Triphoris alternata Pease, 1861

Albano, Paolo G., Bakker, Piet A. J. & Sabelli, Bruno, 2019, Annotated catalogue of the types of Triphoridae (Mollusca, Gastropoda) in the Natural History Museum of the United Kingdom, London, Zoosystematics and Evolution 95 (1), pp. 161-308 : 161

Triphoris alternata Pease, 1861

Figure 73

Triphoris alternata Pease 1861: 434, not illustrated.

Type locality.

"Sandwich Islands" (Hawaiian Islands).

Type material.

Lectotype: NHMUK 1962816, designated by Kay (1965) (coll. H. Cuming). Paralectotypes: NHMUK 1962817, 2 specimens (see Remarks), Hawaiian Islands (coll. H. Cuming) .

Original description.

Shell turreted; whorls composed of three regular-sized rows of granules, the middle one of dark reddish brown, the remaining two of a waxy-yellow colour; base longitudinally striated; canal closed, tubular.

Diagnosis.

Lectotype 6.2 mm high. Shell slightly cyrtoconoid, with very flat whorls. Teleoconch of ten whorls with three spiral cords bearing tubercles at the intersection with slightly prosocline axial ribs. The second cord develops later on the fifth whorl. Very fine growth lines are visible all along the shell. Peristome partly broken in the type specimens, but it apparently bears at least one additional spiral cord between the second and the third. Siphonal canal short. The base has a fourth weakly tubercled spiral cord and two more smooth ones. The apex is missing in the type series. The teleoconch has the first spiral cord very light brown, the second and the third brown and the interspace in between dark brown. The last whorl is very light brown with three distinct dark brown spiral stripes.

Remarks.

Lot NHMUK 1962817 contains two specimens. Both were listed as paralectotypes by Kay (1965), but they actually represent two species. The second (Fig. 73K ) can be easily distinguished from T. alternata by its colour pattern (the first spiral cord and not the second is dark brown), the more numerous axial ribs and smaller tubercles. Triphoris alternata is a junior homonym of T. alternatus C.B. Adams, 1852 ( ICZN 1999, Article 57). Therefore, Pease (1868) introduced Triphoris bicolor Pease, 1868 as a replacement name. A specimen with this name labelled as “holotype” is reported for the MCZ (50057). Jousseaume (1884) also later introduced Mastonia harperi to replace T. alternata .

Figures

Figure 73. Triphoris alternata Pease, 1861. A-H Lectotype NHMUK 1962816, Hawaiian Islands (coll. H. Cuming): front (A, B), side (C, D), back (E), peristome (F, G), aperture (H). I Original labels. J Paralectotype, NHMUK 1962817, Hawaiian Islands (coll. H. Cuming): front. K Triphora sp., NHMUK 1962817, Hawaiian Islands (coll. H. Cuming): front. Scale bars: A-E, J, K: 1 mm; F-H: 0.5 mm.