122,883 research outputs found
Ellenstrongia Amati & Giulio & Oliverio 2023, n. gen.
No full textGenus <i>Ellenstrongia</i> n. gen. <p>urn:lsid:zoobank.org:act: 4E99EFB1-B5EF-4109-BE9F-55A1D328 CAD 6</p> <p> TYPE SPECIES. — <i>Ellenstrongia tarasoc</i> n. gen., n. sp.</p> <p> DIAGNOSIS. <i>—</i> Shell of medium (height> 4 mm) size for the family, robust, slender and acute, with very convex whorls and deep sutures; protoconch multispiral, coloured, strongly sculptured; teleoconch with weak spiral sculpture and narrow, acute, orthocline and flexuose axial ribs; microsculpture of minute pits; umbilical fissure absent; aperture piriform, peristome continuos, wide with rather thick outer varix, sharp outer lip, internally smooth; colouration uniform white with light orange protoconch.</p> <p>Operculum and soft parts not examined.</p> <p>ETYMOLOGY. — The name of the new genus is after Ellen E. Strong (USNM), for her contribution to the knowledge of gastropod systematics and evolution. She has shared her unpublished molecular data, supporting the classification of the new genus in the Rissoidae.</p> <p>REMARKS</p> <p>The new genus is proposed for a species with a unique combination of characters, not shared with any known genus of Rissoidae. Initially, we considered also the hypothesis that it was not a rissoid, but then Ellen E. Strong (pers. comm.) communicated that her still unpublished molecular data confirmed it was nested inside Rissoidae.</p> <p> Shell morphology, i.e., the elongated shell with acute spire, convex whorls, double sculpture on the teleoconch (the axial one stronger), may recall some European species of <i>Alvania</i>, such as <i>A. rudis</i> (Philippi, 1844), <i>A. micalii</i> Chirli, 2006, and <i>A. merlei</i> Van Dingenen, Ceulemans & Landau, 2016. However, the sculpture of the multispiral protoconch is completely different, as is also diagnostic the peculiar pitted microsculpture.</p> <p> A similar teleoconch microsculpture is observed in the genus <i>Porosalvania</i> Gofas, 2007 known from northeast Atlantic Seamounts (Gofas 2007: 848). Known species of <i>Porosalvania</i> all have a nearly smooth, paucispiral, dome-shaped protoconch: the corresponding part of the multispiral protoconch of <i>Ellenstrongia</i> n. gen. (the protoconch I) is more protruding and densely and strongly sculptured by microgranules; additionally, the outline of <i>Porosalvania</i> is neatly more scalariform. Relationships among the rissoid genera with pitted teleoconch microsculpture (e.g. <i>Gofasia</i> Bouchet & Warén, 1994, <i>Manzonia</i> Brusina, 1870, <i>Onoba</i> H. Adams & A. Adams, 1852, <i>Porosalvania</i> Gofas, 2007) should be tested by integrating molecular data. This feature is also present in genera of other rissooidean families (e.g. <i>Barleeia</i> W. Clark, 1843, <i>Rissoina</i> d’Orbigny, 1841).</p> <p> The markedly sculptured and coloured multispiral protoconch of <i>Ellenstrongia</i> n. gen. is very similar to that of some species of <i>Benthonellania</i> Lozouet, 1990 (e.g. <i>B. alvanioides</i> Oliver & Rolán, 2017, <i>B. bouteti</i> Amati, Di Giulio & Oliverio, 2022 and <i>B. tuamotu</i> Amati, Di Giulio & Oliverio, 2022) (Amati <i>et al.</i> 2022). The new genus, however, differs in the more slender teleoconch profile with more convex whorls, and the peculiar pitted microsculpture.</p>Published as part of <i>Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2023, Shallow-water Rissoidae of the genera Alvania Risso 1826 Haurakia Iredale 1915 Parashiela Laseron 1956 Simulamerelina Ponder 1985 and Subestea Cotton 1944 Gastropoda Caenogastropoda Rissooidea from French Polynesia with the description of a new deep-water genus, pp. 803-892 in Zoosystema 45 (25)</i> on page 828, DOI: 10.5252/zoosystema2023v45a25, <a href="http://zenodo.org/record/10458066">http://zenodo.org/record/10458066</a>
Benthonellania megan Amati & Giulio & Oliverio 2022, n. sp.
