Corallana Dana, 1852

Anil, Pathan, Bruce, Niel L. & Jayaraj, K. A., 2022, A new species of Corallana Dana, 1852 (Crustacea: Isopoda: Corallanidae) from the Andaman Islands, northern Indian Ocean, Zootaxa 5087 (2), pp. 357-371 : 360

Genus Corallana Dana, 1852

Corallana Dana, 1852:204 ; 1853:773.— Schioedte & Meinert 1879:286.— Stebbing 1904a:13; 1904b:704.— Barnard 1914:358 a; 1955:59.— Pillai 1967:272.— Kensley 1978:75.—Bruce 1982: 42.— Delaney & Brusca 1985: 728 [key].— Delaney1989: 22.

Type species: Corallana hirticauda Dana, 1853 ; by monotypy.

Remarks. The genus has most recently been reviewed by Delaney (1989) who gave a genus diagnosis, listed all the included species at that time, and gave a key to the genera of Corallanidae . That generic diagnosis is not in need of revision, but we draw attention to the prime characters for identifying the genus, which are elongate maxilliped, with notably quadrate articles and elongate basis (3.5–4.0 as long as wide), frontal lamina generally small, sometimes reduced or absent and, typically in mature individuals, the uropoda have an elongate exopod that extends to or beyond the posterior margin of the endopod. Other characters rest largely with the mouthparts and require dissection to observe; these are maxillula strongly curved, with single unguis-like apex and the maxilla is a simple bi-articled lobe. The genus that is most often confused with Corallana is Tachaea , but the latter genus can best be separated by the maxilliped palp with short and less quadrate articles, and often with some fusion of those articles.

Delaney (1989) identified the following characters as generic apomorphies: mandible incisor either short or long (most other genera have a shorter mandibular incisor); maxilliped slender, basis narrow and very elongate (length = 2.0–4.0 times width); and frontal lamina usually reduced, sometimes absent.

Identification of species of Corallana has long been and continues to be difficult, as evidenced by the numerous instances of misidentified species at both genus and species level. Further, several of the species described in 1800s are simply unrecognizable (see species list herein) and cannot be applied to collected specimens. Many species are very similar to each other and another difficulty lies with the species characters being shown primarily by mature adults. It therefore also must be considered that a number of the species described from one locality (“Ubay”) in the Philippines by Schioedte & Meinert (1879) may be different stages of maturity of the same species.

The frontal lamina in the genus Corallana . Figure 2 provides a comparison of the shape of the frontal lamina for those species of Corallana for which it has been illustrated, including records of Corallana sp. It can be seen that, while the frontal lamina is usually relatively small compared to Argathona and perhaps Alcirona , when present the shape varies considerably between species. As such the frontal lamina is a useful character to both identify species, but also to identify the immature stages of species. At least two species, Corallana nodosa of Beng Chu & Bruce (2010, figs 1–3; not Corallana nodosa Schioedte & Meinert, 1879 ) and Corallana grandiventra Ho & Tonguthai, 1992 appear to lack a visible frontal lamina. A clear figure of the frontal lamina should be included in all descriptions of species of Corallana .

Figures

FIGURE 2. Comparisons of the frontal lamina in Corallana. A, Corallana mishrai sp. nov.; B, C. brevipes Schioedte & Meinert, 1879; C, C. furcilla Barnard, 1955; D, C. estuaria Jones, Icely & Cragg, 1983; E, C. hirticauda Schioedte & Meinert, 1879; F, C. nodosa Schioedte & Meinert, 1879; G, C. tridentata Jones, Icely & Cragg, 1983; H, C. collaris Schioedte & Meinert, 1879; I, C. nodosa of Delaney, 1989; J, C. basalis Schioedte & Meinert, 1879. Note: both Corallana nodosa of Beng Chu & Bruce (2010) and Corallana grandiventra Ho & Tonguthai, 1992 completely lack a frontal lamina.