected longitudinal line through ventral eye border. Dentition examined in two c & s specimens (Fig. 5). Premaxillary teeth 6 or 7, conical. Maxillary teeth 3 or 4, conical. Dentary teeth 7 or 9, 4 or 5 largest tricuspid, 1 bicuspid and 2 or 3 smallest conical. Dorsal-fin rays ii, 9 (8). Dorsal-fin origin at middle body length, slightly posterior to vertical through pelvic-fin ori- gin. Posterior margin of dorsal-fin almost straight or slightly concave. Anal-fin rays iii, 8 (7), 9 (1). Anal-fin border concave with 3 rd unbranched and anterior 1 st- 3 rd branched rays longer, decreasing moderately in length from 4 th- 8 th branched ray. Pectoral-fin rays i, 10 (9). Pectoral fin pointed, 1 st- 3 rd branched fin ray longer, lateral margin straight, posterior margin oblique and straight. Pectoral fin reaching to or slightly beyond pelvicfin origin. Pelvic-fin rays i, 5, i (9). Pelvic fin slightly rounded at tip, reaching anal-fin origin. Principal caudal-fin rays 17 (1), 18 (4), 19 (3). Procurrent caudal-fin rays: dorsal 7 (2), 8 (5), 9 (1), ventral 7 (4), 8 (3), 9 (1). Adipose fin at vertical through middle of caudal peduncle. Caudal-fin lobes equal, somewhat pointed. No hooks on fins. Scales cycloid. Counts estimated on scale pockets: lateral line incomplete with 4 (1), 5 (5) scales, row of longitudinal scales 32, 34 (1); predorsal row 9 (6), 10 (1); scales between lateral line and dorsal-fin origin 4 (8); scales between lateral line and pelvic-fin origin 3 (1), 4 (2). Cleared and stained specimens (2): branchiostegal rays 4; supraneurals 4 (1); precaudal vertebrae, including Weberian apparatus, 15; caudal vertebrae 18 - 19, including posterior half centrum. Anteriormost proximal radial of anal fin with an anteriorly extended lamina slightly entering abdominal cavity unique to A. dalmata, among all known Cheirodontinae (Fig. 2). Upper gill rakers 3, short; lower gill rakers absent (Fig. 6 a). Color in alcohol. General ground body color pale beige. Dorsal midline scales with few black chromatophores on scale borders reaching to caudal peduncle. Scarce or no chromatophores on pseudotympanum area; no humeral blotch. Black chromatophores on mid ventral line between anal-fin base termination and caudal peduncle, forming dotted line. Three conspicuous black blotches on base of dorsal, anal, and caudal fins (Fig. 1). Dorsal blotch formed by black chro- matophores on 1 st and 2 nd unbranched and 1 st to 4 th branched dorsal-fin rays, positioned on base and middle of fin rays, and laterally on body surface close to dorsal-fin base, forming nearly triangular blotch. Anal blotch formed by black chromatophores on 3 rd unbranched and 1 st to 7 th branched anal-fin rays, on middle of anteriormost fin rays, decreasing in size to base of posterior pigmented branched rays, and laterally on body surface close to anal-fin base forming elongated blotch. Caudal black blotch rounded centered at posterior end of caudal peduncle and base of median caudal-fin rays, not reaching upper and lower border of caudal peduncle. Few scattered black chromatophores sometimes present along 2 nd unbranched and 1 st branched dorsal-fin rays. Scarce black chromatophores on base of 1 st branched pectoral fins and 1 st unbranched pelvic fin ray in a few specimens. Adipose fin hyaline. Caudal fin with few scattered black chromatophores on upper and lower lobes, clearer area just behind caudal blotch. Snout with scarce black chromatophores; few chromatophores on upper lip. Epidermis covering fontanels wellpigmented; epidermis covering frontals and parietals, with deep-lying black chromatophores over brain underneath to frontals and parietals. Color in life. Body translucent, allowing view of glass blad- der and vertebral column (Fig. 7). A greenish metallic yellow iridescent line along vertebral column more evident depending on angle of light incidence. Proximal portion of pleural ribs and opercle iridescent (Fig. 7). Sexual dimorphism. No external sexual dimorphism was observed. Four sexed specimens are females, two with immature gonads (MCP 37571, 1 c & s, 14.05 mm SL; INPA 28665, 1, 15.39 mm SL), two with mature gonads (MCP 42017, 1, 15.73 mm SL; INPA 28662, 1, 19.68 mm SL). A small incision was made on left side of abdominal region of holotype (19.63 mm SL), but no discernible gonads were found.	