Nemoura sabina, Fochetti, Romolo & Vinçon, Gilles, 2009

Fochetti, Romolo & Vinçon, Gilles, 2009, A new species of Nemoura (Plecoptera: Nemouridae) from Central Italy, Zootaxa 2216, pp. 64-68 : 64-68

Nemoura sabina sp. nov.

( Fig. 1–5 )

Material examined. Holotype male: Italy, Latium, Posta (Ri), Velino River, m 700, 27.III.64, Sbordoni- Vigna-Consiglio leg. Paratypes: 11 males, 8 females, 16 larvae, same site and date, same collectors. The material is deposited in the Museo di Zoologia (Sezione Entomologia), “Sapienza” Università, Roma, Italy, except 2 males, 1 female, 1 larva in Vinçon’s collection. All the specimens are preserved in 75% alcohol.

Diagnosis. This medium-size Nemoura is characterized by the presence of two dorsal sclerites of the epiproct that are composed of a pair of basolateral bands that arch distally and end in two small, distinct, backward protruding, ovoid plates. Its cerci have a large, blunt tooth distally, while the epiproct in dorsal view is almost rectangular and slightly narrowed apically.

Male: Forewing length 7.6 mm, hindwing length 6.7 mm. Head, antennae, mouthparts and thorax brown; compound eyes dark. Wings brownish; legs yellow. Abdomen brownish with mostly pale hairs.

Terminalia ( Figs. 1 a-c, 2-5): Tergite IX weakly sclerotized, with a broad but shallow mid-anterior incision and two submedial groups of few long hairs along posterior margin. Sternum IX with claviform vesicle, constricted basally and swollen medially, slightly longer than half the length of the hypoproct; hypoproct basally wide and somewhat enlarged medially, then gradually tapering toward papillate tip. Tergite X well sclerotized, with a medial light spot anterior to the tip of the epiproct ( Fig. 1 a). Paraproct inner lobe barely visible, as usual in the genus; outer lobe almost triangular in its distal part, with its inner margin slightly convex near the base ( Fig. 1 b). Cercus with lateral sclerotization and membranous fields in its inner side and around the vestigial second segment; the cercus is nearly straight with its outer edge clearly rounded ( Figs. 1 a, 1c, 2, 4). Vestigial second segment prominent, sclerotization forming a ring around the cercal tip, apical tooth blunt and oriented perpendicular to the cercus ( Figs. 1 a-c, 3, 5). Epiproct stout, sub-rectangular and rounded at the tip ( Fig. 1 a, 2, 4). Lateral arms of the ventral sclerite large, dark, crescent-shaped, carrying two erect plates near their apex; these plates are very narrow, oriented medially and posteriorly, and connected to each other at their tip forming a V in dorsal view ( Figs. 1 a, 2, 4).

Female ( Fig. 1 d): Forewing length 8.5 mm, hindwing length 7.6 mm. General color the same as the male. Hind margin of pregenital plate regularly rounded. Pregenital plate large, covering half the width of VIII segment.

Larva: Undescribed.

Etymology. From the Latin name of the region where it was collected.

Remarks. The males of N. sabina have the basolateral bands of the epiproct forming rearward directed plates whose apices are connected to each other forming a V in dorsal view. However, in N. flexuosa these plates are curved frontward, are slightly larger, and do not form a V in dorsal view. In this respect, N. sabina resembles N. confusa Zwick, 1970 . The tip of the cerci of N. sabina is also different from N. flexuosa in that it has a large, blunt tooth, whereas in both N. flexuosa and N. confusa , a longer and thinner tooth is found (see Zwick 1970, Fig. 1 , p. 264 for a comparison with N. confusa , N. flexuosa and N. marginata ; see also Figs. 1 ac, 3 and 5). Moreover, in N. sabina the sclerotization encompasses the entire cercal tip in apical view. This is not the case in N. flexuosa which has the tip of the cercus membranous in ventral view (see Kis 1974, Fig. 85A).

The males of N. sabina also appear similar to those of an Italian endemic species, N. rivorum , but there are clear differences. In N. rivorum , the erect plates of the epiproct are more rectangular and their apex is bent foreward. The same remarks are also valid for N. marginata , a species quite similar to N. rivorum in this respect. The female and larva cannot be distinguished with certainty from others in the group.

Figures

FIGURE 1. Tip of male abdomen of Nemoura sabina sp. n. in dorsal (a), ventral (b) and lateral (c) view. Tip of female abdomen in ventral view (d).

FIGURE 2. Nemoura sabina sp. n. tip of the epiproct with the arched sclerites (350 X).

FIGURE 3. Nemoura sabina: cercus (350 X).

FIGURE 4. Nemoura confusa: tip of the epiproct with the arched sclerites (350 X).