Philiris diana fortuna, Hacobian & Braby & Petrie, 2023

Hacobian, Bartholomew S., Braby, Michael F. & Petrie, Edward A., 2023, A New Subspecies of Philiris diana Waterhouse & Lyell, 1914 (Lepidoptera: Lycaenidae) from the Wet Tropics of Northern Australia, Records of the Australian Museum (Rec. Aust. Mus.) 75 (2), pp. 65-78 : 69-75

Philiris diana fortuna ssp. nov.

urn:lsid:zoobank.org:act:0B2CBC15-926A-4949-9D84-29891241A703

Figs 12–17

Holotype ♂ “ 7 km SSW of Millaa Millaa, QLD, alt. 920 m asl, emg. 21 Feb 2022, B.S. Hacobian ”, ( ANIC Database no. 31 084524). Paratypes 20♂♂, 15♀♀. Queensland: 1♂ “ 7 km SSW of Millaa Millaa, QLD, alt. 920 m asl, emg. 14 Feb 2022, B.S. Hacobian ” ( BHC); 1♂ same data but date “emg. 21 Feb 2022 ” ( BHC); 1♂ same data but date “emg. 22 Feb 2022 ” ( BHC); 1♀ same data but date “emg. 26 Feb 2022 ” ( BHC); 1♂ same data but date “emg. 17 Feb 2022 ” ( ANIC); 1♀ same data but date “emg. 26 Feb 2022 ” ( ANIC); 1♂ same data but date “emg. 24 Feb 2022 ” ( AMS); 1♀ same data but date “emg. 26 Feb 2022 ” ( AMS); 1♂ same data but date “emg. 26 Feb 2022 ” ( NMV); 1♂ same data but date “emg. 26 Feb 2022 ” ( QM); 1♂ same data but date “emg. 27 Feb 2022 ” ( CMC); 1♀ same data but date “emg. 5 Mar 2022 ” ( CMC); 1♂ same data but date “emg. 17 Jul 2022 ” ( BHC); 1♂ same data but date “emg. 19 Jul 2022 ” ( BHC); 1♀ same data but date “emg. 20 Jul 2022 ” ( BHC); 1♀ “ 6.5 km SSW of Millaa Millaa, QLD, alt. 880 m asl, emg. 15 Mar 2022, B.S. Hacobian ” ( BHC); 1♂ “ 5.5 km S of Millaa Millaa, QLD, alt. 750 m asl, emg. 26 Feb 2022, B.S. Hacobian ” ( BHC); 1♂ same data but date “emg. 2 Mar 2022 ” ( BHC); 1♂ same data but date “emg. 7 Mar 2022 ” ( BHC); 2♂, 1♀ same data but date “emg. 8 Mar 2022 ” ( BHC); 1♀ same data but date “emg. 15 Mar 2022 ” ( BHC); 1♂ “ Whiting Rd Beatrice QLD, E. Petrie, ”, “x-larva, L.leefeana ” ( EPC); 1♂ same data but date “ 21.Feb.2022 ” ( EPC); 1♀ same data but date “ 13. Mar.2022 ” ( EPC); 1♂ “ Whiting Rd Beatrice QLD , R. Mayo, 14 March, 2022” ( RMC); 1♂ “ 5.5 km S of Millaa Millaa, QLD, 750 m asl, 12 Mar 2022, B.S. Hacobian ” ( SAMA); 1♀ same data but date “ 23 Mar 2022 ” ( QM); 1♂, 1♀ same data but date “ 24 Mar 2022 ” ( ANIC); 1♀ same data but date “ 27 Mar 2022 ” ( ANIC); 1♀ same data ( NMV); 1♂ “ 7 km SSW of Millaa Millaa, QLD, 915 m asl, 31 Mar. 2021, B.S. Hacobian ”, “ ANIC Database No. 31-036203”, “ANIC DNA Wash number DNA1499”, “ANIC Genitalia number MFB-121” (ANIC); 1♀ “ 7 km SSW of Millaa Millaa, QLD, 920 m asl, 5 Dec. 2021, B.S. Hacobian ” ( BHC).

