Ceratricula, Larsen, Torben B., 2013

Larsen, Torben B., 2013, Ceratricula and Flandria — two new genera of Afrotropical Hesperiidae (Hesperiinae (incertae sedis )) for species currently placed in the genus Ceratrichia Butler, Zootaxa 3666 (4), pp. 476-488 : 479-481

Ceratricula gen. nov.

Type species: Ceratrichia semilutea Mabille, 1891 . Annales de la Société Entomologique de Belgique 35: 65 (59– 88, 106–121, 168–187).

The genus is part of the subfamily Hesperiinae , the tribal structure of which is unclear (incertae sedis) despite the efforts of Warren et al. (2009). This issue needs much more sampling from both Africa and Asia than has been done so far before any firm conclusions can be made.

Background: The species Ceratrichia semilutea was described from Lagos, Nigeria by Mabille (1891) and placed in that genus because of its superficial resemblance to the common and widespread Ceratrichia phocion Fabricius ; Mabille even qualified his description by stating that it might just be a form of C. phocion . Holland (1896) accordingly downgraded it to a junior synonym thereof, a decision subsequently accepted by its author (Mabille 1904); because of this the name semilutea did not even merit mention by Aurivillius in Seitz (1925). I have not seen the type, but the original description mentions a small white spot in space 2 as well as the black cilia on the apex of the hindwing underside, neither of which is present in C. phocion , which is common in the Lagos area (I caught both sympatrically at Agege just north of Lagos (Larsen et al. 1980)). C. semilutea has never been associated with any genus other than Ceratrichia .

The species was resurrected by Evans (1937) as a valid member of Ceratrichia with the following comments – a) in the genus description: “ C. semilutea is superficially like the other species, but is aberrant structurally, while the 3 on the hindwing above has a recumbent hair pencil from the base of the cell over the origin of vein 2”; b) in the key to species: “Forewing below, no apical spot in space 5, those in spaces 6, 7, and 8 in line if present”; and c) in the actual species description: “The spotting below is of a different type from the other species of the genus”. Evans makes no comment on the fact that the genitalia figured are very different from the other Ceratrichia in the structure of the uncus and the valves [unless by “structurally” he referred to the genitalia].

In the book on West African butterflies I noted that the genitalia were very different from those of Ceratrichia phocion (Larsen 2005) , but having dissected only these two members of the genus did not pursue the issue. As shown in the introduction, the genitalia of Ceratrichia all conform to a structure that differs from any other African Hesperiidae genus, including those of C. semilutea . As also discussed by Larsen (2005), the populations centred on West Africa, Cameroun, and the Albertine Rift respectively seemed sufficiently different to merit subspecies status. C. semilutea is therefore divided into three subspecies, one new and the other re-validating an existing junior synonym.

Description. The antennae of Ceratricula semilutea are distinctly shorter than in Ceratrichia , where they are “equal to five-eighths of the length of the costa”, which is longer than in any other African genus of the Hesperiidae [others and I have used three quarters, which is six-eighths]. The palpi are semi-erect with the third segment very short, hardly visible. This very like in Ceratrichia and is widespread among the other genera of Hesperiinae (incertae sedis). The hindleg tibiae have two pairs of spurs as do most Afrotropical Hesperiidae . The venation was not studied in de-scaled specimens and is similar to many other genera.

The forewing is blackish-brown with a normal complement of hyaline spotting, one in the cell, three subapical spots that are at most slightly out of line, spots in spaces 2 and 3, and a non-hyaline spot in 1b. There are no spots in 4 or 5. However, in two of the subspecies the spotting is usually tiny with one, more, or even all spots lacking completely. The costa of the hindwing upperside is broadly black, the rest of the wing yellow without markings. The forewing underside is like the upperside but with some ochreous dusting of the subapical area, varying by subspecies. The hindwing underside is all yellow, with the apical cilia black, and has slight dark markings in the form of blotches or striae that are not annulated as in Ceratrichia (the three subspecies are illustrated in figure 4).

The male has a recumbent hair-pencil from the base of the hindwing covering the base of vein, as already mentioned by Evans (1937); however, he did not mention that the base of vein 2 covered by the hair-pencil is also swollen and surrounded by androconial scaling (there are no visible androconia in any Ceratrichia ).

Finally the structure of the male genitalia is the most important character of Ceratricula and not compatible with any other genus of the Hesperiinae (figure 3). The tegumen and uncus are of almost equal length with a very small fenestrula at their junction. The uncus tapers to a slightly blunted point. Their combined length is that of the valve (somewhat variable). The tegumen has two small lateral, rounded lobes that are slightly out-turned in dorsal view. There are no chitinized gnathos structures. The valve is more or less almond-shaped, with the pointed end distally. The cucullus occupies only a quarter of the area, except that it has a large, well-chitinized spined lobe loosely attached to its dorsal edge. This lobe is free and in situ may be in a more-or-less horizontal position; it is not really an extension of the cucullus as such (and would be called a harpe if on the disc of the valve). The penis is massive and much longer than the valve, with its dorsal edge fully open, nowhere forming a closed tube (very different from Ceratrichia as illustrated in figure 2a). The fultura has two large, broad irregularly twisted branches, and this structure is as long as the width of the valve (not dissimilar to Pardaleodes ). The saccus is solid and unusually long for the Hesperiinae , over 2/3 the length of the valve.

The combination of characters listed above is not present in any other described genus, though one of each may be found in some other species or genera, except for the curious lobe on the edge of the cucullus, which is special. It is not possible to place the species phylogenetically within the subfamily on the basis these characters, especially in the absence of knowledge of its early stages, but it may have affinities to Pardaleodes .

Three subspecies can be recognized and are discussed below.

Diagnosis. The species does not really resemble any African hesperiine skipper apart from members of the Ceratrichia phocion -group, particularly C. phocion itself (see figure 1). Both sexes of C. semilutea differ on the underside. The forewing has three subapical spots (often present also on the upperside) that are roughly in line, instead of being extremely irregular, usually including additional spots in spaces 9 and 10. The yellow streak along the inside of the costa from base to near the tip is missing; the postdiscal row of dark markings on the hindwing consists of small streaks rather than tiny circles (annulated).

The combination of a black forewing with white hyaline spots and a yellow hindwing without a black margin above is infrequent on African Hesperiinae . The genus Flandria , described later in this paper, actually comes closest in this respect. These are, however, larger species and the forewing hyaline spotting consists of substantial, though still separate, spots. The subapical spots are not in line. Their genitalia are so different as to preclude them being congeneric.

Morphologically or by genitalia C. semilutea matches no other African Hesperiinae . The combination of a the large fultura, a long saccus, the wholly open penis, and the weakly attached spined oval dorsal structure finds no match in any other genus, with the dorsal structure being unique.

Etymology. The genus name is composed of the first part of the name Ceratrichia and the suffix cula (small). C. semilutea has after all been historically associated with Ceratrichia for more than a century, though it now turns out it is not closely related.