Inermonephtys soldius, Franco, Natália Bizzo & Rizzo, Alexandra E., 2016

Franco, Natália Bizzo & Rizzo, Alexandra E., 2016, Nephtyidae (Annelida: Polychaeta) from the Campos Basin, including two new species and a new record, Zootaxa 4114 (3), pp. 291-308 : 299-300

Inermonephtys soldius sp. nov.

Figure 5 (A–E); Figure 9 (A–C)

Type material. 7 specimens: HABITATS: Continental shelf: Holotype: UERJ 4767 (1 spec., 22º8’4.915’’S and 040º27’34.027’’W, HAB.16 E3 R3, 65 m). Paratypes: UERJ 4770 (4 spec., 22º17’37.730”S and 040º27’6.150”W, HAB.16 E4 R 2, 103 m), UERJ 4771 (1 spec., 22º17’37.760’’S and 040º27’5.940’’W, HAB.16 E4 R 3, 103 m), UERJ 4772 (1 spec., 22º17’37.752”S and 040º27’5.941’’W, HAB.11 E4 R 3, 104 m).

Diagnosis. Interramal branchiae from parapodium 5, and basal papillae starting on chaetiger 6.

Description. Based on incomplete holotype in three parts, with 86 chaetigers, measuring 18.5 mm long and 1.1 mm wide (excluding chaetae). Remaining specimens with 10–44 chaetigers, ranging between 1–5.7 mm long and 0.5–0.7 mm wide (excluding chaetae); all are incomplete except one specimen (UERJ 4772). Body slender, rectangular and wider in anterior than posterior region. Prostomium with posterior edge rounded, upper right and left corners rounded, anterior edge slightly rounded, and with slight central dorsal depression ( Figure 5 A–B). Antennae and eye spots absent. Nuchal organs digitiform and long ( Figure 5 A–B). Pair of ventral palps, each with digitiform papilla similar to nuchal organs. Parapodium 1 little developed, projected frontally ( Figure 5 A–B); dorsal and ventral cirri short. Interramal branchiae starting from parapodia 5, curved inward and well developed, becoming longer from median region of body ( Figure 5 C–E). All specimens are incomplete, except one paratype (UERJ 4772), in which branchiae continue to end of body. Basal papillae short and sometimes difficult to see, located on upper part of each branchia ( Figure 5 D), from chaetiger 6. Dorsal cirri short and foliaceous with rounded tips on first 4 chaetigers, becoming long and digitiform on following chaetigers ( Figure 5 C–E). Dorsal cirri occupying up to half of interramal space on anterior parapodia and 2/3 of interramal space from median parapodia. Ventral cirri well developed and similar to dorsal cirri, with base broader than tip, becoming longer and digitiform from middle region ( Figure 5 C–E). Notopodia with preacicular lobe rounded and little developed; acicular lobe conical and larger than preacicular lobe; postacicular lobe translucent, rounded and larger than the others; becoming longer and tapered from middle region; narrower and digitiform in posterior region ( Figure 5 C– E). Neuropodia with preacicular lobe short and rounded; acicular lobe conical and short; postacicular lobe rounded and larger than acicular lobe ( Figure 5 C–E). Neuropodial lobe less developed than notopodial lobe, unlike cirri and branchiae which are well developed. Anterior parapodia with notopodial and neuropodial chaetae long and barred, with rough sandpaper-like appearance, in pre-acicular position ( Figure 9 A); and long and denticulate, in postacicular position. Posterior parapodia with no barred chaetae. Some short lyrate chaetae ( Figure 9 C) in middle region. Barred chaetae decreasing in number from median parapodia until they disappear in posterior parapodia, and denticulate chaetae occurring in larger numbers. One or 2 aciculae per acicular lobe.

Remarks. The new species differs from the others in a set of characteristics including the interramal branchiae from parapodium 5; basal papillae on the upper part of each branchia, from chaetiger 6; and prostomium rounded, with a slight central dorsal depression. In contrast, Inermonephtys brasiliensis Martin, Gil & Lana, 2009 , also described from Brazil, has the interramal branchiae from chaetiger 3 and the basal papillae from chaetiger 5; the prostomium pentagonal, long and with the anterior edge straight; and spinulose chaetae. Inermonephtys soldius sp. nov. is the only member of its genus with interramal branchiae emerging from the 5th parapodia. The barred chaetae with a rough surface are similar to the chaetae found in the glycerid Glycerella magellanica (McIntosh, 1885) , see Miranda et al. (2014).

Etymology. The species name “ soldius ” is dedicated to Solange (“ sol ”) and Diomar (“ dius ”), the grandmother and grandfather of the first author, combining the first part of each name.

Distribution. Known only from the Campos Basin, Brazil, in depths of 65– 103 m.

Figures

FIGURE 5. Inermonephtys soldius sp. nov. Paratype UERJ 4767. (A) Anterior region, dorsal view. (B) Anterior region, dorsal view. (C) Parapodium 10, anterior view. (D) Parapodium 25, anterior view. (E) Parapodium 55, anterior view. (Abbreviations: BP: basal papilla; BR: interramal branchiae; DC: dorsal cirrus; NO: nuchal organ; VC: ventral cirrus). A: 0.5 mm; B: x 100; C – E: x 40.

FIGURE 9. Inermonephtys soldius sp. nov. (A) Barred preacicular chaeta from parapodium 25. (B) Denticulate postacicular chaeta from parapodium 25. (C) Lyrate postacicular chaeta from parapodium 25. A – C: x 400. Inermonephtys inermis. (D) Barred preacicular chaeta from parapodium 10. (E) Lyrate postacicular chaeta from parapodium 40. (F) Bristly preacicular chaeta with a few coarse teeth from parapodium 6. D – F: x 400. Nephtys squamosa. (G) Capillary postacicular chaeta from parapodium 8. (H) Barred preacicular chaeta from parapodium 8. (I) Flattened preacicular chaeta from parapodium 60. G – H: x 100; I: x 400.