Rallicola (Rallicola) tibetana, Gustafsson & Tian & Zou, 2021

Gustafsson, Daniel R., Tian, Chunpo & Zou, Fasheng, 2021, New species of ischnoceran chewing lice (Phthiraptera: Philopteridae) from Chinese birds, Zootaxa 4990 (2), pp. 305-328 : 317-321

Rallicola (Rallicola) tibetana new species

( Figs 16–23 )

Type host: Zapornia bicolor Walden, 1872 —black-tailed crake ( Rallidae ).

Type locality: Pachakshiri, S.E. Tibet, China .

Diagnosis. In the key of Emerson (1955), Rallicola (Rallicola) tibetana new species keys out to Rallicola (R.) ferrisi Emerson, 1955 , but the male genitalia of R. (R.) tibetana are most similar to those of Rallicola (R.) funebris (Nitzsch [in Giebel], 1866). Rallicola (R.) tibetana can be separated from both these species by the following characters: female tergopleurites III–VIII transversally continuous in R. (R.) tibetana ( Fig. 17 ), but medianly interrupted in the other two species; male subgenital plate of R. (R.) tibetana extended distally into a stylus ( Fig. 16 ), but no stylus in either of the other two species.

Furthermore, Rallicola (R.) tibetana can be separated from R. (R.) ferrisi by the following characters: hyaline margin extending more posteriorly along the lateral margin of head in R. (R.) tibetana ( Fig. 18 ) than in R. (R.) ferrisi ; mesosome of R. (R.) tibetana narrowing distally as in Figs 20, 22 , whereas in R. (R.) ferrisi the mesosome widens distally, with a deeply incised distal margin and no marginal thickenings [this character is illustrated erroneously by Emerson (1955)]; parameres of R. (R.) tibetana stout and curved medianly ( Fig. 21 ), but slender and curved laterally in distal third in R. (R.) ferrisi ; vulval margin strongly arched and female subgenital plate with deep sublateral incisions on distal margin in R. (R.) ferrisi , but vulval margin more flattened and subgenital plate without such incisions in R. (R.) tibetana ( Fig. 23 ). Emerson (1955) stated that the female of R. (R.) ferrisi has only two stout setae on each post-vulval tubercle, but all specimens of this species we have examined, including two paratypes, have three setae on the tubercles on each side. However, we have not examined the allotype female of R. (R.) ferrisi . By contrast, all specimens of R. (R.) tibetana have two stout setae on the tubercles ( Fig. 23 ).

In addition, Rallicola (R.) tibetana can be separated from R. (R.) funebris (see Pessoa & Guimarães 1935; Emerson 1955 for illustrations) by the following characters: distal mesosome gently rounded in R. (R.) tibetana ( Fig. 22 ), but with median extension in R. (R.) funebris ; parameres with pointed distal ends and curved overall shape in R. (R.) tibetana ( Fig. 21 ), but with bluntly flattened distal ends and subparallel overall shape in R. (R.) funebris ; male tergopleurites III–VIII transversally continuous in R. (R.) tibetana ( Figs 16–17 ), but interrupted medianly in R. (R.) funebris ; shape of frons and hyaline margin also appears to differ between these two species, based on the illustration of Pessoa & Guimarães (1935). However, photos of R. (R.) funebris available at the NHMUK homepage (https://data.nhm.ac.uk/dataset) suggest that the hyaline margin of R. (R.) funebris is more similar to that of R. (R.) tibetana , and may have been shrunken or overlooked in the specimens examined by Pessoa & Guimarães (1935).

Description. Both sexes. Head trapezoidal, with preantennal section much narrower than postantennal section ( Fig. 18 ); frons with elongated hyaline margin that extends along the lateral head margins to near aperture of as1. Dorsal anterior plate longer than wide, with rounded posterior margin. Head chaetotaxy as in Fig. 18 ; s 1–6 present; s1 and os mesosetae. Antennae sexually dimorphic. Thoracic and abdominal segments and chaetotaxy as in Figs 16–17 ; tergopleurite II divided medianly and tergopleurites III–VIII transversally continuous in both sexes. Measurements as in Table 1 .

Male. Antennae as in Fig. 18 , with scape and pedicel swollen compared to female, and flagellomere I with distinct distal expansion into hook; antennae illustrated as seen in holotype. Tergopleurite III without anterior incision ( Fig. 16 ). Subgenital plate extended distally along midline to form short stylus similar to those found in some Oxylipeurus -complex genera (see Gustafsson et al. 2020); one short seta on each side of stylus near distal end. Basal apodeme rounded, trapezoidal, narrowing distally ( Fig. 20 ); articulation between basal apodeme and parameral head as in Fig. 21 . Mesosome as in Figs 20, 22 ; proximal mesosome bilobed, distal end gently rounded and narrowed. Gonopore dorsal, with U-shaped thickening along distal margin; distinct subparallel dorsal thickenings proximal to gonopore. Paramere overall arched, with distal ends convergent and pointed; no subsidiary median extension of paramere; pst1–2 as in Fig. 21 .

Female. Antennae as in Fig. 19 . Tergopleurite III with deep, narrow incision of anterior margin at midline ( Fig. 17 ). Subgenital plate as in Fig. 23 , without sublateral incisions of distal margin. Vulval margin flattened, with 8–12 short, slender vms and 9–11 short, stout vss on each side; 6–8 short, slender vos on each side of subgenital plate. Vulval margin with sclerotized plate throughout.

Etymology: The species epithet is derived from the type locality.

Type material. Ex Zapornia bicolor : Holotype ♂, Pachakshiri, S.E. Tibet [ China], 6 May 1938, no collector, Brit. Mus. 1946-287, NHMUK010690305 ( NHMUK). Paratypes. 4♀, same data as holotype, NHMUK010690304– 6 ( NHMUK) .

Remarks. Slide NHMUK010690306 also contains a male louse that appears to be close to Rallicola (R.) clayae Tandan, 1951 .

Figures

FIGURES 16–17. Rallicola tibetana new species. 16, male habitus, dorsal and ventral views. 17, female habitus, dorsal and ventral views.

FIGURES 18–23. Rallicola tibetana new species. 18, male head, dorsal and ventral views. 19, female right antenna, ventral view. 20, male genitalia, dorsal view. 21, male paramere and distal basal apodeme, dorsal view. 22, male mesosome, ventral view. 23, female subgenital plate and ventral terminalia. Abbreviations: as1 = anterior seta 1; os = ocular seta; pst1–2 = parameral setae 1–2; s1–6 = sensilla 1–6; vms = vulval marginal seta; vos = vulval oblique seta; vss = vulval submarginal seta.

FIGURES 1–2. Cuculicola calyptocamptus new species. 1, male habitus, dorsal and ventral views. 2, female habitus, dorsal and ventral views. Abbreviation: sts = sternal seta.

FIGURES 3–6. Cuculicola calyptocamptus new species. 3, male head, dorsal and ventral views. 4, male genitalia, dorsal view. 5, male genitalia, ventral view. 6, female subgenital plate, ventral view. Figures 4–5 to same scale. Abbreviations: pst1–2 = parameral setae 1–2; vms = vulval marginal seta; vos = vulval oblique seta; vss = vulval submarginal seta.