Atkinsia, 2022

Toussaint, Emmanuel F. A., Braby, Michael F., Müller, Chris J., Petrie, Edward A. & Kawahara, Akito Y., 2022, Molecular phylogeny, systematics and generic classification of the butterfly subfamily Trapezitinae (Lepidoptera: Papilionoidea: Hesperiidae), Zoological Journal of the Linnean Society 195, pp. 1407-1421 : 1412-1414

ATKINSIA BRABY & TOUSSAINT GEN. NOV.

Zoobank registration: u r n: l s i d: z o o b a n k. org:act: E83BF881-52D1-4204-A205-E22AE305EEA9

Type species: Telesto dominula Plötz, 1884 (hereby designated).

Diagnosis

Atkinsia differs from Dispar Waterhouse & Lyell, 1914 , Pasma Waterhouse, 1932 and Anisynta Lower, 1911 by the following characters. The male genitalia of Atkinsia ( Fig. 2 ) have the upper (dorsal) process of the valva rotated vertically downwards at 90° and projecting posteriorly well beyond the lower (ventral) process, whereas in Dispar , Pasma and Anisynta the dorsal process is relatively straight or with a slight downward curve in Dispar and Pasma . This unique shape of the processes in Atkinsia gives the valva a ‘pliers’-like appearance. The female genitalia of Atkinsia ( Fig. 3 ) possess a unique‘horseshoe-shaped’ sclerotized structure that protrudes from the eighth sterna posterior to the lamella antevaginalis of the sterigma. This structure is absent in the three other genera, and it has not been found in any other species of Trapezitinae (A. F. Atkins, pers. comm., 2020). Although androconia are characters under sexual selection, and therefore not that useful for generic diagnosis, the male sex-brand of Atkinsia ( Fig. 4A ) is highly unusual and possibly unique in the Trapezitinae . The sex-brand on the forewing extends as a broad, linear streak from cell CuA 1 to cell 1A+2A, but it consists of two distinct parallel patches of sex-scales, the inner patch black and the outer, broader patch grey. Sex-brands are absent in Pasma and most species of Anisynta and, within the Anisynta group, are present only in Dispar and Anisynta monticolae (Olliff, 1890) . In Dispar and Anisynta monticolae , however, the sex-brand consists of single linear streak of dark grey scales and is shorter in length, extending from vein CuA

1

to 1A+2A.

Both sexes of Atkinsia are generally larger than adults of the other three genera, and they also differ with regard to the colour pattern elements, particularly the markings on the underside of the hindwing, in which the silvery-white or cream postmedian spots may form a broad convex band that is joined to a prominent tornal spot, an arrangement not found in Anisynta , Dispar or Pasma . In addition, the pupal cap of Atkinsia ( Fig. 5 ) has a long, narrow, sculptured projection that is absent in the other genera and which appears to be unique in the Trapezitinae . In Pasma , the projection of the pupal cap consists of a shorter, laterally spread, raised area ( Atkins, 1988) whereas in Anisynta ( Atkins, 1975b) and Dispar ( Braby, 2000) , the head of the pupa is rounded anteriorly, rugose and lacks a prominent projection (similar to Trapezites ); in Anisynta , the cap is divided into three rounded areas.

Remarks

Atkinsia is closely related to Anisynta , Dispar and Pasma . These four genera form a well-supported monophyletic group, with the following relationships according to our molecular results: Dispar + ( Atkinsia + ( Pasma + Anisynta )), which we refer to as the Anisynta group of trapezitine skippers. Thus, continued recognition of the species dominula in Anisynta renders that genus polyphyletic.