Other material 1♂ 2♀. Queensland: 1♀ “ 17.17S 145.38E, Lake Eacham NP, Q 760 m GPS, 23 Nov 1998, E.D. Edwards, H. Sutrisno ”, “ ANIC Database No. 31 043392”; “Barcode of Life, DNA voucher specimen, Sample ID: 11ANIC-058824, BOLD Proc. ID:ANICS1824-11” (ANIC) ; 1♀ “ Tinaroo Lake , in rainforest, 25 Apr. 1972, 750 m. N Qu, N & K. Tindale ”, “SAMA Database No. 31-011382” ( SAMA) ; 1♂ “ Millaa Millaa Lookout QLD; E. Petrie; -17.52049° 145.56741°; 17 Nov. 2022 ” ( EPC) .

Diagnosis

Adults of P. diana fortuna differ from those of P. diana diana by the following eight characters concerning wing colour pattern and wing shape: (1) In P. diana fortuna males the upperside ground colour varies from deep cobalt-blue to deep purplish-blue, whereas in P. diana diana males the ground colour is a paler shade of violet-blue. (2) The costa and apical areas on the upperside of the hindwing in P. diana fortuna males are grey, whereas in P. diana diana males this area is broadly white. (3) The black terminal band on the upperside of the hindwing is broader in P. diana fortuna males, and this difference is statistically significant ( Table 2 ). (4) In P. diana diana males, the upperside of the forewing has a distinct white central patch, which extends below vein CuA 2, whereas in P. diana fortuna this white patch is generally absent or occasionally represented by a few scattered grey or greyishwhite scales only; this patch, when present, does not extend below vein CuA 2. (5) The shape of the forewing termen is more strongly arched in P. diana fortuna females, and this difference is statistically significant ( Table 2 ). (6) The white central patch on the upperside of the forewing in P. diana fortuna females (range: 20–35% of wing area) is smaller compared to that of P. diana diana females (range: 30–40% of wing area), and this difference is statistically significant ( Table 2 ). (7) On the upperside of the hindwing, the costa and apical areas between veins Rs and M 1 are extensively suffused white and the adjoining central area distal to the discocellular veins between M 1 and M 3 is also white in P. diana diana females, whereas in P. diana fortuna females these areas are substantially reduced in extent and grey in colour or grey with a few white scales.A consequence of the reduction of the white areas in both fore- and hindwings is that the female of P. diana fortuna is a much darker butterfly with more extensive areas of brown-black than the female of P. diana diana . (8) The underside ground colour, in reared specimens of both sexes, is silvery-white in P. diana fortuna , but white with less silver tone in P. diana diana .

The male genitalia of P. diana fortuna ( Figs 18–20 ) are similar to those of P. diana diana ( Figs 21–23 ), particularly with respect to the shape of the phallus, sociuncus, brachia, and valvae which are asymmetrical in profile. The only difference lies in the width of the long, narrowed middle section of the valvae—in P. diana fortuna the middle sections of the right and left valvae are slightly broader than in P. diana diana . The genitalia of the two P. diana subspecies are similar to those of the two subspecies of P. papuanus — P. papuanus kerri and P. papunus papuanus ( Figs 24–29 )—in that they show the same degree of asymmetry among the valvae, but in P. papuanus the curved apical spine of the left valva is substantially longer and more robust, and the middle section of the left valva is more strongly arched (in lateral view) than in P. diana . The apex of the right valva terminates in a short beak-like projection that is oriented dorsolaterally in both subspecies of P. diana , whereas in the two P. papuanus subspecies the apex bears a longer but narrower dorsolateral projection that terminates in an outwardly curved spine.

