Stylocellus sumatranus Westwood, 1874

Clouse, Ronald M., 2012, The lineages of Stylocellidae (Arachnida: Opiliones: Cyphophthalmi), Zootaxa 3595 (1), pp. 1-34 : 8

Stylocellus sumatranus Westwood, 1874

( Fig. 1 )

Stylocellus sumatranus Westwood, 1874: 200 , Plate XXXVII, figs. 7, 7a, 7b. See complete synonymy in Giribet 2000: 68.

Comments: Along with the widening of the prosoma, the pinning of S. sumatranus may have also caused the ozophores to point perpendicular to the long body axis (Hansen and Sørensen draw them pointing anteriorally, Fig. 1 B), as well as the dorsal scutum to appear less arched than S. lornei , sp. nov. Likewise, desiccation of the specimen may have caused the sternal sulci to become more pronounced. Still, the sulci have the same sinusoidal appearance, the ozophores have the same shape, and these features, combined with the anal gland pore, cheliceral sculpturing, and overall body proportions, make the species extremely similar. In fact, this raises the question of whether S. sumatranus and S. lornei , sp. nov., are the same species (unlikely given the biogeography of Cyphophthalmi , but mix-ups in labels and locality identifications among early specimens could have happened). Three features of S. sumatranus clearly distinguish it from S. lornei : the lack of any evidence of a groove in the middle of the smooth strip on the anal plate, the lack of pronounced dorsal opisthosomal sulci, and the fact that its spiracles are completely free of the fourth coxae, not overlapped.

Figures

FIGURE 1. Stylocellus sumatranus Westwood, 1874, male type specimen: A, dorsal; B, dorsal illustration from Hansen & Sørensen (1904); C, ventral; D, lateral. Scale bar = 2.00 mm for all views.