Blaste helenae 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 : 439-441

Blaste helenae Lienhard sp. n. Fig. 7a-f

HOLOTYPE: MHNG, 3, St Helena, Lot Summit, 454m, off St Helena rosemary Phylica polifolia, 29.i.2006, leg. P. & M. Ashmole (sample 4165).

PARATYPES: BMNH 13 , MHNG 1♀ (allotype) and 1 nymph, same data as for holotype .

DESCRIPTION: General colouration and morphology of both sexes very similar to that described by Badonnel (1976) for Blaste basilewskyi , except for less extensive forewing markings (Fig. 7a) and the following characteristics of genital morphology. Hypandrium with a median pair of short but slender terminal processes (Fig. 7d); phallosome on each side with a short outwards-curved hook (Fig. 7c). Subgenital plate of female with a widely opened V-shaped sclerotization, arms of the V relatively slender (Fig. 7f); sclerotization of spermapore region as in Fig. 7e.

MEASUREMENTS: Male holotype: BL = 2.2 mm; IO /D = 2.1; FW = 2.5 mm; F = 440 µm; T = 830 µm; t1= 240 µm; t2 = 150 µm. – Female allotype: BL = 2.4 mm; IO /D = 2.6; FW = 2.5 mm; F = 410 µm; T = 780 µm; t1= 210 µm; t2 = 140 µm .

ETYMOLOGY: The specific epithet refers to the island of St Helena, a British overseas territory in the South Atlantic Ocean, which is named after Saint Helena of Constantinople.

DISCUSSION: This new species is closely related to Blaste basilewskyi , the second species of this genus known from St Helena (junior synonym: Blaste atlantica New, 1977: 255 ; see Lienhard & Smithers, 2002: 379). Both species can be assigned to the subgenus Euclismia Enderlein (see Badonnel, 1976). B. helenae clearly differs from B. basilewskyi by less extensive forewing markings in both sexes (see figures of B. basilewskyi given by Badonnel, 1976), by smaller hooks of the phallosome (see Fig. 7h and Badonnel, 1976: fig. 173) and by slightly longer and more slender median pair of terminal processes of hypandrium (see Fig. 7g and Badonnel, 1976: fig. 172). Female genitalia of both species are almost identical, except for slight differences concerning the sclerotized area surrounding the spermapore (see Fig. 7i and Badonnel, 1976: figs 174, 175). Measurements of B. basilewskyi are rather variable ( Badonnel, 1976), those given here for B. helenae are close to the lowermost values observed by this author for B. basilewskyi , sometimes even lower.

The unique systematic position of Blaste basilewskyi within the genus (see Badonnel, 1976; New, 1977) gives no hint on the possible origin of this species, which is common on St Helena and is associated mainly with the endemic gumwoods Commidendrum spp., although it has also been found on other plants ( Badonnel, 1976 and personal observations). The discovery of Blaste helenae on the endemic St Helena rosemary Phylica polifolia suggests a niche separation between the two species. B.

FIG. 7

Blaste helenae Lienhard sp. n. (a-d, male holotype; e-f, female allotype): (a) Forewing. (b) Hindwing. (c) Phallosome. (d) Hypandrium, ventralview. (e) Spermaporeregion. (f) Subgenital plate. – Blastebasilewkyi Badonnel (g-i): (g) Hypandrium, ventralview. (h) Phallosome. (i) Spermapore region.

helenae was beaten off this plant during the first collecting of invertebrates on the summit of Lot, a massive intrusion of phonolitic rock, exposed by erosion, which forms a striking feature of the landscape of Sandy Bay. Its nearly vertical sides are almost devoid of vegetation but the summit – less than one tenth of a hectare in extent – provides a refuge for a few specimens of Phylica polifolia. The rosemary was formerly widespread in dry places in the west of the island but has now been almost entirely lost as a wild tree ( Cronk, 2000). Further investigation is needed to determine whether B. helenae is also present on any of the other surviving specimens. Badonnel (1976) suggested that Blaste basilewskyi may be derived from one of the earliest colonizers of St Helena. Therefore the existence of the apparently much rarer but extremely closely related sister-species Blaste helenae on the same island is here tentatively interpreted as a result of sympatric speciation, possibly resulting from adaptation to life on different endemic plants, rather than of double invasion.