Description

Male. Head: eyes brown when alive, black when dead, ringed by white scales; labial palpus dark grey dorsally, white ventrally, clothed in piliform scales, second (middle) segment four times longer than third segment; antennae 8.7–9.3 mm long, flagellum with 32–35 segments (shaft 18–20, club 14–15), shaft black prominently ringed with white, club black variably marked ventrally with orange-brown most extensively in apical half; frons dark brownish-grey; chaetosemata predominantly grey. Thorax: dorsal surface dark grey, ventral surface white; legs white, marked with black between segments, tarsi and mid tibiae. Forewing: length 15.2–17.8 mm (x = 16.7 ± 0.66 mm, n = 19), upperside dark purplish-blue, costa narrowly edged with black, a narrow black terminal band tapered along its length and broadest near apex, end of veins black, an obscure central area between veins M 3 to CuA 2 suffused dull grey, terminal scale fringe black near apex but elsewhere black with white tips; underside uniform silvery-white, costa narrowly edged with black, terminal scale fringe black near apex but elsewhere white; costa and termen slightly convex, apex pointed but with outer costa distinctly rounded, tornus rounded, dorsum straight. Hindwing: upperside dark purplish-blue, costal region mid grey, apex dark grey with a few scattered white scales, a narrow black terminal band of constant width between veins M 1 and CuA 2 but broader towards apex and tornus, dorsum broadly grey, terminal scale fringe black near ends of veins M 3, CuA 1, CuA 2 and 1A+2A, elsewhere black with white tips; underside uniform silvery white, black terminal spots at ends of veins M 3, CuA 1, CuA 2 and 1A+2A, a narrow black terminal line joining spots between veins CuA 1 and 1A+2A, terminal scale fringe black adjacent to terminal spots, elsewhere white. Abdomen: dorsal surface dark grey, ventral surface white.

Female. Head: eyes, labial palpus, antenna and frons similar to male; antennae 8.7–9.1 mm long, flagellum with 34–38 segments (shaft 18–21, club 14–17). Thorax: similar to male. Forewing: length 16.4–18.7 mm (x = 17.6 ± 0.73 mm, n = 13), upperside dark brownish-black, with a prominent white central patch edged with suffusion of iridescent blue scales, blue suffusion more extensive towards base of white patch, sometimes a few white scales below central white patch between vein 1A+2A and dorsum; terminal scale fringe black near apex, elsewhere black with white tips; underside similar to male. Hindwing: upperside dark brownish-black, costal and subapical region above vein Rs grey with scattered white scales, sometimes extending to subterminal region below vein Rs, sometimes a few scattered blue scales present in discal cell and subterminal region between veins M 1 and M 3, dorsum grey, terminal scale fringe black near ends of veins M 3, CuA 1, CuA 2 and 1A+2A, elsewhere black with white tips; underside similar to male. Abdomen: similar to male.

Variation. Males vary in several traits, including the hue or tone of the dorsal blue colouration, which ranges from dark cobalt-blue to dark purplish-blue; and the extent of the dorsal greyish central suffusion on the forewing, which is usually absent or rarely present as a very obscure patch; in one individual (5% of specimens examined, n = 22) ( Fig. 14 ) it was far more extensive and overlaid with a few greyishwhite scales, similar to that of P. diana diana . In females, the size of the dorsal white central patch on the forewing shows minor variation, and the white scales may occasionally extend distally into the subterminal area or below vein 1A+2A towards the dorsum; overall, the extent of the white patch varies from 20–35% as a proportion of the wing area. In addition, the extent of the dorsal white scales of the hindwing costa and apex is variable in females, and it may obscure the apex entirely or extend below vein M 1, as does the degree of blue scales between M 1 and M 3, which may be absent.

Remarks

Philiris diana was originally described by Waterhouse & Lyell (1914) based on 17 specimens (10♂, 7♀) from Kuranda, QLD, all collected by F. P. Dodd; however, they did not refer to a type of any sort. Peters (1971) referred to a “ holotype ” male (registration numbers AMS KL.21453 and K.191300) and an “ allotype ” female (AMS KL.21455 and K.584428) in the Australian Museum, Sydney. Edwards et al. (2001) regarded Peters’ incorrect reference to a holotype as a valid lectotype designation. It therefore follows that the subsequent lectotype designations by both Parsons (1998) and Sands (2015) are invalid and thus do not constitute formal nomenclatural acts.

