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. Habitat:
Xyliphius live buried in the sand and perhaps
gravel of swift flowing streams. Etymology:
The genus name Xyliphius:
derived from the Greek word, xylephion = a little
piece of wood (referring to the woodlike appearance
of the type species of the genus). The specific name
sofiae: In honour of the first author’s
daughter, Sofia, (Sabaj, M.H.) “for inspiring
wisdom in her father”.
Common
Name:
None
Synonyms:
None
Family:
Aspredinidae
Distribution:
South America:
Río Amazonas, main channel in vicinity of Iquitos,
Maynas, Loreto, Peru, 03°42'21"S, 073°12'14"W.
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