Boetersiella davisi 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 : 964-967

Boetersiella davisi Arconada and Ramos new species

(®gures 9A±H, 10A±D, 11A±F, 12A±D; tables 1±4)

Material examined

HOLOTYPE. MNCN. 15.05 / 33139 (gold-coated SEM mount) (®gure 9A).

PARATYPES. Durcal ( Granada), Pilar del Mono spring, UTM: 30SVF493951 , 24 September 1989, E. R., MNCN. 15.05 / 33141 (ethyl alcohol material) ; 25 September 1989, E. R., D.M., C.A., MNCN. 15.05 / 33140 (dried material, ethyl alcohol material and gold-coated SEM mount) ; 15 October 1990, D.M., MNCN. 15.05 / 33138 (ethyl alcohol material and gold-coated SEM mount) ; 8 February 1992, D.M, N.M., MNCN. 15.05 / 33139 (dried material, ethyl alcohol material and goldcoated SEM mount) ; 27 March 1998, B.A., MNCN. 15.05 / 33142 (ethyl alcohol, frozen material and gold-coated SEM mount). MZUF: 17999 (two paratypes), MNHN (two paratypes), SMF: 312502 (two paraypes), NNM: 59382 (two paratypes). Padul ( Granada), El Mal Nombre spring, UTM: 30SVF445963 , 27 March 1998, B.A., MNCN. 15.05 / 33143 (ethyl alcohol, frozen material and gold-coated SEM mount) .

Type locality. Durcal ( Granada), Pilar del Mono spring, UTM: 30SVF493951.

Etymology. This species is dedicated to Dr George M. Davis to acknowledge his contribution to hydrobiid taxonomy and his helpful advice.

Morphology

Shell (®gure 9A±H, table 1). The shell is dextral, valvatiform, very small, almost as tall as it is wide and has 3±3.5 whorls. The shape of the aperture can vary from roundish (®gure 9C) to oval with marked angulation in its upper part (®gure 9A). The body whorl length is more than three-quarters of shell length. The inner lip is very developed and extends towards the umbilicus, overlapping it almost completely and showing a slit-like umbilicus. The protoconch has 1.25 whorls, its total width is around 292 m m and the nucleus width approximately 133 m m. The shells were found with a thick black layer of diatoms and inorganic elements which facilitate its visual identi®cation. The periostracum is yellowish.

Operculum (®gure 10A, B, table 2). Although there is a predominance of orange, there are also specimens with yellowish opercula.

External body feature s (®gure 12A). The head is homogeneousl y pigmented black. There is a central unpigmented streak in the tentacles. The snout is unpigmented and it is occasionally possible to distinguish the radular sac by transparency. Behind the eyes there is a roundish area containing some yellow-refringent granules. The mantle epithelium is darkly black pigmented.

Nervous system (®gure 4A). Although the right and left cerebral ganglia are usually the same size, ocasionally, the right ganglion is smaller and narrower in its central part. In some specimens, the right pleural ganglion is elongated and may be misinterpreted as a connective. RPG ratio: 0.37.

Radula (®gure 11A±F, table 3). Radular ribbon measuring 416 m m with approximately 68 teeth rows. It has a central tooth with one basal cusp on each side. The distance between both cusps is approximately 10 m m. The basal tongue is slightly V-shaped. There is a long, blunt middle cusp and ®ve blunt, smaller denticles on each side, which decrease towards the edge.

Female reproductiv e system (®gure 12C, D, table 4). In general, the capsule gland constitutes more than half the pallial oviduct and the albumen gland is less developed. The epithelium of the capsule gland is slightly dark pigmented. The renal oviduct makes a 360ss loop. The bursa copulatrix is pyriform, well developed and protrudes from the albumen gland. The bursal duct is medium-sized, wide and it is inserted in an anteroventral position.

Male reproductive system (®gures 10C, 12A, B, table 4). The penis has a slightly wider base and is as long as the head. It is simple, narrow and occasionally has a double stripe of black spots in its central part. The penis tip is tapered and its narrow duct is straight but slightly undulates at its basis. One third of the prostate lies in the interior part of the pallial cavity and has, in its anterior part, a thin, black-spotted epithelium. Its length varies considerably among the males observed from the type locality.

Remarks. Boetersiella davisi can be distinguished from B. sturmi in the following characters: the overall size is smaller although proportion between SL / SW remains similar in both species, it has a more marked pit-like protoconch microsculpture, the radular ribbon is shorter and narrower, the basal tongue of the central teeth of the radula tends to be V-shaped, the osphradium is signi®catively smaller, the penis base is longer and the bursa copulatrix is larger and its duct shorter and wider than in B. sturmi .

Habitat and distribution. This species was only found in two springs, situated close together. In the type locality it lives adhered to leaves, branches, mosses and arti®cial substrata such as bricks or cement. Other species and genera found in the same place are: Ancylus sp. , Lymnaea sp. , Melanopsis sp. , Theodoxus sp. , Potamopyrgu s antipodarum (Gray, 1843), Neohoratia schuelei ( Boeters 1981) , Pseudamnicola sp. and Pisidium personatum Malm, 1855 .