SOUTH AMERICAN CHARACID FISHES — ^WEITZMAN 151 



(2) Posterior shaft of prevomer reduced or absent in adults and young, 

 never reaching parasphenoid. (3) Preopercle not reaching near articu- 

 lar, extending anteriorly only to lower posterior process of quadrate. 



(4) Maxillary confined to anterior region of first infraorbital bone. 



(5) Premaxillary teeth 1- to 6-cusped, usually 3- to 6-cusped, multi- 

 cuspid teeth flattened and incisor-like. (6) Dentary with outer 

 row of flattened, 3- to 6-cusped incisor-like teeth and one inner 

 row of unicuspid conic teeth. (7) Dentary divided into two distinct 

 regions by a deep inferior groove continuous with the mental foramen. 

 (8) Lower portion of post-temporal fossa not enlarged, its anterolateral 

 border well posterior to vertical from synchondral joint between 

 sphenotic and pterotic, anterolateral border of post-temporal fossa 

 behind vertical from anterior edge of auditory foramen. 



The genera of sub tribe nannostomina are: 



Nannostomus Glinther (1872), with five or six valid species 

 Poecilobrycon Eigenmann (1909b), with three valid species 



Note that Nannobrycon of Hoedeman (1950a) is here considered a 

 subgenus of Poecilobrycon and Archicheir Eigenmann (1909b) is con- 

 sidered a synonym of Poecilobrycon. Archicheir minutus Eigenmann 

 (1909b), the type of Archicheir, is based on the young of Poecilobrycon 

 harrisoni Eigenmann (1909b). A review of the genera and species 

 of the Nannostomina is in preparation. 



SUBFAMILY ERYTHRININAE GILL, 1858 



Definition: (1) Large fenestra between quadrate and metapterygoid 

 present. (2) Two diverging lamellae on ventral surface of ethmoid 

 weU developed. (3) Lateral posterior edge of frontal articulated 

 with spinous process of sphenotic. (4) Six infraorbital bones present; 

 first infraorbital apparently fused with antorbital. (5) Accessory 

 ectopterygoid (or dermopalatine) present, ventral to autopalatine 

 either as an autogenous element or fused with ectopterygoid. (6) 

 Lower limb of cleithrum long and slender, its lateral inferior lamella 

 small. (7) Coracoid lamella small or absent, not large, flat plate 

 as in other characids, not reaching to near anterior border of cleithrum. 

 (8) Anastomosis between supraorbital and dermopterotic latero- 

 seusory canal absent. (9) Parietal and epiphyseal branches of 

 supraorbital canals well developed, parietal canal reaching parietal 

 bone. (10) Perforated lateral fine scales present, continued unin- 

 terrupted to caudal fin. (11) Frontal fontanel always absent in 

 adults. (12) Teeth well developed, unicuspid, conic in both jaws. 

 (13) Premaxillary with one tooth row. (14) Dentary with anterior 

 tooth row bordering length of jaw, inner tooth row confined to pos- 

 terior portion of mandibular ramus. (15) Gape long, reaching 