No full textBenthonellania megan n. sp. (Figs 18 A-K; 19F-H; 25G; 26L; Tables 1; 2) urn:lsid:zoobank.org:act: 9B36A331-6E3D-48ED-8B90-31C7D64BB919 TYPE MATERIAL. — Holotype. Marquesas • 1 dd (height 2.7 mm, width 1.6 mm, Figs 18 A-E; 19F-H); Fatu Hiva, MUSORSTOM 9 Stn DR1247; 10°34’S, 138°42’W; 1.IX.1997; 1150-1250 m depth; MNHN-IM-2000-37695. Paratypes. Marquesas • 5 dd; same locality data as holotype; MNHN-IM-2000-37696. TYPE LOCALITY. — Marquesas, Fatu Hiva, MUSORSTOM 9 Stn DR1247; 10°34’S, 138°42’W; 1150-1250 m depth. OTHER MATERIAL EXAMINED. — Australes • 1 dd; Rimatara, BENTHAUS Stn DW2021; 22°37’S, 152°49’W; 25.XI.2002; 1200-1226 m depth. DISTRIBUTION AND SYMPATRY. — The species is at present known from the South Pacific Ocean, at Marquesas (Fatu Hiva Island) and Australes (Rimatara), with only empty shells collected in 1150- 1250 m depth (Fig. 25G). Benthonellania megan n. sp. is sympatric with Benthonella boucheti n. sp. at the Marquesas (Fatu Hiva Island) and Australes (Rimatara); with Benthonella communis n. sp. at the Australes (Rimatara); with Benthonellania bouteti n. sp. at the Australes (Rimatara); with Benthonellania tarava n. sp. at the Australes (Rimatara); with Benthonellania lozoueti n. sp. at the Marquesas (Fatu Hiva Island); with Benthonellania alis n. sp. at the Australes (Rimatara) (Table 2). ETYMOLOGY. — Dedicated to Megan Zampa, granddaughter of one of the authors (B. Amati). DESCRIPTION OF HOLOTYPE Shell (Figs 18 A-C; 19F-H) Small for the genus, height 2.7 mm, width 1.6 mm, height/ width ratio 1.687, pretty solid, ovate-conical. Protoconch (Figs 18D, E; 19G, H) Multispiral, acute of 2.5 whorls, height 0.40 mm, nucleus diameter 0.095 mm, first half whorl diameter 0.162 mm, maximum diameter 0.437 mm; (protoconch I in poor condition), protoconch II with two fine spiral keels, the lower larger, a fine cordlet of microtubercles in the subsutural area. Microtubercles spread over the entire surface (Fig. 19G, H). Protoconch-teleoconch boundary barely visible, sinuous. Teleoconch Of c. 3.5 convex whorls, suture canaliculate, crowned by small tubercles at tips of axial ribs. Height last whorl 1.75 mm, height/height last whorl ratio 1.542. Axial sculpture of 16 curved, slightly opisthocline ribs on last whorl, slightly narrower than interspaces, abruptly interrupted on the suture line. Spiral sculpture of 3 very weak fine cordlets on the base. Microsculpture of only growth striae (Fig. 19H). Umbilical chink absent. Aperture pyriform, large, height 1.1 mm, height/height aperture ratio 2.454, peristome continuous, varix absent (outer lip broken). Columella arcuate, simple. Colour Coloration of teleoconch translucent white, protoconch orange. Operculum and soft parts Unknown. VARIABILITY Species not very variable (See Table 1 and Appendix 11). REMARKS All the examined specimens have a broken peristome (presence/absence of lip thickening not observable). B. tarava n. sp. differs from B. megan n. sp. in its larger size height 2.92-3.75 mm vs heigh 2.40-2.70 mm in B. megan n. sp., higher height/width ratio 1.859 -1.807 vs 1.662 in B. megan; more whorls 4-4.65 vs 3.20-3.50 in B. megan n. sp., less numerous axial ribs on the last whorl 11-14 (mean 12.6) vs 14-19 (mean 16.5) in B. megan n. sp., and its more slender protoconch with two fine spiral cordlets, with a large smooth median area, and a fine spiral cordlet below the abapical cordlets vs two fine spiral cordlets, the lower larger, a fine cordlet of microtubercles in the subsutural area and microtubercles over the entire surface in B. megan n. sp.Published as part of Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2022, Deep-water Rissoidae of the genera Benthonella Dall, 1889 and Benthonellania Lozouet, 1990 (Gastropoda, Caenogastropoda, Rissooidea) from French Polynesia, pp. 335-389 in Zoosystema 44 (12) on pages 366-368, DOI: 10.5252/zoosystema2022v44a12, http://zenodo.org/record/679484
Mitromorpha (Mitrolumna) alyssae Amati, Smriglio & Oliverio, 2015, n. sp.
