Boetersiella Arconada and Ramos, 2001

Arconada, B. & Ramos, M. A., 2001, New data on Hydrobiidae systematics: two new genera from the Iberian Peninsula, Journal of Natural History 35 (7), pp. 949-984 : 954-955

Boetersiella Arconada and Ramos new genus

Type species Paludina sturmi Rosenhauer, 1856 .

Etymology

This genus is dedicated to Dr Hans D. Boeters for his early studies of the hydrobiid malacological fauna of the Iberian Peninsula.

Diagnosis

Shell. Depressed trochiform or valvatiform. The external surface of the protoconch is smooth, or slightly marked punctum-like sculpture. The teleoconch is smooth with ®ne growth lines. Oval frontal aperture with a thick columellar border that leaves a slit-like umbilicus. Thin outer lip. The peristome is slightly oblique and adapically sinuated.

Operculum. Corneus, thin, oval, usually orangish, paucispiral with a submarginal nucleus. The internal callus is usually large and well developed.

Nervous system. Typically hydrobiid with a long supraoesophagea l and very short suboesophageal connective (®gure 4A). Each pedal ganglion is linked to the cerebral ganglion and to the pleural ganglion by long connectives. The oesophagus runs straight along the cerebral ganglia.

Radula. Typically taeniaglossan. It has a trapezoidal central tooth with lateral wings that have one basal cusp on each side, arising from the lateral margins and not pointing towards the centre of these teeth. The central tooth has a squared basal tongue as long as the lateral margins; the excavation of its base is more than 50% of tooth height. It has a central blunted cusp and on each side a variable number of small cusps. The upper border of the cutting edge of the central teeth is strongly U-shaped. The face of the lateral teeth is rectangular. The cusps of the inner marginal teeth are uniformly distributed and are larger than those of the outer marginal teeth.

Non-genita l anatomy. The ctenidium is totally absent (®gures 4C, 10C, D). There is an osphradium of intermediate width located near the neck, very close to the inner border of the mantle cavity. Pallial tentacle absent. The tentacles are about eight times as long as wide, parallel-sided; the distal end is not expanded and has a totally unpigmented tip. The eyelobe is weakly developed and there are white iridescent granules around the eyes. The foot sole is unpigmented. The buccal mass is large relative to the snout. The posterior chamber of the stomach is rounded, does not have an external caecum and is slightly smaller than the anterior chamber (®gure 4E). It has a single opening to the digestive gland, which is lobed and extends from the posterior chamber of the stomach to the end of the body. In the pallial cavity, the rectum forms an open U-shaped loop inclined towards the prostate or towards the pallial gland and ending very close to the edge of this cavity (®gure 3A, B). The faecal pellets are oval and yellowish. The intestine adheres to the wall of the style sac forming a U-shaped loop from which the style sac slightly protrudes (®gure 4E). The kidney is longitudinal and is located completely behind the pallial cavity, between the prostate gland or pallial oviduct and the style sac (®gure 3B).

Female genital system. The ovary occupies more than 66% of the visceral coil posterior to the stomach (®gure 3B). It is a simple globular mass of vitellogenic oocytes, included in the ovarian follicles. The renal oviduct is unpigmented and forms a simple and open circular loop. The capsule gland constitutes more than half of the pallial oviduct, it is yellowish and frequently has black spots on its surface. The bursa copulatrix clearly protrudes at the end of the pallial oviduct. There is no RS1 but an elongated and non-pedunculate RS2 which, in natural position, leans over the bursa copulatrix.

Male genital system. The testis has simple, stalked lobes and occupies more than 66% of the visceral coil. Its anterior lobes overlap the posterior chamber of the stomach (®gure 3A). The anterior coils of the seminal vesicle also overlap the stomach and enter the prostate gland in its middle zone (®gure 4D). The vas eOEerens and seminal vesicle can be clearly seen because of the iridescent colour of the sperm. The prostate gland extends to the pallial wall at approximatel y one-half of its length and is typically bean-shaped. The pallial vas deferens exits near its anterior end (®gure 4D). The penis is inserted in the middle right part of the head, behind the base of the right tentacle. It is simple, unpigmented, cylindrical in transverse section and gradually tapered towards the tip. The base of the penis is widened in relation to its distal part.