Guimaraesiella (Dicrurobates) lurida Gustafsson & Bush, new species

(Figs 29–35)

urn:lsid:zoobank.org:act: F85A70C6-AD91-4314-9CD1-4815A6E78A72

Type host. Dicrurus leucophaeus Vieillot, 1817 —ashy drongo.

Type locality. Chiang Saen, Chieng Rai Province, Thailand .

Diagnosis. Guimaraesiella (Dicrurobates) lurida is morphologically closest to Guimaraesiella (Di.) regis n. sp. (see below), but these two species can be separated by the following characters: (1) the dorsal preantennal suture reaches lateral margin of head in Guimaraesiella (Di.) regis (Fig. 52), but not in Guimaraesiella (Di.) lurida (Fig. 31); (2) the ventral anterior plate is wider than long in Guimaraesiella (Di.) lurida (Fig. 31), but longer than wide in Guimaraesiella (Di.) regis (Fig. 52); (3) aps is present on female tergopleurite VIII in Guimaraesiella (Di.) lurida (Fig. 30), but absent in Guimaraesiella (Di.) regis (Fig. 51); (4) the anterior margin of the proximal mesosome is concave in Guimaraesiella (Di.) lurida (Fig. 33), but is straight in Guimaraesiella (Di.) regis (Fig. 54); (5) the ventral sclerite tapers markedly anteriorly, with the anterior end about a third as wide as the proximal mesosome at its widest point in Guimaraesiella (Di.) lurida (Fig. 33), but it tapers less markedly, with the narrowest point about half as wide as the proximal mesosome in Guimaraesiella (Di.) regis (Fig. 54).

For differences between Guimaraesiella (Di.) lurida and the other morphologically close species— Guimaraesiella (Di.) nana n. sp. and Guimaraesiella (Di.) luzonica n. sp. — see under the Diagnosis of each of these species.

Description. Both sexes. Head shape and chaetotaxy as in Fig. 31. Lateral margins of preantennal area straight to slightly convex, frons broadly flattened; marginal carina broad, irregular, narrowing anteriorly; dorsal preantennal suture reaches dsms and extends toward but does not reach ads, and does not reach lateral margins of head; ventral anterior plate broad, but short, roughly, semi-circular; coni broad but short, temples rounded; gular plate rhombic with anterior and lateral points (Fig. 31). Thoracic and abdominal segments as in Figs 29–30.

Male. Thoracic and abdominal chaetotaxy as in Fig. 29; aps absent on tergopleurite IV, but present on tergopleurites V–VII. Genitalia as in Figs 32–34: basal apodeme slightly trapezoidal, narrowing anteriorly with rounded anterior end and slight or no constriction at mid-length (Fig. 32). Proximal mesosome broad, widening anteriorly, with concave proximal margin; ventral sclerite narrowing markedly in anterior end; mesosomal lobes roughly triangular, with sinuous lateral margins; rugose nodi small; 2 ames sensilla on each side near antero-lateral corners of mesosomal lobes; 2 pmes sensilla on each side of gonopore, near rugose nodi; gonopore oval, with slender marginal thickening (Fig. 33). Parameral heads roughly triangular and blades broad, tapering distally (Figs 32, 34). Measurements: Ex Dicrurus leucophaeus (n = 7): TL = 1.52–1.65; HL = 0.37–0.40; HW = 0.31–0.34; PRW = 0.20–0.22; PTW = 0.30–0.32; AW = 0.43–0.50.

Female. Thoracic and abdominal chaetotaxy as in Fig. 35; psps present on tergopleurite VIII. Subgenital plate roughly rectangular, with concave lateral margins in distal half; lateral submarginal bulges broad, rounded; vulval margin rounded, with 3–4 short, slender vms on each side, and 4–5 short, thorn-like vss on each side; 3–6 short, slender vos on each side; distal 1 vos anterior to vss (Fig. 35). Measurements: Ex Dicrurus leucophaeus (n = 11): TL = 1.67–1.89 (1.79); HL = 0.41–0.43 (0.42); HW = 0.35–0.38 (0.36); PRW = 0.21–0.24 (0.23); PTW = 0.33–0.36 (0.34); AW = 0.45–0.52 (0.49).

Etymology. The species epithet derives from “ luridus ” Latin for “wan, pale”, referring to the comparatively pale tergal and sternal plates of the species.

Type material. Ex Dicrurus leucophaeus: Holotype ♂, Chiang Saen, Chieng Rai Province, Thailand, 25 Jan. 1965, H.E. McClure, SE-1890 (NHML). Paratypes: 1♀, same data as holotype (NHML); 2♂, 2♀, Pang Nam Un, Bun Yun, Nan Province, Thailand, 18 Jan. 1953, R. E. Elbel & H.G. Deignan, RE-2089, RT-B-12206 (NHML); 1♂, 1♀, Chiang Saeh Kao, Chiang Rai Province, Thailand, 17 Feb. 1953, R. E. Elbel & H.G. Deignan, RE-2287, RT-B-17791 (NHML); 1♂, 1♀, same data (BPBM); 1♂, 1♀, Pang Nam Un, Bun Yun, Nan Province, Thailand, 26 Jan. 1953, R. E. Elbel & H.G. Deignan, RE-2209, RT-B-17733 (BPBM); 1♂, 1♀, Hin Laem, Tha Khanun, Kanchanaburi Province, Thailand, 13 Nov. 1952, R. E. Elbel & H.G. Deignan, RE-1500, RT-B-13044 (BPBM); 4♀, Chiang Saen Kao, Chiang Rai Province, Thailand, 17 Feb. 1953, R.E. Elbel & H.G. Deignan, RE-2287, RT-B-17791 (USNM) .

Remarks. Guimaraesiella lurida was represented in the phylogeny of Bush et al. (2016) by one specimen from the type host and by one specimen from Geokichla citrina . Although both of these host species are known to participate in mixed-species foraging flocks (Sridhar & Sankar 2008) with opportunities for louse exchanges in the wild, all other lice from G. citrina we have examined belong to other groups within Guimaraesiella . Therefore, we do not regard G. citrina as a natural and regular host of Guimaraesiella lurida until further specimens from this host confirm this host-louse association.