Redescription of Antarctophthirus microchir (Anoplura: Echinophthiriidae) from the South American Sea Lion, Otaria flavescens, from Patagonia, Argentina

Abstract

Antarctophthirus microchir was originally described from Phocarctos hookeri on the basis of 1 female and 1 male only. We redescribe adults and describe, for the first time, the 3 nymphal stages from specimens collected from Otaria flavescens from Patagonia, using light and scanning electron microscopy. The present material can be distinguished from other Antarctophthirus species by the presence of a fringe of setae on the back of the head, only present in Antarctophthirus trichechi and Antarctophthirus callorhini. However, A. trichechi also possess a prominent proboscis with large hooks, and A. callorhini presents less abundant and nonuniform abdominal scales in shape and size. Other differential features of A. microchir are the pattern of ovoid and uniform scales and longitudinal grooves in the surface of spines. Nymphal stage 1 differs from 2 and 3 mainly by the absence of scales and thorax without ventral spines or hairs. Nymphal stages 2 and 3 may be distinguished by the disposition of the occipital apophyses. Antarctophthirus microchir has been reported from 5 sea lion species from both hemispheres. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we raise the question of whether A. microchir from different sea lion hosts may represent a complex of cryptic species.

Phylogenomic analysis of seal lice reveals codivergence with their hosts

“…Kim () suggested that A. microchir constitutes a complex of cryptic species that are morphologically indistinguishable. In their re‐description of the species infesting the South American sea lion, Leonardi et al () could not differentiate between A. microchir from several host species. The results of this study confirm the hypothesis proposed by Kim () that A. microchir comprises several cryptic species from different hosts.…”

“…In contrast to lice from different Antarctic seal hosts, we found a high genetic distance between the two samples of A. microchir from the South American and Australian sea lions (33.4% mitochondrial divergence). This species has been described as a parasite from all five extant species of sea lions: the Steller's and Californian sea lions from North America (Ferris, ), the South American sea lion (Leonardi et al , ), the Australian sea lion (McIntosh & Murray, ) and the New Zealand sea lion (Trouessart & Neumann, ). Members of Echinophthiriidae are mainly host‐specific (i.e.…”

Ectoparásitos del lobo marino sudamericano (Otaria flavescens) de la costa peruana

“…Comentario: Las características morfológicas de nuestro material coinciden con las descripciones de Leonardi et al (2009). Antarctophthirus microchir ha sido registrado en una variedad de pinnípedos del continente Americano, Nueva Zelanda y Australia.…”

“…Estos son el león marino de Steller (Eumetopias jubatus Schreber, 1776), el león marino australiano (Neophoca cinerea Peron, 1816), el lobo marino sudamericano (Otaria byronia), el león marino de Nueva Zelanda (Phocarctos hookeri Gray, 1844), el león marino de California (Zalophus californianus Lesson, 1828) y el león marino de las islas Galápagos (Zalophus wollebaeki Silvertsen, 1953) (Kim et al 1986, Durden & Musser 1994, Crovetto et al 2008. Su distribución abarca la Antártida, aguas del Pacífico Norte de California hasta el círculo Ártico, costa de Chile, Ecuador y Argentina (Durden & Musser 1994, Dailey et al 2005, Crovetto et al 2008, Leonardi et al 2009). El hallazgo en el presento estudio representa el primer registro de A. microchir para el Perú.…”

Antarctophthirus carlinii (Anoplura: Echinophthiriidae), a new species from the Weddell seal Leptonychotes weddelli

“…Names and abbreviations of setae used in this paper follow those of Kim and Ludwig (1978) and Leonardi et al (2009): spines are pointed setae, scales are flattened setae, and hairs are the long and thin setae.…”