No full textMitromorpha (Mitrolumna) alyssae n. sp. (Figs 17; 18 A–E; 27 F; 28 F) Type material. Holotype, type locality, (H 7.3 mm, W 3.45 mm) (Fig. 18 A–C; 28 F) (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; 27 F), 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. 28 F) 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. 6 D). 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.Published as part of 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, pp. 151-195 in Zootaxa 3931 (2) on pages 172-174, DOI: 10.11646/zootaxa.3931.2.1, http://zenodo.org/record/23842
Oil whip and unstable whirling in anisotropic rotors on lubricated bearings
No full texthe dynamics of rotors running on lubricated bearings is complex. While the linearized analysis allows to study the stability in the small and phenomena like oil whirl and oil whip, more complex behaviour, that may include chaotic motion, requires a fully nonlinear analysis. Since lubricated bearings behave like anisotropic supports, complex whirling pattern can be expected when the rotor is anisotropic. The aim of the present paper is to investigate to what extent the anisotropy of the rotor affects its dynamic behaviour. In particular, the interactions between the instability ranges due to rotating anisotropy and to oil whip are searched. The rotor models are built using DYNROT FEM code to build the basic rotor model and to obtain linearized solutions. The linear model of the rotor is then mated to nonlinerar bearing models and integrated numerically in time. Time domain results allow to draw some general conclusions applicable to simplified models as well as to real-world rotors
Benthonellania hertzogi Amati & Giulio & Oliverio 2022, n. comb.
No full textBenthonellania hertzogi (Thiele, 1925) n. comb. (Figs 7 A-J; 9A, B; 13A; 26D; Table 1) Rissoa hertzogi Thiele, 1925: 82, pl. 6, fig. 15. TYPE MATERIAL. — Syntypes. South AFrica • 2 dd; Agulhas-Bank, Valdivia Stn 109; 35°19’S, 20°12’E; 126 m depth; ZMB /Moll. no. 64981 • 1 dd; Agulhas-Bank, Valdivia Stn 106; 35°26.8’S, 20°56.2’E; ZMB /Moll. no. 64981. DISTRIBUTION AND SYMPATRY. — Benthonellania hertzogi n. comb. is known so far only from south of South Africa (Agulhas-Bank) (Fig. 13A). DESCRIPTION [BASED ON THE TYPE MATERIAL] Shell (Figs 7 A-F; 9A) Small for the genus, height 2.47-2.85 mm width 1.75-1.95 mm, height/width ratio 1.411 -1.461, rather solid, ovate-conical. Protoconch (Figs 7 I-J; 9B) Dome-shaped, paucispiral, of 1.25 whorls, height 0.375 - 0.400 mm, nucleus diameter 0.200 - 0.212 mm, first half whorl diameter 0.350 -0.362 mm, maximum diameter 0.500 mm, glossy, smooth. Protoconch-teleoconch boundary distinct, slightly prosocline and marked by a slight thickening. Teleoconch Of 2.75-3.1 very slightly convex whorls, suture subcanaliculate, crowned by weak thinkening at tips of axial ribs, enhanced by a slight subsutural depression.Height last whorl 1.8-2.07 mm. height/height last whorl ratio 1.372 -1.377. Axial sculpture of 24-26 ribs on last whorl, slightly narrower than the interspaces, continuing partly on the base, prosocline, slightly curved on first whorls, markedly curved on last whorl. Spiral sculpture of 4-5 cordlets on last whorl, well spaced, slightly bulging at intersection with axial ribs, 1 above the aperture, 1 on the suture line and 2-3 on the base. Microsculpture of a very fine subsutural thread on first two teleoconch whorls (Fig. 9B) and weak growth striae on whole surface. Umbilical chink narrow. Aperture pyriform, height 1.25-1.4 mm, height/height aperture ratio 1.976 -2.036, peristome continuous, varix absent. Lip thin, orthocline or slightly prosocline, flexuose, smooth on the inside. Columella arcuate, simple. Colour Coloration of teleoconch and protoconch translucent white. Operculum and soft parts Unknown. VARIABILITY The variability of shell morphology is low in the few specimens examined (See Table 1 and Appendix 4). REMARKS The study of the type material showed that Rissoa hertzogi Thiele, 1925 (Figs 7 A-J; 9A, B) and Rissoa africana Thiele, 1925 (Figs 8 A-N; 9C, D) belong to this genus, with their paucispiral protoconchs devoid of spiral sculpture. Both species are very similar to e.g. B. agastachys, B. fayalensis and B. oligostigma with their slender shell and the crown of adapical thickening of axials, enhanced by the subsutural depression. We proposed thus, Benthonellania hertzogi (Thiele, 1925) n. comb. and Benthonellania africana (Thiele, 1925) n. comb. as new combinations for Rissoa hertzogi Thiele, 1925 and Rissoa africana Thiele, 1925, respectively. Benthonellania hertzogi n. comb. differs from B. basistriata n. sp. paucispiral vs multispiral protoconch, in its less canaliculated sutures, its tight umbilical chink, absent in B. basistriata, more numerous axial ribs (24-26 vs 14-20 in B. basistriata). See under Benthonellania africana n. comb. and B. thielei n. sp. for diagnostic comparison.Published as part of Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2022, Deep-water Rissoidae of the genera Benthonella Dall, 1889 and Benthonellania Lozouet, 1990 (Gastropoda, Caenogastropoda, Rissooidea) from French Polynesia, pp. 335-389 in Zoosystema 44 (12) on pages 349-351, DOI: 10.5252/zoosystema2022v44a12, http://zenodo.org/record/679484
Benthonellania maestratii Amati & Giulio & Oliverio 2022, n. sp.