Of the type series in AMS, we have examined and identified the lectotype male (AMS K.191300) and 13 paralectotypes (7♂, 6♀). Waterhouse and Lyell (1914) illustrated two of their syntypes: the lectotype male on pl. 15, figs 270, 271, and a paralectotype female on pl. 13, fig. 183, each in black and white. The lectotype male ( Figs 4, 5, 7 ) and paralectotype female ( Figs 8, 9, 11 ) referred to by Peters (1971) and originally illustrated by Waterhouse and Lyell (1914) are both illustrated here for comparison with P. diana fortuna . The lectotype male is slightly unusual compared with the rest of the type series and other material we have examined in ANIC, NMV and SAMA in that it has a much broader black apical band on the forewing. Newly emerged adults of a male ( Fig. 6 ) and a female ( Fig. 10 ) of P. diana diana from the Cairns district reared by us are illustrated for comparison; they agree with Waterhouse and Lyell’s concept of diana considering that the types are 115 years old.

Braby (2000) noted that P. diana had been recorded from the Atherton Tableland at Lake Eacham (760 m) based on an anomalous female in the ANIC that was collected at night from a light sheet (E. D. Edwards, pers. comm. 1998). Subsequently, Sands (2015, figs 7, 8) illustrated this specimen and noted that “Females of P. diana are very variable in the extent of white areas on the upperside of both wings…” ( Sands, 2015, p. 222). However, close examination of this specimen confirms that it is P. diana fortuna . Further examination of museum material revealed another female, from Lake Tinaroo (750 m) in SAMA. Thus, the concept of the P. diana diana female needs to be reconsidered—females only show slight variation in the extent of the white patches on both wings.

Etymology

The subspecific epithet is derived from the Latin word fortuna, which means chance or luck. This name reflects the part played by luck in the discovery of this subspecies. The first specimen collected by us was a crippled male that could not fly which was found walking on the ground of a vehicle track through rainforest; the second specimen was a female captured whilst laying eggs on foliage of a rainforest tree, thereby enabling documentation of the early stages and confirmation of the larval foodplant.

Distribution and habitat

Philiris diana fortuna is currently known only from the Atherton Tableland in the Wet Tropics of northeastern Queensland. It has been recorded from Lake Tinaroo, Lake Eacham, Beatrice near Millaa Millaa and Millaa Millaa lookout at altitudes between 750–1,090 m asl. All sites occur in upland and montane tropical rainforest where the larval foodplant Litsea leefeana occurs as a mediumsize tree reaching the rainforest canopy or along edges of smaller patches of rainforest regrowth. Within the known extent of occurrence, the foodplant is a relatively common component of regenerating rainforest following disturbance. All known occurrence records of Philiris diana fortuna are from vegetation communities growing on basalt soils.

Biology

The larval foodplant and morphology and colour pattern of the immature stages of P. diana fortuna ( Figs 30–35 ) are fundamentally the same as those of P. diana diana . The only observable differences concern the ground colour of instar III, which is always green in P. diana fortuna but sometimes yellow in P. diana diana , and in the colour of the reddish dorsal blotches in the early instars, which are deep red-brown in P. diana fortuna but often pinkish in P. diana diana . The larvae of P. diana fortuna undergo six instars, like P. diana diana ( Petrie & Hacobian, 2022) and Philiris ziska titeus D’Abrera, 1971 ( Samson & Johnson, 2009). The pupae are usually more heavily striped in P. diana diana , although the degree of pale brown lateral bands or stripes on the wing case and abdomen is variable in P. diana fortuna and our samples of the former taxon are limited. In P. diana fortuna , the extent of red-brown blotching on segments T1-A2 is variable in larval instars II–IV, and the colour of the dorsal longitudinal band varies from yellow-brown to reddishbrown in instars V and VI.

