Nannoniscus perunis, MENZIES & GEORGE, 1972

Kaiser, Stefanie, Kihara, Terue Cristina, Brix, Saskia, Mohrbeck, Inga, Janssen, Annika & Jennings, Robert M., 2021, Species boundaries and phylogeographic patterns in new species of Nannoniscus (Janiroidea: Nannoniscidae) from the equatorial Pacific nodule province inferred from mtDNA and morphology, Zoological Journal of the Linnean Society 193, pp. 1020-1071 : 1037

NANNONISCUS PERUNIS MENZIES & GEORGE, 1972

( FIG. 7G–I )

M a t e r i a l e x a m i n e d: H o l o t y p e, f e m a l e, U S N M 121017–121018.

Diagnosis: Body slender, length about 4.7 pereonite × 1 width; pereonite 2 anterolateral tergites each with robust seta; pereonites 3–4 anterolateral tergites without setae; pereonite 7 lacking ventral spine; Op with ventral posteriorly bent spine, Urp biramous, not projecting beyond Plt posterior margin; Urp exopodite minute, endopodite length ≥ 7.8 exopodite length.

Redescription female holotype: Habitus ( Fig. 7G, H ), body length 4.7 × pereonite 1 width. Coxae not visible in dorsal view. Cephalothorax ( Fig. 7G ) length 0.8 width. Anterior margin slightly concave, lateral margins straight, posterior margin slightly rounded. Antennae inserting frontolaterally in deep fold. Pereonites 2–7 decreasing in width; pereonite 2 widest, length 0.4 width, width 1.1 pereonite 1 width. Pereonites 2 and 3 of similar length, length 1.3 pereonite 1 length; pereonite 4 length 1.9 pereonite 1 length. Pereonites 1–4 anterior margins frontally directed, anterolateral tergites of pereonite 2 each tipped with robust seta. Pereonite 5 not illustrated. Pereonites 6 and 7 dorsolmedially fused, pereonite 6 anterior margin strongly convex. Plt length 2.7 pereonite 1 length, length 1.3 width; posterior margin strongly rounded, anterior margin slightly convex. Urp ( Fig. 7H, I ) drawn in situ. Biramous, length 0.2 Plt length, not projecting beyond Plt posterior margin. Protopodite length 1.3 width. Exopodite minute, length 0.2 protopodite length. Endopodite length 7.8 exopodite length, length 4 width, with few long setae terminally.

Remarks: Illustrations of the holotype of N. perunis made by Menzies & George (1972) show a coxal seta on pereonite 2, a character state atypical for nannoniscids. However, examination of type material could instead confirm robust setae on the anterolateral tergites of pereonite 2.

Figures

Figure 7. A–C,Nannoniscus ovatus Menzies & George, 1972, allotype female (USNM 121022); (D–F) holotype male (USNM 121022); (G–I) N. perunis Menzies & George, 1972, holotype female (USNM 121017–121018): (A) habitus, dorsal view; (B) Plt and Op, lateral view; (C) Plt and Op, ventral view; (D) habitus, dorsal view; (E) Plt, lateral view; (F) Plt, ventral view incl. Urp.; (G) habitus, dorsal view; (H) Plt, ventral view; (I) Urp. Scale bars: A, G–I = 100 µm; B–F = 200 µm.