Atropacarus clavigerus (Berlese) Kamill, B. W. & Baker, A. S., 1980

Kamill, B. W. & Baker, A. S., 1980, The genus Atropacarus Ewing (Acari: Cryptostigmata), Bulletin of the British Museum of Natural History (Zoology series) 39, pp. 189-204 : 195-197

Atropacarus clavigerus (Berlese) comb. nov.

(Figs 13-19)

Hoploderma clavigerum Berlese . 1904:275: 1913: 104. Holotype, Pisa, Italy (ISZA. Florence, no. 141/9). [Photographs examined] [Schweizer, 1956: 363. Misidentification.]

Hoploderma clavigera : Sellnick. 1929: 40.

Aspis (Figs 16-17): 188-246 µm long and with a maximum width of 127-165 µm. All the dorsal setae are short, stout and distinctly feathered. Setae (il) and (la) are more or less equal in length and extend to the anterior limits of the bothridia. The sensilli, 77-96 µm in length, are expanded and serrated distally, while the basal portion is smooth, slender and distinctly cranked. In front of the il-la setae there is a prominent median keel and posteriorly the integument is raised into a number of longitudinal and transverse ridges. The ornamentation of the prodorsal integument (apparently always encrusted with detritus) is rather striking and may be described as raised reticulate.

Notogaster (Figs 13-14): The notogaster ranges in length from 354-167 µm with a greatest depth of 188-283 µm. There are 20 pairs of setae, all of which are very short (less than c1-d1), stout and bear three or four whorls of blunt serrations. In comparison with the notogastral chaetotaxy of striculus , A. clavigerus has four additional pairs of setae, one in the c series, another in the h series, and two pairs in the ps series. The vestiges of setae f1 and f2 are present, f1 being localcd ventral to the seta h1 and f2 ventral to the seta e2. The notogastral integument is ornamented in a raised reticulate pattern.

Ano-genital region (Fig. 15): The four pairs of anal setae (an1-4) are located marginally with a single pair of adanals (ad) (missing in speeimen figured) located submarginally and rather close to (an4). All the anal setae are short. the anterior two pairs (an3-4) being approximately twice as long as the posterior two. There are nine pairs of minute genital setae (g1-9) arranged in a pattern of 6 + 3 along the paraxial margins of the genital plates. The ornamentation of the genital and anal plates is similar to that of the notogaster.

Chelicerae: The chelicerae resemble those of A. striculus although the antiaxial and paraxial surfaces carry a smaller number of spines.

Legs (Figs 18-19): The setal and solenidial formulae for the legs are as in A. striculus . All the solenidia are long and straight. On tarsus I the seta coupled with solenidion omega2 is short with only a weakly developed distal process (see Parry, 1979). Seta a" is rather short (approximately half as long as the famulus) and closely associated with the long posterior fastigial seta ft". Setae (tc) and (u) on tarsus I and (tc), (u), (p) and s on tarsi II to IV are ribbon-like, hooked distally and bear whorls of sharply pointed spicules in the middle third. On femur I seta d is short and somewhat thickened while seta v' on this segment is stout and strongly serrated.

Material: Eight specimens. BMNH 1979.6.21.6-13, from oak litter ( Quercus ilex ), Boboli Gardens, Florence, Italy. The material was collected by Dr J. G. Sheals, 18 March 1971.

Remarks: Berlese (1904) recorded clavigerus from dead leaves in the Boboli Gardens, Florence, but described the type of the species from Pisa. Unfortunately, we have not been able to examine the holotype but we have studied photographs of the latter taken by Dr J. G. Sheals (BMNH). The specimen appears to be in good condition and although undissected the integumental ornamentation and chaetotactic characters can be discerned. Material collected from the Boboli Gardens has been compared with photographs of the holotype - no morphological differences could be detected.

A. clavigerus differs from the other members of the genus by having four additional pairs of setae on the notogaster. Moreover, the very striking ornamentation of the prodorsal and notogastral integument serves to characterize this species.