Cristarma ortmanni
Creators: name: Schubart, Christoph D.
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Sesarmidae
Cristarma
Cristarma ortmanni

description: Cristarma ortmanni (Crosnier, 1965)
(Figs. 13F, 14F, 15E, F, 18D, 20I–K, 43H)
Sesarma quadrata – Hilgendorf, 1869: 90, pl. 3 fig. 3c, pl. 4 fig. 3 [not Cancer quadratus Fabricius, 1798].
Sesarma erythrodactyla var. africana – Ortmann, 1894: 56 [not Sesarma africana H. Milne Edwards, 1837].
Sesarma ortmanni Crosnier, 1965: 51, figs. 70, 71.
Sesarma (Holometopus) ortmanni – Serène, 1968: 107.
Holometopus ortmanni – Hartnoll, 1975: 308, 311, 316.
Chiromantes ortmanni – Naderloo & Schubart, 2009: 67.
“ Chiromantes ” ortmanni – Ng et al., 2008a: 220; Emmerson, 2016: 240, unnumbered colour fig.
Material examined. Lectotype (here designated): male (10.7 × 8.2 mm) (MNHN B16741a), Nosy Be, Tuléar, Madagascar, coll. A. Crosnier, 1960s. Paralectotypes: 1 male (8.6 × 6.7 mm), 2 females (10.9 × 8.6 mm, 12.7 × 9.8 mm) (MNHN B16741b), same data as lectotype. KENYA – 2 males (19.4 × 14.4 mm, 15.1 × 11.9 mm), 2 females (13.1 × 10.2 mm, 10.9 × 8.6 mm) (ZRC 2000.1783), Gazi, coll. M. Vannini, November 1991. MOZAMBIQUE – 1 male (20.0 × 15.5 mm) (ZRC 1968.1.22.1), Inhaca Island, coll. MacNae, April 1967.
Diagnosis. Carapace proportionately broader, transversely rectangular; lateral margin almost straight; dorsal margin of male cheliped dactylus with about 12 slightly asymmetrical tubercles which get progressively smaller distally; male pleon proportionately broader, shorter.
Colour. According to Crosnier (1965: 53), the carapace is green with the ambulatory legs yellowish. Emmerson (2016: 240, unnumbered colour fig.) depicts a specimen with bright red chelae and a beige transverse faceband on the carapace.
Remarks. Some nomenclatural notes on this species are necessary. In describing Sesarma (Holometopus) ortmanni, Crosnier (1965) suggested that it may be the same as Sesarma erythrodactyla var. africana Ortmann, 1894. Crosnier (1965: 53) commented that “le type de Sesarma erythrodactyla var. africana ne se trouve pas au Muséum de Strasbourg où est déposée la collection d’ORTMANN. La description de cette espèce est, d’autre part, assez sommaire. Il est donc impossible de savoir avec certitude si l’espèce que nous considérons ci-dessus est la même que celle décrite par ORTMANN. Nous pensons toutefois qu’il y a de fortes chances qu’il en soit ainsi et c’est pour cela que nous dédions notre espèce à ORTMANN. L’examen de spécimens des espèces de Sesarma existant à Dar es Salam (localité du type d’ORTMANN) permettrait vraisemblablement d’éclaircir le problème. Sesarma erythrodactyla Hess appartient au sous-genre Parasesarma; l’espèce que nous appelons S. ortmanni au sous-genre Holometopus. Si donc S. ortmanni et S. erythrodactyla var. africana sont identiques, l’espèce d’ORTMANN ne doit pas être considérée comme une variété de S. erythrodactyla mais comme une espèce distincte. Il n’est pas possible de l’appeler S. africana, ce nom ayant déjà été donné par H. MILNE EDWARDS à une espèce de Sesarma de la côte oust de l’Afrique. Sesarma ortmanni est donc soit une espèce nouvelle, soit simplement, si son identité avec l’espèce d’ORTMANN peut être clairement établie, une nouvelle désignation de S. erythrodactyla var. africana ”. Sesarma erythrodactyla var. africana Ortmann, 1894, is clearly a junior primary homonym of Sesarma africana H. Milne Edwards, 1837, and according to article 57.2 of the current zoological code (ICZN, 1999), the name needs to be replaced. Although Article 23.9.5 allows for a junior primary homonym to be retained, it states that “When an author discovers that a species-group name in use is a junior primary homonym [Art. 53.3] of another species-group name also in use, but the names apply to taxa not considered congeneric after 1899, the author must not automatically replace the junior homonym; the case should be referred to the Commission for a ruling under the plenary power and meanwhile prevailing usage of both names is to be maintained [Art. 82]”. The requirements of Article 23.9.5 are not fulfilled because even after 1899, H. Milne Edwards’ and Ortmann’s names were used together in the same genus by some authors. For example, Tesch (1917) uses both “ Sesarma (Chiromantes) africana H. Milne Edwards ” (p. 129) and “ Sesarma (Parasesarma) erythrodactyla africana Ortmann ” (p. 140); and although he has them in different subgenera and species-groups, the fact remains that both taxa were placed in “ Sesarma ” and the zoological code (Article 57.1) treats species and subspecies as species-group names and therefore of equal status. As such, Sesarma erythrodactyla var. africana Ortmann, 1894, is not an available name. This situation remains even if Sesarma africana H. Milne Edwards, 1837, is currently regarded as a junior subjective synonym of Perisesarma huzardi (Desmarest, 1825). As discussed by Crosnier (1965), it is likely that Sesarma erythrodactyla var. africana Ortmann, 1894, is conspecific with Sesarma (Holometopus) ortmanni Crosnier, 1965. In the event they are not, then Ortmann’s (1894) name must be replaced if there is no senior synonym.
In naming this species, Crosnier (1965: 51) stated he had two males and two females but did not specify a holotype. As such, all his specimens are syntypes. The largest male (10.7 × 8.2 mm) (MNHN B16741a) is here designated the lectotype of Sesarma ortmanni Crosnier, 1965.
Biology. Hartnoll (1975: 316) records this species as occurring in terrestrial vegetation above the supralittoral zone all the way down to the sand flats and Avicennia mangrove zone.
Distribution. Along the eastern and southern coasts of Africa (Crosnier, 1965; Hartnoll, 1975; Emmerson, 2016). Emmerson (2016: 241–243) provides a detailed summary of the known ecology and biology of the species.
description: Published as part of Schubart, Christoph D. & Ng, Peter K. L., 2020, Revision of the intertidal and semiterrestrial crab genera Chiromantes Gistel, 1848, and Pseudosesarma Serène & Soh, 1970 (Crustacea: Brachyura: Sesarmidae), using morphology and molecular phylogenetics, with the establishment of nine new genera and two new species, pp. 891-994 in Raffles Bulletin of Zoology 68 on pages 930-934, DOI: 10.26107/RBZ-2020-0097, http://zenodo.org/record/5351295