A new species of Tarracoblaniulus Mauriès & Vicente, 1977: description, postembryonic development, life cycle, and spatial distribution (Diplopoda, Julida, Blaniulidae)

Abstract

Tarracoblaniulus phantasmanus n. sp. is described from Tarragona province, Spain and compared with the only known other species known in the genus, T. lagari Mauriès & Vicente, 1977, from which it differs mainly in having only 5, instead of 15 or more, straight spines on the posterior gonopod. The female vulva (unknown in T. lagari) is very different from all known blaniulid vulvae. Based on a large number of specimens, the postembryonic development (euanamorphosis) from stadium II onward is described. This is highly variable, with three to six apodous body rings in stadium IV, which is the most variable number so far recorded in Blaniulidae. Accordingly, specimens beyond stadium VIII could not be assigned to a specific stadium. At least some males are morphologically distinguishable in stadium IV, morphologically mature males appear in stadium VIII, possibly already in stadium VII. The life cycle of the new species is tentatively suggested to involve at least three years. The monthly mean density of the total population was 28.82 ind/m2 across the whole soil profile. Statistically significant differences in density values between months and Spearman’s rank correlation analyses between the monthly mean values of density and temperature show that T. phantasmanus presents a maximum density in the coldest months and a minimum one in the summer. Significant differences between monthly mean densities of different soil levels and the Usher index values show that during the spring and summer T. phantasmanus is concentrated in the mineral horizon A. In autumn, during winter and up to early spring, the population shows a clear tendency to move up towards horizon H and horizon L/F. Concerning horizontal distribution, Morisita index monthly values for each of the horizons indicate that the species is distributed in patches.