Bryconops sapezal
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| Bryconops sapezal | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Characiformes |
| Family: | Iguanodectidae |
| Genus: | Bryconops |
| Species: | B. sapezal |
| Binomial name | |
| Bryconops sapezal | |
Bryconops sapezal is a species of freshwater ray-finned fish belonging to the family Iguanodectidae. This species is found in the Rio Tapajós basin of Brazil. It is one of the more recent additions to its genus, described in 2018, and has a name that means "covered in sapê", or thatching. This originates from the Sapezal municipality of Mato Grosso, Brazil, which is type locality of B. sapezal.
Sexual dimorphism
Bryconops sapezal ranges from 3.03 to 6.99 cm SL (standard length), with the largest specimen at 9.12 cm SL.[1][2] Most species of Bryconops are within the 6 to 8 cm SL range.[3] It is a rather slender and elongate species, with a relatively small head and a body that tapers away from the origin of the dorsal fin. The scales are dark-gray on the back, silver with a bluish tint on the sides, and pale on the belly.[1] A blue tint is rare in Bryconops (only otherwise seen in B. inpai and B. marabaixo);[4][5] most species are plain silvery or slightly greenish.[6] The lower jaw ranges from dark-yellow to black. The dorsal fin is red, the adipose fin yellow, the pectoral fins translucent, and the base of the anal fin is reddish, the rest also translucent.[1]
One of the most distinctive traits of B. sapezal is the pattern on its caudal fin, which has prominent dark pigmentation in the distal region of the upper lobe and dark-gray pigmentation along the lower margin of the lower lobe. (The base of the fin is red.)[7] It can be told apart from various other species in the genus via other traits as well, such as its lack of a humeral spot and lack of a caudal-fin ocellus (eyespot).[1]
Bryconops sapezal is relatively similar in appearance to congener Bryconops rheoruber. B. rheoruber and B. sapezal both have 8–9 predorsal scales, but B. rheoruber has more scales around the circumference of its caudal peduncle (14–16 vs. 10–13 in B. sapezal).[2]
A feature seen in most members of Bryconops is the presence of hooks or spines on select pelvic- and anal-fin rays of mature males.[8] B. sapezal is no exception to this, bearing larger hooks on the pelvic fin than on the anal fin. There is also a slight difference in fin shape, with females bearing a more falcate (hooked) anal fin and males with a more rounded one.[1]