Cerobasis atlantica Lienhard, 2011

Lienhard, Charles & Philip Ashmole, N., 2011, The Psocoptera (Insecta: Psocodea) of St Helena and Ascension Island (South Atlantic) with a new record from South Africa, Revue suisse de Zoologie 118 (3), pp. 423-449 : 427-429

Cerobasis atlantica Lienhard sp. n. Fig. 2

HOLOTYPE: MHNG, 3, St Helena , Earwig Gully , Prosperous Bay Plain , S15º57.459' W5º39.059', ca 290-310m, a gully southeast of the Central Basin, 27.ix.2003, leg. P. & M. Ashmole (site PBP4 , sample 79).

PARATYPE: MHNG, ♀ (allotype), St Helena , Cliff Top, S15º57.318' W5º39.873', ca 290- 310m, part of the cliff edge east of Prosperous Bay Plain, 27.ix.2003, leg. P. & M. Ashmole (site PBP3 , sample 61) .

DESCRIPTION: Colouration: Body light yellowish white with a small dark brown median patch on pronotum and some tiny brown spots on abdominal tergites, arranged in segmental transversal rows. Compound eyes black, labrum dark brown, flagellomeres apically brown, in distal half of antenna almost completely brown. Winglets unpigmented, no brown transversal tibial rings recognizable on legs.

Morphology: Maxillary palp with P4 much enlarged and slightly shorter than P2 (Fig. 2c), lacking forked sensillum. Lacinial tip with three relatively shallow tines (Fig. 2b). Forewing reduced to an oblong winglet, bearing a longitudinal row of 3-5 stout truncate setae in addition to the normal pilosity (Fig. 2a), hindwing absent. Winglets laterally clearly protruding from mesothorax in dorsal view, not covering lateral parts of metanotum as in many other Cerobasis species (see Lienhard, 1998: fig. 24b). Therefore dorsal pilosity not only well-developed in middle but also on each lateral 1/3 of metanotum. Mesonotum relatively long (length almost equal to half width of vertex), its hindmargin slightly indented laterally in dorsal view. Pearman's organ of hindcoxa well-developed, hindtibia with 4 terminal spurs and 3 internal spurs in apical half (one hindtibia of the female with 4 internal spurs of normal size and one additional short internal spur close to the apical spurs). Pretarsal claws lacking preapical tooth, with basal appendix and slightly enlarged membranous pulvillus.

FIG. 2

Cerobasis atlantica Lienhard sp. n., male holotype (a-d), female allotype (e-g): (a) Right mesothoracic winglet. (b) Tip of lacinia. (c) Maxillary palp (pilosity not shown, except for spur sensillum of P2). (d) Phallosome. (e) Gonapophyses. (f) Spermathecal parietal gland. (g) Spermapore region.

Hypandrial brush with about 40 acuminate setae. Phallosome as in Fig. 2d, lacking strongly sclerotized internal structures near apex of parameres, mushroomshaped apodemes well-developed. Female gonapophyses as in Fig. 2e, dorsal valvula reduced to a short rudiment, external valvula suboval, relatively broad, setose, with two stouter setae about in middle and relatively short apical hairs. Region of spermapore characteristic (Fig. 2g). Both spermathecal parietal glands similar in size, with numerous pores and a central rosette of papillae (Fig. 2f). Spermatheca containing one spermatophore with a very long channel, similar to that of Cerobasis annulata figured by Lienhard (1998: fig. 21f).

MEASUREMENTS (µm): Male holotype: BL = 1370; FW = 180; F = 300; T = 460; t1= 168; t2 = 52; t3 = 60; length of phallosome = 250. – Female allotype: BL = 1510; FW = 220; F = 350; T = 560; t1= 180; t2 = 56; t3 = 65.

ETYMOLOGY: The specific epithet refers to the distribution of the species on the

Atlantic island of St Helena.

DISCUSSION: Cerobasis atlantica seems to be endemic to the island of St Helena and has so far been recorded only from Prosperous Bay Plain, an arid habitat. It belongs to a group of species close to the widespread Cerobasis annulata , most of which are endemics of one or several Macaronesian islands (see Lienhard, 1984, 1998, 2004b and Lienhard & Smithers, 2002). The new species is easy to distinguish from C. annulata , which has also been recorded from St Helena ( Badonnel, 1976), by its reduced pigmentation, its more elongate winglets, the presence of 4 terminal spurs on hindtibia (3 in C. annulata ), the absence of a sclerotized longitudinal internal structure near the apex of the paramere, the structure of the spermapore region and the broad suboval external valvula (for C. annulata see description by Badonnel, 1976 and Lienhard, 1998). The structure of the phallosome of C. atlantica is similar to that of the Macaronesian species C. harteni Lienhard, 1984 (see Lienhard, 1984: fig. 19), known from Cabo Verde and the Azores ( Lienhard & Smithers, 2002; Lienhard, 2004b). However, C. harteni is completely apterous, lacking Pearman's organ on hindcoxa, with only two apical and two internal spurs on hindtibia and with more elongate external valvulae and a very characteristic spermapore region (see Lienhard, 1984: figs 7 and 18).