Siamoglaris zebrina Lienhard, 2004

Lienhard, Charles, 2011, A new species of Siamoglaris from Thailand with complementary description of the type species (Psocodea: ‘ Psocoptera’: Prionoglarididae), Revue suisse de Zoologie 118 (2), pp. 293-306 : 295-301

Siamoglaris zebrina Lienhard, 2004 Figs 1-4

Siamoglaris zebrina Lienhard, 2004: 866 ; description of male.

TYPE MATERIAL: MHNG, 3 holotype (re-examined), Thailand, Kanchanaburi Province, Sai Yok District, near Wang Badan Cave , ca. 2 km N of Sai Yok Noi Waterfall, dry stream bed (on low vegetation), 9.xii.2003, leg. P. Schwendinger.

NEW MATERIAL EXAMINED: MHNG and QSBG, Thailand, Kanchanaburi Province, Khuean Srinagarindra National Park, 93 and 5♀ in Malaise traps from the following localities, leg. TIGER-project: Huai Mae Kamint / Tourist center (13, 11-18.ix.2008, T3442 ; 23, 2♀, 18-25.ix.2008, T3443 ; 1♀, 25.ix-2.x.2008, T3444 ; 13, 1♀, 2-9.x.2008, T3445 ; 13, 23- 30.x.2008, T3463 ; 13, 30.x-6.xi.2008, T3464 ); Tha Thung-na / Chong Kraborg (13, 1♀, 30.x- 6.xi.2008, T3472 ; 23, lacking abdomen, 6-13.xi.2008, T4431 , these two specimens could be identified as males due to their small body size and their relatively large compound eyes, i.e. IO / D 1 .16 and 1.15, see also Complementary description of male, below) .

FIG. 1

Siamoglaris zebrina Lienhard , male: Habitus, lateral view (body length 2.5 mm); antenna incomplete; pilosity, hindwing and right appendages not shown.

DESCRIPTION OF FEMALE: Colouration and general morphology as described for male by Lienhard (2004). Body size distinctly larger than in male, but compound eyes relatively smaller (see Complementary description of male, below). Femora lacking dark brown transversal band of hypodermal pigment in 2/3 of their length (Fig. 4d, cf. Fig. 5i showing this band in S. theresiae ). Colour pattern of eyes not well-preserved in the specimens examined (observed after two years in alcohol), but still partially visible (cf. Fig. 5a). Pterostigma colourless, transparent or very slightly opaque. Antennae damaged in all specimens examined. Anterodorsal region of abdomen without small humps (see also Fig. 6f, showing pair of humps present in male of S. theresiae ). Terminalia shown in Figs 2, 3; see also revised generic diagnosis, above. Epiproct relatively small, pilosity only developed in apical half, consisting of a pair of long setae and some shorter hairs. Paraproct in middle with a transversal row of some long setae, in its apical half with a dense group of hairs, some of them differentiated as papilliferous setae, similar to those on the external gonapophysis (in some cases weakly differentiated, see Fig. 2b: 4); sense cushion well-differentiated, bearing one normal seta and numerous fine trichobothria, the latter without basal rosettes. Subgenital plate short, with a anteriorly narrowing pigmented area. External gonapophyses welldeveloped, bearing some long stout setae and many shorter acuminate hairs; towards posteroventral margin with numerous apically thin-walled and usually slightly curved papilliferous spatulate or club-shaped setae of unknown function (see Discussion, below). An approximately oval structure present on each side at base of external gonapophysis (shown by interrupted lines in Fig. 2a), originating from anteroventral margin of clunium, covered by rounded basal part of gonapophysis and lateral part of subgenital plate (rudiments of ventral and dorsal gonapophyses?). Spermapore region with a weakly sclerotized suboval posterior area and a membranous anterior area bearing the spermapore. Spermathecal duct very long and more or less spirally coiled FIG. 2

Siamoglaris zebrina Lienhard , female: (a) Subgenital plate, ovipositor valvulae (pilosity on right side not figured), ventrolateral parts of clunium, spermapore region and distal part of spermathecal duct. (b) Papilliferous setae on external gonapophysis and paraproct; 1 erect seta, 2 curved seta, 3 slender seta, 4 weakly differentiated seta. (c) Epiproct and right paraproct.

(at least more than twice as long as the distal part of the spermathecal duct shown in Fig. 2a), spermathecal sac not examined (lost during dissection). Measurements (female of sample T3472): BL = 3.5 mm; FW = 4.2 mm; HW = 2.8 mm; F = 917 µ m; T = 1610 µ m; t1 = 818 µ m; t2 = 182 µ m; t3 = 185 µ m; IO/D = 1.35.

