Cossula, BAILEY, 1882

Davis, Steve R., Gentili-Poole, Patricia & Mitter, Charles, 2008, A revision of the Cossulinae of Costa Rica and cladistic analysis of the world species (Lepidoptera: Cossidae), Zoological Journal of the Linnean Society 154 (2), pp. 222-277 : 261-262

COSSULA BAILEY, 1882

Cossula Bailey, 1882: 93 , type species: Cymatophora magnifica Strecker, 1876 ; Barnes & McDunnough, 1911; Donahue, 1995: 126.

Costria Schaus, 1892: 327 , type species: Costria abnoba Schaus, 1892 ; Dyar & Schaus, 1937: 1270; Donahue, 1995: 126.

Allostylus Hering, 1923: 12 , type species: Cossula coerulescens Schaus, 1911 . [syn. nov.]

Dimorphoctena Clench (1957: 900) , type species: Dimorphoctena egregia Clench, 1957 . [syn. nov.]

Type species: Cymatophora magnifica ( Strecker, 1876; Barnes & McDunnough, 1911).

Description

Male: Forewing length: 16–33 mm.

Female: Forewing length: 20–33 mm. Head: Antenna with inner serrate rami reduced in size in some species and developed in others, almost to a point where the antenna appears symmetrical; scales on antennal shaft from cream and light brown to dark brown and fuscous; labial palpus normally cream to light or dark brown ventrally, and light brown to dark or rusty-brown dorsally; one species with labial palpus crimson; frons ranging from cream and light brown to dark or rusty-brown and fuscous; vertex same as frons; one species with frons and vertex crimson.

Thorax: Forewing with terminal patch at distal area adjacent to termen. Wing venation highly variable; R 2 of forewing most often fused and forked with R 3, sometimes separate; R 3 or R 2+3 of forewing most often separate from R 4, sometimes fused and forked; R 4 or R 3+4 of forewing most often separate from R 5.

Abdomen: From pale brown to dark or rusty-brown dorsally; cream and pale brown to dark or rustybrown ventrally.

Male genitalia: Valva somewhat oblong, broad basally, narrowing slightly and rounded apically; saccular process often spiniform, with projection variable in shape and length; spines can be lenticular and flattened, short, truncate and with a blunt apex, or rather long and with an acute apex; base of costa with basal lobe gradually to strongly ascended dorsally, weakly to very pronounced, and projecting at an angle. Uncus bifurcate, mostly very shallowly and broadly bifid; often elongate and fairly slender, protruding beyond valvae in some species; dense setal patches at base and terminus of uncus. Invagination between tergite 9 of genital capsule and uncus crescent-shaped and ascending dorsally to lobeshaped and curving around base of gnathos. Gnathos with dorsum of bridge often bearing heavily sclerotized ridges; bridge variable, often globose, with a prominent ridge, and sometimes elongate and tubular; arms not protruding beyond bridge and mostly not recurving into tergite 9. Anal tube mostly membranous. Juxta process elongate, digitiform and free from valva; processes mostly membranous, but can be lightly sclerotized. Aedoeagus with dorsal crest developed and prominent to reduced in size or absent; coecum reduced to nearly absent; rostellum digitiform and slender, with apex acute and rounded; vesica with spines often absent, but when present, spines large and heavily sclerotized.

Female genitalia: Sternite 8 variable, from developed and sclerotized to reduced and mostly membranous; when developed, triangular in shape and with sides slightly concave; when reduced, intersegmental membrane often enlarged. Intersegmental membrane between abdominal sternites 7 and 8 variable, but most often developed and forming two lobes on either side of ostium; most often sclerotized and smooth, but sometimes rough and sculptured with cuticular pits and wrinkles; when reduced, mostly membranous. Ductus bursae variable, from shortened to elongate, most often membranous, but occasionally with parts sclerotized and enlarged. Corpus bursae variable, from enlarged and oblong when ductus bursae is shortened to small and oblong or spherical when ductus bursae is elongate.

Discussion: Barnes & McDunnough (1911) synonomized Cymatophora magnifica Strecker, 1876 with Cossula magnifica Bailey, 1882 , and designated magnifica Strecker as the type species.

The cryptic forewing pattern possessed by most species of Cossula probably provides protection from potential predators when the moths rest on various substrates such as tree trunks. This pattern consists of dark transverse striae that usually extend over the entire wing. All members have a terminal patch ( Fig. 11 ) distally on the forewing, which displays a characteristic pattern for every species in the genus. Although a terminal patch also occurs in Magulacra and Simplicivalva , the patch pattern is distinctly different for Cossula ( Figs 34–49, 51, 52 ). The adults of Cossula are among the largest of all Cossulinae , with many museum specimens typically becoming greasy soon after being collected.

Although the usually distinctive wing patterns exhibit relatively little variation within the species of Cossula , wing venation can be quite variable, especially within the radial system. The male and female genitalia are also quite variable between species. The male gnathos displays the greatest variation, which may vary from a globular structure with many strong ridges present dorsally, to being globular but lacking the dorsal ridges entirely, or more elongate and tubular. The uncus can be variable, but it is always bifurcate, varying in the degree of bifurcation. The saccular process on the male valvae is always spiniform, differing only in the length and shape of the spine. Within Cossula , and because of many of these differences, it appears that this genus could be divided further based on genitalic characters. For instance, there are a few characters that define three distinct species groups within Cossula (see Phylogenetics below) such as the shape and structure of the gnathos, the lateral appearance of the gnathos, the invagination between tergite 9 and the uncus, and the basal lobe at the base of the costa on the valvae. Some of these characters are quite homoplasious, however, and the differences could not be distinctly mapped onto the phylogeny.

The terminal forewing patch, particularly the pattern displayed within the patch, constitutes the most diagnostic external characteristic for Cossula . Many species of Cossula possess spots within the patch or a thick curved band that joins the wing termen. Because some species of Magulacra and Simplicivalva possess similar wing patterns as well as terminal patch patterns, examination of the male genitalia may be necessary to determine the generic placement of those species. The males of Cossula are characterized by their large, rounded valvae, elongate and digitate juxta processes, and shallow, often broadly bifid uncus apex. The uncus and gnathos are typically closely associated, with the gnathos arms short and extending parallel to the uncus.

Figures

Figures 4–11. Morphology. Representative antennae of the Cossulinae: 4, Biocellata alfarae; 5, Spinulata acutipennis; 6, unidentified species of Simplicivalva; 7, Magulacra niveogrisea; 8, unidentified species of Cossula. Cossulinae wing venation: 9, Cossula magnifica, fore and hindwing. Cossulinae legs: 10, Cossula arpi, fore, mid and hind leg. Representative Cossulinae wing patterns and terminology: 11, Cossula gaudeator. Scale bar = 10.0 mm.

Figures 32–43. Adults: 32, male, Magulacra niveogrisea; 33, female, Magulacra niveogrisea; 34, male, Cossula arpi; 35, female, Cossula arpi; 36, male, Cossula buspina; 37, male, Cossula coerulescens; 38, female, Cossula coerulescens; 39, male, Cossula cossuloides; 40, female, Cossula cossuloides; 41, male, Cossula duplex; 42, female, Cossula duplex; 43, male, Cossula duplexata. Scale bar = 10.0 mm.

Figures 44–52. Adults: 44, male, Cossula gaudeator; 45, female, Cossula gaudeator; 46, male, Cossula longirostrum; 47, female, Cossula longirostrum; 48, male, Cossula minutiloba; 49, female, Cossula minutiloba; 50, unidentified female 1; 51, unidentified female 2; 52, unidentified female 3. Scale bar = 10.0 mm.