| Family: |
Goodeidae (Splitfins), subfamily: Goodeinae |
| Max. size: |
5.5 cm SL (male/unsexed); 5 cm SL (female) |
| Environment: |
benthopelagic; freshwater |
| Distribution: |
Central America: endemic tothe Coahuayana River drainage in Jalisco, Mexico. |
| Diagnosis: |
Dorsal soft rays (total): 12-14; Anal soft rays: 13-14. Xenotoca lyonsi differs from the congeners occurring in the Pacific Coast drainages by the combination of the following characters (none unique to the species): females posses 13 dorsal rays (vs. 15 or 16 in X. melanosoma and 14 in X. doadrioi); for males and females the differences are as follows: 14 anal fin rays (vs. 15 or 16 in X. melanosoma), 12 pectoral fin rays (vs. 13 in Xenotoca eiseni), 8 caudal peduncle scales (vs. 9 in Xenotoca eiseni and X. melanosoma), 30-31 scales in a lateral series (vs. 32 in X. doadrioi), 9 transversal scales (vs. 11 or 12 in X. eiseni and X. doadrioi) and 11 suparorbital pores (vs. 10 in X. doadrioi). Both male and female have a smaller eye diameter (head lengthL/ eye diameter = 3.7 vs. 3.0 in X. doadrioi and 3.5 in X. eiseni for females, and head length/ eye diameter= 3.6 vs. 3.3 in X. eiseni in males), high dorsal fin base (standard length /dorsal fin base length = 6.5 vs. 6.9 in X. eiseni for females and and 5.5 vs. 5.9 in X. eiseni in males) (Ref. 117630). |
| Biology: |
The type locality where the this species occurs is characterized by high seasonal changes in water clarity and volume, from a turbid and deep high flow running water in the rainy season to clear and low flow water other times of the year, sometimes reduced to a few shallow pools in the dry season. Its bottom is composed mainly of mud and gravel, and water plants are only evident in the stream bed. Other fishes present in the area include Xenotoca melanosoma (now extirpated), Ilyodon whitei, Poecilia butleri, Allodontichthys tamazulae, Astyanax anaeus, Cyprinus carpio and Oreochromis sp. (Ref. 107630). |
| IUCN Red List Status: |
Critically Endangered (CR); Date assessed: 14 March 2018 (B1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv)) Ref. (130435)
|
| Threat to humans: |
harmless |
| Country info: |
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