live buried in the sand and perhaps gravel of swift
flowing streams. Description:
Xyliphius sofiae, is described based on a unique
specimen exhibiting four autapomorphies: eyes absent
vs. present (though reduced); colour pale, lacking
pigment vs. head and body darkly pigmented; branchiostegal
rays five vs. four; and unculiferous tubercles on
posterior body distributed evenly vs. enlarged unculiferous
tubercles typically arranged in five distinct rows
above pelvic-fin base to posterior end of caudal peduncle.
In addition, the pectoral fin of X. sofiae has
one ossified proximal radial vs. two in congeners
(except X. magdalenae, not examined). Xyliphius
sofiae differs from all congeners except X.
lepturus by snout tip elongated and
narrowly rounded vs. short and broadly rounded, often
with small median notch; fifth ceratobranchial relatively
narrow with elongate acicular teeth vs. broadly expanded,
leaf-shaped, with shorter and broader, conical teeth;
anterior limits of branchial apertures separated by
distance less than length of aperture vs. greater
than length of aperture; anal-fin rays modally nine
vs. seven; and lateral line extending onto base of
caudal-fin rays vs. finishing in hypural region. Based
on the single specimen collected in the main channel
of the Río Amazonas near Iquitos, Peru, we
describe the osteology of X. sofiae using
a non-invasive technique: high-resolution X-ray computed
tomography (HRXCT). We consider Xyliphius lombarderoi
Risso and Risso, 1964, a species based on a unique
holotype that is now lost, to be a subjective junior
synonym of X.
barbatus Alonso de Arámburu
and Arámburu, 1962. Variable characteristics
are summarized for the seven species of Xyliphius
treated here as valid, and their distributions are
plotted based on a comprehensive review of museum
specimens (Abstract: Carvalho et.al.). The total species
described so far is 8.
Río Amazonas, main channel in vicinity of Iquitos,
Maynas, Loreto, Peru, 03°42'21"S, 073°12'14"W.
Tiago P. Carvalho,
Roberto E. Reis, and Mark H. Sabaj;
Description of a New Blind and Rare Species of Xyliphius
(Siluriformes: Aspredinidae) from the Amazon Basin
Using High-Resolution Computed Tomography Copeia 2017
105 (1), 14-28.