Drymaeus arcuatostriatus (L. Pfeiffer, 1855)

Figs 12, 13

Bulimus arcuatostriatus L. Pfeiffer, 1855: 95: ” Peru ” ” Long. 30, lat. 13 mill. ” (Cuming coll.).

Drymaeus (Drymaeus) arcuatostriatus (L. Pfeiffer, 1855) — Breure and Ablett 2014: 23, fig. 41 A – C (lectotype NHMUK 1975455, dimensions H 27.6, D 15.6, W 6.5)

“ Drymaeus meesi Breure, 1976 ” — Tillier 1980: 75, pl. 4 fig. 1, text-figs 60, 61.

Link.

https://molluscabase.org/aphia.php?p=taxdetails&id=1364218.

Material examined.

French Guiana • 1 dry specimen; Saül, Arbre à contreforts au niveau du belvédère de Saül, crête sud de Bœuf Mort (SAUL 20); 3.62593 ° N, 53.21714 ° W; alt. 297 m; 16 Nov. 2018; OG, SS, ST, BF (PAG & MNHN) leg.; MNHN -IM-2012-21920 • 1 dry specimen; Saül (SAUL 12); 3.61951 ° N, 53.20751 ° W; 08 Jul. 1999; TR, OG leg.; MNHN -IM-2012-21547 • 1 dry specimen; Saül (SAUL 12); 3.61951 ° N, 53.20751 ° W; 08 Jul. 1999; TR, OG leg.; MNHN -IM-2013-21248 .

Remarks.

The specimen illustrated by Tillier (1980: pl. 4 fig. 1) and Massemin et al. (2009: pl. 6 A) identified as Drymaeus meesi Breure, 1976 conchologically differs greatly from the holotype RMNH. MOL. 55077 of Drymaeus glaucostomus meesi Breure, 1976 (Breure 1976: pl. 1). Tillier (1980: 77) already stated that his species should be more related to Drymaeus strigatus (G. B. Sowerby I (1838: fig. 95, original illustration) (Breure and Ablett 2014: fig. 30 A – C, possible syntype NHMUK 20090168) rather than to Drymaeus glaucostomus and consequently elevated the taxon to species level. Indeed Drymaeus strigatus, together with the synonymised Bulimus musivus L. Pfeiffer, 1855 (Richardson 1995; Breure and Ablett 2014: fig. 29 J – L, lectotype NHMUK 1975292), Bulimus saccatus L. Pfeiffer, 1855 (Breure and Ablett 2014: fig. 30 D – F, lectotype NHMUK 1975207), as well as Drymaeus schunkei F. Haas (1949: 237, fig. 50 b; Holotype FMNH 30040), all described from Peru, share the same global shape, chromatic pattern, and expanded aperture with the French Guianan species. However, they lack two characters that are shared between the French Guiana species and Drymaeus arcuatostriatus, i. e., the distinctive impressed radial white calcareous ribbing and the dark early whorls. Thus, we tentatively identify the French Guiana species previously known as “ Drymaeus meesi ” sensu Tillier (1980) as Drymaeus arcuatostriatus L. Pfeiffer, 1855 .

The species is to be considered within the Drymaeus (Drymaeus) expansus (L. Pfeiffer, 1848) species complex as defined by Breure and Borrero (2019), although the latter does not share the black early whorls.

A living specimen (Fig. 13, https://www.inaturalist.org/observations/74538163) shows a yellow body, mostly on the sole and the head, whitish otherwise; longitudinal black lines extend from the bottom of the optical tentacle to the aperture. The optical tentacles are conical and elongated.