Gallancyra Gustafsson, 2020

Gustafsson, Daniel R. & Zou, Fasheng, 2020, Gallancyra gen. nov. (Phthiraptera: Ischnocera), with an overview of the geographical distribution of chewing lice parasitizing chicken, European Journal of Taxonomy 685, pp. 1-36 : 11-17

Genus Gallancyra Gustafsson & Zou gen. nov.

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Figs 5–14

Lipeurus Nitzsch, 1818: 292 (in partim).

Oxylipeurus Mjöberg, 1910: 91 (in partim).

Reticulipeurus Kéler, 1958: 332 (in partim).

Type species

Lipeurus dentatus Sugimoto, 1934 .

Diagnosis

Lipeurus dentatus was previously placed either in Oxylipeurus (e.g., Price et al. 2003) or in Reticulipeurus (e.g., Mey 2003). Of these two genera, Gallancyra is most similar to Reticulipeurus (see, e.g., Kéler (1958) and Gustafsson et al. (2020) for illustrations of most of these characters in Reticulipeurus , and Mey (1990) for corresponding characters in Oxylipeurus s. str.; see also Table 3), with which it shares the following characters: stylus extends beyond distal margin of abdomen ( Fig. 7 ); intertergal plates absent ( Figs 5–6 ); mesosome large, with hook-shaped antero-lateral corners, rugose distal margins, and ventral gonopore associated with transverse sclerite which bears setae laterally ( Fig. 13 ); parameres symmetrical, at most about twice as long as mesosome, and roughly finger-shaped ( Fig. 12 ); female subgenital plate much reduced, typically divided medially ( Fig. 8 ); vulval opening converging medially to single, typically narrow, point, not forming convex lobes laterally ( Fig. 12 ); post-antennal suture absent ( Fig. 9 ).

Etymology

Gallancyra is constructed from the Latin name ‘ gallus ’, for ‘chicken’ and the genus of the type host of the type species, and the Greek word ‘ ancyra ’, for ‘anchor’. This refers to the shape of the stylus of the male subgenital plate. The gender is feminine.

Differential diagnosis

Gallancyra gen. nov. can be separated from Reticulipeurus by the following characters: preantennal head pointed in Gallancyra gen. nov. ( Fig. 9 ), but rounded in Reticulipeurus ; preantennal head in Gallancyra gen. nov. ventrally with clypeo-labral suture that divides sclerotized section of ventral head into two lobes, and that expands in anterior end, seemingly making ventral side of frons hyaline ( Fig. 9 ), but without any clypeo-labral suture and with no ventral hyaline region in Reticulipeurus ; tergopleurites with clear reticulation at least laterally on some segments in Reticulipeurus , but without clear reticulation in Gallancyra gen. nov. ( Figs 5–6 ); stylus arising from distal margin and with protruding section expanded into anchor-shape in Gallancyra gen. nov. ( Fig. 7 ), but arising subterminally and with protruding section not or only little expanded, and never anchor-shaped in Reticulipeurus ; rugose section of distal mesosome limited to lateral margins and expanding medially in anterior end in Gallancyra gen. nov. ( Fig. 13 ), but typically limited to distal margin and not expanded in anterior end in Reticulipeurus ; sclerotized plate present on distal mesosome in Gallancyra gen. nov. ( Fig. 13 ), but absent in Reticulipeurus ; pst1–2 placed close-together subterminally, and both with visible microsetae in Gallancyra gen. nov. ( Fig. 12 ), but pst1 is a sensillus and typically placed well proximal of pst 2 in Reticulipeurus ; subvulval sclerites present in Reticulipeurus , but absent in Gallancyra gen. nov. ( Fig. 8 ).

1 This character is not clearly visible in the illustrations of Mey (1990), and we have not examined any specimens belonging to any species of Oxylipeurus s. str.

The structure of the preantennal head ( Fig. 9 ) and the stylus ( Fig. 7 ) of Gallancyra dentata gen. et comb. nov. are unique within the Oxylipeurus -complex and, to the extent of our knowledge, the entire Ischnocera . These two characters should separate Gallancyra gen. nov. from all other genera of ischnoceran chewing lice.

Description

Both sexes

Head overall trapezoidal, widening posteriorly, but with frons triangularly extended into medial point ( Fig. 9 ). Hyaline margin seemingly present as very narrow translucent band near frons; this is not visible in all examined specimens, and in many cases differs between sides of the same specimen. Marginal carina uninterrupted, but displaced dorsally anterior to as2; most preantennal setae with clear attendant canals going through the marginal carina. Internal thickenings present anterior to ads, varying in extent among specimens. Dorsal preantennal suture present, enveloping aperture of ads, and approaching but not reaching lateral margins of head. Ventrally, head capsule appears to be hyaline medially and anteriorly, with sclerotized sections densely decorated with semi-reticulated pattern. Ventral carina not clearly visible. Head and antennal chaetotaxy as in Fig. 9 . Preantennal nodi large, bulging. Antennae sexually dimorphic ( Figs 9–10 ). Pre-and postocular nodi present. Occipital carinae not visible. Temporal carinae visible only in posterior section, connecting to bulbous nodi. Gular plate diffuse, approximately as in Fig. 9 ; area around gular plate with conspicuous spiculate thickenings.