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDFF42AEAB98E3EFB8B7F90.taxon	distribution	Distribution. Amazonspinther dalmata is known from small streams of middle rio Purus (rio Açuá) and middle and lower rio Madeira basins, State of Amazonas, Brazil (Fig. 8). Ecological notes. The holotype of Amazonspinther dalmata was collected syntopically with several characid species, such as Axelrodia lindeae, Iguanodectes spp., Microschemobrycon geisleri, Tyttocharax madeirae, Gnathocharax steindachneri, Phenacogaster beni, Hemigrammus sp., Knodus sp., and with the crenuchids Odontocharacidium aphanes, Elachocharax pulcher, Ammocryptocharax elegans, and Microcharacidium sp. The type locality was characterized by possessing slow current, muddy substratum, and silty, turbid water. There was abundant riparian vegetation, and the maximum depth was 1.3 m (Fig. 9). The site of collection in the tributary of rio Purus (MCP 37572) had perceptible current, some submerged vegetation, transparent water, sandy and muddy substratum, riparian vegetation, and a maximum depth of 1 m.	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDFF42AEAB98E3EFB8B7F90.taxon	etymology	Etymology. The epithet refers to the Portuguese word “ dalmata ”, in allusion to the color pattern of the skin of the dogs of the Dalmatian breed which resembles the color of A. dalmata. The origin of this word is linked to the Dalmatia region currently in Croatia, where the dog breed was possibly developed. A noun in apposition.	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDBF429E8048FF9FB1B7F25.taxon	description	A single most parsimonious cladogram (tree length = 53, Consistency Index = 0.88, Retention Index = 0.92) was obtained from the analysis of 44 characters and 8 taxa (Table 2, excluding the fossil Megacheirodon, discussed below). Amazonspinther was found to be closely related to Spintherobolus, and both genera as sister group to Serrapinnus (Fig. 10). Amazonspinther dalmata is a miniature characid according to Weitzman & Vari’s (1988) definition. Those authors stated that miniature characid fish species mature sexually at less than 20 mm SL, and are not reported to exceed 25 to 26 mm SL in the wild. Females of A. dalmata are fully mature at a very small size (15.73 mm SL), and the largest known specimen reached less than 20 mm SL. Mature males, however, were not found among the specimens examined. The current phylogenetic hypothesis available (Malabarba, 1998) for the small sized cheirodontines is strongly based on secondary sexual characters of males, and the lack of mature males of A. dalmata does not allow the examination of thirteen characters potentially informative to access the relationships of A. dalmata with cheirodontines. Nevertheless the new species is found to share several uniquely derived characters with the species of Spintherobolus as defined by Weitzman & Malabarba (1999), supporting a hypothesis of phylogenetic relationship between A. dalmata and the Neotropical Cheirodontinae. Coding of characters 6, 7, 8, 9, 10, 11, 12, 13, 14, 22, 23, 32 and 37 below depended on the examination of fully mature males. We performed two distinct analyses, one in which all these characters were coded as missing for A. dalmata, and the second with all these characters coded as the outgroup (“ 0 ”) for A. dalmata. Character 28, the relatively short pectoral-fin was also coded as missing in the latter analysis, because the average percentuals of SL would fit in state 1, but minimum and maximum percentiles of SL would not (Appendix 1). In both analyses, A. dalmata resulted as sister taxon to Spintherobolus (Fig. 10, characters coded as missing). Characters 1 through 35 were extensively described and discussed by Malabarba (1998) and Weitzman & Malabarba (1999), and are presented here in summarized format reporting the respective numeration in those papers (Appendix 1).	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
