Abstract
Southern-African Longitarsus capensis species-group, which is closely related to the Mediterranean anchusae species-group is revised. L. capensis species-group includes 15 species, 8 of which are new to science: Longitarsus capensis Baly, 1877, L. cedarbergensis Biondi, 1999, L. luctuosus Biondi, 1999, L. lugubris Biondi, 1999, L. melanicus Biondi, 1999, L. neseri Biondi, 1999, L. transvaalensis Biondi, 1999, L. afromeridionalis sp.n., L. debiasei sp.n., L. grobbelaariae sp.n., L. hexrivierbergensis sp.n., L. malherbei sp.n., L. piketbergensis sp.n., L. rouxi sp.n., and L. sudafricanus sp.n. A key to all the species is presented as well as line drawings of male and female genitalia, scanning electron micrographs of some diagnostic morphological characters, and auto-ecological and zoogeographical data. Relationships within the capensis-group, and between the anchusae and capensis-group are better defined and hypotheses explaining the separate distributions of Mediterranean and south African anchusae and capensis species-groups proposed. Finally, the host-plant shift from native Lobostemon spp. to the introduced plant Echium plantagineum L. shown by some species of the capensis group is also discussed.
Highlights
Longitarsus Latreille, as described in Berthold (1827), is a very large flea beetle genus (Chrysomelidae, Alticinae), which occurs throughout all zoogeographical regions, and includes about 600 known species.In the Mediterranean area, where Longitarsus is better known from an autecological standpoint, some speciesgroups, such as aeneus, anchusae, exsoletus and echii, are closely associated with Boraginaceae and generally show trophic specialization (Jolivet & Hawkeswood, 1995; Biondi, 1996): 34% of Longitarsus species are monophagous, 56% oligophagous and only 10% polyphagous
In the literature there are only a few reports of Longitarsus species associated with Boraginaceae, namely Longitarsus punctifrons Weise, 1895 (= gossypii Bryant, 1941) collected on Heliotropium sp. (Furth, 1985), and species of the capensis group collected on Lobostemon spp., Anchusa capensis Thumb. and Echium plantagineum L. (Biondi, 1999)
Median lobe of aedeagus in Longitarsus capensis species-group; lateral, ventral and dorsal view: L. capensis Baly, Western Cape Province, Cape Town, Lion’s Head (16); L. debiasei sp.n., Western Cape Province, Kogmanskloof (17); L. transvaalensis Biondi, Eastern Transvaal, Nelshoogte Pass (18); L. neseri Biondi, Western Cape Province, Piketberg (19); L. melanicus Biondi, Western Cape Province, Danabaai (20); L. hexrivierbergensis sp.n., Western Cape Province, 35 km NE Ceres (21); L. rouxi sp.n., Western Cape Province, Cedarberg (22); L. sudafricanus sp.n., Western Cape Province, road Citrusdal-Middelberg Pass (23); L. cedarbergensis Biondi, Western Cape Province, Pakhuis Pass (24); L. luctuosus Biondi, Western Cape Province, Akkedisbergpas, neigh
Summary
Longitarsus Latreille, as described in Berthold (1827), is a very large flea beetle genus (Chrysomelidae, Alticinae), which occurs throughout all zoogeographical regions, and includes about 600 known species. As reported in Biondi (1999), the South African species of the capensis-group are closely related to the Western-Palaearctic, especially Mediterranean, species of the anchusae-group (sensu Biondi, 1995) Both these Longitarsus species-groups, containing exclusively species with a black integument, are strictly associated with Boraginaceae and share the following updated morphological characteristics that differentiate the anchusae and capensis groups within Longitarsus: (i) head with impunctate vertex and frons with some large punctures impressed near the frontal grooves; (ii) elytra apically subtruncate or widely and independently rounded; (iii) humeral callus always completely absent in capensisgroup, rarely developed in anchusae-group; (iv) hind wings strongly reduced (species always subapterous in capensis-group; brachypterous, sub-brachypterous or very rarely macropterous in anchusae-group); (v) large spermatheca (generally longer than 0.30 mm) with ducts often widely arcuate and usually uncoiled or with one coil, very rarely with two coils; (vi) median lobe of aedeagus strongly sclerotized, mostly with a distinct apical median small tooth and a ventral sulcus invariably with clear impressions; (vii) impressed elytral punctation generally dense and without signs of striae even in sutural area. Zoogeographical and autecological data on the species of the Longitarsus capensisgroup were collected during zoological collecting trips that were part of an Italian research project (PRIN 2004057217) aimed at interpreting the disjunct distribution of different plant and animal groups in the Mediterranean-South African regions (cf. Axerold & Raven, 1978; Balinsky, 1962; Coleman et al, 2003; Jürgens, 1997; La Greca, 1970, 1990)
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