Calappa praelata Lőrenthey in Lőrenthey & Beurlen, 1929

Ossó, Àlex & Gagnaison, Cyril, 2019, An appraisal of the Middle-Late Miocene fossil decapod crustaceans of the ‘ Faluns’ (Anjou-Touraine, France), Geodiversitas 41 (9), pp. 367-383 : 370-372

Calappa praelata Lőrenthey in Lőrenthey & Beurlen, 1929 ( Fig. 3 A-C)

Calappa praelata Lőrenthey in Lőrenthey-Beurlen, 1929: 132 , 133, pl. 6, fig. 3. — Glaessner 1929: 71. — Müller 1984a: 66, pl. 35, figs 1-2, 7; pl. 36, fig. 6; 1984b: pl. 2, fig. 4; 1996: 9, pl. 1, fig. 11; 1998: 22. — Gatt & De Angeli 2010: 1329, pl. 2, fig. 2. — Schweitzer et al. 2010: 83. — Pasini et al. 2012: 135-140, fig. 1A-C. — Collins 2014: 37-36, t. 1, pl. 2, fig. 9. — Díaz-Medina et al. 2017: 180, 181, fig. 9A-C.

Calappa heberti – Glaessner 1928: 174, 175. — Veiga Ferreira 1958: 203-207, text-figs 1-3, pl. 1, figs 1-3 (non Brocchi, 1883).

Calappa cf. heberti – Da Carvalho 1959: 79, pl. 2, figs 4-6.

Calappa heberti sp. 2 – Bachmayer 1962: 41, pl. 2, fig. 1.

Calappa aff. granulata – Bachmayer 1962: 42 .

Calappa aff. heberti – Förster 1979: 255, 257, pl. 1, figs 2, 3 (non fig. 4).

Calappa sp. – Artal & Gilles 2007: fig. 2a.

Carapace de crabe – Gagnaison et al. 2009: 1, fig. 2.

MATERIAL EXAMINED AND MEASUREMENTS (in mm). — Complete dorsal carapace embedded of bioclastic limestone, cuticle preserved, MS2006 FS 134a: L = 30, W = 39.5, FOW = 13.

LOCALITY AND HORIZON. — ‘La Sonneterie’ quarry, Meigné-le- Vicomte (Maine-et-Loire). ‘Savignean facies’, Langhian-Serravallian (Middle Miocene).

DESCRIPTION

Carapace medium sized, transversely subovate in outline, expanded clypeiform process (wing-like extension) in posterolateral angles; wider than long, maximum width at posterolateral angle; strongly vaulted longitudinally and transversely.Cuticle well preserved. Maximum width at level of third posterolateral tooth. Front narrow, medial notch; orbits small, rounded; supraorbital margin entire.Anterolateral margin strongly arcuate, ornate with blunt teeth and nodes. Posterolateral margin strongly convex; wing-like extension with largest tooth at posterolateral angle, preceded by three teeth progressively smaller, and followed by two teeth that decrease in size progressively; all of them triangular with an axial elevated ridge. Posterior margin short, slightly convex, bounded by two blunt teeth. Carapace surface covered anteriorly by large tubercles and swellings, smaller posteriorly, forming longitudinal rows. Central regions bounded longitudinally by two parallel grooves running from orbits to cardiac region. Ventral parts and appendages not present.

REMARKS

The carapace outline, toothed posterolateral wing-like extension, and dorsal features of the ‘Faluns’ specimen, fit well with the description and images of the holotype figured by Müller (1984a: 66, pl. 35, figs 1-2), as well as with the specimens in literature, widely described and depicted by diverse authors through time (see for instance the synonymies list above). Further, comparisons with specimens of the collection of the first author (AO), allow us to place the French specimen within this species with confidence. Differences of the French specimen with Calappa heberti Brocchi, 1883 from the Middle Miocene of the Paratethys are clear, since the dorsal surface of the carapace of C. heberti is ornate with short squamous ridges in the posterior portion and have less produced teeth in its posterolateral angle (e.g. Lőrenthey in Lőrenthey & Beurlen 1929: pl. 6, fig. 3; Müller 1984a: pl. 35, figs 1-2, 7; pl. 36, fig. 6). It differs as well with C. saheliensis Van Straelen, 1937, from the Late Miocene of North Africa and Southern Iberian Peninsula, in having large tubercles in the anterior half of carapace and by the absence of longitudinal grooves, more or less marked, in the branchial regions ( Van Straelen 1937: pl. 32, fig. 1; type series from MNHN: MNHN.F.R03768). Calappa zurcheri Bouvier, 1899 from the Oligocene-Miocene of Mexico and Panama, also differs clearly from the studied specimen in having stronger tuberculation along almost all the dorsal carapace surface (e.g. Bouvier 1899: 189-192 text-fig. 1; Luque et al. 2017: fig. 12M).

Calappa praelata is widespread during the Miocene along the Paratethys and Proto-Mediterranean; it is also present in the Atlantic along the southern coast of Portugal. Díaz-Medina et al. (2017: 181) summarized the known previous records of this species. Calappa praelata is morphologically very close to the extant C. granulata , mainly dorsally; however, different features in chelae and in the posterior margin distinguish both species (see Müller 1984a: pl. 36, figs 1-5).

Figures

FIG. 3. — A-C, Calappa praelata Lőrenthey in Lőrenthey & Beurlen, 1929, MS2006 FS 134a: A, dorsal view; B, frontal view; C, close-up of posterolateral margin; D, E, Calappa sp., MS2018-2-1: D, left chela, MS2018-2-2; E, right chela; F-J, Hebertides jurassica Guinot, De Angeli & Garassino, 2007; F-H, MS2018-1-1: F, right lateral view; G, frontal view; H, dorsal view; I, J, ULB-SO-1: I, fragment of right dorsal carapace; J, the same fragment showing bryozoans incrusted. Scale bars: A-H, 10 mm; I, J, 5 mm. Photographs by À. Ossó.