D320B92EFFDBF425EA158C64FEB47FE6.taxon	discussion	A close relationship between Amazonspinther dalmata and Spintherobolus is strongly supported by fifteen unam- biguous synapomorphies, described below. The first ten characters herein analyzed were more extensively discussed by Malabarba (1998) and Weitzman & Malabarba (1999) as synapomorphies for Spintherobolus, and are herein expanded as synapomorphies of A. dalmata + Spintherobolus. A complex, patterned series of exposed neuromasts is distributed on the head and body (ch. 69 in Malabarba, 1998: 216, see discussion under ch. 15 in Weitzman & Malabarba, 1999: 12 - 13, figs. 4, 10 and 11). This is a character shared by A. dalmata and Spintherobolus species. Patterns of exposed neuromasts found in A. dalmata are similar and homologous to those of Spintherobolus (compare Fig. 4 here with Weitzman & Malabarba, 1999: 124, 10). The dentary has a large anterior fenestra (Fig. 5), associated with a large epidermal, papilla-like structure surrounded by a deep groove that has its deep internal portion lodged in the dentary fenestra. The external surface of this papilla bears several exposed neuromasts. The ventral face of the dentary bone, posterior to the fenestra, is concave (ch. 5 in Malabarba, 1998: 216, and ch. 16 in Weitzman & Malabarba, 1999: 128, fig. 12). Infraorbital bones are reduced in number and possibly fused. Amazonspinther dalmata has the first and second infraorbitals fused and slightly bifurcated anteriorly, and the third infraorbital reduced (Fig. 11). Fourth to sixth infraorbitals are absent, as observed for Spintherobolus (see discussion under ch. 9 in Malabarba, 1998: 216, and ch. 18 in Weitzman & Malabarba, 1999: 128, fig. 13). There is a small number of pelvic-fin rays, not exceeding six branched rays (see ch. 14 in Malabarba, 1998: 216, and discussion under ch. 19 in Weitzman & Malabarba, 1999: 129, fig. 14). Amazonspinther dalmata has i, 5, i and Spintherobolus species i, 4, i; i, 5; i, 5, i or i, 6, while remaining cheirodontines show i, 7 - 8 branched rays. The anal fin has a small number of 9 - 16 branched rays. This number varies among the species of this clade, with the highest range observed in S. broccae (13 - 16 branched rays; state 1), an intermediate range in S. ankoseion and S. leptoura (11 - 14; state 2), and the smallest number found in A. dalmata and S. papilliferus (8 - 9 and 9 - 10, respectively; state 3). State 0 corresponds to 16 to 24 branched rays, following Weitzman & Malabarba (1999: character 20; figs. 9 and 15). Reduction in the number of branched anal-fin rays is a synapomorphy of A. dalmata + Spintherobolus. The remarkably reduced number of branched anal-fin rays in A. dalmata and S. papilliferus is the lowest observed in Cheirodontinae but it is most parsimoniously accepted as basal in the clade Amazonspinther + Spintherobolus. An anterior pseudotympanum lies anterior to the first pleural rib (Fig. 1) (ch. 2 in Malabarba, 1998: 216, and ch. 21 in Weitzman & Malabarba, 1999: 130). The symphyseal dentary joint surfaces are smooth oval articulations lacking the intercalated and folded bony surfaces found in outgroup characids. The articulation is supported by tough ligamentous tissue (ch. 4 in Malabarba, 1998: 216 and ch. 24 in Weitzman & Malabarba, 1999: 131). Lateral line is reduced to 2 - 6 perforated scales (see ch. 60 in Malabarba, 1998: 216, and discussion under ch. 25 in Weitzman & Malabarba, 1999: 131). Amazonspinther dalmata has 4 - 5 scales, averaging 4.8, similar to that of S. papilliferus (4.6). The coracoid bone of the pectoral girdle (Fig. 12) is reduced in length, and more or less discoid in shape (ch. 13 in Malabarba, 1998: 216, and ch. 26 in Weitzman & Malabarba, 1999: 131, fig. 18). The pectoral-fin is relatively short. Weitzman & Malabarba (1999: 132; ch. 28) found this character to be ambiguous, supporting two equally parsimonious hypotheses: the acquisition in a common ancestor to Spintherobolus and a reversal in S. ankoseion, or the independent acquisition in S. papilliferus and in the clade S. broccae + S. leptoura. The presence of a short pectoral fin in A. dalmata (13.82 - 16.30 % of SL, mean 15.19) supports this character as a synapomorphy of Amazonspinther + Spintherobolus, and the longer pectoral fin of S. ankoseion as autapomorphic and a reversal. New characters added herein are as follows: The teeth are conical to tricuspid (ch. 36, Fig. 5). We treat the conical or tricuspid teeth separately and independent of teeth pedunculation (ch. 3). The conical to tricuspid teeth are proposed as a synapomorphy of A. dalmata + Spintherobolus (vs. multicuspid teeth of remaining cheirodontines - except the compsurin