Stylocellinae Hansen & Sorensen 1904

Clouse, Ronald M., 2012, The lineages of Stylocellidae (Arachnida: Opiliones: Cyphophthalmi), Zootaxa 3595 (1), pp. 1-34 : 6-7

Stylocellinae Hansen & Sorensen 1904

Comments: The first large molecular analysis to include both genera of Stylocellinae ( Stylocellus —represented at that time by the Phayam Island species, described below—and Meghalaya) recovered the subfamily as monophyletic under all cost schemes, with 99% parsimony bootstrap support and 100% likelihood bootstrap support ( Clouse & Giribet 2010), and the same result was obtained in the most recent combined molecular and morphological analysis of Cyphophthalmi ( Giribet et al. 2012). Clearly, molecular data contain a robust set of characters for this subfamily, but finding a morphological synapomorphy is more difficult. Meghalaya ’s morphology, the most distinctive in the family, is quite autapomorphic: the large, rectangular gonostome, scooplike male tarsus IV, thickened male tibia III, and deep ventral opisthosomal depression are not found in other genera at all ( Giribet et al. 2007). Both Meghalaya and Stylocellus lornei , sp. nov., do have common features in their modified areas on the male fourth tarsi (what I interpret here as homologous to the Rambla’s organ in Fangensinae), and perhaps the deeply sinusoidal anterior sternal opisthosomal sulci of Stylocellus are a result of the same ecological or developmental process that has resulted in the ventral depression of Meghalaya.

Description: Eyes present; anal gland pores variable; chelicerae with distinct second ventral process, first process reduced; chelicerae claw-like; granulations on second cheliceral article variable, low ridge variable; Rambla’s organ diffuse, large, lacking microgranulations but often with larger tuberculate-granulations encroaching irregularly, with micropores and microtubercles bearing pores; ozophores pronounced and pointing forward; posterior prosoma not especially large or bulging, the widest part of body usually across the opisthosoma ( Fig. 4 , B–C); lateral edges of fouth coxae tapered anteriorally ( Fig. 5 , B–C); ventral prosomal complex variable; sternum variable; body profile deep, arching of dorsal scutum variable ( Fig. 6 , B–C); sternal opisthosomal sulci between sternites 3 and 4, 4 and 5, and 5 and 6 variable ( Fig. 5 , B–C); posterior gonostome edge weakly concave.

Included genera: Stylocellus Westwood, 1874 (Type genus) and Meghalaya Giribet, Sharma & Bastawade, 2007

Distribution: Sumatra (more specific locality information not recorded), southern, central, and northern Thailand, and northeastern India.

Figures

FIGURE 4. Dorsal prosomal views of Stylocellidae genera: A, Fangensis spelaeus Schwendinger & Giribet, 2005; B, Giribetia insulana (Schwendinger & Giribet, 2005); C, Stylocellus lornei, sp. nov.; D, Meghalaya annandalei Giribet, Sharma & Bastawade, 2007; E, Miopsalis silhavyi (Rambla, 1991); F, Leptopsalis cf. beccarii (“ Sumatra sp. 4 d ” in previous analyses, MCZ DNA 101478, collected by P. Schwendinger). All images were scaled to the same ozophore width and aligned along the ozophore ends.

FIGURE 5. Ventral opisthosomal views of Stylocellidae genera: A, Fangensis spelaeus Schwendinger & Giribet, 2005; B, Giribetia insulana (Schwendinger & Giribet, 2005); C, Stylocellus lornei, sp. nov.; D, Meghalaya annandalei Giribet, Sharma & Bastawade, 2007; E, Miopsalis silhavyi (Rambla, 1991); F, Leptopsalis cf. beccarii (“ Sumatra sp. 4 d ” in previous analyses, MCZ DNA 101478, collected by P. Schwendinger). All images were scaled to the same total body length and aligned along the posterior edge.

FIGURE 6. Lateral views of Stylocellidae genera: A, Fangensis spelaeus Schwendinger & Giribet, 2005; B, Giribetia insulana (Schwendinger & Giribet, 2005); C, Stylocellus lornei, sp. nov.; D, Meghalaya annandalei Giribet, Sharma & Bastawade, 2007; E, Miopsalis silhavyi (Rambla, 1991); F, Leptopsalis cf. beccarii (“ Sumatra sp. 4 d ” in previous analyses, MCZ DNA 101478, collected by P. Schwendinger). All images were scaled to the same total body length and aligned along the ozophore ends.