| Family: |
Hemiodontidae (Halftooths) |
| Max. size: |
13.56 cm SL (male/unsexed) |
| Environment: |
benthopelagic; freshwater; pH range: 6.4 - 6.8 |
| Distribution: |
South America: known of the type locality in the rio Amana, rio Maués-Açu drainage, near the boundary of the States of Pará and Amazonas, Brazil |
| Diagnosis: |
Dorsal soft rays (total): 11-12; Anal soft rays: 11-13; Vertebrae: 36-36. Distinguished from other species of Hemiodus by its high body (27.1-35.3%, average 32.3% SL vs. 18.8-28.5% in remaining species). Other diagnostic characters include the following: presence of a large lateral dark spot that is equal to, or greater than, the eye diameter (vs. smaller in remaining species except for Hemiodus microlepis); absence of conspicuous lateral stripe or transverse bands; 68-74 scales on lateral line (vs. 94-123 in Hemiodus argenteus, 124-148 in Hemiodus microlepis, 86-99 in Hemiodus orthonops and 77-92 in Hemiodus parnaguae). Differs from Hemiodus unimaculatus (which overlaps in the number of lateral line scales) by having 9-10 scales between the lateral line and the pelvic fin origin (vs. 4-7), which are similar sized above and below lateral line (vs. scales larger bellow the lateral line in Hemiodus unimaculatus) (Ref. 91067).
Description: Dorsal-fin rays ii, 9; Anal-fin rays ii, 9-11; pectoral fin rays i, 17-19; pelvic fin rays i, 10-11 (Ref. 91067). |
| Biology: |
Found in slow-flowing stretches of the rio Amana and igarapé Porquinho (1.0-2.5 m deep) and in artificial ponds (4.0-5.0 m deep and 40-70 m in diameter) resulting from gold-mining activities. The Rio Amana and its tributaries are characterized by clear water (not stained by humic acids) but turbid due to excess of fine suspended solids (clay) as a result of mining activities along river margins and/or bottom such as dredging (Ref. 91067). |
| IUCN Red List Status: |
Data deficient (DD); Date assessed: 17 November 2018 Ref. (130435)
|
| Threat to humans: |
harmless |
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