Napaeus ornamentatus Moro, 2009

Yanes, Yurena, Martín, Javier, Moro, Leopoldo, Alonso, María R. & Ibáñez, Miguel, 2009, On the relationships of the genus Napaeus (Gastropoda: Pulmonata: Enidae) with the descriptions of four new species from the Canary Islands, Journal of Natural History 43 (35 - 36), pp. 2179-2207 : 2200-2202

Napaeus ornamentatus Moro sp. nov.

Type material

Holotype ( Figures 4F , 7C ): TFMC ( MT 0400 ). Type locality: Mirador de Taguluche (La Gomera; UTM coordinates: 28 RBS7113 ; 800 m altitude). Leg. Javier Martín and Leopoldo Moro, 5 March 2008.

Paratypes: 15 specimens and 26 shells, collected between 1981 and 2009, from western La Gomera ( UTM coordinates: 28 RBS7011 , 28 RBS7016, 28RBS7113, 28RBS7115, 28RBS7116, 28RBS7212, 28RBS7214, 28RBS7319, 28RBS7405, 28 RBS7508 and 28 RBS7609 ), deposited in TFMC ( MT 0136 /1), CML (six shells) and AIT .

Etymology

The specific name derives from the distinctive shell ornamentation.

Geographic range and habitat Ground dweller endemic to La Gomera, with a distribution area of about 60 km 2 on

the western side of the island, mainly related to lowland vegetation and semi-arid subtropical scrub and palm grove, ranging in altitude from 175 to 1000 m ( Figure 1B ).

Diagnosis

Shell elongated ovate–cylindrical, cone-shaped above. Protoconch very fragile. Teleoconch heavily ornamented with strong, laminar, prominent and irregularly undulating radial oblique ribs. Shell colour tan brown, with first whorls slightly darker than the rest. Epiphallus without epiphallar caecum. Bursa copulatrix duct without diverticulum.

Description

Shell ( Figures 7C, E ) obese (SB/SH index), elongated ovate–cylindrical, cone-shaped above, 7–7½ convex whorls, deeply marked suture. Body whorl intermediate (BH/SH index), protoconch smooth, shiny, with 1½–1¾ whorls. Protoconch very fragile, broken in many shells and living specimens. Aperture short, wide (AH/SH and AB/SB indices, respectively), with elliptical section at palatal side, rounded at union of columellar and palatal edges. Upper palatal side forms angle slightly less than 90º with parietal side, aperture juts out only slightly from body whorl beginning. Whitish discontinuous peristome expanded as lip, more developed in lower part of palatal edge, reflected in columellar edge, where it partially covers umbilical slit. Older specimens with callosity between peristome edges, nodule at union of parietal–palatal area.

Shell colour dark brown, first teleoconch whorls slightly darker than rest. Heavily ornamented teleoconch characterized by strong, laminar, prominent, irregularly undulating, sometimes interrupted radial oblique ribs ( Figures 7C, E , 10D ). Ribs of body whorl more regularly located.

Genital system ( Figure 11B ; five specimens dissected). Atrium very short. Penis mainly tubular, slightly longer than A 1 portion of penial appendix. Penis with three portions, distal portion located between atrium and insertion of the penial retractor muscle; proximal portion small, slightly widened, with incipient penial papilla; intermediate portion slender, tubular, slightly longer than distal portion. Epiphallus long, tubular, without epiphallar caecum, opening distally on penis. Flagellum short. Vas deferens opens laterally on proximal end of epiphallus. Penial appendix arises near distal end of penis, is longer than penis and epiphallus together. A 1 penial appendix portion similar in length to penis. Appendicular retractor muscle inserted laterally, at certain distance of proximal top of A 1 portion; insertion on diaphragm walls very close, but not fused to penial retractor. Free oviduct slightly longer than vagina. Bursa copulatrix complex without diverticulum.

Remarks

Shell morphology. Within the conchological group of N. variatus , the shell of N. ornamentatus sp. nov. ( Figure 4F ) is quite similar in form and size to that of N. propinquus ( Figure 4E ), and also comparable with that of N. maffioteanus ( Figure 5A ), although the latter species is more cylindrical. The first whorls of N. ornamentatus and N. propinquus are smaller than those of N. maffioteanus ( Figure 6G ). The body whorl and the aperture of N. ornamentatus and N. maffioteanus are similar in form and size but smaller than those of N. propinquus ( Figure 6H ). The main difference between N. ornamentatus and the other two species is in the shell ornamentation, which is smooth and not strongly developed in N. maffioteanus and N. propinquus ( Figures 12E and 12F , respectively), in contrast to that of N. ornamentatus ( Figure 10D ). Besides, N. ornamentatus has a high protoconch.

Genital system anatomy. The genital systems of N. ornamentatus and N. propinquus are similar in shape and dimensions but N. propinquus has an epiphallar caecum that is absent in N. ornamentatus . The genital system of N. maffioteanus has an epiphallar caecum and also a well-developed diverticulum in the bursa copulatrix complex, whereas N. ornamentatus lacks both structures.