No full textBenthonellania maestratii n. sp. (Figs 23; 24 A-C; 25G; 26O; Tables 1; 2) urn:lsid:zoobank.org:act: B89A1D9D-C9AE-42A4-9F2E-B76C317DF351 TYPE MATERIAL. — Holotype. Australes • 1 dd (height 2.50 mm, width 1.62 mm, Figs 23 A-E, 24A-C); Récif Neilson, BENTHAUS Stn DW1925; 27°00’S, 146°05’W; 12.XI.2002; 560-790 m depth; MNHN-IM-2000-37704. TYPE LOCALITY. — Australes, Récif Neilson, BENTHAUS Stn DW1925; 27°00’S, 146°05’W; 560-790 m depth. OTHER MATERIAL EXAMINED. — Australes • 3 dd; South coast of Rurutu, BENTHAUS Stn DW 2010; 22°32’S, 151°21’W; 24.XI. 2002; 520-950 m depth; MNHN. DISTRIBUTION AND SYMPATRY. — The species is known in the South Pacific Ocean from the Australes (Récif Neilson, South coast of Rurutu), with only empty shells collected in 520-950 m depth (Fig. 25G). Benthonellania maestratii n. sp. is sympatric with Benthonella boucheti n. sp., Benthonella communis n. sp., Benthonellania bouteti n. sp. and Benthonellania tuamotu n. sp. at the Australes (Récif Neilson, South coast of Rurutu); with Benthonellania tarava n. sp. and Benthonellania alis n. sp. at the Australes (South coast of Rurutu) (Table 2). ETYMOLOGY. — Named after Philippe Maestrati (MNHN), for his friendship and his long lasting, precious contribution to sample treating in the field and at the Muséum. DESCRIPTION OF HOLOTYPE Shell (Figs 23 A-E; 24A-C) Of medium size for the genus,height 2.50 mm width 1.625 mm, height/width ratio 1.538, not very solid, ovate-globose. Protoconch (Figs 23D, E; 24B, C) Multispiral, dome-shaped, of 2.3 whorls, height 0.325 mm, nucleus diameter 0.062 mm, first half whorl diameter 0.150 mm, maximum diameter 0.450 mm; protoconch I with 4 spiral threads interspaced by microtubercles more or less welded together (Fig. 24C), protoconch II with one abapical cordlet, the rest of surface covered with delicate lace-shaped structures, and two median with wavy spiral cordlets (Fig. 24B). Protoconch-teleoconch boundary marked. Teleoconch Of 3.2 convex whorls, suture non impressed, with clathrate sculpture. Height last whorl 1.75 mm, height/height last whorl ratio 1.428. Axial sculpture of 35 curved and opisthocline ribs on last whorl, well spaced c. 4 times narrower than interspaces, continuing through the columellar fissure. Varix broad, not thickened. Spiral sculpture on the last whorl of 22 cordlets not equidistant, narrower than axial ribs: 15 very fine adapical, 7 basal more spaced; others very fine spiral cordlets in the periumbilical area. Microsculpture of only growth striae. Umbilical chink present. Aperture subpyriform, simple, rounded, height 1.10 mm, height/ height aperture ratio 2.272, peristome continuous, outer lip weakly prosocline and slightly varicose, internally smooth. Columella arcuate, simple. Colour Coloration of teleoconch translucent white, protoconch orange. Operculum and soft parts Unknown. VARIABILITY Species not very variable (See Table 1 and Appendix 14), only four specimens examined, two adults, one sub-adult and one juvenile. Maximum dimensions: height 3.13 mm, width 2.05 mm (from South coast of Rurutu). The number of axial ribs and spiral cordlets on the last whorl, are respectively 35-57 and 22-35. REMARKS Benthonellania maestratii n. sp. resembles some European species of Alvania: A. stenolopha Bouchet & Warén, 1993, A. adiaphoros Bouchet & Warén, 1993, A. microstriata Hoenselaar & Goud, 1998 and A. seinensis Gofas, 2007. It is easily distinguished from all those species, in its more convex whorls and the multispiral protoconch of 2.25-2.3 whorls vs paucispiral protoconch of 1.4, 1.5, 0.9-1.0 and 1.25 whorls respectively (see Bouchet & Warén 1993: 652-653, figs 1447, 1482-1487, 1516; Hoenselaar & Goud 1998: 91, figs 44-47; Gofas 2007: 795, figs 7E-H). Alvania nicobarica (Thiele,1925) [described as Rissoa (Alvania) nicobarica by Thiele (1925: 86, pl. 6, fig. 30) (MolluscaBase 2021f)] differs from B. maestratii n. sp. for the smaller size (0.95 mm in height and 0.7 mm in width vs 2.5-3.12 mm and 1.62-2.07 in width in B. maestratii n. sp.), the lower height/ width ratio (1.357 vs 1.507 -1.538 in B. maestratii n. sp.) and for the protoconch described without sculpture vs protoconch with abapical cordlets and microsculpture in B. maestratii n. sp. Benthonellania listera (Dall, 1927) [Rissoa listera Dall, 1927: 117], from the Atlantic Ocean differs from B. maestratii n. sp. in its more slender outline with less convex whorls; the crown formed by the subsutural thickening of the axial ribs vs absent