Mitromorpha (Mitrolumna) alyssae, Amati, Bruno, Smriglio, Carlo & Oliverio, Marco, 2015

Amati, Bruno, Smriglio, Carlo & Oliverio, Marco, 2015, Revision of the Recent Mediterranean species of Mitromorpha Carpenter, 1865 (Gastropoda, Conoidea, Mitromorphidae) with the description of seven new species, Zootaxa 3931 (2), pp. 151-195 : 172-174

Mitromorpha (Mitrolumna) alyssae n. sp.

( Figs 17 ; 18A–E; 27F; 28F)

Type material. Holotype, type locality, (H 7.3 mm, W 3.45 mm) ( Fig. 18 A–C; 28F) ( MNHN IM- 2000-27707); paratypes: 9 sh (5 adults and 4 juv.: BA) type locality, 2 sh (MO), all from the type locality; 4 sh, Salina Is. , - 46 m bioclastic sand, 2002 (CS).

Type locality. Salina Is., Aeolian Islands , Italy, - 35 m.

Etymology. Dedicated to Alyssa Rocchino, granddaugther of one of the authors (B. Amati).

Distribution and habitat. Found so far only from the type locality area, Salina Is. , in the southern Tyrrhenian Sea. Recent. Empty shells in bioclastic sands, - 35 m (cave) and - 46 m. Found sympatric with M. columbellaria and M. karpathoensis .

Description. (in parentheses the data of the holotype) Shell of medium size for the genus ( Figs 18 A–E; 27F), height 7–7.95 (7.3 mm), width 3.3–3.6 (3.45 mm), solid, fusiform, biconic, slender, H/W=2.028–2.208 (2.115). Protoconch paucispiral ( Fig. 28F ) shiny, of 1.3–1.35 (1.35) convex whorl, d 0.20–0.225 (0.20 mm), Do 0.40–0.45 (0.40 mm), DM 0.55 mm, h 0.45 mm. sculptured by many densely arranged microgranules. Protoconchteleoconch boundary well marked, flexuose, opisthocline. Teleoconch of 5–5.5 (5) slightly convex whorls. Sculpture starting with 3 (3) strong spiral cordlets crossed by 12 (12) equally strong axial ribs on the first whorl. Additional spiral cordlets between the adapical ones, and between the suprasutural one and the suture. Last whorl sculptured over the entire surface by 22–25 (24) spiral cordlets, of which 7–10 (8) above the aperture. First 4 abapical spirals, rather strong, broader than the interspaces, lower 9 thinner, flat, those on the base stronger and more spaced. Axial ribs (13–16) present only on the first 3.5 whorls of all shells, producing rounded nodules at the intersection with the spirals and quadrangolar interspaces. Two columellar folds, the posterior larger and frequently bifid on the outer tip ( Fig. 6D ). Growth lines visible over the entire surface. Outer lip sharp, thickened internally with 10 (10) small denticles, the second or third posterior more pronounced. Anal sinus shallow. Siphonal canal short, and wide. Coloration brown in the background, with subsutural lighter band, and periphery with small darker blotches and whitish rounded spots. Tubercles lighter than the background. Outer lip lighter, with occasional darker stripes posteriorly. Soft parts unknown.

Remarks. M. alyssae n. sp. is similar to M. olivoidea in the chromatic pattern with a brown background and dark and light blotches in the peripheral area, but the blotches are larger, darker and more numerous. M. alyssae lives probably in shallower habitat (empty shells in 35–46 m v. 60 –170 m of M. olivoidea ), and differs also in having less spirals on the last whorl (22–25 v. 34 –39 of M. olivoidea ) and a coarser sculpture in the first whorls. M. columbellaria has a different chromatic pattern, usually monochrome, and less spirals above the aperture (4–6 v. 7–10 of M. alyssae n. sp.). M. alyssae n. sp. differs from M. karpathoensis (including all morphs), in its less brilliant and colorful chromatic pattern, in having less spirals on the last whorl (22–25 v. 30–40 in karpathoensis ) and above the aperture (7– 10 v. 3–4 in karpathoensis ). The morphs A and B of karpathoensis have less evident spiral and axial sculpture.

Figures

FIGURE 17. Distribution of Mitromorpha spp. based on the type material and the material examined in this work. Closed circles, Mitromorpha wilhelminae (van Aartsen, Menkhorst & Gittenberger, 1984). Grey circle, Mitromorpha alyssae n. sp. Open circles, Mitromorpha nofronii n. sp. Black box, Mitromorpha mifsudi n. sp. Open box, Mitromorpha mariottinii n. sp. Grey box, Mitromorpha cossyrae n. sp. Star, Mitromorpha tricolorata n. sp.

FIGURE 18. Mitromorpha alyssae sp. n.. A – C. Holotype, Salina Is., Italy, 35 m, H = 7.4 mm (MNHN, IM- 2000 - 27707); D. Salina Is., Italy, 35 m, H = 2.8 mm (BA); E. Salina Is., Italy, 35 m, close-up of the first whorls (BA).

FIGURE 28. A – L. Mitromorpha spp. Fist whorls (SEM). A. Mitromorpha columbellaria, Marina di Camerota, Italy (CS); B. Mitromorpha olivoidea, Lampedusa Is., Italy (MO); C. Mitromorpha karpathoensis, Salina Is., Italy (BA); D. Mitromorpha wilhelminae morph A, Alboran Is., Spain (CS); E. Mitromorpha wilhelminae morph B, Alboran Is., Spain (MO); F. Mitromorpha alyssae, holotype (MNHN); G. Mitromorpha bogii, paratype, Secca delle Vedove, Italy, 200 – 300 m, (MCZR, 00080); H. Mitromorpha cossyrae, holotype (MNHN); I. Mitromorpha mariottinii, holotype (MNHN); J. Mitromorpha mifsudi, olotipo (MNHN); K. Mitromorpha nofronii, holotype (MNHN); L. Mitromorpha tricolorata, holotype (MNHN). Scale bars: 100 µm.

FIGURE 6. A – D. A – C— Mitromorpha columbellaria (Scacchi, 1836), (SEM), Torre San Giovanni, Apulia, Italy (MO). D, schematic drawing of the posterior columellar fold. Scale bar: 500 µm (A, B), 100 µm (C).