Crocosia Hampson, 1914

Genus Crocosia Hampson, 1914 View in CoL

Crocosia Hampson, 1914 View in CoL , Catalogue of the Lepidoptera Phalaenae in the British museum (Supplement), 1: 470.

Type species: Crocosia phaeocraspis Hampson, 1914 , by original designation.

Diagnosis. Species of the genus ( Figs 1–6 View Figures 1–8 ) are externally reminiscent of members of the genera Zobida Birket-Smith, 1965 (illustrated by Krüger (2015)), Cragia ( Figs 15, 16 View Figures 9–16 ) and Pseudocragia Krüger, 2015 (illustrated by Krüger (2015)) with their pair of small black spots on the forewing but are characterised by the substantial sexual dimorphism: the male has an orange forewing with a greyish-brown outer third while the female forewing is unicolourous greyish-brown, with only slight orange suffusion basally.

The male genitalia of Crocosia ( Figs 17–19 View Figures 17–19 ) are similar to Cragia ( Fig. 22 View Figures 20–22 ) but differ in the following features. (1) In the valva, the sacculus is reduced, very short and lacks processes whereas in Cragia it is elongate, reaching the base of the valvula, and bears a medial process directed ventrad or inwards. (2) The proximal end of the sacculus bears a weakly sclerotised ribbon-like ental process separated from its counterpart by a membrane whereas in Cragia the homologous processes are connected by the thin intersaccular bridge. (3) The costa is short, trapezoidal and occupies only the basal section of the dorsal margin of the valva whereas in Cragia it is elongate, occupying the majority of the dorsal margin of the valva. (4) The valval section of the transtilla is short, overlapping with the costa and bears a short, conical and serrulate ampulla. Cragia also has a similar (but larger) ampulla but the valval section of the transtilla in this genus is considerably longer and its distal part is extended into the medial section of the valva. (5) The diaphragmal section of the transtilla has a weakly sclerotised, ribbon-like tendon separated from its counterpart by the membrane (similar to Cragia ). (6) The juxta is trapezoidal with a tapered and heavily sclerotised dorsal section, which has a broad V-shaped medial notch, its lateral ventral corners firmly articulated with the sacculi. Unlike Crocosia , the juxta in Cragia is broader, and its dorsal section is weakly sclerotised and fused with the anellus. (7) The anellus is membranous and firmly articulated with the phallus making it non-removable from the phallocrypt, whereas in Cragia the anellus bears hook-shaped valvellae ventro-laterally, and the phallus is hardly removable from the phallocrypt. (8) The phallus of Crocosia is moderately broad (the length to width ratio is 2.0–2.2:1) and has a membranous, longitudinally wrinkled and expandable distal (external) section bearing a broad, plate-like and weakly sclerotised ventral carina forming an outer wall of the subbasal diverticulum. Unlike in Crocosia , the phallus of Cragia is broader (the length to width ratio is ca. 1.5–1.6:1), its distal section is more protruding posteriorly, non-expandable, and lacks the carina while the proximal (internal) section is markedly shorter. Among the Lithosiina genera, the similar longitudinally wrinkled and expandable distal section of the phallus is found in the genus Brunia Moore, 1878 (illustrated, e.g., by Holloway (2001), Bucsek (2017), and Volynkin (2022)) but in the latter, the carina is absent and the phallus is easily removable from the phallocrypt. (9) The vesica of Crocosia is broad, with a few diverticula of various shapes, and bears two strongly elongate, horn-like distal cornuti subapically and apically near the base of the vesica ejaculatorius, which originates distally, whereas in Cragia the vesica lacks the cornuti and has a vesica ejaculatorius originating proximo-ventrally. Birket-Smith (1965) erroneously treated the cornuti of Crocosia as valvellae supporting his conclusion by the observation that certain muscles (assumed by the author as homologous to the muscles originating from the ventrolateral processes of the juxta and inserted into the valvellae in Cragia ) are inserted into them. This treatment was followed by Krüger (2015), who did not examine the vesica structure. However, subsequent examination of the male genitalia musculature of Crocosia by the author of the present paper revealed no juxtal muscles inserted into those sclerotised structures of Crocosia . Although they are nearly as long as the phallus and their distal ends are extended distally from the phallus tube (and protected by the carinal process by a cover) ( Figs 23–25 View Figures 23–29 ), they are in fact situated on the distal section of the vesica and are therefore the true cornuti.

The female genitalia of Crocosia ( Figs 30, 31 View Figures 30–35 ) are characterised by the following features. (1) The ductus bursae is membranous and tubular, its posterior section is funnel-shaped, and the ventral margin of the ostium bursae bears an antevaginal plate divided into two lateral lobes. Compared to Crocosia , the ductus bursae of Cragia ( Fig. 32 View Figures 30–35 ) is shorter, broader, its anterior section is densely covered with spinulose scobination while the posterior section forms a broad (as wide as the anterior end of the 8 th abdominal segment), more or less rectangular and gelatinous antrum bearing pockets to receive the male valvellae during copulation, and the ventral margin of the ostium bursae is rugose, lacking the antevaginal plate. (2) The corpus bursae is pyriform, its anterior section is membranous while the posterior one is sclerotised, bears two short thick-walled and rugose posterior diverticula directed posteriorly, and a large, pyriform anterior diverticulum, which is directed anteriorly, with a membranous distal section, and a weakly sclerotised proximal section. At the base of the latter, the corpus bursae bears a short sclerotised pocket. Unlike Crocosia , in Cragia the corpus bursae has a tubular and densely spinulose posterior section (its scobination is extended into the ductus bursae), and a membranous and helicoid anterior section, which is longer than the posterior one; and the posterior section has a single pyriform and membranous diverticulum. (3) The appendix bursae is conical, proximally sclerotised and apically membranous, originating from the posterior section of the corpus bursae postero-laterally and directed posteriorly, whereas in Cragia the appendix bursae is not developed and the ductus seminalis originates from the anterior end of the helicoid anterior section of the corpus bursae.

The diagnostic comparison with Cragiosia gen. n. ( Figs 7–14 View Figures 1–8 View Figures 9–16 , 20, 21 View Figures 20–22 , 33–35 View Figures 30–35 ) is provided below in the diagnosis of the latter.

Distribution. The genus is widespread in rainforests of the Guineo-Congolian Region reaching western Kenya (Kakamega Forest) in the east.

Molecular data. Although they display substantial and stable morphological differences, two allopatric species of the genus were recovered as polyphyletic ( Fig. 36 View Figure 36 ). The intraspecific divergences were in the ranges of 0.00–2.84% in C. phaeocraspis and 0.00–2.99% in C. divisa , while the pairwise distances between C. phaeocraspis and C. divisa were 0.00–2.83%. Thus, Crocosia is another example of a group in which the COI marker is not informative for purposes of species delimitation, this phenomenon being quite widespread among various genera of Lepidoptera (e.g., Schmidt & Sperling 2008; László & Hausmann 2022, etc.).