The species dominula Plötz, 1884 has had a relatively unstable classification. Originally described in the genus Telesto Boisduval, 1832 by Plötz, Miskin (1891) placed dominula and Telesto drachmophora Meyrick, 1885 (a junior synonym of dominula ) under Hesperilla . Meyrick & Lower (1902), however, maintained dominula under Telesto , noting the close similarity between it and drachmophora . However, Lower (1911) later assigned dominula to Hesperilla , noting that Telesto was preoccupied (i.e. a junior homonym of Telesto Lamouroux, 1812 , a genus of soft corals in Clavulariidae ), and cast doubt on the status of drachmophora . Subsequently, Waterhouse & Lyell (1914) placed dominula and Hesperilla monticolae Olliff, 1890 in the genus Motasingha . Although Lower (1911) introduced the concept of Anisynta a few years earlier, in 1911, dominula (and monticolae ) were not transferred from Motasingha to that genus until 21 years later by Waterhouse (1932b), who also provided a revised diagnosis for Anisynta , and he described the genus Pasma to accommodate the species Hesperilla tasmanica Miskin, 1889 and Hesperilla polysema Lower, 1908 [the concept of Pasma was subsequently revised by Atkins (1973)]. For the past 90 years, dominula has remained in Anisynta . We now place the taxon in a new genus that is monotypic. Waterhouse (1932a, 1938) recognized and described several infraspecific taxa within dominula , although most of these were not recognized by Braby (2000) owing to the extent of variation. There is negligible variation in the male and female genitalia across the geographical range of the species, from northern New South Wales ( Figs 2A, B , 3A ) to Tasmania ( Figs 2C, D , 3B ). Thus, the nomenclature, new combinations and synonyms recognized for Atkinsia are as follows:

Atkinsia dominula (Plötz, 1884) comb. nov. Atkinsia dominula dominula (Plötz, 1884) comb. nov. = Telesto drachmophora Meyrick, 1885 = Anisynta dominula draco Waterhouse, 1938 = Anisynta dominula dyris Waterhouse, 1938

Atkinsia dominula pria (Waterhouse, 1932) comb. nov.

Shared characters of the Anisynta group include: (1) the origin of vein CuA 2 of the forewing nearer the end of the discal cell than the base ( Fig. 4A ); (2) the origin of vein M 1 of the forewing well separated from R 5, with the intervening discocellular vein (i.e. between M 1 and R 5) inclined toward the termen; (3) the origin of vein CuA 1 of the hindwing closer to M 3 than to CuA 2, with the intervening discocellular vein (i.e. between M 3 and CuA 1) aligned at a similar angle to the middle and lower discocellulars (i.e. between M 1 and M 3) such that the end of the discal cell is broadly truncate ( Fig. 4B ); and (4) the hind tibia with two pairs of spurs. Vein 1A+2A of the forewing is slightly distorted in the middle in Dispar and Atkinsia , but it is relatively straight in Pasma and Anisynta . The club of the antenna is evenly curved, with the apiculus short and pointed in Dispar and short and blunt in Atkinsia and Anisynta , whereas in Pasma it is sharply bent before middle, with the apiculus long and blunt. The male genitalia of all four genera are unusual in that the valvae are deeply divided apically into two long processes or ‘arms’, which are heavily sclerotized, with short spines at their apices ( Atkins, 1973, 1994; Sands & Sands, 2017). In all genera, the apical portion of the lower (ventral) process is rotated vertically upward at 90°, or 135° in Dispar , and slightly inwards in Atkinsia . The uncus is similar in profile in Anisynta , Atkinsia and Pasma in that the apex is broadly truncate, whereas in Dispar the uncus is long and narrowly tapered to a point and with a slight downward curve.

Members of the Anisynta group occur in temperate grassland, open woodland, woodland, open forest or tall open forest, and all use Poaceae as their larval food plant families. Dispar has occasionally also been recorded on Cyperaceae and Asparagaceae .

Etymology

The new genus is named in honour of Mr Andrew Atkins for his substantial and pioneering research on the taxonomy and biology of Australian butterflies, particularly the Trapezitinae , spanning> 40 years.

Figures

Figure 2. Male genitalia of Atkinsia dominula comb. nov. from the northern and southern ends of its geographical range: A, lateral view with left valva removed, Deervale, NSW, Australia; B, external view of left valva, Deervale, NSW, Australia; C, lateral view with left valva removed, Great Lake, TAS, Australia; and D, external view of left valva, Great Lake, TAS, Australia.

Figure 3. Female genitalia of Atkinsia dominula comb. nov. from the northern and southern ends of its geographical range: A, ventral view, Barrington Tops, NSW, Australia; and B, ventral view, Great Lake, TAS, Australia.

Figure 4. Wing venation of male Atkinsia dominula comb. nov.: A, forewing, showing sex-brand; and B, hindwing.

Figure 5. Pupal cap of Atkinsia dominula comb. nov.: A, anterior view; B, ventral view; and C, lateral view.