Sigmoria simplex Shelley 1981

Sigmoria simplex
Type specimens.— Male holotype (NCSM A668) and 4 male and 6 female paratypes collected by R.M. Shelley and J.C. Clamp, 24 July 1975, Figs. 29-34, Sigmoria simplex. 29, process of 4th sternum of holotype, caudal view. 30, gonopods in situ, ventral view of paratype. 31, telopodite of left gonopod of holotype, medial view. 32, the same, lateral view. 33, telopodite of left gonopod of specimen from 4.4 mi. SW Spruce Pine, Mitchell Co., North Carolina, medial view. 34, the same, lateral view. Scale line for fig. 30 = 1.00 mm; line for other figs. = 1.00 mm for 29, 31-32, 1.17 mm for 33-34. from Mitchell Co., NC, 6.8 mi. SW Spruce Pine, along county road 1225, 0.6 mi. W junction of county road 1002, PNF. Male and female paratypes deposited in FSCA and RLH.
Diagnosis. — A moderate-size species of Sigmoha with medial flange on proximal portion of peak and with red or yellow paranota and concolorous stripes along caudal margins of metaterga; gonopods with following diagnostic characters: anterior bend poorly defined, beginning near base of acropodite and continuing smoothly to apical curve; peak broadly curved, apex at apical curve; apical curve varying from broadly continuous with anterior bend, to sharp and well defined; distal zone usually curved broadly into arc; tip simple, subacuminate, directed toward base of acropodite; medial flange relatively long and narrow, merging imperceptibly with stem of acropodite, with only slight to moderate lobe at midlength; tooth and lateral flange absent.
Holotype. — Length 38.5 mm, maximum width 8.5 mm, W/L ratio 21. 8%, depth/width ratio 64.7%. Segmental widths as follows: Color in life: paranota red, metaterga black with wide, red, transverse stripes along caudal edges connecting paranotal spots; collum with red stripes along both anterior and caudal edges.
Somatic features similar to those of /. latior, with following exceptions:
Width across genal apices 4.6 mm, interantennal isthmus 1.2 mm. Antennae reaching back to middle of third segment; relative lengths of antennomeres 2>3>6>4 = 5> 1>7. Facial setae as follows: epicranial and interantennal absent, frontal 1-1, genal 2-2, clypeal about 10-10, labral about 12-12.
Collum broad, extending slightly beyond ends of following tergite. Caudal edges of all tergites relatively straight. Scapulorae pronounced.
Process of 4th (Fig. 29) and 5th sterna low and indistinct, much shorter than widths of adjacent coxae; 6th sternum slightly recessed between 7th legs to accommodate apical curvature of acropodites, 7th legs set slightly farther apart than 6th. Postgonopodal sterna without lobes, relatively flat, with shallow impressions and grooves.
Gonopodal aperture subelliptical, 3.2 mm wide and 1.7 mm long at midpoint, indented on anteriolateral margin, sides slightly elevated above metazonal surface, caudomedial edge raised into slight lobe. Gonopods in situ (Fig. 30, of paratype) with acropodites overlapping in midline and extending straight forward over anterior edge of aperture to between 7th legs, apices crossing. Gonopod structure as follows (Figs. 31-32): prefemoral process short, acuminate and simple, directed toward midlength of acropodite. Acropodite relatively thin, arch broad, overhanging and extending well beyond level of prefemoral process; anterior bend broad, poorly defined, beginning near base and continuing into peak region; latter broadly curved, apex distally at apical curve; apical curve broad but relatively well defined, subcontinuous with anterior bend through peak, beginning about 3/4 length, subtending semicircle; distal zone moderately long, curved broadly into arc; tip simple and subacuminate, directed
toward base of acropodite. Medial flange long, merging imperceptibly with stem of acropodite, arising near start of anterior bend, expanding rapidly near peak of arch into relatively small, rounded lobe, slightly obscuring stem of acropodite, narrowing rapidly distal to lobe and merging into stem of acropodite at beginning of apical curve. Tooth and lateral flange absent. Prostatic groove running along inner surface of acropodite, crossing from medial to lateral sides on basal zone and continuing to tip.
Male paralypes. — The male paratypes agree with the holotype in most features, but the prefemoral process is apically bifurcate on two specimens.
Female paratype. — Length 41.3 mm, maximum width 9.2 mm, W/L ratio 22.0%, depth/width ratio 72.5%. Agreeing with holotype in somatic features, but paranota much more strongly depressed, angling sharply ventrad, producing appearance of more highly arched body.
Cyphopods in situ with side of receptacle visible in aperture, valves directed caudolaterad. Receptacle moderate in size, extending slightly down lateral side of valves, surface wrinkled with numerous ridges. Valves large, surface wrinkled.
Variation. — The color of simplex varies, and about half the specimens I collected had yellow paranota and stripes rather than red. Both colors were represented in the material collected in Mitchell County, 4.4. mi. SW Spruce Pine (NCSM A1989). These color differences are not associated with anatomical changes. However, one male in this sample has epicranial setae in the amount of 1-1.
The length and height of the arc of the acropodite varies, along with the degree to which it overhangs the prefemoral process. In males from Crabtree Meadows the arc is short, high, and distally rounded, and the acropodites extend only slightly beyond the level of the prefemoral process. In other males, however, the arc is longer, lower, and flatter, and the acropodite extends well beyond the prefemoral process in medial view. The condition in the holotype is about halfway between these two extremes. The males in NCSM sample A1989 (Figs. 33-34) from 4.4 mi. SW Spruce Pine have the longest arc, and there is also an apical difference in that the tip is not bent inward into the arc but instead points downward toward the coxa in medial view. The apical curve is superimposed on the arc, which obscures most of it. Associated with the arc variation are differences in length and configuration of the medial flange. It tends to be longer and more uniform in width in specimens with longer arcs, and the rounded lobe at midlength is reduced. Hence, in the extreme case of sample A1989, the flange may be described as being long and narrow, poorly demarcated from the stem of the acropodite, arising on the anterior bend, expanding gradually to about midlength of the peak, then narrowing rapidly and merging with the stem of the acropodite at the apical curve, or about 3/4 length. It is difficult to determine exactly where the flanges of these males begin or end, because they do not expand into a definite rounded lobe as do those of the holotype.
There is no discernible geographic pattern to this gonopodal variation.