Monday, July 17, 2017

[Mollusca • 2017] Scutalus chango • A New Terrestrial Snail Species (Gastropoda: Bulimulidae) from the Región de Antofagasta, northern Chile


Scutalus chango
Araya​ & Breure, 2017

  DOI: 10.7717/peerj.3538 

Abstract

A new species of Scutalus Albers, 1850 (Gastropoda: Bulimulidae), Scutalus chango sp. n., is described from a coastal area of northern Chile. Empty shells of this new species were found buried in sand and under boulders and rocks in the foothills of the Chilean Coastal Range at Paposo, Región de Antofagasta. This new species is distinguished from all other Chilean terrestrial snails by its slender shell with a flared and reflected aperture, and by the presence of a columellar fold. This is the first record of Scutalus in Chile, and the southernmost record for this endemic South American bulimulid genus. The presence of this species in Paposo highlights the need for further research and for conservation guidelines in coastal areas of northern Chile, which have comparatively high levels of biodiversity and endemism.


Figure 2: Type locality and habitat of Scutalus chango sp. n.: under boulders at foothills of the Chilean Coastal Range (SE view), north of Paposo, Región de Antofagasta, northern Chile.

Figure 4: Scutalus chango n. sp. Holotype MPCCL 020617, (A) apertural view, (B) side view (external lip view), (C) abapertural view, (D) side view (umbilical view), (E) detail of sculpture and sutures, (F) detail of umbilicus and columellar lip, (G) detail of columellar fold, (H) basal view; Paratype 5 MPCCL 030617D, (I) detail of columellar fold; Paratype 1 MPCCL 030617A, (J) apertural view, (K) abapertural view; Paratype 2 MPCCL 030617B (juvenile specimen), (L) apertural view, (M) side view (external lip view), (N) abapertural view; Paratype 3 MPCCL 030617C (juvenile specimen), (O) apertural view, (P) side view (external lip view), (Q) abapertural view.

Scale bars are 10 mm for (A–D), (G–H), (J–K), (L–Q), and 5 mm for (E–F) and (I).

Systematic account

Superfamily Orthalicoidea Martens, 1860
Family Bulimulidae Tryon, 1867

Genus Scutalus Albers, 1850

Diagnosis (Modified from Breure, 1979): Shell elongate-ovate to rather globose or depressed conical; (broadly) perforate; solid. Whitish to brownish in color, often with darker spiral bands, with axial streaks or coalescent spots in some species. Surface granulate or with incrassate growth striae. Protoconch pit-reticulate. Whorls slightly convex. Aperture (sub) ovate. Peristome more or less expanded. Columella in some species with a fold within the last whorl.

Type species Bulinus proteus Broderip, 1832


Scutalus chango new species 
Diagnosis: A species with a medium sized thick and elongated shell (H to 25.5 mm), whitish or variegated in color, sculptured by growth lines and sometimes presenting shallow varices. The shell is mainly characterized by the subovate peristome with an expanded and reflexed outer lip, a narrow and deep umbilicus and by the presence of a columellar fold.

Type locality: Foothills of the Chilean Coastal Range, north of Paposo (24°55′S; 70°30′W, altitude 150–170 m), Comuna de Taltal, Región de Antofagasta, northern Chile.


Distribution and habitat: Only known from type locality; shells found in humus under boulders and fallen rocks, usually near communities of the arborescent cacti Eulychnia iquiquensis, the large succulent shrub Euphorbia lactiflua and other small vegetation in the foothills of the Chilean Coastal Range. Many old shells and shell fragments were found buried in sediments in creeks and gullies, but no live specimens were recovered.

Etymology: A patronym (noun in apposition) in honor of the Chango people (now extinct) who inhabited coastal areas of northern Chile, having their last communities at Paposo, the type locality of the new species.

......

Conclusions
A new terrestrial bulimulid species (Gastropoda: Orthalicoidea), Scutalus chango sp. n., is described from Paposo, Región de Antofagasta, northern Chile, being the first record of the genus Scutalus in Chile and the southernmost record for this endemic South American genus. The new species may represent part of a relict fauna at the coastal area of northern Chile, with close relationship with species from central-northern Peru.


Juan Francisco Araya​ and Abraham S.H. Breure. 2017. A New Terrestrial Snail Species (Gastropoda: Bulimulidae) from the Región de Antofagasta, northern Chile.
 PeerJ. 5:e3538.  DOI: 10.7717/peerj.3538

   

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