Material

Two lots of live-collected shells were obtained recently from commercial shell dealers. One lot of twelve specimens is from Borongan, Samar, and the other lot of 40 specimens reached the author without locality data except >Philippines<. Both lots were mixed with larger quantities of cicercula, margarita and globulus, as well as typical bistrinotata bistrinotata, suggesting that the origin is indeed the Philippines. Since both lots of shells show identical shell features, it is assumed that they were collected in the same area. It is astonishing that despite the vast exploitation of the Philippines Islands, even today shells appear which have never before been illustrated or studied. The new taxon is described here in honor of Dr. Marco Chiapponi of Lecco, who has contributed for a long time to the study of the interesting genus Pustularia.

Pustularia chiapponii n. sp.

Description

Greatly inflated, globular. The extremities are distinctly rostrated but barely margined. The spire is large, somewhat projecting, completely covered by a thick callus. Dorsum and margins are densely granulose; those granules are less distinct towards the middle of the dorsum. There is a deep dorsal groove running longitudinally across the shell, forming a Y-shaped depression bordering the posterior extremity. The posterior terminal callosity is well developed. The aperture is narrow and conspicuously curved to the left in the posterior third.

The teeth on both sides are fine, rather weak, but well defined throughout their way across both labrum and base and far onto the margins on both sides where they meet the dorsal pustules. The posterior labral margin is crossed by the teeth, which thus are visible as spiny processes in the dorsal view. The entire shell is pale yellow, there are no traces of basal blotches, nor is there any staining of the teeth. The yellow color is slightly paler only towards the aperture. There are three barely perceptible darker patches dorsally, which may be interpreted as blotches. These are, however, not separated by the dorsal groove. There are no traces of smaller marginal or dorsal spots.

The paratypes correspond exactly with the holotype, none of the features described above are subject to perceptible variation.

Designated types
Length x width x height (mm), (labral teeth: columellar teeth), depository
Holotype: 19.1 x 12.6 x 11.4 (24 : 22) coll. HDN Cismar
Paratype 1: 19.1 x 12.6 x 11.6 (24 : 18) coll. Chiapponi
Paratype 2: 16.4 x 10.4 x 9.4 (25 : 18) coll. Chiapponi
Paratype 3: 17.7 x 11.5 x 10.2 (24 : 18) coll. Lorenz
Paratype 4: 19.4 x 12.3 x 11.0 (22 : 18) coll. Lorenz
Paratype 5: 18.7 x 11.5 x 10.3 (25 : 19) coll. Lorenz
Paratype 6: 19.7 x 12.3 x 11.0 (25 : 19) coll. Chiapponi
Paratype 7: 17.9 x 11.1 x 9.9 (24 : 18) coll. Chiapponi

Type locality

The only ascertained locality of the new species is Borongan, Eastern Samar Island, Philippines. The habitat is unknown but suspected to be rather shallow water.

Discussion

Pustularia chiapponii belongs to the group of pustulose species without a spire blotch. The only similar species, therefore, is P. bistrinotata from which it differs by the following features: complete absence of basal blotches in all specimens known. There are some specimens of bistrinotata, especially of its Melanesian subspecies mediocris, in which the basal blotches are reduced, incomplete, or even absent. In mediocris, the percentage of specimens without basal blotches is 40% for Solomon populations and 25 % for New Caledonian populations. In 60% of the Solomon specimens and 75% of the New Caledonian specimens, there are at least apparent remnants of basal blotches.

Fig. 1: The characteristic posterior extremity of a Pustularia. Left: P. chiapponii n. sp., right: P. bistrinotata. (SEM photos)

In chiapponii, the teeth are long, extending far across the base and the labrum, they are never interrupted by a callus-bridge, and in no specimen are they shorter mid-way on either side. In none of the populations of bistrinotata are there teeth of comparable length. Furthermore, the teeth meet with the dorsal granules, which are often connected.

In P. bistrinotata, the pustules are usually separate and distinct from each other (Fig. 2). The posterior labral teeth cross the terminal margin (Fig. 1, left). This feature is seen only in exceptional specimens of bistrinotata. All populations of bistrinotata show a brown spotting of the margins as well as the dorsum. Smaller spotting is not developed in chiapponii

. The dorsal blotches characteristic of bistrinotata are almost absent in chiapponii, in which the darker zone is not split in two by the groove mid-dorsally. The spire of chiapponii is large, situated right of the posterior extremity, and despite being covered by callus, is still visible as a slight projection (Fig. 1, right). This is usually not seen in bistrinotata. The distinctly curved aperture is typical in the Polynesian sublaevis but rarely in populations of the Western Pacific. Finally, the general shape of chiapponii differs by being more globular, with the extremities being coarser and rather knobby.

The pale yellow color all over is only found in southeastern Melanesian populations of mediocris, and especially in New Caledonian shells. Those, however, are less inflated, their dorsal groove is indistinct, the basal blotches are faint but visible, the teeth are coarser and much shorter, and the posterior columellar teeth do not cross the posterior labral margin towards the dorsum.

A distinction of chiapponii from other members of the genus represents no problem.

Fig. 5: The characteristic posterior extremity of a Pustularia (columellar view)
Left: P. chiapponii n. sp., right: P. bistrinotata. (SEM photos). Note the connected pustules in P. chiapponii.