in B. maestratii n. sp.; the umbilical chink absent vs present in B. maestratii n. sp. (see also the drawing of one syntype by Moolenbeek & Faber 1991: 53). Benthonellania maestratii n. sp. is also similar to Benthonellania colombiana (Romer & Moore, 1988) n. comb., but the latter differs in its smaller size (height 1-1.3 mm vs height 2.5-3.13 mm in B. maestratii n. sp.), fewer axial ribs (26 vs 35-57 in B. maestratii n. sp.), different spiral sculpture (subsutural groove and 7-9 cords vs 22-35 fine cords in B. maestratii n. sp.); protoconch with two spiral cordlets, one finer and median, the other suprasutural with a zigzagging pattern, and with tubercles scattered over the entire surface vs protoconch II with abapical cordlet, the rest of surface covered with delicate lace-shaped structures with wavy and oblique spirals in B. maestratii n. sp.Published as part of Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2022, Deep-water Rissoidae of the genera Benthonella Dall, 1889 and Benthonellania Lozouet, 1990 (Gastropoda, Caenogastropoda, Rissooidea) from French Polynesia, pp. 335-389 in Zoosystema 44 (12) on pages 373-377, DOI: 10.5252/zoosystema2022v44a12, http://zenodo.org/record/679484
Mitromorpha (Mitrolumna) cossyrae Amati, Smriglio & Oliverio, 2015, n. sp.
No full textMitromorpha (Mitrolumna) cossyrae n. sp. (Figs 17; 21 A–D; 28 H) Type material. Holotype, Off Pantelleria Is., Central Mediterranean Sea, - 430 m, Marco Oliverio leg., (MNHN IM- 2000-27712) (Fig. 21 A–D; 28 H). Type locality. Off Pantelleria Is., Central Mediterranean Sea, - 430 m. Etymology. After the ancient Greek-Latin name of Pantelleria Is. (Kossoura or Cossyra). Distribution and habitat. Known only from the type locality, off Pantelleria Is., Central Mediterranean Sea. Recent, although a possible fossil origin (from a reworked assemblage) cannot be ruled out. Only one empty shell in bioclastic sediment, from 430 m depth. Found sympatric, often at different depths, with M. columbellaria and M. karpathoensis. Description. Holotype: Shell of medium size for the genus (Fig. 21 A–D), height 8 mm, width 3.3 mm, solid, fusiform, biconic, rather slender, H/W= 2.424. Protoconch paucispiral (Fig. 28 H), shiny, of 1.3 barely convex whorl, d 0.30 mm, Do 0.475 mm, DM 0.65 mm, h 0.50 mm, sculptured by sparse rare microgranules. Protoconchteleoconch boundary well marked, flexuose, opisthocline. Teleoconch of da 4.8 convex whorls, first two whorls more convex. Sculpture starting with 4 spiral cordlets crossed by 17 axial opisthocline ribs on the first whorl. Third cordlet more pronounced giving a keeled outline to the first two whorls. Additional spiral cordlets between the adapical ones, and between the suprasutural one and the suture. Last whorl sculptured over the entire surface by 29 fine spiral cordlets, equidistant, of equal size, half as broad as the interspaces, of which 9 above the aperture. Axial ribs (16–17) present only on the first 2.5 whorls. Axial ribs of variable strength producing weak nodules at the intersection with the spirals. Two weaks well spaced columellar folds, the posterior with a slightly bifid outer tip (Fig. 6 D). Growth lines visible over the entire surface. Outer lip sharp, thickened internally with 10 elongated denticles, disposed in pairs. Anal sinus shallow. Siphonal canal short, and wide. Coloration light beige in the background, with darker vertical flammulae, and intense darker subsutural blotches. Soft parts unknown. Remarks. We would normally be rather reluctant in describing a new species based on a single specimen. However, the holotype of M. cossyrae n. sp. is so distinct with its rather slender shell (H/ W 2.424) and the spiral sculpture, regularly spaced apart and more pronounced than the axial one that it could not be considered an anomalous specimen of any of the other species. M. bogii n. sp. (Figs 19 A–L; 27 N) has a lower H/W (1.956–2.407), has a smaller number of axial ribs on the first whorl (14 v. 17 in M. cossyrae n. sp.) and a denser and less pronounced spiral sculpture. M. olivoidea (Figs 8 A–O; 9 A–E; 27 G) has a lower H/W (2.021–2.306), smaller apical diameters, more spirals on the last whorl (34– 39 v. 29 in M. cossyrae), 3 spirals on the first whorl (v. 4).Published as part of 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, pp. 151-195 in Zootaxa 3931 (2) on pages 176-177, DOI: 10.11646/zootaxa.3931.2.1, http://zenodo.org/record/23842
Alvania prosocostata Amati & Giulio & Oliverio 2023, n. sp.
