Claraia Bittner, 1901 is a prominent extinct bivalve genus of the Permian-Triassic transition (Newell and Boyd, 1995). Although it first appeared in the Wuchiapingian (Late Permian; Fang Zong-Jie, 2010), its massive proliferation in the immediate wake of the end-Permian mass extinction makes it the archetype of a cosmopolitan and eurytopic disaster species and a hallmark of the base of the Triassic (e.g., Schubert and Bottjer, 1995). Diener (1923, p. 38) fixed “Posidonomya Clarai Emmrich (1844)” as the type species of Claraia by subsequent designation, but spelling and authorship of this species have been controversial. This short contribution aims to clarify these issues.

The history of this taxon began when Emmrich (1844, p. 793) erected Posidonomya clarae, named for Franz Clara, a priest from Kastelruth (South Tyrol) who provided his fossil collection including the species in question to Emmrich. In the following years, the species has been repeatedly reported in its original spelling (e.g., Hauer, 1850; Schauroth, 1855) until Lepsius (1878, p. 348) changed the species name from clarae to clarai. Lepsius (1878) did not comment on his emendation, but it is obvious that he regarded the Latin a-declination (which is grammatically usually feminine) as inappropriate for a species that had been named for a man. Since then, both spellings have been used in the literature, although Lepsius' emended spelling has dominated.

To my knowledge, the issue of different spellings has found only two mentions in the literature. Newell and Boyd (1995, p. 25) stated without further explanation that the “trivial [sic] name is usually mistakenly translated to clarai,” and accordingly, they applied the original spelling clarae in their paper. In contrast, Posenato (2008, p. 99) emphasized that “the specific term clarae, as indicated by some recent authors, is wrong because the species was dedicated to a man.” I followed this conclusion in my own work (e.g., Hautmann et al., 2015; Hofmann et al., 2015), but recent consultation of the International Code of Zoological Nomenclature (ICZN; International Commission on Zoological Nomenclature, 1999) has convinced me that this is incorrect.

First, the case of an apparently incorrect gender of a nomen would not justify an emendation under ICZN Article 32.5. Generally, “incorrect transliteration or latinization … are not to be considered inadvertent errors” (ICZN Article 32.5.1). Second, Emmrich's (1844) treatment of the modern personal name “Clara” as a Latin name of a man in a-declination is correct according to the rules of the ICZN. ICZN Article 31.1.1 states that “a species-group name, if a noun in the genitive case formed from a personal name that is Latin, or from a modern personal name that is or has been latinized, is to be formed in accordance with the rules of Latin grammar.” The ICZN cites the following example: “[…] Nicolaus Poda, even though the name of a man, if accepted as a Latin name, gives [the species name] podae.” ‘Clara’ can clearly be regarded as a Latin surname that is declined in the a-declination, even if it refers to a man. Historical examples of men’s names in the a-declination are the conspirator Catilina, the commander Agrippa, and the philosopher Seneca.

The correctness of the species name clarae is unaffected by ICZN Article 31.1.2, which states that authors can also decide to latinize modern personal names by adding -i to the stem of that name (in the ICZN example, the species name podai from Poda is also admissible). Thus, clarae and clarai are two possible options for a species name honoring Franz Clara, and Emmrich (1844) chose the first of these.

A second short note refers to the validity of the authorship by Emmrich (1844). Emmrich's authorship had been generally accepted until the Treatise on Invertebrate Paleontology (Newell, 1969, p. N337) indicated that Emmrich (1844) published the name as a nomen nudum and assigned the authorship to Hauer (1850). This treatment has found occasional consideration (e.g., Newell and Boyd, 1995), but verification shows that this is incorrect. When introducing the new species, Emmrich (1844, p. 793) provided a description of Posidonomya clarae that fulfills all requirements of ICZN Article 12 (“Names published before 1931”). Emmrich (1844, p. 793) described the new species as follows [my translation from German]: “The former (a peculiar Posidonomya) is distinguished from all other species of this genus by fine radial ribs in addition to the characteristic broad commarginal folds,” which is an appropriate description according to the standards of his time. Although not required under ICZN Article 12, Emmrich (1844) also indicated the exact location and stratigraphic position of the fossil localities and an indication of the institution where the material is housed. The lack of an illustration does not affect the availability of the species name according to the ICZN.

Summarized, both Emmrich's (1844) authorship and his original spelling of Posidonomya clarae must be accepted.