New species of Rissoidae (Mollusca, Gastropoda) from the Archipelago of the Azores (northeast Atlantic) with an updated regional checklist for the family Author Cordeiro, Ricardo Author Avila, Sergio P. text ZooKeys 2015 480 1 19 http://dx.doi.org/10.3897/zookeys.480.8599 journal article http://dx.doi.org/10.3897/zookeys.480.8599 1313-2970-480-1 9E128E1898304CE0897CDA703E620408 9E128E1898304CE0897CDA703E620408 Taxon classification Animalia Littorinimorpha Rissoidae Manzonia martinsi Avila & Cordeiro sp. n. Figure 4 Type material. Holotype, DBUA 788 (sh., 1.75 x 1.13 mm); paratype 1, DBUA 1092 (sh., 1.88 x 1.20 mm); paratype 2, DBUA 1093 (sh., 1.76 x 1.14 mm); paratype 3, DBUA 1094 (sh., 1.72 x 1.10 mm); paratype 4, DBUA 1095 (sh., 1.76 x 1.06 mm), Sao Miguel Island ( Sao Vicente Ferreira, 4.7 m depth, 16/07/1997). Type locality. Sao Vicente Ferreira, Sao Miguel Island, Azores. Etymology. Named after Antonio M. de Frias Martins, a malacologist from the University of the Azores. Description. Shell minute, white, oval-conical, up to 1.9 x 1.2 mm (Fig. 4A). Protoconch paucispiral, clearly demarcated convex whorls 1.25, diameter 340-365 µm ; whorls with a pronounced keel adapically (Fig. 4I) and 5-6 faint spiral cords visible on surface between suture and keel (Fig. 4H and I). Teleoconch with 3 to 3.5 inflated, rounded, strongly convex whorls, angulated at a distance abapically from suture (Fig. 4 B-F ). Spire moderately high. Suture very deep, strongly constricted (Fig. 4 B-F ). Last whorl large, globose, 65% of shell length (Fig. 4 B-D and F). Base large, rounded (Fig. 4 B-D and F). Spiral sculpture consisting of flat cords (5-6 on first teleoconch whorl, 8-9 on penultimate whorl and 9-10 on body whorl) equal to two times broader than the interspaces ornamented with minute pits arranged in spiral lines (Fig. 4G); interspaces with 4 to 6 raised spiral striae (Fig. 4G). Abapical area of body whorl (base) with two strong spiral cords separated by broad spiral depression; third spiral cord located nearer the lip may be present (Fig. 4B and F). Axial sculpture consisting of 10-14 flexuous, opisthocline, moderately broad and strongly elevated ribs (body whorl), fading on base (about 7-8th spiral cord) (Fig. 4B, D and F). Intersection of axial and spiral sculptures raising small knobs (Fig. 4E). Aperture oval, strongly thickened, oblique with continuous peristome (Fig. 4 B-D and F). Parietal region slightly convex (Fig. 4 B-D and F). Outer lip with very thickened edge (smooth inside) (Fig. 4 B-D and F). Inner lip moderately thickened and slightly concave (Fig. 4 B-D and F). Umbilicus lacking (Fig. 4 B-D and F). Figure 4. Manzonia martinsi sp. n. A Holotype DBUA 788 (1.75 x 1.13 mm) B Paratype 1 (1.88 x 1.20 mm), DBUA 1092 (shell) C Paratype 2 (1.76 x 1.14 mm), DBUA 1093 (shell) D Paratype 3 (1.72 x 1.10 mm), DBUA 1094 (shell) E Paratype 1, DBUA 1092 (shell, apical view) F Paratype 4 (1.76 x 1.06 mm), DBUA 1095 (shell) G Paratype 1, DBUA 1092 (microsculpture of the bodywhorl) H Paratype 1, DBUA 1092 (protoconch, lateral view) I Paratype 1, DBUA 1092 (protoconch, apical view). Habitat. In the infralittoral on rocks covered by algae. Geographical distribution. Sao Miguel Island. Probably endemic to the Azores. Remarks. Manzonia martinsi sp. n. is similar in shell shape to Manzonia lusitanica Gofas, 2007 and Manzonia crispa (Watson, 1873). It differs from Manzonia lusitanica in having a lower number of spiral cords on the body whorl (9-10 in the new species and 12-13 in Manzonia lusitanica ). Manzonia martinsi sp. n. has 9-10 spiral cords on the body whorl and 4-6 raised spiral striae on the interspaces between cords, while Manzonia crispa has 7 spiral cords on the body whorl and 8-10 lower spiral striae between cords. Manzonia martinsi sp. n. differs from Manzonia arata Gofas, 2007 in the number of raised spiral striae on the interspaces as well as on the number of spiral lines with pits on the spiral cords, which are lower 2 to 3 times in the new species (Table 1). Table 1. Comparison of the conchological characters of Manzonia arata , Manzonia crispa , Manzonia lusitanica , and Manzonia martinsi sp. n.

Species	Number of spiral cords adapical area (body whorl)	Number of spiral cords abapical area (body whorl)	Number of axial cords (body whorl)	Number of raised spiral threads (interspaces)	Number of spiral lines with pits (spiral cords)	Interspaces and spiral cords
Manzonia arata
Manzonia crispa
Manzonia lusitanica
Manzonia martinsi