No full text<i>Alvania prosocostata</i> n. sp. <p>(Figs 16; 17; 49B; 53E; Tables 1; 2)</p> <p>urn:lsid:zoobank.org:act: F00C4E5C-4A4E-407B-8D50-FEEB9E99589B</p> <p> TYPE MATERIAL. <i>—</i> <b>Holotype.</b> Gambier • dd (height 2.05 mm, width 1.2 mm, Figs 16 A-D; 17A-C; 53E); Taraururoa; 23°6’25”S, 134°51’43”W; 1-3 m; J. Letourneux leg.; MNHN-IM-2000-38708.</p> <p> <b>Paratypes. Gambier</b> • 5 dd (Fig. 16 E-J); same data as holotype; MNHN-IM-2000-38709.</p> <p> TYPE LOCALITY. <i>—</i> Gambier, Taraururoa; 23°6’25”S, 134°51’43”W; 1- 3 m.</p> <p> OTHER MATERIAL EXAMINED. <i>—</i> <b>Gambier</b> • 6 dd; Mangareva, Rikitea; 23°6’39”S, 134°58’1”W; beached; coll. JL • 8 dd; Mangareva, Rikitea; 23°6’39”S, 134°58’1”W; beached; coll. MB • 2 dd; Mangareva, Taku; 23°4’58”S, 134°56’56”W; 1-3 m; coll. JL • 8 dd; Tenoko; 23°4’26”S, 135°0’35”W; 1-3 m; coll. JL • 10 dd; Tenoko; 23°4’26”S, 135°0’35”W; 1-3 m; coll. JL • 5 dd; Totegegi; 23°5’2”S, 134°52’58”W; 1-3 m; coll. JL.</p> <p> <b>Australes •</b> 2 dd; Rapa, Pararaki; 27°36’46”S, 144°19’1”W; beached; coll. MB.</p> <p> DISTRIBUTION AND SYMPATRY. <i>—</i> The species is known in the South Pacific Ocean from the Gambier and Australes (Pararaki Bay, Rapa), with only empty shells collected in 1-3 m depth (Fig. 49B).</p> <p> <i>Alvania prosocostata</i> n. sp. is sympatric with <i>Alvania herosae</i> n. sp. and <i>Alvania uapou</i> n. sp. in the Australes (Rapa); with <i>Alvania herosae</i> n. sp. in the Gambier (Table 2).</p> <p> ETYMOLOGY. <i>—</i> From the Greek πΡόσω, forward, and the Latin <i>costatus</i>, ribbed; for the prosocline inclination of the axial ribs.</p> <p> DIAGNOSIS. <i>— Alvania</i> with medium sized and robust shell; protoconch paucispiral; teleoconch with faint spiral sculpture on the body-whorl, well marked on the base; 3 spiral cordlets starting after protoconch-teleoconch boundary; prosocline axial ribs; colouration uniform dark brown with two whitish spots on the aperture (specimens from Gambier) or yellowish with small whitish spots scattered on the teleoconch, dark spot on the last whorl before the varix, columellar lip brown (specimens from Australes).</p> <p>DESCRIPTION OF HOLOTYPE</p> <p> <i>Shell (Figs 16 A-C; 17A; 53E)</i></p> <p>Small for the genus, height 2.05 mm, width 1.2 mm, height/ width ratio 1.71, robust, ovate-conical.</p> <p> <i>Protoconch (Figs 16D; 17B, C)</i></p> <p>Paucispiral, with nucleus moderately intorted, of 1.25 rather convex whorls, height 0.237 mm, nucleus diameter 0.112 mm, first half whorl diameter 0.225 mm, maximum diameter 0.325 mm, nucleus with weak discontinuous sculpture, the remainder with five or six thin, irregular, very fragmented and widely spaced spiral threads. Protoconch-teleoconch boundary scarcely marked, prosocline.