Delias aestiva smithersi, Daniels, 2012

Braby, Michael F., 2014, Taxonomic Status of Delias aestiva smithersi Daniels, 2012 (Lepidoptera: Pieridae) comb. nov. from the Gulf Country of Northern Australia, with Description of the Female, Records of the Australian Museum 66 (5), pp. 241-246 : 242-243

Delias aestiva smithersi comb. nov.

Delias mysis smithersi Daniels, 2012

Figs 1, 2

Material examined. Holotype ♂ “Karumba, Qld, 17°29'S, 140°50'E, 9 Oct. 2003, G.&A. Daniels ” ( AM); paratype ♂ “Karumba, Qld, 17°29'S, 140°50'E, 12 Dec. 2002, G. Daniels ” ( AM); paratype ♂ “ Mitchell River [ Kowanyama ], Q., 26.x.[19]71”, “ I.S.R. Munro ”, “ I.S.R. Munro Collection ”, “genitalia 082, Delias aestiva smithersi ♂. Det. M.F. Braby ” ( AM); 1♀ labelled “Weipa, N. Qld., 3–5 Feb., 1976, [K. DeWitte]”, “QM Reg. No. T100951”, “AN31 000858” ( QM); 1♂ labelled “ Weipa Qld, 29 Aug 1994, [R.A. Eggleton]” ( ANIC); 1♂, 1♀ labelled “ Uningan Nature Reserve, Weipa, Q., 13.ix.1997, T.A. Lambkin ” ( TALC); 3♂♂ labelled similarly in ANIC; 2♂♂ labelled similarly but with date “ 18. ix.1997 ” ( ANIC).

Description

Female ( Figs 1, 2 ). Forewing length 34.6 mm. Upperside pearly-white, with yellow markings on underside faintly visible; forewing with a black terminal band enclosing a series of three conspicuous cream subapical spots and three cream subterminal spots, the last between veins CuA 1 and CuA 2 very obscure, terminal band extends narrowly along costa to base and may extend proximally along veins M 3, CuA 1, CuA 2 and 1A+2A; hindwing with a black terminal band, the inner edge of which may extend proximally along all main veins (M 1 – CuA 2), red markings on underside faintly visible. Underside forewing similar to upperside except basal area broadly suffused with yellow, and the series of six subapical and subterminal spots larger, more conspicuous and of a different colour, the three spots between veins R 1 and M 2 yellow, while the three spots between veins M 2 and CuA 2 white; hindwing ground colour white, with base and dorsum broadly suffused with yellow, and a black terminal band enclosing a bright red narrower subterminal band, which extends from costa (above vein Rs) to dorsum (below vein 1A+2A).

Diagnosis. Braby (2012) listed 10 unique character states of the adult wing colour pattern elements and an additional eight morphological characters of the male genitalia by which D. aestiva aestiva is distinguished from D. mysis mysis . Daniels (2012) provided a number of characters (6 wing colour pattern elements) in which D. aestiva smithersi (originally placed in synonymy with D. mysis ) is distinguished from D. mysis mysis and D. aestiva aestiva . However, taxonomic reappraisal of the status of the speciesgroup name smithersi and the discovery of the female sex of this taxon, has necessitated a review of the features that distinguish D. aestiva and D. mysis , and the two subspecies of D. aestiva , because some of the characters were found to be non-applicable while others were overlooked.

A revised list of characters, and their states, that separate D. aestiva from D. mysis are tabulated in Table 1. A total of 10 diagnostic characters were found that distinguish the two species. Delias aestiva smithersi possesses all of these characters, the states of which are listed under D. aestiva in Table 1.

The males of D. aestiva smithersi may be distinguished from those of D. aestiva aestiva by the following four characters: (a) the apex of the forewing is more pointed; (b) the subapical spots on the upper- and underside of the forewing are proportionally larger; (c) the black terminal band on the upperside of the hindwing is narrower; in D. aestiva aestiva the band is particularly broad, being approximately twice the width of D. aestiva smithersi ; and (d) the black terminal band on the underside of the hindwing is narrower, with the inner margin almost confluent with the red subterminal band; in D. aestiva aestiva the band is broader, with the inner edge extending proximally well beyond the red subterminal band.

