Ametor, Semenov, 1900

Jia, Fenglong & Zhao, Shuang, 2013, Descriptions of eleven Opatrini pupae (Coleoptera, Tenebrionidae) from China, Acta Entomologica Musei Nationalis Pragae 53 (1), pp. 127-139 : 135-138

Key to all known Ametor and Hydrocassis species

The genus Ametor is closely related to Hydrocassis and it is difficult to distinguish between them using only external features. However, the median lobes are clearly different between the two genera. As stated by SCHÖDL & JI (1995), the corona is always situated on the apex of the median lobe in Ametor , but more basally in Hydrocassis .

KNISCH (1921) described Hydrocyclus formosus Knisch, 1921 (later transferred to Hydrocassis ) from Fujian, China. However, the type of the species was destroyed during World War II and it is impossible to diagnose the species from other species of the genus only based on the original description. SCHÖDL & JI (1995) mentioned that ‘it is impossible to state whether [any other species of Hydrocassis ] is a synonym of Hydrocyclus formosus ’ but listed the name as a dubious synonym of Hydrocassis schillhammeri Schödl & Ji, 1995 . Here, Hydrocassis formosa is not treated.

The following key is a modified version of the keys by SCHÖDL & JI (1995) and LIU et al. (2008). Aedeagi are illustrated by SATÔ (1971, 1998), SCHÖDL & JI (1995), JI & SCHÖDL (1998), SCHÖDL (2000) and LIU et al. (2008).

1. Median lobe with gonopore situated apically (genus Ametor Semenov, 1900 ). ............ 2

– Median lobe with gonopore situated more basally (genus Hydrocassis Deyrolle & Fairmaire, 1878 ). .................................................................................................................. 7

2. Body elongate oval, slightly convex in lateral view, rugulosely sculptured between elytral punctures ( Ametor scabrosus group). ............................................................................. 3

– Body moderately to strongly convex in lateral view; smooth between punctures. ........ 5

3. Body length 3.8–6.5 mm. Eleventh elytral interval forming a ridge which conceals lateral margin at least in distal half. Hind margin of last visible abdominal sternite entire, without apical emargination. ..................................................... Ametor scabrosus ( Horn, 1873)

– Body length 8.0– 9.5 mm. Elytra without lateral ridge. Hind margin of last visible abdominal sternite distinctly emarginated and fringed by stiff setae. ................................... 4

4. Head, pronotum and elytra strongly rugose, strongly punctuate, without fine punctures intermixed among coarse ones (except on extreme anteromedial portion of frons); alternate elytral intervals elevated apically; aedeagus with median lobe gradually narrowed apicad, rounded apically. ................................................................ Ametor xizangensis sp. nov.

– Head, pronotum and elytra less rugose and less coarsely punctate, with fine punctures mixed with coarse punctures; elytral intervals not elevated; aedeagus with median lobe subparallel towards apex. .................................... Ametor rudesculptus Semenov, 1900

5. Brown species. Hind angles of pronotum broadly rounded, distinctly interrupted between pronotum and elytra ( Ametor latus group). Length 5.8–6.7mm. Nearctic Region. .......... ........................................................................................................ A. latus ( Horn, 1873)

– Black species. Hind angle of pronotum narrowly rounded, widest at base ( Ametor rugosus group). Length 6.5-9.0 mm. Oriental and southern Palaearctic Regions. ...................... 6

6. Head and pronotum with metallic sheen; pronotum with less distinct and more scattered, coarser punctures. Aedeagus with slender median lobe. .................................................. ............................................................................... Ametor elongatus Ji & Schödl, 1998

– Head and pronotum without metallic sheen; pronotum with more distinct and less scattered coarser punctures. Aedeagus with wider median lobe. ..... Ametor rugosus ( Knisch, 1924)

7. Parameres with tooth-like projections on inner surface ( Hydrocassis scaphoides group). ......................................................................................................................................... 8

– Parameres without tooth-like projections on inner surface. ......................................... 11

8. Projections situated near the apex of the parameres, slightly pointing to base. ............. 9

– Projections situated in distal half but closer to the midlength of the paramere. .......... 10

9. Tooth-like projections on the inner face of parameres situated closer to apex, apical area of parameres thus being shorter; median lobe apically acutely pointed, as long as parameres. ............................................................. Hydrocassis uncinata Ji & Schödl, 1998

– Tooth-like projections on the inner face of parameres situated more distal to apex, apical area of parameres thus being longer; median lobe apically not so acutely pointed, shorter than parameres. ............................................. Hydrocassis scaphoides Orchymont, 1942