</p> <p> <i>Teleoconch</i></p> <p>Of 3.5 slightly convex whorls, suture impressed, canaliculated. Axial sculpture on the last whorl of 24 prosocline ribs slightly narrower than interspaces, abruptly interrupting on the first basal spiral cordlet. Spiral sculpture of 13 flat cordlets on the last whorl, 6 above the aperture very faint, one on the suture line and 6 on the base more marked. Cordlets I and VI separated from other cordlets with a more marked groove. Cordlets I, II and VI starting immediately after the protoconch-teleoconch boundary. Microsculpture of growth lines and very faint, minute spiral threads (Fig. 17B, C). Umbilical fissure absent. Aperture piriform, height 0.90 mm, height/aperture height ratio 2.28, peristome continuous, outer varix broad and rather thick; outer lip sharp, internally smooth, prosocline.</p> <p> <i>Colour</i></p> <p>Colouration of teleoconch uniform dark brown with two whitish spots on the aperture: one median, the other basal.</p> <p> <i>Operculum and soft parts</i></p> <p>Unknown.</p> <p>VARIABILITY</p> <p>Height 1.77-2.05, width 1.10-1.25; height/width ratio 1.56- 1.71. Axial ribs on the last whorl 22-29. Colouration varies in the intensity of the background from dark brown to white. Two specimens from the Australes (numbers 8 and 9 in Appendix 5) have the inclination of the axial ribs less accentuated, the protoconch more densely sculptured (Fig. 17D) (see Table 1 and Appendix 5) and cordlets I, II and VII starting immediately after the protoconch-teleoconch boundary; colouration yellowish background with small whitish spots, dark blotch on last whorl before the varix. Columellar lip brown. (See Table 1 and Appendix 5).</p> <p>REMARKS</p> <p> <i>Alvania prosocostata</i> n. sp. is very similar to the European species of the group of <i>Alvania lineata</i> Risso, 1826 (Amati <i>et al.</i> 2019), and in particular to the Mediterranean <i>Alvania schwartziana</i> Brusina, 1866 for the similar outline, robustness of the shell and in particular for the uniform brown colour (Brusina 1866: 25, pl. III, fig. 9; Amati <i>et al.</i> 2019: fig. 57). The most evident differences are in the larger size (height <i>c</i>. 4 mm vs <i>c</i>. 2 mm in <i>A. prosocostata</i> n. sp.); in the sculpture of the paucispiral protoconch (1.3 whorls, maximum diameter 0.511 mm, sculptured by <i>c.</i> 12 undulated spiral cordlets, also on the nucleus vs 1.25 rather convex whorls, maximum diameter 0.325 mm, with nucleus moderately intorted and smooth, the remainder with five or six thin, irregular, very fragmented and widely separated spiral threads in <i>A. prosocostata</i> n. sp.); and for the inclination of the axial ribs (orthocline vs prosocline in <i>A. prosocostata</i> n. sp.).</p>Published as part of <i>Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2023, Shallow-water Rissoidae of the genera Alvania Risso 1826 Haurakia Iredale 1915 Parashiela Laseron 1956 Simulamerelina Ponder 1985 and Subestea Cotton 1944 Gastropoda Caenogastropoda Rissooidea from French Polynesia with the description of a new deep-water genus, pp. 803-892 in Zoosystema 45 (25)</i> on pages 821-824, DOI: 10.5252/zoosystema2023v45a25, <a href="http://zenodo.org/record/10458066">http://zenodo.org/record/10458066</a>
Benthonellania africana Amati & Giulio & Oliverio 2022, n. comb.