Examination and comparison of two females of D. aestiva smithersi with a large sample of D. aestiva aestiva females (n = 35, MFBC) revealed similar character differences to the males. For example, the black terminal band on the upperside of the hindwing in D. aestiva smithersi females is narrower (in one specimen the inner margin of this band extends proximally along the major veins, but not in the other specimen); in D. aestiva aestiva females the band is broader, with the inner extensions along the veins less pronounced. In the specimen illustrated ( Fig. 2 ) the fourth and fifth spots in the series of six submarginal spots on the underside of the forewing (i.e. those in cells M 3 and CuA 1) are white suffused yellow in D. aestiva smithersi , but in the other specimen they are white; in D. aestiva aestiva these spots are always white without the yellow suffusion. In D. aestiva smithersi females, the inner margin of the black terminal band on the underside of the hindwing, like the males, extends only narrowly beyond the red subterminal band. The red subterminal band on the underside of the hindwing appears to be slightly broader compared with D. aestiva aestiva ; however, additional material is needed to assess this character. The width of the red subterminal band is variable in D. aestiva aestiva , and the accompanying plate shows the extremes of variation ( Figs 3, 4 ). For example, the width of the red spot in cell M 3 in this subspecies ranges from 1.0 mm to 2.3 mm (mean = 1.5 mm + 0.26 s.d., n = 35) ( Fig. 5 ). The width of this spot in both females of D. aestiva smithersi is 2.0 mm, which falls within the observed range of D. aestiva aestiva ( Fig. 5 ). Further specimens are required to ascertain if they are significant differences in the sample means of this character between the two taxa.

Male genitalia. The genitalia of one of the paratype males are illustrated in Fig. 6 . The specimen possesses features that place the taxon with D. aestiva rather than D. mysis (see Braby, 2012 for comparative illustrations). These features include the shape of the saccus, and the shape of the valva, which, in lateral view, is rounded and convex at its posterior end (in D. mysis , the posterior end of the valva is distinctly pointed or protruded). The valva, in dorsal view, in D. aestiva smithersi and D. aestiva aestiva is broader in width and less tapered apically with shorter setae on its inner surface compared with D. mysis mysis . The uncus of the two species is similar in profile, with the apex divided into three lobes; however, in D. aestiva smithersi and D. aestiva aestiva , the uncus is slightly broader and shorter in length, and there are substantial differences at its point of attachment with the tegumen, which is also broader than that of D. mysis mysis . The phallus was missing in the specimen dissected and therefore not available for comparison. Dissection of several specimens of D. aestiva aestiva (in MFBC) revealed minor variation in the male genitalia, particularly the form of the valva, but there was insufficient material to assess the extent of intrasubspecific variation within D. aestiva smithersi .

Distribution. Delias aestiva smithersi occurs in the eastern Gulf of Carpentaria where it is known from three locations on the western side of Cape York Peninsula, from Weipa to Karumba, QLD ( Fig. 7 ). All locations are situated in coastal lowland areas that support extensive stands of mangroves, particularly in estuarine areas along banks of rivers and creeks. The geographical range is allopatric with D. aestiva aestiva , which is restricted to the northern coastal areas of the Top End of the Northern Territory on the western side of the Gulf of Carpentaria.

Figures

Figure 5. Frequency distribution of the size of the red subterminal band (width of red spot in cell M3) on the underside of the right hindwing of female Delias aestiva aestiva based on a sample (n = 35, MFBC) of specimens from Darwin,Northern Territory.Sample mean and standard deviation are indicated above graph. The grey bar indicates the size of the corresponding band in the two female specimens of D. aestiva smithersi examined.

Figure 6. Male genitalia of Delias aestiva smithersi from Mitchell River, Queensland (AM); lateral view with left valva and phallus removed. Scale bar = 1.0 mm.

Figure 7. Spatial distribution of Delias aestiva smithersi, showing known locations on western Cape York Peninsula in the eastern Gulf of Carpentaria, Queensland, Australia.

Figures 1–4. Female Delias aestiva from northern Australia: (1, 2) D. aestiva smithersi from western Cape York Peninsula, Queensland (Weipa) (QM), showing upper- and underside; and (3, 4) D. aestiva aestiva from the Top End, NT (Darwin) (MFBC) showing extent of variation in underside pattern, particularly the width of the red subterminal band on the hindwing. Scale bar = 20 mm.