Figures

Figure 1. (A) Geographical location of the Azores, Madeira and the Canaries; arrows indicate possible colonization patterns used by land snails; position of sea mounts comes from Van den Broeck et al. 2008; (B) geographical distribution of the Napaeus species; symbols represent 1×1 km Universal Transverse Mercator squares; arrow points to the Pleistocene deposit from Mancha de La Laja-Bajamar, where the oldest Napaeus species (N. lajaensis) has been collected (Castillo et al., 2006).

Figure 4. Napaeus shell drawings. (A) N. tenoensis (holotype, AIT); (B) N. bajamarensis sp. nov. (holotype, TFMC MT 0397); (C) N. boucheti (holotype, AIT); (D) N. obesatus; (E) N. propinquus; (F) N. ornamentatus sp. nov. (holotype, TFMC MT 0400); (G) N. orientalis (holotype, AIT); (H) N. ocellatus (syntype, ZMZ 513767); (J) N. rupicola; (K) N. avaloensis (holotype, TFMC MT 0382); (L) N. maculatus (holotype, TFMC MT 0386); (M) N. helvolus; (N) N. voggenreiteri (holotype, TFMC MT 0384); (O) N. isletae (holotype, AIT); (P) N. variatus; (Q) N. encaustus; (R) N. moquinianus; (S) N. teobaldoi sp. nov. (holotype, TFMC MT 0399); (T) N. lajaensis (holotype, TFMC MT 0381); (U) N. procerus (holotype, TFMC MT 0385); (V) N. rufobrunneus.

Figure 5. Napaeus shell drawings. (A) N. maffioteanus; (B) N. chrysaloides; (C) N. indifferens; (D) N. huttereri (holotype, AIT); (E) N. elegans (holotype, AIT); (F) N. esbeltus (holotype, AIT); (G) N. exilis (holotype, AIT); (H) N. subgracilior; (J) N. osoriensis; (K) N. palmaensis (syntype, NHM 1895.2.2.219); (L) N. myosotis; (M) N. lichenicola (holotype, TFMC MT 389); (N) N. gruereanus; (O) N. barquini (holotype, TFMC MT 0383); (P) N. roccellicola; (Q) N. beguirae (holotype, AIT); (R) N. nanodes; (S) N. doliolum (paratype, AIT); (T) N. bechi (holotype, AIT); (U) N. texturatus; (V) N. taguluchensis (holotype, AIT); (X) N. tagamichensis (paratype, AIT); (Y) N. pygmaeus (holotype, AIT).

Figure 6. Scatter plots of some shell measurements for the new species and the nearest species of their respective conchological group. AH, aperture height; AS, aperture surface (plane view); FH, first whorls height; FP, first whorls perimeter; FS, first whorls surface (plane view); SB, shell breadth; SH, shell height.

Figure 7. Holotype shells (A–D) and a specimen (E). (A) N. bajamarensis sp. nov.; (B) N. tafadaensis sp. nov.; (C) N. ornamentatus sp. nov.; (D) N. teobaldoi sp. nov.; (E) N. ornamentatus, paratype from Mirador de Taguluche (L. Moro photograph).

Figure 10. Holotype shell ornamentation details of the penultimate whorl (A, B, D, E) and that of the body whorl columellar zone, near the peristome (C). (A) N. bajamarensis sp. nov.; (B–C) N. tafadaensis sp. nov.; (D) N. ornamentatus sp. nov.; (E) N. teobaldoi sp. nov.; (F) shell ornamentation detail of the penultimate whorl of N. badiosus, from Barranco de Valle Seco (Tenerife); pt, peristome.

Figure 11. Genital system. (A) N. tafadaensis sp. nov., paratype from Montaña Tafada; (B) N. ornamentatus sp. nov., paratype from Mirador de Taguluche; (C) N. teobaldoi sp. nov., paratype from Barranco Hondo. A1, A5, parts of the penial appendix; ag, albumen gland; bc, bursa copulatrix; di, diaphragm; dp, distal penis; e, epiphallus; ec, epiphallar caecum; f, flagellum; go, genital orifice; o, free oviduct; par, penial appendix retractor; pp, proximal penis; v, vagina; vd, vas deferens.

Figure 12. Shell ornamentation details of the penultimate whorl (A–C, E, F) and that of the two last whorls (D). (A) N. tenoensis holotype, from Tamargo (Tenerife); (B) N. boucheti holotype, from Llano del Lance (La Palma); (C) N. obesatus, from La Milagrosa (Gran Canaria); (D) N. tabidus, from La Laguna (Tenerife); (E) N. maffioteanus, from Barranco de La Aldea (Gran Canaria); (F) N. propinquus, from Barranco de Las Galgas (Tenerife).