Epsteinius Lin, Braby & Hsu, 2020

Lin, Yu-Chi, Braby, M. F. & Hsu, Yu-Feng, 2020, A new genus and species of slug caterpillar (Lepidoptera: Limacodidae) from Taiwan, Zootaxa 4809 (2), pp. 374-382 : 376

Epsteinius Lin, Braby & Hsu , gen. nov.

( Figs 1–4, 11 , 13, 14 , 17 , 29, 30 , 36, 37, 45, 46 )

Type species. Epsteinius translucidus Lin , sp. nov. (here designated).

Diagnosis. Epsteinius differs from Microleon ( Figs 5–9, 12 , 15, 16 , 18 , 34, 35, 43, 44 ; Solovyev, 2008; Sasaki, 2016; Sohn et al., 2018) by the following characters: (1) adults are smaller in size—male forewing length of Epsteinius is 5.3–5.5 mm compared with 6.3–7.9 mm for that of Microleon ; (2) in Epsteinius the hindwing is narrower with the termen rounded, whereas in Microleon it is broader with the termen distinctly angular; (3) the labial palpus of Epsteinius is shorter (approx. 2.0–2.5 times the diameter of the eye) than that of Microleon (approx. 3 times the diameter of the eye); (4) in Epsteinius the upperside of the forewing has the inner half dark brown with a purple iridescent suffusion, whereas in Microleon there are usually two large irregular orange patches, one at base and the other in the median area of dorsum, and it lacks the purple suffusion; (5) in Epsteinius the scale fringe of the hindwing is grey, whereas in Microleon it is conspicuously black at the tornus.

In addition, the male genitalia of Epsteinius ( Figs 13, 14 ) differs from that of Microleon ( Figs 15, 16 ) in many characters, including the form of the gnathos which has a sharply down curved tip, the valva which has two long processes along the dorsal margin, and the phallus which is shorter and basally enlarged and rounded with two conspicuous cornuti. In contrast, the genitalia of Microleon has the gnathos with a T-shaped end, no process along the dorsal margin of the valva, and a relatively straight phallus without cornuti. The female genitalia of Epsteinius ( Fig. 17 ) differs from Microleon ( Fig. 18 ) in having a short and wide ductus bursae, and an ovate corpus bursae containing two signa each with a row of flat complex teeth. In Microleon , the ductus bursae is long and coiled, and the corpus bursae is ovate, containing only one signum with a set of sharp complex processes over its surface.

Although the early instar larvae of Epsteinius ( Figs 24, 25 ) and Microleon spp. ( Figs 19, 20 ) are very similar, they diverge considerably in color pattern and shape in the final instar larvae, as follows: (1) in Epsteinius ( Figs 26, 27, 31, 32 ) the shape of the body is elliptical, whereas in Microleon spp. ( Figs 21, 22 ) it is narrower with a humped dorsal surface; (2) in Epsteinius there is usually an indistinct brown lateral patch (which varies among individuals), whereas in Microleon spp. there is a distinct red subdorsal patch; (3) in Epsteinius the body is semi-translucent, whereas in Microleon spp. it is opaque; (4) in Epsteinius the spine-bearing protuberances are similar to those of its early instars, whereas in Microleon spp. the protuberances in the final instar diminish in size compared with its early instars.

Etymology. The generic name is named in honor of Marc E. Epstein for his enormous and longstanding contribution to the study of limacodid moths.

Figures

FIGURES 1–12. Adults of Epsteinius translucidus and Microleon longipalpis: 1, 2, E. translucidus Lin, sp. nov. holotype male upper side and underside; 3, 4, E. translucidus Lin, sp. nov. paratype female upper side and underside; 5, 6, M. longipalpis male upper side and underside; 7, 8, M. longipalpis female upper side and underside; 9, 10, M. longipalpis holotype male upper side and label data (Yokohama, Japan) (NHM); 11, 12, male heads of E. translucidus Lin, sp. nov. and M. longipalpis.

FIGURES 13–16. Male genitalia of Epsteinius translucidus and Microleon longipalpis: 13, 14, genitalia (ventral) and phallus (lateral) of E. translucidus Lin, sp. nov.; 15, 16, genitalia (ventral) and phallus (lateral) of M. longipalpis.

FIGURES 17–18. Female genitalia of Epsteinius translucidus and Microleon longipalpis: 17, E. translucidus Lin, sp. nov.; 18, M. longipalpis.

FIGURES 19–33. Life history of Epsteinius translucidus and Microleon longipalpis: 19–23, M. longipalpis, showing dorsal and subdorsal views of early instar larva, dorsal view and subdorsal views of final instar larva, and cocoon without reverse neat and circular cut after adult emergence; 24–33, E. translucidus Lin, sp. nov.; 24–25, early instar larva, showing dorsal and subdorsal views; 26–27, final instar larva with brown lateral patch, showing dorsal and subdorsal views; 28, cocoon, without reverse neat and circular cut after adult emergence; 29–30, adult female, showing lateral and ventral views; 31–32, final instar larva without brown lateral patch, showing dorsal and subdorsal views; 33, final instar larva on host plant, showing transparent edge of larval body from abaxial leaf surface under sunshine.

FIGURES 34–46. Head, pupa, and female 5th tarsomere of Epsteinius translucidus and Microleon longipalpis: 34–35, head with right labial palpus and galeae of M. longipalpis; 36–37, head with right labial palpus and galeae of E. translucidus Lin, sp. nov.; 38–39, eclosed pupa and ruptured pupal eye of M. longipalpis (arrow denotes fracture line); 40–42, uneclosed pupa, uneclosed pupal eye, and eclosed ruptured pupal eye of E. translucidus Lin, sp. nov. (arrow denotes fracture line); 43–44, female 5th tarsomere and sensilla of M.longipalpis; 45–46, female 5th tarsomere and sensilla of E. translucidus Lin, sp. nov..