Echinoaesalus

Huang, Hao & Chen, Chang-Chin, 2015, Discovery of a second species of Aesalini from Taiwan, with description of the new species of the genus Echinoaesalus Zelenka, 1993 (Coleoptera: Lucanidae), Zootaxa 3920 (1), pp. 163-170 : 169-170

Key to males of the Echinoaesalus species

The females of the most of the Echinoaesalus species have not been carefully studied, thus only the male characters are used in the following key. The characters of hindwing in veins 3dA1 and 3dA2 are probably also good key characters to separate the species groups, but these characters have not been checked for all species described by Zelenka (1993, 1994) and Krikken (1975, 2008).

1 Dorsal surface of the body with only the stick-like bristles and tomenta, but devoid of the scale-like bristles. Cephalic lobe of the 9th abdominal segment of male obsolete................................................................ 8

- Dorsal surface of the body more or less with clumps of the scale-like bristles. Cephalic lobe of the 9th abdominal segment of male well marked.................................................................................... 2

2 Abdominal ventrites without the sublongitudinal sulci. Semicircular punctures along the anterior margin of the abdominal ventrites 3–5 transverse and markedly broader than those of the abdominal ventrites 1–2. Dorsal surface of the body with the clumps of the scale-like bristles and the sparsely distributed stick-like bristles.......................3 ( E. hidakai group)

- Abdominal ventrites 1–3 on either side with the sharply defined sublongitudinal sulcus to receive metatibia and metatarsi. Semicircular punctures along the anterior margin of the abdominal ventrites 3–5 as broad as those of the abdominal ventrites 1–2. Dorsal surface of the body with the clumps of the scale-like bristles but devoid of the stick-like bristles................................................................. 5 ( E. timidus group = subgenus Zelenkaesalus Krikken, 2008)

3 Anterior margin of the head projected medially. Scutellum about as long as wide.................................. 4

- Anterior margin of the head not projected medially. Scutellum markedly longer than wide. Malay Peninsula................................................................................................ E. schuhi Zelenka, 1994

4 Intercoxal process of the prosternum longer than wide. Paramere longer than half of the medial lobe of parameres. Malay Peninsula......................................................... E. hidakai hidakai ( Araya, Kon, & Johki, 1993)

- Intercoxal process of the prosternum as long as wide. Paramere less than 1/3 times as long as medial lobe of parameres. Borneo................................................................ E. hidakai borneoensis Huang & Imura, 2011

5 Mentum with short (comma-shaped) pit-like groove on either side of mentum but without transversal groove in front. Dorsal line of the body in lateral view semicircular. Sumatra, Malay Peninsula, Thailand, Borneo....... E. timidus ( Krikken, 1975)

- Mentum with complete (variably deep) arcuate groove, transversely. Dorsal line of the body in lateral view produced at the summit.............................................................................................. 6

6 Pronotum and elytra with yellowish brown bristle clumps but lacking black bristle clumps. Metasternum and abdominal ventrite shiny. Protibia slender. Anterolateral corner of metasternum shallowly impressed along mesocoxae. Anterolateral edge of mentum broadly rounded. Java...................................................... E. javanus Krikken, 2008

- Pronotum and elytra with black bristle clumps. Metasternum and abdominal ventrite matt. Protibia robust. Anterolateral corner of metasternum with deep furrow along mesocoxae. Anterolateral edge of mentum distinctly produced................ 7

7 Groove on mentum immediately behind anterior margin of mentum, interrupted in width at lateral sides, with the lateral ends broader and deeper. Parameres at most 1/4 times as long as the sclerotized part of medial lobe of parameres. West Java................................................................................ E. gedeensis Huang & Wu, 2011

- Groove on mentum remoter from anterior margin of mentum, not interrupted in width at lateral sides, with the lateral ends not broader. Parameres about half as long as the sclerotized part of medial lobe of parameres, Borneo.......................

.............................................................................. E. sabahensis Zelenka, 1994 8 All punctures on the elytra placed serially in longitudinal lines. Intercoxal process of the prosternum with anterior margin produced medially, Sulawesi............................................................. E. jaechi Zelenka, 1993

- Some punctures on the elytra placed irregularly, not serially in longitudinal lines. Intercoxal process of the prosternum with anterior margin rather flat............................................................... 9 ( E. matsuii group)

9 Outline of elytra in lateral view unevenly rounded or obtusely angled, with anterior half more arched than posterior half. Sumatra......................................................................... E. barriesi Zelenka, 1993

- Outline of elytra in lateral view rather evenly rounded, not more arched at anterior half than at posterior half........... 10

10 Pair of cavities on the metasternum just behind the mesocoxae oblique. Sulcus on mentum indistinct. Parameres very long, almost reaching the distal end of the pigmented part of medial lobe of parameres (not counting the distal sclerite of medial lobe of parameres). Malay Peninsula....................................................... E. matsuii (Araya, 1993)

- Pair of cavities on the metasternum just behind the mesocoxae almost longitudinal. Sulcus on mentum clearly marked. Parameres short and remote from the distal end of the pigmented part of medial lobe of parameres (not counting the distal sclerite of medial lobe of parameres).................................................................... 11

11 Parameres markedly shorter than the width of the medial lobe of parameres in dorsal or ventral view. Medial lobe of parameres wider and globe-like in basal portion and contracted in distal portion........................................... 12

- Parameres markedly longer than the width of the medial lobe of parameres in dorsal or ventral view. Medial lobe of parameres nearly even in width in dorsal view..................................................................... 13

12 Elytra longer than wide. 9th abdominal segment of male more elongate. Well pigmented part of medial lobe of parameres longer. Thailand... E. dharma ( Araya, Matsui, Nabhitabhata, & Panha, 1995)

- Elytra nearly as long as wide. 9th abdominal segment of male stouter. Well pigmented part of medial lobe of parameres shorter. Malay Peninsula, Borneo............................................................. E. yongi (Araya, 1993)

13 Size larger. Elytra nearly as long as wide. Insertion of the bristle placed centrally in the puncture on dorsal surface of the body. Bristles on elytra not placed serially. Medial lobe of parameres with most part of dorsal surface less pigmented, and with distal sclerite continuous. Borneo..................................................... E. arayai Huang & Imura, 2011

- Size smaller. Elytra longer than wide. Insertion of the bristle placed anteriorly in the puncture on dorsal surface of the body. Bristles on elytra placed serially. Medial lobe of parameres with only distal half of dorsal surface less pigmented, and with distal sclerite interrupted. Taiwan....................................................... E. chungi Huang & Chen