Males have been observed perching on sunlit leaves during the early and late afternoon, between 1230–1400 h and again c. 1700 h AEST, in late March in the canopy of trees of the larval foodplant Litsea leefeana and other adjacent tree species at heights of 10–25 m above the ground. An adult female was observed, and subsequently captured, perched and basking on a leaf in the lower canopy of the foodplant growing in a small patch of regenerating rainforest approximately 5 m above ground level during the early afternoon (c. 1300 h). Another female was observed at a similar time (1320 h) being pursued by two or three males around sunlit foliage of Flindersia brayleyana F.Muell. growing adjacent to the foodplant. The female was subsequently found in copulation with one of the males ( Figs 14 , 37 ) settled on foliage c. 10 m above ground level close to the original pursuit. The pair was captured and remained in copulation for 35 mins until they finally separated at c. 1400 h.

Females ( Fig. 36 ) have been observed ovipositing on dried skeletonized patches on the abaxial surface of mature leaves of the foodplant, as low as 1 m above ground level. Hatched eggs and larvae have been found in similar situations. Eggs were never found on soft new growth or juvenile leaves. Larvae were never observed to be attended by ants. However, pupae were noted to stridulate when exposed to strong light. A pupal exuvium was found on the abaxial surface of a partly eaten leaf, but no live pupae were located in the field. In captivity, all but one larva reared (n = 28) pupated on the abaxial surface of the leaf of the foodplant; the single exception pupated on the adaxial surface just above the junction with the petiole.

In terms of phenology and duration of the immature stages, the following developmental times were recorded in captivity during the wet season in December-March: egg 7–10 days; larva 51–82 days (instar I 6–7 days, instar II 6–8 days, instar III 7–9 days, instar IV 8–12 days, instar V 9–15 days, instar VI 15–31 days); pupa 10–14 days. Total developmental time from egg to adult varied from 2–3 months. Adults were collected from the field in November, December, March, and April. Some adults reared from eggs (laid by a captive female in early December) emerged in late February, and three adults reared under laboratory conditions from larvae collected in April emerged in mid-July. One larva, collected from the field in early June, was reared under unheated conditions and pupated in late October. Thus, the broad flight period, as currently known, extends from November to April, with at least two generations completed annually.

Figures

Figures 18–29. Male genitalia of the Philiris diana species-group in Australia and Papua New Guinea: (18–20) P. diana fortuna ssp. nov. showing posterior, left lateral and right lateral views; (21–23) P. diana diana showing posterior, left lateral and right lateral views; (24–26) P. papuanus kerri showing posterior, left lateral and right lateral views; (27–29) P. papuanus papuanus showing posterior, left lateral and right lateral views. Scale bar = 1 mm.

Figures 12–17. Adults of Philirisdiana fortuna ssp. nov.: (12, 13) holotype male, showing dorsal and ventral views (ANIC); (14) paratype male, dorsal view showing variation (BHC); (15, 16) paratype female, showing dorsal and ventral views (ANIC); (17) paratype female, dorsal view showing variation (BHC). Scale bar = 10 mm.

Figures 4–11. Adults of Philiris diana diana: (4, 5, 7) lectotype male in AMS, showing dorsal and ventral views and label data; (8, 9, 11) paralectotype female in AMS, showing dorsal and ventral views and label data; (6) male, dorsal view, reared from larva from near Kuranda (BHC); (10) female, dorsal view, reared from larva from near Cairns (EPC). Scale bar = 10 mm.

Figures 30–37. Life history and habitus of Philiris diana fortuna ssp. nov.: (30, 31) larva instar III, showing examples of variation in colour pattern, with lightly-marked and heavily-marked forms; (32, 33) larva instar VI, showing examples of variation in colour pattern, with yellow-brown striped and red-brown striped forms; (34, 35) pupa, showing examples of variation in colour pattern, with lightly marked and heavily marked forms; (36) adult female, newly-emerged at rest on foliage of Litsea leefeana; (37) adult pair in copula, with male on left and female on right.