Macropsobrycon uruguayanae). The antorbital of A. dalmata and Spintherobolus species is short and rounded to oval (ch. 38, Fig. 11), instead of elongate, slender and ventrally expanded, as observed in the remaining Cheirodontinae. It resembles that of Carnegiella, Gasteropelecidae (adnasal in Weitzman, 1954). Not checked in S. leptoura. The gill rakers are short and conical, instead of elongate and lanceolate (ch. 40, Fig. 6). The gill rakers on the lower branch of the first gill arch are absent or only the posteriormost gill raker at the junction of the ceratobranchial and the epibranchial is present (ch. 41, Fig. 6). Gill rakers on the lower branch of the first gill arch are always present on remaining cheirodontines. First branchial arches of the four known Spintherobolus species were checked for comparisons with A. dalmata. All the species lack gill rakers or have only one gill raker (the posteriormost) on lower branchial branch, and the gill rakers are conical and the shortest among cheirodontines (Figs. 6 a-d). Amazonspinther dalmata has 3 upper gill rakers and none on the lower branch (two c & s specimens) (Fig. 6 a). Spintherobolus papilliferus has none (1), 5 (4), 6 (6), 7 (2) upper gill rakers, and one (13) lower gill raker (the posteriormost). The anteriormost gill rakers on upper branch are very short in the specimen photographed (Fig. 6 b). Spintherobolus broccae has 1 (2), 2 (4) on upper gill rakers, and none (2) or 1 (4) lower gill rakers (Fig. 6 c). Spintherobolus ankoseion has 1 (4), 2 (2), 3 (2), 4 (1), 5 (2) upper gill rakers and one (11) lower gill raker (the posteriormost, in photographed specimen not visible, damaged) (Fig. 6 d). In contrast, Spintherobolus leptoura has 2 - 3 upper gill rakers, and one lower gill raker (two alcohol specimens examined). For comparison, Cheirodon ibicuhiensis has 7 gill rakers on upper branch and 11 on lower branch, and Serrapinnus heterodon has 5 on upper branch and 13 on lower branch (Fig. 6 e-f). The maxillary shape is irregular, not bearing a smooth dorsal border. Instead, there are two concave sections in the dorsal border of the maxilla separated by a dorsal short projection in the bearing tooth region of the bone (ch. 42, Fig. 5). The anterior arm of the maxilla that articulates to the premaxilla is thicker than usual in the Characidae. Remaining cheirodontines have a smooth dorsal border in the maxilla. Monophyly of Spintherobolus Most characters previously used to diagnose Spintherobolus by either Malabarba (1998) or Weitzman & Malabarba (1999) are herein proposed as synapomorphies of Amazonspinther + Spintherobolus. Two characters remain synapomorphic for Spintherobolus: the lack of an adipose fin (Weitzman & Malabarba, 1999: 131, ch. 17), and the relatively small eye. The eyes of Spintherobolus species are remarkably small compared to that of remaining cheirodontines (see discussion in Weitzman & Malabarba, 1999: 131, ch. 27). Amazonspinther dalmata has large horizontal eye diameter 33.0 - 39.4 % of head length compared to 21.3 - 28.7 % observed in Spintherobolus. The hypothesis of relationships among Spintherobolus species proposed herein (Fig. 10) agrees with that proposed by Weitzman & Malabarba (1999), in which S. papilliferus is the sister species of one clade formed by the other three species of the genus. Additionally, the polytomy formed by S. broccae, S. leptoura, and S. ankoseion (Weitzman & Malabarba, 1999) was resolved in the present study. The low number of gill rakers on the upper branch of the first gill arch (1 - 3, ch. 39) supports a hypothesis of sister group relationship between S. broccae and S. leptoura (Fig. 10), a character that independently appears in A. dalmata. The higher number of gill rakers observed in S. ankoseion and S. papilliferus is suggested as plesiomorphic. Remarks on Amazonspinther apomorphic characters A high number of ventral procurrent caudal-fin rays (11 - 28) is a synapomorphy for the Cheirodontini, and the small number (7 - 9) observed in Amazonspinther (Fig. 3) is a reversal (Malabarba, 1998; Bührnheim, 2006). Similarly, the ventral procurrent caudal-fin rays articulating with the hemal spines of at least the four posterior caudal vertebrae is a synapomorphy of the tribe Cheirodontini, and the reduced articulation observed in Amazonspinther (Fig. 3) is a reversal (Weitzman & Malabarba, 1999: 9, ch. 9; fig. 8). The phylogenetic position of † Megacheirodon unicus † Megacheirodon unicus (Travassos & Santos, 1955) is an extinct cheirodontine, previously proposed as sister-group to Spintherobolus by M. C. Malabarba (1998 a, b). The species is known only through two fossilized specimens, a female and a highly sexually dimorphic male. Support for its inclusion in the tribe Cheirodontini is given by the apomorphic traits found in both anal and caudal fins of the male specimen. The inclusion of the fossil in the analysis and the most parsimonious resulting tree allowed the recognition of † Megacheirodon as sister group to Spintherobolus + Amazonspinther (Fig. 13), but we have reservations about these results. Three apomorphic traits are shared by † M. unicus and Spintherobolus species and are absent in Amazonspinther, and six synapomorphies are shared by Spintherobolus species and Amazonspinther, and are absent in † M. unicus. Sixteen characters, however, are missing in the fossilized remains of this fish (1, 2, 15, 16, 17, 21, 24, 28, 31, 34, 35, 38, 39, 40, 41, and 43). Further complications are related to the lack of mature males of Amazonspinther dalmata that resulted in coding 13 characters as missing in this species (6, 7, 8, 9, 10, 11, 12, 13, 14, 22, 23, 32 and 37). Although monophyly of the Clade † Megacheirodon + Spintherobolus + Amazonspinther, seems to be strongly supported, the internal relationships among the three genera may change with the addition of the missing information. So far, characters supporting a close relationship between Spintherobolus and Amazonspinther and that are absent in † Megacheirodon unicus (see M. C. Malabarba, 1998 for characters description in † M. unicus) are, infraorbital bones reduced or fused (ch. 18); one unbranched and five or six branched pelvic-fin rays (ch. 19); anal fin with iii unbranched and 8 - 16 branched rays (ch. 20); lateral line with 2 to 6 perforated scales (ch. 25), the coracoid bone of the pectoral girdle discoid in shape (ch. 26), and the teeth conical or with three cusps (ch. 36). Two synapomorphies are shared by all Spintherobolus species and † Megacheirodon unicus, but these are observed only in mature males, and mature males of A. dalmata were unavailable for comparisons. Both characters, however, are related to the fusion and reduced proximal portion of the anteriormost ventral procurrent caudal-fin rays. Since A. dalmata has a small number of ventral procurrent caudal-fin rays, located posteriorly and in the usual position found in other characids (Fig. 3), we expect the following characters are unlikely to occur in A. dalmata: the anterior ventral procurrent caudal-fin rays in adult males, those that have their proximal ends inserted anterior to the hemal spine of the antepenultimate vertebrae, are proximally fused to one another (Weitzman & Malabarba, 1999: 130, ch. 22; fig. 8); and the anterior ventral procurrent caudal-fin rays of males have reduced proximal portions, not rising above the area of fusion between the rays, while the posterior dorsal portions of these rays are fused into a flat compressed plate that inserts between the hemal spine of the antepenultimate vertebra and the hemal spines of the anterior vertebrae (Weitzman & Malabarba, 1999: 131, ch. 23; fig. 8). One additional apomorphic trait present in † Megacheirodon unicus, clearly discernible in the male specimen (M. C. Malabarba, 1998: 195, fig. 3), is the pterygiophore of the sixth branched anal-fin ray, directed dorsally, away from the fifth which is directed anteriorly and in parallel with the pterygiophores anterior to it (Sarraf, 1997: Fig. 6; Weitzman & Malabarba, 1999: character 33; fig. 9). Such character is shared with S. ankoseion, S. leptoura and S. broccae, again suggesting a close relationship of † Megacheirodon unicus to Spintherobolus.	en	Bührnheim, Cristina M., Carvalho, Tiago P., Malabarba, Luiz R., Weitzman, Stanley H. (2008): A new genus and species of characid fish from the Amazon basin - the recognition of a relictual lineage of characid fishes (Ostariophysi: Cheirodontinae: Cheirodontini). Neotropical Ichthyology 6 (4): 663-678, DOI: 10.1590/S1679-62252008000400016, URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400016&lng=en&tlng=en
