Alutella sp.

Álvarez, María Eugenia Dies, Gozalo, Rodolfo, Cederström, Peter & Ahlberg, Per, 2008, Bradoriid arthropods from the lower-middle Cambrian of Scania, Sweden, Acta Palaeontologica Polonica 53 (4), pp. 647-656 : 653

Alutella sp.

Fig. 3E.

2003 Hipponicharion sp. ; Axheimer and Ahlberg 2003: 156.

Material.—Two partially overlapping valves belonging to the same individual ( LO 9351t). The left valve is almost complete, whereas the right valve is incomplete, showing only the posterior and ventral areas (the anterior and dorsal areas are obscured by the left valve).

Description.—Valves postplete of medium size (5.5 mm long). Dorsal margin fairly straight, ca. 75% of valve length, with a posterodorsal curve and a more pronounced anterior curve. Lateral outline suboval. Lateroadmarginal ridge entire between cardinal corners, separated from lateral surface by distinct furrow. Anterodorsal node ventrally confluent with inflated lobal area. Anterodorsal sulcus broad and V−shaped. Both node and sulcus weakly developed (although the overlapping between the two valves partly obliterates the relief of this area). Anterior cardinal angle is smaller than posterior cardinal angle. Lateroadmarginal ridge is expanding into a pointing edge at posterior cardinal angle. Outer surface of carapace is punctate.

Remarks.—The outline of the valve, the broad and V−shape anterodorsal sulcus, the single anterodorsal node and the absence of connecting ridges allow us to include this material in the genus Alutella . With the limited and poorly preserved material it is left under open nomenclature. It differs from the Chinese species (see Huo et al. 1991; Hou et al. 2002; Peng et al. 2005) and Alutella sp. ( Melnikova et al. 1997) from Kazakhstan in having a suboval outline. The most similar species is Alutella usloniensis ( Melnikova, 1988) but the posterior margin of this species is completely different from that of Alutella sp. described herein.

The genus Quetopsis Hinz−Schallreuter, 1999 from lower/ middle Cambrian strata of Australia shows a similar morphology; especially the juvenile specimen of Q. katarcha Hinz−Schallreuter, 1999 has a very similar outline. However, Alutella sp. differs from that specimen by the presence of a V−shaped sulcus and a dorsal node.

Liangshanella nitida ( Wiman, 1905) is a poorly known species from glacial erratics in the southern part of the Gulf of Bothnia , Scandinavia. It is closely comparable to the specimen from Scania and appears to have a similar outline and sculpture, but lacks the posterodorsal curve and the V−shaped anterodorsal sulcus .

Stratigraphic and geographic distribution.— Lower part of the traditional middle Cambrian (probably Acadoparadoxides oelandicus Superzone ) in the Almbacken drill core (depth: 29.40 m) of Scania, southern Sweden .