Acrosternum Fieber

Tribal Placement: This genus has always been considered to be relatively closely related to the genus Nezara, the type genus for the Nezarini.

Comments: This genus has had a confusing taxonomic history. Many of the species were described or placed in the genus Nezara at one time or another. Also, at one time, many more species were included in Acrosternum; these were transferred to Chinavia, then moved back to Acrosternum, and more recently have been moved back to Chinavia. In general, species of Acrosternum are smaller, more pale green in color, and usually occur in dryer, more arid regions; Chinavia species tend to be larger, more bright or vivid green, and they usually occur in more tropical or temperate areas.

To help with identifications in this important genus, I have added three keys (see below), one modified from Wagner (1959), and the other two modified from Linnavuori papers. The African key is lacking A. nigeriensis. When Wagner (1961) described A. nigeriensis, he gave characters to separate his new species from several other species (e.g. millierei, arabicum, and insularum). He did not mention several other species known to occur in Africa (eg. heegeri, miliaris, and prunasis); it is possible that his A. nigeriensis may be a synonym of one of these species. For example, Wagner described the head of A. nigeriensis as being longer and narrower than other related species (this is one of the same characters Linnavuori used to separate A. heegeri from other related species).

Several other species also seem to be geographically isolated, which that alone should be helpful in their identification. For example, A. gramineum only occurs in the Indian/Pakistan/Sri Lanka region; the only other species known from that area is A. pusniensis recently described by Ahmad & Rana (1989). Also, A. curticeps is only known from Yemen, A. insularum is only known from the Cape Verde Islands, A. malickyi is only known from Crete, and A. rubescens is only known from the Canary Islands.

1 Tylus enclosed apically by juga	breviceps (Jakovlev)
- Tylus free apically, not enclosed by juga	2

2(1) Apex of rostrum reaching to or beyond middle of second abdominal segment; margins of head in front of eyes only slightly recessed	3
- Apex of rostrum not extending beyond hind coxae; margins of head in front of eyes strongly curved	4

3(2) Emargination in posterior margin of male pygophore relatively deep, nearly rectangular, posterolateral angles of pygophore very broad and rounded; head before eyes clearly less than twice as broad as long	heegeri Fieber
- Emargination in posterior margin of male pygophore relatively shallow, sides divergent, not rectangular, posterolateral angles of pygophore more narrowly rounded; head before eyes distinctly broader than long (Canary Islands)	rubescens (Noualhier)

4(2) Posterolateral angles of male pygophore broad, angular, nearly rectangular in dorsal view; emargination in posterior margin of pygophore deep, nearly rectangular	millierei (Mulsant & Rey)
- Posterolateral angles of male pygophore narrowly rounded, nearly pointed; emargination in posterior margin of pygophore often shallower, not rectangular	5

5(4) Posterolateral angles of male pygophore with narrowly rounded apex, with rounded rectangular part next to it, whose edge right-angularly leads inward; rostrum reaches middle of hind coxae; eyes very small, vertex 3.0-3.4 times as broad as an eye (Cape Verde Islands)	insulare Lindberg
- Posterolateral angles of male pygophore simple, narrowly rounded, whose edge diagonally leads inward; rostrum reaches anterior margin of hind coxae; eyes large, vertex 2.5-2.7 times as broad as an eye	arabicum Wagner

1 Hemelytral membrane immaculate	2
- Hemelytral membrane with small pale green spots	3

2(1) Head elongate, about 1.22-1.27 times as broad as long, lateral margins only slightly insinuated in front of eyes; body generally larger and more elongate	heegeri Fieber
- Head 1.3-1.5 times as broad as long, lateral margins distinctly insinuated in front of eyes; body usually smaller and broader	millierei (Mulsant & Rey)

3(1) Dorsal surface strongly uneven due to numerous small whitish callosities, forming vermiculate transverse ridges on pronotum, confluent spots on scutellum, and sparse roundish spots on elytra	miliaris (Klug)
- Dorsal surface without pale callosities	prunasis (Dallas)

Key to Arabian Species
(modified from Linnavuori & Al-Safadi, 1993)

1 Juga extending distinctly beyond apex of tylus; caudoventral margin of pygophore with a deep U-shaped median incision, delimited on each side by a sharply triangular lobe	breviceps (Jakovlev)
- Juga not extending beyond apex of tylus; pygophore different	2

2(1) Hemelytral membrane with small, round, green spots; dorsal surface strongly uneven due to numerous small whitish callosities, forming transverse vermiculate ridges on pronotum, confluent spots on scutellum, and sparse, round spots on elytra	miliaris (Klug)
- Hemelytral membrane hyaline, immaculate; dorsal surface without conspicuous, whitish callosities	3

3(2) Apex of scutellum broadly callose, white	apicale Linnavuori
- Scutellum uniformly green	4

4(2) Large species, length 10-14mm; caudoventral margin of pygophore only shallowly insinuated	arabicumWagner
- Smaller, length 9.0-11.5mm; pygophore different	5

5(4) Head short and broad, lateral margins of juga distinctly mesad apically, apex of tylus narrowly visible; caudoventral margin of pygophore in ventral view shallowly insinuated	curticeps Linnavuori & Al-Safadi
- Head longer, lateral margins of juga anteriorly subparallel, apex of tylus broadly visible; caudoventral margin of pygophore in ventral view deeply insinuated in middle	millierei (Mulsant & Rey)

References:

David A. Rider
Professor of Entomology
North Dakota State University
202 Hultz Hall
Fargo, ND 58105
E-Mail: David.Rider@ndsu.edu