COMPLEMENTARY DESCRIPTION OF MALE: Body size smaller than in female (BL3 <3 mm; BL ♀> 3 mm), but compound eyes relatively larger (IO/D3 <1.2; IO/D ♀> 1.3). Colouration as in female. Antennae damaged in all specimens examined. Anterodorsal region of abdomen without small humps (see also Fig. 6f, showing pair of humps present in male of S. theresiae ). Terminalia (Fig. 4a-c): Paraproct simple (see Lienhard, 2004: fig. 14), its pilosity normal (i.e. lacking the papilliferous setae observed in female). Shape of apical part of phallosome variable due to different positions of the eversible distal structures and variable tumescence of the membranous blisters. For a view of all structures completely everted and blisters swollen see Fig. 4c and the figures of the holotype in Lienhard (2004); for retracted apical structures and collapsed blisters see Fig. 4a; for everted apical structures but collapsed blisters see Fig. 4b. Characteristical distal pair of sclerotized hooks visible in all positions. Rounded medioventral process (sensu Lienhard, 2004) posteriorly delimited by a transversal reticulate membrane; slightly concave mediodistal margin of this membrane well visible in ventral view (Fig. 4b), but also visible in dorsal view on cleared phallosome (Fig. 4c, interrupted line), always lacking sclerotized posterolateral lobes (see also Figs 5f, g and 6d, e showing posterolateral lobes present in S. theresiae ).

DISCUSSION: The female terminalia of S. zebrina resemble those of the other known prionoglaridine genera due to symplesiomorphy. However, the presence of special papilliferous setae on the gonapophyses (some of them also on paraprocts) can be interpreted as an autapomorphy of Siamoglaris . This interesting character deserves additional comments. The socket and the basal part of these modified setae are identical to those of the adjacent acuminate hairs. The basal part is brown, thick-walled and longitudinally grooved (Fig. 2b) as usual in chaetal sensilla (grooves not visible in the scanning electron micrographs of Fig. 3, but clearly visible under a light microscope; see also Slifer & Sekhon, 1977 and Hu et al., 2009). However, the distal half of these modified setae is thin-walled and completely transparent, and the surface area is augmented by its broadening (spatulate to club-shaped) and by the presence of many small papilliform spicules (Figs 2b; 3d, f). Several more acuminate spicules are also present in the basal half of many of these setae (Figs 2b, 3c). As far as I know, it is the first time that such modified setae have been observed in Psocoptera. In general, the pilosity of the female gonapophyses of psocids consists of normal acuminate setae (probably mechanoreceptors). The particular morphology of these modified setae suggests a possible function as scent organs involved in sexual behaviour (emitting an aphrodisiac pheromone?). Brush-like pheromone-diffusing scent scales of somewhat similar morphology have been observed in several Lepidoptera ( Grassé, 1975; Wüest, 1996).

The presence of eversible distal structures on the phallosome, often retracted in alcohol preserved specimens, may pose a problem for the interpretation of the micromorphology of the posterior part of the phallosome. Therefore they have been illus- FIG. 3. Siamoglaris zebrina Lienhard , female, scanning electron micrographs (made by A. Piuz, MHNG): (a) Abdominal apex (ventral side above, paraprocts left). (b) Posteroventral margin of external gonapophyses (same position as in Fig. 3a). (c) Papilliferous setae on posteroventral margin of external gonapophysis. (d) Papilliferous seta on posteroventral margin of external gonapophysis (same seta also recognizable in Fig. 3b, slightly left above middle). (e) Ditto (other seta, not recognizable in Fig. 3b). (f) Detail of apical part of same seta.

FIG. 4

Siamoglaris zebrina Lienhard , male: (a) Posterior part of phallosome (dorsal view) with retracted distal structures. (b) Ditto (same specimen, ventral view) after artificially provoked eversion of distal structures (see Material and methods). (c) Ditto (other specimen, dorsal view) with naturally everted distal structures and swollen membranous blisters. (d) Hindleg (pilosity not shown).

trated here in the retracted (Fig. 4a) and in the everted position (Fig. 4b, c). In Fig. 4c the membranous blisters of this region of the phallosome are presented in the swollen position, though not exhibiting the maximal swelling as shown for the holotype by Lienhard (2004: fig. 11). In this figure of the holotype the slightly concave mediodistal margin of the reticulate membrane is not well recognizable (probably due to the excessive swelling of lateral blisters), but in the re-examined phallosome of the holotype it is well visible (blisters collapsed after permanent slide-mounting). The eversion of the distal structures of the phallosome could be directly observed under the stereomicroscope for the specimen shown in Fig. 4a, b (see Material and methods). In the retracted position the distal part of the phallosome is anterodorsally folded and the tips of the pair of sclerotized claspers are anteriorly directed, well visible in dorsal view (Fig. 4a). During eversion this part rises dorsally and finally unfolds backwards, so that the free tips of the hooked claspers are situated at the posterior end of the phallosome (Fig. 4b). Several intermediate states can be observed in alcohol preserved material. When identifying males of Siamoglaris one has to pay attention to this phenomenon and not mistake it for variation in the morphology of the terminal structures of the phallosome. For a distinction between S. zebrina and S. theresiae see Discussion of the latter species.

Almost nothing is known about the biology of this species. The type locality is situated about 200-300 m from the main entrance of Wang Badan Cave, in a rocky limestone region full of subterranean crevices ( Lienhard, 2004). The new material has been collected in a very similar limestone region of Kanchanaburi Province. Therefore it seems possible that Siamoglaris zebrina has some affinities to caves or similar subterranean habitats, at least during its nymphal life, as known for most Prionoglarididae (see Lienhard et al., 2010a, 2010b).