No full textBenthonellania africana (Thiele, 1925) n. comb. (Figs 8 A-N; 9C, D; 13A; 26G; Table 1) Rissoa africana Thiele, 1925: 83, pl. 6, figs 20-22. TYPE MATERIAL. — Lectotype. Somalia • dd (height 3.85 mm, width 2.15 mm, here designated, Figs 11 A-C; 13A, B); Valdivia Stn 251; 1°40.6’S, 41°47.1’E; ZMB/Moll. no. 64955a. Paralectotypes • 223 dd (comprising 34 shells of Benthonellania africana n. comb. and 199 shells of Benthonellania thielei n. sp.); same locality data as lectotype; ZMB /Moll. no. 64955b. There might be also material from Valdivia, Stn 245; 5°27.9’S, 39°18.8’E; 463 m depth (Zanzibar) that we have not examined. DISTRIBUTION AND SYMPATRY. — Benthonellania africana n. comb. is known from East Africa (off Somalia and possibly Zanzibar) 693 m depth. Benthonellania africana n. comb. is sympatric with Benthonellania thielei n. sp. at its type locality, off Somalia, and possibly with Benthonellania aequistriata at Zanzibar (fide Thiele) (Fig. 13). DESCRIPTION OF LECTOTYPE Shell (Figs 8 A-C; 9C, D) Large for the genus, height 3.85 mm width 2.15 mm, height/ width ratio 1.790, rather solid, ovate-conical. Protoconch (Figs 8J, K; 9D) Dome-shaped, paucispiral,of 1.4 whorls, height 0.375 mm, nucleus diameter 0.200 mm, first half whorl diameter 0.362 mm, maximum diameter 0.525 mm, glossy, smooth, except for a faint and confused spiral sculpture on the nucleus (Fig. 9D). Protoconch-teleoconch boundary barely visible. Teleoconch Of 4.1 very slightly convex whorls, suture canaliculate, crowned by small tubercles at tips of axial ribs, highlighted by a slight subsutural depression. Height last whorl 2.50 mm, height/ height last whorl ratio 1.540. Axial sculpture of 9 ribs on last whorl, as broad as the interspaces, prosocline and slightly curved, curvature more pronounced on last whorl, gradually vanishing at the base; last half whorl progressively devoid of axial sculpture. Spiral sculpture of 4 very weak cordlets on last whorl above the aperture and on the suture line, the uppermost suprasutural visible on all whorls, base smooth (Fig. 8N). Microsculpture of only growth striae. Umbilical chink conspicuous. Aperture pyriform, large, height 1.55 mm, height/height aperture ratio 2.483, peristome continuous, varix absent. Thin lip with prosocline inclination. Columella arcuate, simple. Colour Coloration of teleoconch and protoconch translucent, white. Operculum Thin, light yellow with an eccentric nucleus. Soft parts Unknown. VARIABILITY Species not very variable (See Table 1 and Appendix 5). It reaches 4 mm in height and 2.35 mm in width; height/width ratio 1.574 -1.860; number of axial ribs on the last whorl: 8-10. Maximum diameter of the protoconch 0.575 mm. REMARKS Rissoa africana Thiele, 1925 is currently classified in Haurakia based on Ponder (1985: 30). Ponder (1985) also considered Rissoa africana and R. aequatorialis as synonyms (selecting Pusillina (Haurakia) africana as senior one, as first reviser).This is clearly a member of Benthonellania, with its shell with canaliculate suture, crowned by small tubercles at the tips of axial ribs, enhanced by a slight subsutural depression. We accordingly propose Benthonellania africana (Thiele, 1925) n. comb. as a new combination for Rissoa africana Thiele, 1925. Cithna africana Bartsch, 1915 (taxon inquirendum: MolluscaBase 2021e) from South Africa, has a small shell (height 0.7 mm, width 0.7 mm), devoid of sculpture, and cannot be classified either in Benthonella or in Benthonellania (see Bartsch 1915: 120, pl. 21, fig. 5). The examined type material of Rissoa africana, comprises two distinct species: one (corresponding to Thiele 1925: fig. 20) has a rather thick shell, more or less slender profile, spiral sculpture of 3-4 very weak cordlets on the last whorl above the aperture and on the suture line and a crown of small tubercles at tip of axial ribs, paucispiral protoconch smooth, except for a faint and confused spiral sculpture on the nucleus; 199 shells (corresponding to Thiele 1925: figs 21, 22) belong to a distinct species that we describe below as B. thielei n. sp. To stabilize the use of the name, the lectotype of Rissoa africana Thiele, 1925 is herein designated on a specimen of the first form. Benthonellania africana n. comb. differs from B. hertzogi n. comb. by its higher height/width ratio (1.574 -1.860 vs 1.250 -1.400 in B. hertzogi n. comb.), the lower axial ribs in B. hertzogi n. comb. and the presence of a very fine subsutural thread on first two teleoconch whorls in B. hertzogi n. comb., absent in B. africana n. comb. See under, Benthonellania thielei n. sp., Benthonellania aequatorialis n. comb. and Benthonellania alis n. sp. for diagnostic comparison.Published as part of Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2022, Deep-water Rissoidae of the genera Benthonella Dall, 1889 and Benthonellania Lozouet, 1990 (Gastropoda, Caenogastropoda, Rissooidea) from French Polynesia, pp. 335-389 in Zoosystema 44 (12) on page 351, DOI: 10.5252/zoosystema2022v44a12, http://zenodo.org/record/679484
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