Lunaceps rileyi Timmermann, 1954a

Gustafsson, Daniel R. & Olsson, Urban, 2012, 3377, Zootaxa 3377, pp. 1-85 : 64-66

Lunaceps rileyi Timmermann, 1954a

( Fig. 26a – d; Table 1)

Lunaceps rileyi Timmermann, 1954a: 635

Lunaceps rileyi Timmermann ; Malcomson, 1960: 190

Lunaceps numenii rileyi Timmermann ; Emerson, 1972: 95

Lunaceps numenii rileyi Timmermann ; Price et al., 2003: 196

Type hosts: Numenius borealis ( Forster, 1772)

Diagnosis: Head ovoid ( Fig. 26a). Marginal carina interrupted laterally and antero-laterally, but present at the ventral anterior plate, which it augments, bulging posteriorly and extending across the ventral preantennal suture. One portion of this extension seems to reach the dorsal side. Dorsal preantennal suture appears to be missing in type, but is present in other material, where it is narrow, widely interrupted medially, and not bulging to envelop the apertures of the ADS. Lateral nodi broad and blunt. Dark preantennal band very short and thin, appearing as a pair of triangular darkening near the lateral nodi. AVS2 anterior to AVS3, at least in males and some females, but both pairs of setae markedly posterior to ADS.

Pterothorax with rounded posterior margin.

Setal arrangement of abdomen very distinct in both sexes ( Fig. 26b). Ventral setae of segment II often far anterior, aligned with the anterior dorsal pair. Males with two pairs of ventral setae on segments IV–V and VII (sometimes also in III). Females with an extra submedian pair of ventral setae in segment VI. Anterior margin of segments II–III in males and II–IV in females with narrow wedge-shaped median indentation. Dorsal median and submedian setae of males positioned very close together. Paratergal plates broad. Sublateral indentations clearly visible only in segments III–V, but shallow and narrow. No tergal heads, and the anterior-lateral end of most tergites blunt and broad.

Female genital lobes rounded with 8 posterior marginal setae, 8 sub-marginal setae, and 7 median marginal setae ( Fig. 26c). Sub-marginal setae thorn-like and quite long. Parameres with abrupt turn about one third from distal tip, and another, in the opposite direction, roughly one fifth from distal tip, with ends approaching parallel ( Fig. 26d). One ventral aperture visible in distal fourth of paramere. Ventral side of mesomere triangular, but whole structure with very bulging lateral sides and elongated, very slender, distal end. No visible setae or apertures along lateral margins of mesomere. Dorsal mesomeral fingers stout, and divergent anteriorly, forming small hooks. Mesomeral groove wide and quite deep, square-shaped, but with rounded corners. Lower endomere broad and semicircular, connected to apodemal bridge by broad triangle. Apodemal bridge diffuse. Basal apodeme relatively short.

Discussion: Like L. lissmanni , the male has an extra pair of setae on the ventral side of several abdominal segments, and the parameres are abruptly bent at approximately two fifths from the distal end. These characters are sufficient to separate males of L. rileyi from all other Lunaceps , except L. lissmanni . The shape of the head and the width of the abdomen separates L. rileyi from L. lissmanni , and in general the abdominal setae are more slender in L. rileyi than in L. lissmanni . Females can be separated from all other species, except L. lissmanni , by the number of sub-marginal setae, but differ from L. lissmanni by the number of abdominal setae.

The host, the Eskimo Curlew Numenius borealis , is now believed to be extinct ( IUCN, 2011b), and it is unlikely that any species of louse endemic to this bird species has survived.

Etymology: Named in honour of Norman Denbigh Riley (1890–1979), Keeper of the Department of Entomology of the (then) British Museum (Natural History) in London.

Material examined:

Ex Numenius borealis

Holotype: ♂ 1, USA, Meinertzhagen Collection 12546 ( NHML).

Allotype: ♀ 1, USA, Meinertzhagen Collection 12546 ( NHML).

Paratypes: ♀ 4, ♂ 3, USA, Meinertzhagen Collection 12546 ( NHML) .

Non-types : ♂ 2, Barbados, 5 September 1886, J. Waterston Collection BM 1930-232 ( NHML) .