Stellantia Armbruster & Lujan, 2024

Armbruster, Jonathan W. & Lujan, Nathan K., 2024, New tribe-level classification of Hypostominae (Loricariidae) based on optimization of morphological states on DNA-based relationships, with descriptions of three new tribes and two new genera, Neotropical Ichthyology (e 240108) 22 (4) : -

Stellantia Armbruster & Lujan , new genus urn:lsid:zoobank.org:act:894AA6EB-3851-4EA7-B4FB-24724F2A0491

( Figs. 1B, 2B)

Type-species. Pseudancistrus sidereus Armbruster, 2004b

Included species.

Pseudancistrus sidereus Armbruster, 2004b:8 , fig. 3. Río Siapa from 10–15 kilometers downstream, Río Casiquiare - Río Negro drainage, 01.50000°, -065.71667°, Río Orinoco drainage, Amazonas, Venezuela.

Phylogenetic diagnosis. Reversal to large interhyal (27: 1>0), tall walls of metapterygoid channel (56: 0>1), reversal to narrow quadrate (64: 1>0), loss of flap of quadrate extending below symplectic foramen (66: 1>0), reversal to two to four cheek plates between canal plate and opercle (88: 3>2); no contact between infraorbital 4 and orbit (90: 1>2), anterior margin of mesethmoid flared (102: 0>1), loss of exterior contact between sphenotic and posteriormost infraorbital (117: 0>1), and increase in number of vertebrae to 12–15 from first normal neural spine posterior to dorsal fin up to and excluding the hypural (121:1).

Comparative diagnosis. Stellantia is readily identified from all other Hypostominae except Colossimystax by having the dorsal lamina of each ventral plate of the caudal peduncle concave, accentuating the caudal peduncle keel (vs. caudal peduncle ventral plates rounded, lacking concave dorsal lamina, caudal peduncle keel weak or absent); and from Colossimystax by having seven branched dorsal-fin rays (vs. 10).

Geographical distribution. Known from main channels of the upper Orinoco River basin upstream of San Fernando de Atabapo, including the lower Ventuari River, and the Casiquiare River basin upstream of its confluence with the Negro River, including the lower Siapa River, exclusively in Amazonas, Venezuela.

Description. See Tab. S3 and Armbruster (2004b).

Etymology. An abstract, feminine noun modified from the Latin adjective stellans for starry in reference to the dark body with white to yellow spots which appear like a field of stars, a feature that inspired the species epithet as well. Stellantia requires a change of ending for the single species in the genus: Stellantia siderea .

Conservation status. Stellantia siderea was evaluated as Least Concern (LC) by the

IUCN (Armbruster, 2023b). The species is common throughout its range.

Material examined. Río Orinoco drainage, Amazonas, Venezuela. Holotype: MCNG 26125, 175.6 mm SL , Paratypes: AUM 37562 , 1, 148.7 mm SL ; FMNH 105294 , 4 , 149.5 – 176.7 mm SL ; MCNG 48261 , 1 c&s, 149.8 mm SL .