Elasmobranchii (sharks and rays) > Rajiformes
(Skates and rays) > Arhynchobatidae
Etymology: Rioraja: Latin, rivus = river (in Greek, rheo) + Latin, raja, -ae = ray, fish. More on authors: Müller & Henle.
Environment: milieu / climate zone / depth range / distribution range
Marine; demersal; depth range ? - 130 m (Ref. 26375). Subtropical
Southwest Atlantic: Espírito Santo, Brazil to Argentina.
Length at first maturity / Size / Weight / Age
Maturity: Lm 42.5, range 39 - 45.7 cm
Max length : 33.0 cm WD male/unsexed; (Ref. 26408)
A coastal species found on sand, mud or gravel bottoms (Ref. 26375). Feeds on crustaceans, mollusks and fishes (Ref. 26375). Oviparous (Ref. 50449). Eggs have horn-like projections on the shell (Ref. 205).
Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449).
McEachran, J.D. and K.A. Dunn, 1998. Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (Chondrichthyes: Rajidae). Copeia 1998(2):271-290. (Ref. 27314)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 123416)
Threat to humans
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates based on models
Preferred temperature (Ref. 115969
): 10.4 - 22.6, mean 14.8 °C (based on 300 cells).
Phylogenetic diversity index (Ref. 82805
= 1.0000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00501 (0.00318 - 0.00791), b=3.02 (2.89 - 3.15), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref. 93245
Trophic level (Ref. 69278
): 3.6 ±0.0 se; based on diet studies.
Generation time: 5.2 ( na - na) years. Estimated as median ln(3)/K based on 1 growth studies.
Resilience (Ref. 120179
): Low, minimum population doubling time 4.5 - 14 years (Assuming fecundity<100).
Vulnerability (Ref. 59153
): Moderate to high vulnerability (49 of 100) .