Cerobasis maya García Aldrete, 1991

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 : 429-432

Cerobasis maya García Aldrete, 1991 Fig. 3

Cerobasis maya García Aldrete, 1991: 324 ; description of male from Mexico.

Cerobasis cf. maya García Aldrete, 1991 . – Ashmole & Ashmole, 1997, 2000a. – Lienhard & Smithers, 2002. – Lienhard, 2004b.

HOLOTYPE (examined): UNAM, 3, Mexico, Yucatan Peninsula, Quintana Roo, Cancun , 2.xi.1971, on dead hanging fronds of coconut palm, leg. A. N. García Aldrete.

NEW MATERIAL: MHNG, 13, Ascension Island, Command Hill , 17.-21.iii.1990, leg. N. P. & M. J. Ashmole, trapping on lava (grass cover low, small quantities of several different

FIG. 3

Cerobasis maya García Aldrete , male holotype (a), males from St Helena (b-g): (a) Phallosome, apical part. (b) Tip of left lacinia. (c) Tip of right lacinia (same specimen). (d) Maxillary palp (pilosity not shown, except for spur sensillum of P2). (e) Right mesothoracic winglet with insertion points of setae. (f) Phallosome (closed position). (g) Half of phallosome (open position, axis of symmetry indicated by broken line).

lichens) (sample 0008 Asc). – MHNG, 23, Ascension Island, South Gannet Flow , 23.- 27.iii.1990, leg. N. P. & M. J. Ashmole, trapping off-lava (thistles, no moss or lichen) (sample 0818 Asc) . – BMNH, 13, Ascension Island, South Gannet Hill , S7º58' W14º23', 4.viii.2003, leg. H. Mendel (litter, extracted by Winkler apparatus) .

DESCRIPTION OF MALE FROM ASCENSION ISLAND: Colouration: Not very well preserved. Body yellowish, frons medially with an approximately anchor-shaped brown patch, sometimes subdivided into smaller spots, several other brown spots on head, thorax and abdomen, laterally often fused to form larger patches or bands, winglets hyaline or with some brown pigment (as figured by García Aldrete, 1991: fig. 2). Compound eyes black, basal flagellomeres apically brown (distal half of antennae lost in all specimens examined). Femora with some redbrown hypodermal pigment towards apex, tibiae with two transversal rings of redbrown hypodermal pigment.

Morphology: Maxillary palp as in Fig. 3d, P4 lacking forked sensillum. Lacinial tip as shown in Fig. 3b, c (usually both laciniae of same shape, corresponding to Fig. 3c). Forewing reduced to a short winglet bearing 2-3 stout setae in addition to the normal pilosity (Fig. 3e), hindwing absent. Winglets laterally clearly protruding from mesothorax in dorsal view (as figured for the holotype by García Aldrete, 1991: fig. 2), covering only the lateral corners of metanotum, therefore pilosity covering almost all the metanotum, except for 1/6 of its dorsal surface near lateral margin (Note: in many other Cerobasis species lateral parts of metanotum extensively covered by winglets and each lateral 1/3 of its dorsal surface lacking pilosity; see Lienhard, 1998: fig. 24c). Mesonotum relatively long (its length about equal to half width of vertex), its hindmargin almost straight in dorsal view. Pearman's organ of hindcoxa well-developed, hindtibia with 4 terminal spurs and 2 internal spurs in apical half (3 internal spurs in one of 8 hindtibiae examined). Pretarsal claws lacking preapical tooth, with basal appendix and slightly enlarged membranous pulvillus. Hypandrial brush with about 60-90 acuminate or slightly truncate setae. Phallosome as in Fig. 3f and Fig. 3g, weakly sclerotized, mushroom-shaped apodemes well-developed, parameres internally with a short pointed process; shape of this process different in closed (Fig. 3f) and open (Fig. 3g) position of the phallosome (see Discussion below).

MEASUREMENTS (µm): Male holotype (data from García Aldrete, 1991, except for length of phallosome): FW = 113; F = 287; T = 486; t1= 184; t2 = 50; t3 = 58; length of phallosome = 180. – Male from Ascension Island ( MHNG 7146 ): BL = 1260; FW = 120; F = 280; T = 460; t1= 172; t2 = 47; t3 = 57; length of phallosome = 165.

DISCUSSION: The above mentioned material collected by Philip and Myrtle Ashmole has already been mentioned by these authors as Cerobasis cf. maya ( Ashmole & Ashmole, 1997, 2000a; see also Lienhard & Smithers, 2002 and Lienhard, 2004b). All males from Ascension Island are so similar to the only previously known specimen of C. maya , its holotype, that there is no reason to consider them as belonging to a different species or subspecies in spite of some slight differences concerning phallosome morphology. The whole phallosome of the holotype is figured by García Aldrete (1991: fig. 4), details of its distal part are also represented in Fig. 3a (mushroomshaped apodemes of the parameres not shown in this figure). The comparison with Fig. 3f, g, representing the phallosome of two males from Ascension Island in closed and open position, shows the variable aspects of the apical structures depending on its position after slide-mounting. The position of these parts in Fig. 3f is rather similar to that observed in the slide of the holotype (Fig. 3a). A careful analysis of these stuctures in all available males showed that the differences between Fig. 3a and Fig. 3f are largely due to slightly different positions after slide-mounting. The only significant difference between the holotype and the males from Ascension Island is the presence, in the holotype, of a small field of scale-like sculpture on the parameres near the base of the internal process (Fig. 3 a and García Aldrete, 1991: fig. 4); this sculpture is absent or only very weakly developed in the males from Ascension Island (Fig. 3f, g). However, compared to usual interspecific differences in phallosome morphology in the genus Cerobasis , this extremely slight difference does not justify any taxonomic decision about specific or subspecific separation of the Ascension population, especially in view of the low numbers of individuals available at present.

According to García Aldrete (1991) this species seems to be more closely related to some Macaronesian species than to the other known Mexican species of the genus Cerobasis ; he mentions the possibility that C. maya may have been introduced to Yucatan Pensinsula from the Caribbean. Ashmole & Ashmole (1997) tentatively suggested that this species was native to Ascension, but pointed out that it provides one of the rare examples of apparent New World affinities in the Ascension arthropod fauna (see also Biogeographical discussion, below).