Lunaceps paschalis Timmermann, 1954

Gustafsson, Daniel R. & Olsson, Urban, 2012, 3377, Zootaxa 3377, pp. 1-85 : 60-62

Lunaceps paschalis Timmermann, 1954

( Fig. 24a – d; Table 1)

Lunaceps paschalis Timmermann, 1954a: 630

Lunaceps paschalis Timmermann ; Malcomson, 1960: 191

Lunaceps limosella paschalis Timmermann ; Keirans, 1967: 114

Lunaceps limosella paschalis Timmermann ; Emerson, 1972: 94

Lunaceps paschalis Timmermann ; Price et al., 2003: 196

Type host: Limosa haemastica ( Linnaeus, 1758)

Diagnosis: Head roughly triangular ( Fig. 24a). Marginal carina very narrow, and evenly thick around the head; anterior portion on marginal carina may be virtually invisible. Ventral anterior plate small, often with indistinct posterior margin. Dorsal preantennal suture and dark preantennal band missing entirely. Lateral nodi small and pointed. Marginal temporal carina weak and narrow. Pre- and post-ocular nodi reduced. Head setae weak. AVS2 and AVS3 aligned, but somewhat posterior to the ADS.

Antero-median indentation of tergites variable. Some males with only II–IV indented, whereas others have II–VII. In females, the type has II–VII indented, whereas other females have only II–VI indented. Female dorsal intermediate setae on segment VII approximately as long as the median setae. Female dorsal intermediate setae on segment IX medium size and slender. Paratergal plates very broad and those on segments IV–VII overlap ( Fig. 24b). Tergal heads missing, or may be present as a very narrow bar. Males have a submedian pair of setae on the ventral side of segment VIII.

Female genital lobes with 6 posterior marginal setae, 7 sub-marginal setae, and 5–6 median marginal setae ( Fig. 24c). Sub-marginal setae quite stout, but short. Parameres gently rounded, parameral heads not elongated ( Fig. 24d). Mesomere elongated, and bulging slightly in distal half. Lower endomere narrow. Apodemal bridge vaguely delimited, and appears narrow.

Discussion: Without a dorsal preantennal suture, and with a similar shape of the head and abdomen, L. paschalis is morphologically close to Rotundiceps cordatus ( Osborn, 1896) , originally described from the same host ( Edwards, 1952). However, R. cordatus has an even rounder abdomen, a much wider heart-shaped head, and different pterothoracic and marginal temporal chaetotaxy. The male genitalia are similar in the two species and the genera are probably closely related, but the mesomere of R. cordatus is constricted in the middle, and the parameres are more angular, with almost pincer-like distal ends. There is also a great difference in size, R. cordatus being at least 0.84 mm longer and twice as broad in the head and abdomen ( Osborn, 1896; Timmermann, 1954a). Edwards (1952) stated that he could find no R. cordatus on the type host, Limosa haemastica , but plenty on L. fedoa , and apparently transferred the type host status to this species in his description of Rotundiceps .

Kellogg and Mann’s (1912) description of Nirmus lucidus states that the species is close to R. cordatus (as “ N. cordatus ). Emerson (1972) synonymised N. lucidus under R. cordatus , and Price et al. (2003) followed his decision. Nirmus lucidus is also longer and wider than most Lunaceps , but supposedly more slender than R. cordatus . Timmermann (1954a) mentions N. lucidus only in the summary, where he mentions that this species was “described from [the] wrong host”, but does not elaborate.

Whether or not N. lucidus and R. cordatus are synonymous, and whether or not either, or both, of these are the same as L. paschalis , the existence of two similar species on the same host highlights the need for further louse collection from Limosa haemastica , as well as from L. fedoa , in order to establish whether N. lucidus is distinct from R. cordatus . Edwards’ (1952) remarks that the niche differentiation of the two genera is not necessarily helpful, as I have observed Lunaceps sp. on the head of fumigated birds several times (unpublished data).

Within Lunaceps , L. paschalis is probably closest to L. limosae , which also lacks the dorsal preantennal suture, but differs from this species in the preantennal setal arrangement, and in the details of the genitalia of both sexes. The ventral submedian setae on abdominal segment VIII, found only in males, is unique within the genus. The preantennal setal arrangement is similar to that of L. clayae , but L. paschalis differs in the male genitalia and the female genital setal arrangement, and in the lack of a dorsal preantennal suture. However, only a very small number of have been examined.

Etymology: The term paschalis is apparently a form of “Pascal”, meaning “Easter child”. Whether this is the intended etymology and, if so, what this refers to, is not mentioned by Timmermann (1954a).

Material examined:

Ex Limosa haemastica (sometimes as Limosa hudsonica )

Holotype: ♀ 1, United States: Texas: Brownsville , 20 October 1891, J. Waterston Collection, BM 1930-232 ( NHML).

Allotype: ♂ 1, United States: Texas: Brownsville , 4 May 1890, J. Waterston Collection BM 1930-232 ( NHML).

Paratypes: ♀ 3, United States: Texas: Brownsville , 4 May 1890, J. Waterston Collection. BM 1930-232 ( NHML) . ♀ 2, ♂ 1, United States: Dakota , 25 May 1924, DM 16317 ( MONZ) . ♂ 1, United States: Texas: Brownsville , 20 October 1891, J. Waterston Collection, BM 1930-232 ( NHML) .