Lincus singularis Rolston, 1983

Figs. 1-9

Lincus singularis Rolston, 1983: 1, 4, 5, 18-20, Figs. 34-35 (female holotype from Chauchamayo, Peru, deposited in USNM 76690, not examined, no paratypes); Couturier & Khan, 1992: 719 (map); Campos & Grazia, 2006: 153 (list).

Description of the male. The color of males is dark brown to fuscous and the general morphology is similar to that described for females by ROLSTON (1983) (Fig. 1). Genitalia. Pygophore oval, opening of genital cup narrow. Dorsal rim uniformly concave (Fig. 2, dr), bearing 1+1 tufts of setae lateral to segment X. Posterolateral angles rounded, projected distinctly beyond the ventral rim, depressed dorsally (Fig. 2, pa). Basal 1/3 of segment X membranous, lateral margins sinuous tapering to apex (Fig. 2, X). Ventral rim V-shaped, with setae along margin (Fig. 3, vr). Ventral surface tumescent on disc, with 1+1 lateral sulci following ventral rim (Fig. 3, t); ventral surface of posterolateral angles tumescent (Fig. 3). Parameres inconspicuous and covered by segment X, attached to the articulatory apparatus of phallus, subtriangular in lateral view, bearing a dorsal dense tuft of setae on apex (Figs. 4- 6). Phallus. Phallotheca globose (Figs. 7-9, ph), strongly sclerotized. Vesica longer than the combined lengths of phallotheca and ductus seminis distalis (Figs. 7-9, v, ds), bearing an dorsal subtriangular process posteriorly directed (Figs. 7-9, dp), and 1+1 lateral processes short and truncate (Figs. 7- 9, lp). Free portion of ductus seminis distalis very short, about half the length of the inner portion, projecting ventrad of vesica before the lateral processes (Figs. 7-9, ds).

Male. Measurements (n = 5). Total length 10.75 ± 0.29 (10.37-11.00); width of abdomen 6.62 ± 0.36 (6.12-7.00); head length 1.67 ± 0.08 (1.57-1.76); head width 2.24 ± 0.10 (2.14- 2.39); eye length 0.50 ± 0.03 (0.47-0.55); eye width 0.55 ± 0.02 (0.52-0.57); interocellar distance 1.20 ± 0.03 (1.17-1.2); interocular distance 1.21 ± 0.06 (1.13-1.26); pronotum length 2.17 ± 0.14 (1.95-2.27); pronotum width 5.66 ± 0.19 (5.42-5.90); length of pronotal lobe 0.23 ± 0.03 (0.20-0.27); pronotal lobe width 0.17 ± 0.02 (0.15-0.20); scutellum length 4.27 ± 0.25 (3.91-4.60); scutellum width 3.55 ± 0.13 (3.39-3.72); length of antennomers: I 0.77 ± 0.03 (0.75-0.80); II 0.82 ± 0.03 (0.77- 0.85); III 1.01 ± 0.04 (0.97-1.07); IV 1.42 ± 0.04 (1.37-1.45); V 1.81 ± 0.11 (1.62-1.92); length of labial segments: I 1.28 ± 0.11 (1.12-1.37); II 2.36 ± 0.09 (2.25-2.37); III 1.87 ± 0.03 (1.82-1.9); IV 1.79 ± 0.06 (1.75-1.90).

Material examined. PERU, Tocache: 5 males and 1 female, San Martin (Palmas del Espino S.A., Cultivo Palma Aceitera, parcela A11a [-8.41; -76.41] 500 m a.s.l.), 2009, E. Trindad leg .

Distribution. Peru, Cusco and San Martín regions.

Remarks. Although no phylogenetic hypothesis has been advanced for species of Lincus, the genus was recovered in the Herrichella Distant, 1911 clade in a cladistic analysis of the Ochlerini (CAMPOS & GRAZIA 2006). The relationship between Lincus and the other members of the clade, however, remained unresolved. More recently, the genus (represented by L. lobuliger) was recovered as the sister group of the remaining taxa of the Herrichella clade in the phylogenetic analysis of GARBELOTTO et al. (2013). The monophyly of the genus, however, remains to be tested. Several species of Lincus are recognizable by their well-developed pronotal lobes, and all known males have tubular proctiger and reduced parameres (ROLSTON 1983, 1992). These characters were not used in the phylogenetic studies mentioned above. Regarding the phylogenetic relationships among the species of Lincus, ROLSTON (1983) placed L. singularis along with Lincus parvulus (Ruckes, 1958) and L. tumidifrons in the “swollen head” informal group of species (“species group of convenience” sensu ROLSTON 1983). This group was characterized by having a tumid vertex. Some features of the pygophore of L. singularis are consistent with Rolston’s proposal to place the species in it, e.g. the ‘V’ shape of the ventral rim of the pygophore; subrectangular proctiger with acute apex; and globose phallotheca, the latter also observed in L. tumidifrons . Lincus singularis can be differentiated from the other species in the “swollen head” group by having the anterior and posterior margins of the pronotal lobes subparallel and each lobe projected laterad of its corresponding eye; the vertex of head not as tumid as in L. parvulus and L. tumidifrons (Fig. 1; for L. parvulus and L. tumidifrons see ROLSTON 1983, Figs. 30 and 36); and the ventral opening of the pygophore is narrower than in those species (Fig. 3, vr; for L. parvulus and L. tumidifrons see ROLSTON 1983, Figs. 32 and 41).