Thoracic segments and chaetotaxy as in Figs 5–6 . Pronotum and pteronotum each medially continuous. Meso- and metanota fused into single plate. Metepisterna broad, medial end with finger-like extension that may reach pteronotum. Legs and leg chaetotaxy as in Fig. 14 ; anterior setae of trochanters II–III may be present, but not visible in examined species as legs are distorted. At least two setae on medial margin of tibiae II–III appear to be hyaline and larger than other setae (illustrated as hollow). Abdominal segments and chaetotaxy as in Figs 5–6 . Tergopleurites II–VIII medially divided, tergopleurite IX+X medially continuous. Internal thickening of antero-lateral corners of tergopleurites present on segments III–VII. Sternal plates present on segments II–VII.

Male

Antennae as in Fig. 9 ; scape, pedicel, and flagellomere I expanded compared to female; flagellomere I with thumb-like extension and rugose medial surface. Subgenital plate seemingly protruding internally to sternal plate VII ( Fig. 7 ). Stylus arises from distal margin of subgenital plate and reaches beyond distal margin of abdomen; distal section of stylus expanded, with lateral margins extended into small “hooks” in anterior end. Basal apodeme slender, lateral margins slightly concave, anterior end diffuse ( Fig. 11 ). Mesosome with antero-lateral sclerotized hook-shaped extensions, distally with rounded margin and rugose area only laterally ( Fig. 13 ). Gonoporal complex small compared to mesosome. Sclerotized plate with arched antero-lateral extensions. Parameres as in Fig. 12 ; pst1–2 both microsetae.

Female

Antennae as in Fig. 10 . Distal end of abdomen as in Fig. 8 . Subgenital plate divided medially, with conspicuous honey-comb reticulation in central parts. Vulval margin deeply concave. Most distal anal seta apparently modified to sensilla, as only alveoli are visible in examined specimens.

Host distribution

Presently only known from hosts in the genus Gallus Brisson, 1760 . This genus is closely related to the genus Bambusicola Gould, 1836 ( Armstrong et al. 2001; Dyke et al. 2003; Kimball & Braun 2008; Wang et al. 2013), but no species of the Oxylipeurus -complex lice are known from hosts in the genus Bambusicola .

Geographical range

See Table 1 and Fig. 4 ; primarily the Indo-Malayan region and Central America, but also known from New Guinea, the Caribbean, and islands in the Central Pacific. Seemingly absent over large parts of the host’s (introduced) range, but may be overlooked.

Remarks

Złotorzycka (1966) considered the species here placed in Gallancyra gen. nov. to belong in Oxylipeurus s. str., but did not justify this placement other than by reference to published illustrations. Presumably her judgement was based on the presence of an anteriorly pointed head in both Gallancyra dentata gen. et comb. nov. and species of Oxylipeurus , whereas other genera in the complex generally have rounded preantennal heads. Comparing G. dentata gen. et comb. nov. to more recent illustrations of Oxylipeurus s. str. (e.g., Mey 1990) shows that, apart from the pointed head, there are few morphological similarities between the two genera. For instance, Oxylipeurus s. str. has intertergal plates, medially continuous tergopleurites VII–VIII, a post-antennal suture, much reduced and highly modified male genitalia, and a small, distally blunt, stylus.

Figures

Figs 5–6. Gallancyra dentata (Sugimoto, 1934) gen. et comb. nov. ex Gallus gallus (Linnaeus, 1758) (NHMUK010682393). 5. Habitus, ♂, dorsal and ventral view. 6. Habitus, ♀, dorsal and ventral views. Legs II and III distorted in all examined males, here illustrated approximately, and rotated compared to how they are in the slide specimen.

Figs 7–8. Gallancyra dentata (Sugimoto, 1934) gen. et comb. nov. ex Gallus gallus (Linnaeus, 1758) (NHMUK010682393). 7. Male subgenital plate and terminal end of abdomen, ventral view. 8. Female subgenital plate and terminal end of abdomen, ventral view. Abbreviations: vms = vulval marginal setae; vss = vulval submarginal setae.

Figs 9–13. Gallancyra dentata (Sugimoto, 1934) gen. et comb. nov. ex Gallus gallus (Linnaeus, 1758) (NHMUK010682393). 9. Male head, dorsal and ventral views. 10. Female antenna, ventral view. 11. Male genitalia, dorsal view. 12. Male paramere, dorsal view. 13. Male mesosome, ventral view. Female antenna at same scale as male head. Abbreviations: ads = anterior dorsal seta; as2 = anterior seta 2; pst1–2 = parameral setae 1–2. All genitalic component drawn at same scale.

Fig. 14. Gallancyra dentata (Sugimoto, 1934) gen. et comb. nov. ex Gallus gallus (Linnaeus, 1758) (NHMUK010682393). Male legs I–III, dorsal and ventral views. Legs II and III distorted in all examined males, and here illustrated approximately; note that marginal and near-marginal setae (marked with small black circles) are illustrated on both dorsal and ventral side, as their exact placement is difficult to establish due to the distortion of the legs. Some setae on tibiae II–III appear hyaline in examined specimens, and have here been illustrated as hollow.

Fig. 4. Geographical distribution of the known records of Gallancyra dentata (Sugimoto, 1934), based on the reports cited in Table 1. Black circles indicate countries where G. dentata has been reported at in at least one survey, including the present report. Hollow circles indicate countries for which surveys of domestic chicken have been published, but G. dentata has not been found. In addition to the areas indicated on the map, Emerson (1956) reported G. dentata from “various islands in the Central Pacific Area”, but gave no detail.