Mitromorpha (Mitrolumna) mariottinii, 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 : 177-179

Mitromorpha (Mitrolumna) mariottinii n. sp.

( Figs 17 ; 22A–E; 23A–D; 27H; 28I)

Type material: Holotype, Marina di Camerota, - 33 m bioclastic sand, (H 5 mm, W 2.35 mm) ( MNHN IM- 2000- 27709) ( Fig.22 A–C, E); paratypes: 60 sh type locality (CS-PM); 28 sh, type locality - 30 m (CS-PM); 2 sh, type locality (BA); 2 sh, type locality (MO); 1 sh, type locality ( MCZR); 1 sh, type locality ( MZB); 10 paratypes Palinuro (SA) (SB-MS).

Type locality: Marina di Camerota, - 33 m.

Other material examined. Italy: “Occhi” cave, Capo Palinuro, - 12 m, bioclastic sand, 1987–1995, 18 sh (CS- PM), 5 sh (MO), 1 sh (SB-MS); Capo Palinuro, 45/ 55 m, bioclastic sediment, 57 sh (SB-MS); “Trombetta” cave, Capo Palinuro, 20 m, ix.2013, 13 sh + 1 juv. (CS-PM); “Cattedrale II” cave, Capo Palinuro, 12 m, viii.1988, 3 sh (MO).

Etymology. Dedicated to our dear friend Paolo Mariottini (Roma) expert malacologist, who collected the sediments with the type material.

Distribution and habitat. Known so far only from the type locality (Marina di Camerota) and neighboring sites of Capo Palinuro, in the southern Tyrrhenian Sea. Recent. Empty shells in bioclastic sediments, from 12–55 m, including samples from marine caves. Found sympatric, often at different depths, with M. olivoidea , M. columbellaria and M. karpathoensis .

Description. (in parentheses the data of the holotype) Shell small for the genus ( Figs 22 A–E; 23A–D; 27 H), height 4.65–6.5 (5 mm), width 2.25–2.8 (2.35 mm), solid, fusiform, biconic, slender, H/W=2.000–2.321 (2.127). Protoconch paucispiral ( Fig. 28I ) shiny, of 1.2–1.35 (1.3) convex whorl, d 0.20 mm, Do 0.375–0.40 (0.375 mm), DM 0.50–0.55 (0.50 mm), h 0.40–0.45 (0.45 mm), sculptured by sparse microgranules arranged in spiral rows. Protoconch-teleoconch boundary well marked, flexuose, opisthocline. Teleoconch of 3.8–4.7 (4.2) slightly convex whorls. Sculpture starting with 3–4 spiral cordlets crossed by 12–15 (15) axial opisthocline 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 14–18 (18) spiral cordlets, pronounced, equidistant, of equal size, twice as broad as the interspaces, of which 3–5 (4) above the aperture. Axial ribs of variable strength, 18–22 (21) on the last whorl, vanishing toward the base and slightly broader than the spirals, producing slightly elongated nodules at the intersection with the spirals. Two columellar folds. Growth lines visible over the entire surface. Outer lip sharp, thickened internally with 7 weak denticles, the second posterior more pronounced. Anal sinus very shallow. Siphonal canal short, and wide. Coloration of background brown, suprasutural cordlet whitish with one darker nodule every 3–4; the two subsutural cordlets darker brown. Protoconch of the same color as the teleoconch. Soft parts unknown.

Remarks. M. mariottinii n. sp. is easily diagnosed by the peculiar chromatic pattern with brown background, the suprasutural cord with white blotches, and the two adapical ones (sometimes only the most adapical) darker, by the small size and the blunt apex. M. columbellaria is similar, being diagnosed (they are sympatric at Marina di Camerota and Palinuro) by the monochrome pattern ( v. the colored suprasutural and subsutural cords in mariottinii ) and the more acute apex. See under M. mifsudi n. sp. and M. tricolorata n. sp. for the differences with these species. The specimens from Capo Palinuro (Trombetta cave, 20 m) are all more slender (H/W = 2.321) and larger than the average (H. 6.5 mm) ( Fig. 23 D).

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 22. Mitromorpha mariottinii sp. n .. A – C, E. Holotype, Marina di Camerota, Italy, 35 m, H = 5 mm (MNHN, IM- 2000 - 27709); E. close-up of the first whorls. D. Cape Palinuro, Italy, H = 3.6 mm, juvenile (CS).

FIGURE 23. Mitromorpha mariottinii n. sp. A – C. Paratype, Marina di Camerota, Italy, 35 m, H = 5.15 mm (CS); D. Cape Palinuro, Italy, Trombetta cave, 20 m, H = 6.65 mm (CS).

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.