| SOURCE FOR OCCURRENCE IN ECUADOR: This is a relatively new species described by Roberts in 1973. The species has been listed in western Ecuador in recent works from the area including Roberts (1973a), Glodek (1978), Barriga (1991). |
| ORIGINAL DESCRIPTION: Roberts, T.R. 1973. The Glandulocaudine characid fishes of the Guayas basin in western Ecuador. Bulletin of the Museum of Comparative Zoology, Harvard University, 144(8):489-514. |
| TYPE SPECIMENS: Holotype: MCZ 48658, paratypes MCZ 48659. |
| TAXONOMIC STATUS: Valid (Eschmeyer and Fricke, 2011). No major taxonomic issues. |
| RANGE ECUADOR: Previously thought to be endemic to the Guayas River drainage (Roberts, 1973), but has recently been collected in the Santa Rosa River close to Peru by Aguirre and collaborators and in the Esmeraldas River drainage by Lujan and collaborators (Aguirre et al., 2014). Probably also occurs in the small coastal mountain streams south of the Guayas River drainage. |
| RANGE OUTSIDE OF ECUADOR: None. |
| COLLECTIONS IN ECUADOR: Examples include: MECN-DP 2543 (Museo Ecuatoriano de Ciencias Naturales), MCZ Ich 48658 (Museum of Comparative Zoology), MCZ Ich 48659, ROM Fishes 93676 (Royal Ontario Museum), ROM Fishes 93759,FMNH Fishes 79144 (Field Museum of Natural History), FMNH Fishes 79147. |
| MAXIMUM SIZE: 21.8 mm SL (Weitzman and Fink, 1985). |
| DISTINGUISHING FEATURES: Iotabrycon praecox is one of three monotypic genera in a small endemic radiation of characids that occurs in the Guayas River basin and neighboring rivers. These were formerly placed in the subfamily Glandulocaudinae based on the presence of specialized caudal glands on the caudal peduncle of males. Most former Glandulocaudinae including I. praecox are now classified in the subfamily Stevardiinae (Mirande 2009; Oliveira et al. 2011). Males of I. praecox have the most elaborate caudal glands of the species in the Guayas. Iotabrycon praecox is the smallest characid in western Ecuador with a maximum size of just over 2 cm SL. The species is sexually dimorphic with females being somewhat larger than males. The caudal fin is larger in males (Roberts, 1973). Females have a small black spot on the base of the caudal fin while males have modified scales covering the cuadal gland. Fin counts are dorsal fin: ii,7; anal fin iii,21 to v,23 (although Glodek, 1978 lists 21 to 24 rays); pelvic fin 7 (Roberts, 1973). Lateral body scales 38-40 (Glodek, 1978). The adipose fin is absent which distinguishes it from other small characids in western Ecuador (Glodek, 1978). Teeth are conical (Roberts, 1973). |
| ECOLOGY: Little is known about the ecology of this species. Roberts (1973) collected I. praecox in an isolated, seasonal pool close to Rio Nuevo (a tributary of the Vinces River). Glodek (1978) also collected I. praecox in shallow isolated pools along large rivers and in small forest streams. Aguirre et al. (2008) collected a few specimens in the main river at the Rio Palenque Biological Reserve. |
| ECONOMIC IMPORTANCE: Not of economic importance because of its small size. |
| CONSERVATION STATUS: Unknown. |
| LINK TO FISHBASE PAGE: Click here for link |
| SPECIES PROFILE CREATED BY: Windsor Aguirre |
| SPECIES PROFILE CONTRIBUTORS: NA |