10. Head and pronotum black, densely and regularly punctate with coarse punctures; sides of clypeus and pronotal margins brown. Elytra usually brown with dark spots, seldom black. Projections on parameres somewhat curved, pointing dorsally. Length 8.5–9.0 mm. ...... ................................................................ Hydrocassis schillhammeri Schödl & Ji, 1995

– Head and pronotum black, with few scattered coarse punctures. Head with metallic sheen. Elytra black. Projections on parameres flat, pointing towards middle. Length 7.2–8.5mm. .............................................. Hydrocassis baoshanensis Schödl & Ji, 1995

11. Median lobe and parameres slender, gradually narrowed to apex. ( Hydrocassis scapha group). .......................................................................................................................... 12

– Median lobe abruptly narrowed towards apex, apical portion sometimes compressed. ( Hydrocassis scapulata group). ................................................................................... 18

12. Median lobe of aedeagus with accessory ventral plate, wider than median lobe (see SCHÖDL 2000: Figs. 1a,b ). ................................................... Hydrocassis hebaueri Schödl, 2000

– Median lobe of aedeagus without accessory ventral plate. .......................................... 13

13. Outer margin of parameres distinctly pointing laterad apically, curved mesally on apical third, considerably longer than median lobe, median lobe gradually narrowed toward tip and pointed apically, gradually widened towards base. ...... Hydrocassis gansu sp. nov.

– Outer margin of parameres at most slightly curved; median lobe obtuse apically. ...... 14

14. Aedeagus slender and elongate; sides of parameres almost straight on inner margin and little longer than median lobe. ..................................................................................... 15

– Aedeagus stouter; parameres narrowed and slightly sinuate on inner margin in apical third and conspicuously longer than median lobe. ............................................................... 16

15. Aedeagus slender. Median lobe slender, gradually widened to base. ............................... ............................................................................. Hydrocassis scapha Orchymont, 1942

– Aedeagus robust. Median lobe stout, in apical third distinctly narrowed, almost parallelsided towards apex. ............................... Hydrocassis pseudoscapha Ji & Schödl, 1998

16. Median lobe gradually widened to base, apical portion not digitate. ............................... ......................................................................... ... Hydrocassis imperialis ( Knisch, 1921)

– Median lobe strongly narrowed in apical portion, digitate. ......................................... 17

17. Median lobe strongly narrowed in apical third, apex expanded. ...................................... ......................................................................... Hydrocassis sichuana Ji & Schödl, 1998

– Median lobe narrowed in apical third, almost parallel-sided towards apex. ..................... ................................................................... Hydrocassis mongolica Liu, Ji & Jing, 2008

18. Median lobe of aedeagus slender, not strongly dilated to base. ........................................ ........................................................................................... Hydrocassis jengi Satô, 1998

– Median lobe of aedeagus strongly dilated to base. ....................................................... 19

19. Endemic to Japan. .................................................. Hydrocassis lacustris ( Sharp, 1884)

– Distributed in China and Southeast Asia. ..................................................................... 20

20. Large species, 8.5–9.0 mm. Median lobe strongly narrowed and compressed on apical portion. ......................................................................................................................... 21

– Smaller species, 6.5–8.0 mm. Median lobe not so strongly narrowed and compressed on apical portion. ............................................................................................................... 22

21. Median lobe narrower apically, parameres distinctly arcuate at apical third, bent towards middle. ......................................................................... H. anhuiensis Ji & Schödl, 1998

– Median lobe somewhat broader apically, parameres gradually bent towards middle. ...... ...................................................................................................... H. taiwana Satô, 1971

22. Brown to dark brown. Coarse punctures on pronotum arranged densely and evenly. Elytral striae distinctly impressed, lateral intervals convex; primary punctures on elytra situated on minue protuberances (especially on posterior portion). Apical portion of median lobe narrow, abruptly widened towards base; parameres narrowed in apical portion, roundly widened apically, abruptly widened towards base. ........................................................... ........................................................................... Hydrocassis scapulata Fairmaire, 1878

– Dark brown to black. Pronotum smooth and shinning, with spare coarser punctures; elytral intervals flat, primary punctures not situated on protuberances. Median lobe narrowly rounded towards apical half, widened more gradually; parameres gradually widened towards base, somewhat angulate. .......... Hydrocassis metasternalis Schödl & Ji, 1995

Figures

Figs 1–6. Habitus of selected Chinese Ametor and Hydrocassis. 1 – A. xizangensis sp. nov. (holotype, dorsal view); 2 – A.elongatus Ji & Schödl,1998 (holotype, dorsal view); 3 – H.gansu sp.nov.(holotype, dorsal view); 4 – H. hebaueri Schödl, 2000; 5 – H. scapulata Fairmaire, 1878; 6 – H. imperialis (Knisch, 1921).