Pseudamnicola (Pseudamnicola) gasulli, BOETERS, 1981

Delicado, Diana, Machordom, Annie & Ramos, Marian A., 2014, Vicariant versus dispersal processes in the settlement of Pseudamnicola (Caenogastropoda, Hydrobiidae) in the Mediterranean Balearic Islands, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 171 (1), pp. 38-71 : 64-66

PSEUDAMNICOLA (PSEUDAMNICOLA) GASULLI BOETERS, 1981 ( FIGS 16–18 )

Type locality

Hotel Fenicia, Santa Eulalia, Ibiza ( Boeters, 1981).

Type material

Holotype SMF 253582 ; paratypes SMF 253583 /1, RMNH, GAS, and BOE 856 and 929.

Other populations studied

After several visits to the area surrounding the Hotel Fenicia (type locality), we did not find the species either in the Santa Eulalia River or in a wetland situated near the hotel. We also did not find this species in the Rambla locality from Puerto de la Cadena in Murcia province, Spain ( Suárez & Vidal-Abarca, 1983; Boeters, 1988). However, this species was eventually found and collected in several locations from Almería province ( Spain) (see Supporting Information Appendix S1).

Material examined for morphometry

Shell, anatomical, operculum, and radular measurements were taken from specimens collected at two localities, both located in Almería province ( Spain): at Retamar Rambla and a stream at Barranco de las Negras. Both males and females were dissected and measured (Appendix S2: Tables S1–S 7).

Diagnosis

Shell ovate-conic, yellowish with body whorl occupying two-thirds of shell length; whorls convex with deep sutures; protoconch microsculpture granulated; central radular tooth formula 4(5)−C−4(5); pigmented intestine; pyriform bursa copulatrix with a duct approximately one and a half times longer than bursal length; absence of seminal receptacle; prostate gland twice as long as wide; strap-like penis dark pigmented, with a narrow base attached to central area of head; nervous system brown pigmented with supraoesophageal connective about five times longer than suboesophageal.

Description

Shell ovate-conic ( Fig. 16A–C ), yellowish periostracum with 4–5.5 spire whorls, and a height of between 2.0 and 4.0 mm (Appendix S2: Table S1); protoconch approximately 375 μm wide with 1.5 whorls and a nucleus around 100 μm long ( Fig. 16E, F ); protoconch microsculpture granulated ( Fig. 16G ); body whorl about two-thirds of the total length; whorls convex with deep suture; peristome frontal, complete, oval, with thick inner lip partially hiding umbilicus; outer peristome simple, straight ( Fig. 16D ).

Operculum corneous, yellowish, thin, pliable, ellipsoidal, paucispiral, with nucleus submarginal ( Fig. 17A, B ; Appendix S2: Table S2); oval muscle attachment near nucleus.

Radula medium in size (15% total shell length) with around 50 rows of teeth, ( Fig. 17C ; Appendix S2: Table S3); central tooth with a pointed median cusp and four or five pointed lateral cusps ( Fig. 17D, E ); lateral teeth with a long, tongue-shaped median cusp and four tapered lateral cusps; inner and outer marginal teeth bear approximately 20 and 22 sharp cusps, respectively ( Fig. 17D, F ).

Pigmentation and anatomy

Head intensely brown pigmented from snout to neck except around ocular lobes ( Fig. 18F ); pigment on neck less pigmented than on head; tentacles pigmented except along a longitudinal stripe; snout as long as wide, with medial lobation; foot of intermediate length, pigmented on dorsal region. Ctenidium in the anterior region of pallial cavity with about 18–23 gill filaments; osphradium ellipsoidal under central gill filaments ( Fig. 18C , Appendix S2: Table S4). Stomach slightly longer than wide (Appendix S2: Table S4); style sac slightly shorter than stomach, surrounded by the intestine, slightly pigmented in its proximal part ( Fig. 18E ).

Female genitalia with a pallial oviduct about three times longer than wide ( Fig. 18G , Appendix S2: Table S5); capsule gland and albumen gland similar in size; the capsule gland is thicker in posterior region; pyriform bursa copulatrix with a duct approximately one and a half times longer than bursa length; in some specimens, bursal duct has a thickening of the duct in its mid-section; renal oviduct black pigmented until loop and very coiled; absence of seminal receptacle ( Fig. 18H ).

Male genitalia bear a bean-like prostate gland about two times longer than wide ( Fig. 18D , Appendix S2: Table S6); strap-like penis with black pigment in the middle region and a narrow base attached to central area of head ( Fig. 18F ); coiled penis observed in some living specimens; uncoiled vas deferens running straight, close to the external margin.

Nervous system brown pigmented, cerebral ganglia equal in size and darker than other ganglia, connectives and commissures; supraoesophageal ganglion larger than suboesophageal; supraoesophageal connective around five times longer than suboesophageal ( Fig. 18A, B ; Appendix S2: Table S7). Mean RPG ratio 0.50 (elongate).

Remarks

In 1981, Boeters described this species from the island of Ibiza. It was also later discovered in the provinces of Almería ( Boeters, 1988) and Murcia ( Suárez & Vidal-Abarca, 1983). After visiting all of these regions, we only found the species in some localities from Almería province; hence, we can only compare anatomical features of the collected specimens from Almería with Boeters’ illustrations. The intraspecific variability is mainly reflected in the sizes of the shell, penis, and bursa copulatrix. Individuals from these localities share characteristics originally described for this species ( Boeters, 1981); that is, an ovate-conic shell, a pyriform bursa copulatrix, the absence of a seminal receptacle, and a strap-like penis with black pigment in the middle region.

These characteristics, especially the absence of a seminal receptacle and the presence of a strap-like penis, make P. (P.) gasulli exceptional within the genus as all other Pseudamnicola species share these traits. Another important difference in character state is the size of the prostate gland: P. (P.) gasulli has the smallest prostate gland of any of the species within the genus. Genetically, this species is distant from species of both Pseudamnicola subgenera. For instance, P. (P.) gasulli differs from P. ( Corrosella ) spp. by 11.1% for COI, 8.0% for 16S, and 5.6% for 28S and by 12% for COI, 6.4% for 16S, and 6.4% for 28S from the other Ibero-Balearic P. ( Pseudamnicola ) spp.

Figures

Figure 16. Shells of Pseudamnicola (Pseudamnicola) gasulli. A, shell from a stream at Barranco de las Negras, Almería, Spain. B, shell from Retamar Rambla, Almería, Spain. C–G, shells from a stream at Rambla de los Yesos, Alboloduy, Spain. E–G, protoconch and microsculpture of the protoconch. Scale bar: 1 mm.

Figure 17. Operculum and radula of Pseudamnicola (Pseudamnicola) gasulli from Retamar Rambla, Almería (operculum) and stream at Barranco de las Negras, Almería (radula). A, internal side of the operculum. B, external side of the operculum. C, radula. D, rows of teeth of the radula. E, central teeth. F, outer marginal teeth.

Figure 18. Anatomy of Pseudamnicola (Pseudamnicola) gasulli from a stream at Barranco de las Negras, Almería, Spain. A, B, partial nervous system. C, ctenidium and osphradium. D, prostate gland. E, stomach. F, head and penis of a male. G, female genitalia. H, bursa copulatrix.