Pseudopusula parcicosta
Creators: name: Sacchetti, Claudia
name: Landau, Bernard
name: Ávila, Sérgio P.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Triviidae
Pseudopusula
Pseudopusula parcicosta

description: Pseudopusula parcicosta (Bronn, 1862)
Plate 3 J 1 -J 4
* Cypraea (Trivia) parcicosta Bronn in Reiss 1862: 24, pl. 1, fig. 3.
Trivia parcicosta Bronn — Mayer 1864: 85: 7, fig. 64.
Trivia parcicosta — Zbyszewski & Ferreira 1962: 276, pl. 2, figs. 14, 17.
Pseudopusula parcicosta (Bronn in Reiss, 1862)— Fehse & Grego 2014: 54, pl. 27, figs. 165-168, pl. 35, figs. 223-224.
Type material. Holotype height 8.0 mm, width 6.0 mm, Pinheiros, Santa Maria, Azores; whereabouts unknown (Beu 2017:165).
Mayer (1864: 85) wrote that he had received two specimens from the Heidelberg Museum. Fehse & Grego (2014: 54) alleged that the two specimens were sold to the USA. Those authors were unable to find any type material in Germany, Switzerland or the USA. They designated a neotype from the Museo de Ciencias Naturales de Tenerife, Canary Islands, Spain, from the locality of Baoranco [sic; Barranco] Seco, Las Palmas, Gran Canaria. The type material must have been lost sometime after 1967, as Schilder’s (1967: 74) shell formula was based on four specimens (see Historical section for further discussion).
Santa Maria material examined. Maximum height 9.0 mm, width 6.5 mm. DBUA-F 469-1 (2), DBUA-F 937-C (1), Ponta do Castelo; DBUA-F 1210 (1), DBUA-F 1428-B (2), Ponta dos Cedros; DBUA-F 1189-D (1), Pedra-que-pica; DBUA-F 1016 (1), Malbusca, Santa Maria, Azores, Touril Complex, Lower Pliocene.
Original description. “ Unter den kleinen Trivia-artigen Cypräen von etwa 3 bis 4 Länge ausgezeichnet durch die anfänglich geringste Anzahl, gr̂sste Schärfe und nachherige stärkste Verästelung der Queerrippen. Am meisten stimmt sie mit C. Europaea Mtg. bei Ĥrnes ̧berein, die aber ebenfalls mehr und feinere Rippchen hat. (Fig. e ist von der Seite in naţrlicher Gr̂sse gesehen.) [Among the small Trivia -like cypraeids of about 3 to 4 [?] lengths, distinguished by the initially smallest number, and sharpness and subsequently strongest bifurcations of the transversal ribs. It most agrees with C. Europaea Mtg. at Ĥrnes, which also has more and finer ribs. (Fig. e is seen from the side in natural size.)]” (Bronn in Reiss 1862: 24).
Latin description. “ Testa parva, ovata, ventre subdepressa, labro externo marginata; dorso gibbo linea mediana impresso utrinque noduloso, nodulis septenis vel octonis in costulas acutas semel aut bis furcatas excurrentibus; costulis labii utriusque 16-18, aliis 1-2 brevioribus.” (Bronn in Reiss, 1862: 24).
Revised description. “Shell small, solid and ovate. Spire covered by callus. Body whorl elongated-globose and rounded, almost 90% total of height. Terminals not produced with blunt tips. Dorsum roundly elevated, completely covered by 6 fine, irregular ribs, which are somewhat wavy and frequently branched on both dorsal sides. A short, incised dorsal sulcus extends longitudinally across the centre of the dorsum, bisecting all of the ribs, the latter not thickened adjacent to the furrow. Ventrum convex. The aperture narrows over its entire length. Labrum broadened, convex, widest in mid-portion becoming narrower towards the terminals and regularly rounded. Out margin angularly callused. The lip bear 12-16 fine, equal teeth. Siphonal and anal canals follow the shell profile. Parietal lip almost straight, slightly keeled, crossed by 11-14 ribs. Fossula concave and not clearly delimited from the rest of the columella. Inner fossular edge slightly protruded.” (Fehse & Grego, 2014: 54).
Intraspecific variation. The material at hand from the type island of Santa Maria has 14 labial denticles and 14 columella denticles. The ribs on the dorsum of the only complete specimen fade some distance from the apex leaving a smooth elongated area at the top. The Santa Maria specimens differ from those from the Canary Islands in having a broader smooth dorsal area and they seem to have a wider aperture. They probably represent the same species, but it would have been preferable to choose a neotype from the type locality.
Discussion. Fehse & Grego (2014: 47) erected the genus Pseudopusula based mainly on radula morphology. According to those authors the dorsal depression distinguishes Pseudopusula from Trivia Broderip, 1837, Pusula Jousseaume, 1884 and Quasipusula Fehse & Grego, 2014. We await molecular data to verify the validity of these genus groups.
Pseudopusula canariensis (Rothpletz & Simonelli, 1890) from Gran Canaria was said to differ from P. parcicosta in having a slenderer shell and more numerous ribs (original description: 19 labral, 15 columellar). The number of labral and columellar ribs seen in the neotype illustrated by Fehse & Grego (2014: pl. 27, figs. 172) does have more ribs. However, a further specimen from Las Palmas (2014: pl. 16, figs. 96) has fewer ribs and it is closely similar to the Santa Maria specimens of P. parcicosta. It is possible that these shells represent extreme forms of a single species, as already suggested by Fehse & Grego (2014: 59).
Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores (Bronn in Reiss 1862; Mayer 1864; Zbyszewski & Ferreira 1962), Gran Canaria (Mayer 1864), Las Palmas (Fehse & Grego 2014).
description: Published as part of Sacchetti, Claudia, Landau, Bernard & Ávila, Sérgio P., 2023, The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications, pp. 1-150 in Zootaxa 5295 (1) on pages 55-56, DOI: 10.11646/zootaxa.5295.1.1, http://zenodo.org/record/7965273