Hennissen et al. (2010) described a chitinozoan fauna from the Dawangou section in the Xinjiang region of China, an auxiliary Global Stratoype Section and Point (GSSP) for the base of the Upper Ordovician Series. The fauna contained one new species, which they named Cyathochitina giraffa. Their paper was published in December 2010 (formally accepted 10 July 2010). However, Grahn & Nõlvak (2010) had already published a paper in June of the same year, including a different new species that was also named Cyathochitina giraffa. According to the rules of the International Code of Zoological Nomenclature (ICZN, 1999, Art. 52.3.), the species Cyathochitina giraffa Grahn & Nõlvak, 2010 is the senior homonym and, therefore, has nomenclatural priority. The species described by Hennissen et al. (2010) needs to be renamed. Here, we introduce a new name for this species: Cyathochitina cycnea nom. nov.

Incertae Sedis Group Chitinozoa Eisenack, 1931

Order Prosomatifera Eisenack, 1972

Family Lagenochitinidae Eisenack, 1931

Subfamily Cyathochitininae Paris, 1981

Genus Cyathochitina Eisenack, 1955 emend. Paris et al., 1999

Cyathochitina cycnea nom. nov.

(Fig. 1a–e)

v2010 Cyathochitina giraffa sp. nov. Hennissen et al.: 109, pl. 4, figs 8–11, 11a.

non 2010 Cyathochitina giraffa sp. nov. Grahn & Nõlvak: pl. 3, figs I–L.

2007 Cyathochitina sp. 1 Tang et al.: 482, fig. 19.

2001 Cyathochitina sp. cf. C. jenkinsi Ottone et al.: 109, pl. 3, figs 6, 8, 9.

2000 Cyathochitina jenkinsi Geng et al.: pl. 4, fig. 8.

1984 Cyathochitina sp. cf. C. jenkinsi Achab: 135, pl. V, figs 1–9.

Derivation of name. The name C. giraffa (Hennissen et al., 2010) was derived from the fact that the species has a long ‘neck’, just like a giraffe. The swan, cycnus in Latin, also has a particularly long neck. ‘Cycneus’ is the derived adjective. In biology, a slightly different spelling is used to indicate the bird genus Cygnus of the Anatidae family.

Diagnosis. Cyathochitina cycnea is a long and slender chitinozoan, characterized by a very long neck: the ratio neck length/total length is at least 0.4 and commonly larger than 0.5. Typically, its maximal diameter is situated at about one-fifth of the total chamber length above the base of the vesicle. This produces a two-dimensional chamber morphology (specimens from Hennissen et al., 2010 are flattened) that has the shape of an oval, i.e. tapering towards both aboral and oral ends of the chamber, but truncated (flattened) at the base. Depending on the degree of roundness, the chamber shape can be close to that of an asymmetrical rhombus (diamond), truncated along the largest diagonal, a short distance below the smallest diagonal.

Holotype. Hennissen et al. (2010, pl. 4, fig. 10), as ‘Cyathochitina giraffa n. sp.’. Holotype repository: Royal Belgian Institute for Natural Sciences, collection number RBINS_b_5103. Holotype not refigured here.

Locality and horizon. Type locality is the Dawangou section, Xinjiang region of China. Type stratum is the Saergan Formation.

Age. Late Darriwilian to early Sandbian (i.e. late Middle Ordovician to early Late Ordovician).

Description. See Hennissen et al. (2010).

Dimensions. The total vesicle length (L) varies between 260 and 580 μm (400 μm on average) and the maximal (chamber) width (Dp) varies between 100 and 190 μm (140 μm on average – see Hennissen et al., 2010, fig. 7, table 17, p. 111).

Stratigraphic occurrence. Late Darriwilian–early Sandbian, Dawangou section in NW Tarim, China (Hennissen et al., 2010): Didymograptus murchisoni, Dicellograptus vagus and Nemagraptus gracilis graptolite biozones; Middle–Lower Ordovician, Charchaq Formation, Mt. Querrqueke section, Kuruktag area, NE Tarim, China (Tang et al., 2007); Late Darriwilian–early Sandbian, Los Azules Formation, Central Precordillera in Argentina (Ottone et al., 2001): Pterograptus elegans to Climacograptus bicornis graptolite biozones; Late Darriwilian, Tarim, China (Geng et al., 2000): D. murchisoni graptolite biozone; Late Darriwilian–early Sandbian, Anticosti Island, Canada (Achab, 1984): D. multidens and N. gracilis graptolite biozones.

Remarks. Hennissen et al. (2010) discussed how the long neck C. cycnea sets it apart from other cyathochitinids, in combination with the shape of the chamber: in most species of Cyathochitina, the chamber is conical and the maximal width of the chamber is at, or very close to, the basal edge. Closer to it in overall shape than to other cyathochitinids, C. cycnea lacks the longitudinal ridges of C. jenkinsi. The length of the neck of Cyathochitina cycnea is not significantly different from that of C. giraffa of Grahn & Nõlvak (2010), which is described as ‘about half the total length or longer’ Grahn & Nõlvak (2010, p. 46). If anything, C. cycnea has a slightly shorter neck, based on two of the four illustrated specimens of Grahn & Nõlvak (2010, p. 65, pl. 3, figs J, K). The most important difference, however, between C. cycnea and C. giraffa is the morphology of the vesicle’s chamber: C. giraffa has a conical chamber, much like that of C. campanulaeformis, and its maximal width is at the basal margin. In contrast, C. cycnea has an oval-shaped chamber, with its maximal width clearly above the basal margin.