Plagiodera

Eva Sprecher- Uebersax & Mauro Daccordi, 2016, Notes on the species of Plagiodera CHEVROLAT, 1836 of the Australian, Oceanic and Oriental regions, with a description of P. hiekei n. sp. (Coleoptera, Chrysomelidae), Entomologische Blätter und Coleoptera 112 (1), pp. 373-385 : 374

Species groups of Plagiodera CHEVROLAT, 1836

The genus Plagiodera was divided into several subgenera ( DACCORDI 1987, BALSBAUGH & DACCORDI 1986) with particular reference to the Neotropical region. Additional study in future should clarify in particular the species from the Afrotropical and Oriental regions.

In spite of the rather monotonous nature of its homogeneous external characters and aspect (roundish body, maxillary palpi proximate at the base with terminal article sharpened, epipleura folded inward, elytral punctures irregular, simple claws), the spermathecal complex offers good characters for taxonomy. Other interesting characters are the postcoxal lines extending on the first abdominal segment or not, the dimensions of the eyes and of the antenna, the shape of the onychium etc.

In the Oriental, Australian and Oceanic (sensu USINGER 1963) regions, two large species groups can be recognized based on the presence or absence of a prominent carina on the first abdominal segment. The species of the Oriental region (China, India, Sri Lanka, Nepal etc.) lack a prominent carina on the first abdominal seg- ment, where the coxal lines follow the cavity margins. In some species of the Oriental region (P. atmanama DACCORDI, 1982, P. cupreata CHEN, 1934, P. rufescens GYLLENHAL, 1808 and P. yunnanica CHEN, 1934, Fig. 1) the carina is present broadens at the base into a more or less wide plate, in other exclusively Oceanic species (P. cheni LHOSTE, 1934, P. fulvicollis BRYANT, 1936, P. violaceipennis BRYANT, 1925, P. chapuisi JACOBY, 1885, P. philippinensis DUVIVIER, 1885, P. samoana MAULIK, 1929) it is reduced to a simple line, which doesn’t touch the anterior margin of the second segment ( Fig. 2, 3, 4). In P. aerea (EYDOUX &SOULEYET, 1839), P. hiekei n. sp. and P. riparia JACOBY, 1885 the carina reaches the anterior margin of the second abdominal segment without broadening to a distinct plate ( Figs 5, 6, 7, 8).

Within the species with a symmetrical carina on the first abdominal segment, particularly in the Pacific area, two species groups can be distinguished. The first one in- cludes species with normal roundish eyes ( Figs 9, 10), a “sickle” shaped spermatheca ( Figs 11, 12, 13, 14, 15, 16, 17, 18) and the aedeagus with sides subparallel almost to the apex (P. aerea, P. hiekei n. sp., P. punctipennis, P. riparia, Figs 19, 20, 21, 22, 23, 24 ). The antennae of the species of this group are shown in Figs 25, 26, 27, 28, 29 and 30 . The species of Plagiodera of tropical Asia belong to this group. The second group is characterized by a plication on the first abdominal segment, but without touching the anterior margin of the second segment ( Figs 31, 32 ), and a “fibula” shaped spermatheca ( Figs 33, 34, 35, 36, 37, 38, 39 ) and includes P. cheni, P. fulvicollis, P. violaceipennis, P. chapuisi, P. philippinensis, P. lownei, P. amplipennis, P. nitidipennis and P. samoana. These species occur in Australia, New Guinea and various archipelagos of the Pacific Ocean until Samoa.

Some species of this group (P. cheni, P. fulvicollis, P. violaceipennis, P. samoana) have very large eyes ( Figs 40, 41 ) and particularly long and thickened antenna ( Figs 42, 43, 44, 45, 46, 47, 48, 49 ). The aedeagi are shown in Figs 50, 51, 52, 53, 54, 55, 56 and 57 . The antennae of other species of the group are shown in Figs 58, 59, 60 and 61 . Based on the label data “at light” they are assumed to be nocturnal. As a conclusion based on all these characters, to simplify handling, a division of the Oriental and Oceanic species of Plagiodera into three groups is proposed:

1. group “A” or aerea -group (P. aerea, P. hiekei n. sp., P. punctipennis, P. riparia);

2. group “ B” or lownei -group (P. amplipennis, P. chapuisi, P. lownei, P. nitidipennis, P. philippinensis);

3. group “ C” or violaceipennis -group (P. cheni, P. fulvicollis, P. samoana, P. violaceipennis).

