Gracililema Krüger, 2015

Volynkin, Anton V., 2022, Taxonomic review of the Afrotropical genus Gracililema Krüger with descriptions of three new species (Lepidoptera: Erebidae: Arctiinae: Lithosiini), Zootaxa 5115 (1), pp. 63-78 : 65-66

Genus Gracililema Krüger, 2015

Gracililema Krüger, 2015 , Generic classification of Afrotropical footman moths sensu stricto (Lepidoptera: Erebidae: Arctiinae: Lithosiini (partim): 72.

Type species: Ilema proleuca Hampson, 1914 , by original designation.

Remark. A detailed description and diagnosis of the genus was provided by Krüger (2015) based on two described species. However, in the description of the female genitalia, Krüger characterised the corpus bursae wall as membranous while it is in fact gelatinous in all species. This error was likely due to the old genital preparations of the females of G. proleuca and G. proleucodes (deposited in NHMUK) being over-macerated resulting in the thinning of the corpus bursae walls. The configuration of the vesica was not discussed by Krüger and is described below.

Diagnosis. Adults of Gracililema are externally reminiscent of members of the genus Mimelilema Krüger, 2015 (illustrated by Krüger (2015)), but are slightly smaller with a somewhat narrower forewing and paler colouration. In the male genital capsule of Gracililema , the valvae are symmetrical (asymmetrical in Mimelilema ) and the distal saccular process is narrow having a spine-like tip (a feature characteristic for the genus) whereas the saccular process in other similar genera is densely covered with spinules ( Mimelilema Krüger, 2015 , Mkalama Krüger, 2015, Birketsmithiola Krüger, 2015 and Lomilema Krüger, 2015) or evenly tapered distally (Pseudotigrioides Krüger, 2015) (illustrated by Krüger (2015)). Among Afrotropical Lithosiina , the spine-like tip of the distal saccular process is also known in the genera Stenilema Hampson, 1909 and Zadadrina Kiriakoff, 1954 which are dissimilar to Gracililema both externally as well as in the structures of the genitalia of both sexes (illustrated by Krüger (2015)). In the female genitalia, the gelatinous corpus bursae with a broad posterior diverticulum are characteristic for the genus.

Re-description. Adults ( Figs 1–16 ). Forewing length 10.0–15.5 mm in males and 11.0–16.0 mm in females. Species vary in size within the same population. Antenna ciliate with somewhat longer cilia in male. Head pale yellow. Thorax grey, collar pale yellow. Forewing ground colour from pale to deep grey, costal stripe and cilia from pale to deep yellow. Hindwing pale yellow. Abdomen ochreous. Male genitalia ( Figs 17–24 ). Uncus elongate, slender, dorso-ventrally flattened, evenly curved and apically pointed. Tuba analis membranous with thin and weakly sclerotised scaphium. Tegumen ca. 3 times shorter than valva, with moderately broad arms fused in posterior half. Vinculum approximately equal in length to tegumen, its arms anteriorly connected by membrane forming medial depression. Intravincular area with one short corema medially. Valva with almost parallel margins medially, tapered distally and apically rounded. Costa with extensive, moderately sclerotised plate subapically. Sacculus moderately wide and sclerotised, basally connected by a thick membranous commissure. Distal saccular process heavily sclerotised, cylindrical and curved inwards, bearing a robust apical spine. Juxta shield-like with elongate and narrow anterio-medial protrusion. Phallus elongate and narrow, with relatively long coecum, somewhat curved at ostium ducti ejaculatorii. Vesica curved dorsally or laterally, with short lateral diverticula and elongate distal diverticulum bearing granulation or spinulose scobination and one spine-like apical cornutus. Vesica ejaculatorius originating subbasally. Female genitalia ( Figs 25–29 ). Papilla analis rectangular with rounded corners, weakly setose. Apophyses thin, apophyses anteriores somewhat longer than posterior ones. Ductus bursae shorter than corpus bursae, with short, membranous medial and sclerotised, dorso-ventrally flattened anterior section; antrum (posterior section of ductus bursae) more or less caliciform, weakly sclerotised. Corpus bursae more or less pyriform or teardrop-shaped with thin gelatinous walls and broad, thickly gelatinous posterior diverticulum. Appendix bursae conical, very short but broad, membranous, positioned postero-dorsally or postero-laterally between diverticulum and base of ductus bursae.

Molecular data. The intraspecific divergence of COI-5P sequences of three Gracililema species sampled ranges between 0.00 and 1.08%. The uncorrected pairwise distance between Gracililema species ranges between 3.30 and 6.44% ( Table 2 ; Fig. 30 ). Molecular data for G. proleucodes and G. bettoni sp. n. are currently unavailable.

Gracililema species content

- G. proleuca ( Hampson, 1914)

- G. proleucodes ( Kiriakoff, 1958)

- G. bettoni sp. n.

- G. lydiae sp. n.

- G. smithi sp. n.

Figures

FIGURE 30. Maximum Likelihood tree of Gracililema based on COI-5P sequenced. Scale indicates substitution rate per site. Bootstrap support values indicated on branches.

FIGURES 1–8. Gracililema spp.: adults. Depositories of the specimens: 1 and 4–6 in NHMUK (©The Trustees of NHMUK); 2, 3 and 8 in ANHRT; 7 in ZSM.

FIGURES 9–16. Gracililema spp.: adults. Depositories of the specimens: 9, 11–16 in ANHRT; 10 in ZSM.

FIGURES 17–20. Gracililema spp.: male genitalia. Depositories of the specimens dissected: 17 and 19 in NHMUK (©The Trustees of NHMUK); 18 in ANHRT; 20 in ZSM.

FIGURES 21–24. Gracililema spp.: male genitalia. Depositories of the specimens dissected: 21, 23 and 24 in ANHRT; 22 in ZSM.

FIGURES 25–29. Gracililema spp.: female genitalia. Depositories of the specimens dissected: 25, 28 and 29 in ANHRT; 26 and 27 in NHMUK (©The Trustees of NHMUK).