During the study of these groups, one species from New Guinea was recognized as new to science and is described above.

Their distribution is shown in Fig. 62 .

Figures

Fig. 62. Plagiodera spp., distribution area of the studied species. The dotted area represents the track Pliocene-Pleistocene (L. MATILE 1990). □ GroupA:P.aerea(Philippines);P.riparia(Sulawesi,Bali,NewGuinea,Australia:N.Territory?);P.hiekei n.sp.(NewGuinea); P.punctipennis (Philippines). ● Group B: P. chapuisi (New Guinea); P. lownei (Australia); P. nitidipennis (Australia); P.amplipennis (Australia); P. philippinensis (Philippines). * Group C: P.cheni (New Guinea,Bismarck:New Ireland); P.violaceipennis(Solomon, Fiji,Tonga);P.fulvicollis (New Hebrides, New Caledonia?); P.samoana (Samoa). M = male; F = female. Notes:The data of Tonga (P.cheni group) is taken from the catalogue of C.A.M.REID: Chrysomelinae ofAustralia, New Guinea, New Zealand, Pacific Region and relevant S EAsian Taxa. 1993, unpublished manuscript kindly provided to one of the authors (M.D.).Probably P.violaceipennisandP.fulvicollisare synonyms andP.samoanais onlyasubspecies ofthis complex.For more precise findings we need deeper studies based on much more material.

Figs 19-32. Plagiodera spp., aedeagus (19-24), antenna (25-30), and abdomen (31-32). 19 – P. aerea (EYDOUX & SOULEYET, 1839), dorsal view; 20 – P. aerea, lateral view; 21 – P. riparia JACOBY, 1885, dorsal view; 22 – P. riparia, lateral view; 23 – P. punctipennisCHEN, 1934dorsalview;24– P.punctipennis, lateralview;25– P.aerea, male;26 -P.aerea,female;27–P.riparia, male; 28 – P.riparia, female; 29 – P.punctipennis, male; 30 – P.punctipennis, female; 31 – P.lownei (BALY, 1863); 32 – P.amplipennis (LEA, 1929).

Figs 33-41. Plagiodera spp., spermateca (33-39), habitus (40), and head (41). 33 – P. chapuisi JACOBY, 1885; 34 – P. philippinensis DUVIVIER, 1885; 35 – P.lownei (BALY, 1863); 36 – P.cheni LHOSTE, 1934; 37 – P.violaceipennis BRYANT, 1925; 38 – P. fulvicollis BRYANT, 1936; 39 – P.samoana MAULIK, 1929; 40 – P.violaceipennis; 41 – P.violaceipennis.

Figs 42-61. Plagiodera spp., antenna (42-49, 58-61) and aedeagus (50-57). 42 – P. cheni LHOSTE, 1934, male; 43 – P. cheni, female;44 – P.violaceipennisBRYANT, 1925, male; 45– P.violaceipennis, female;46 – P.fulvicollisBRYANT, 1936, male;47 –P. fulvicollis,female;48–P.samoanaMAULIK,1929,male;49–P.samoana,female;50–P.cheni,dorsalview;51–P.cheni,lateral view; 52 – P.violaceipennis, dorsal view; 53 – P.violaceipennis, lateral view; 54 – P.fulvicollis, dorsal view; 55 – P.fulvicollis, lateral view; 56 – P.samoana, dorsalview; 57 – P.samoana, lateral view;58 – P.chapuisi JACOBY, 1885, male; 59 – P.chapuisi, female; 60 – P.philippinensis DUVIVIER, 1885, male; 61 – P.philippinensis, female.