Neosarmatium meinerti ( De Man, 1887 )

Ragionieri, Lapo, Fratini, Sara & Schubart, Christoph D., 2012, Revision Of The Neosarmatium Meinerti Species Complex (Decapoda: Brachyura: Sesarmidae), With Descriptions Of Three Pseudocryptic Indo-West Pacific Species, Raffles Bulletin of Zoology 60 (1), pp. 71-87 : 78-82

publication ID	https://doi.org/ 10.5281/zenodo.5346767
persistent identifier	https://treatment.plazi.org/id/682C762C-2817-AD27-05C2-FB8F9075FEE8
treatment provided by	Tatiana
scientific name	Neosarmatium meinerti ( De Man, 1887 )
status

Treatment

Neosarmatium meinerti ( De Man, 1887) View in CoL

( Figs. 1b View Fig , 2b View Fig , 3b,f View Fig , 4b,f View Fig , 5b View Fig , 6c,d View Fig )

Sesarma tetragona: H. Milne Edwards, 1837: 73 View in CoL ; 1853: 184–185; A. Milne-Edwards, 1873: pl.16: Fig.4 View Fig [not Cancer tetragona Fabricius, 1798: 341 ].

Sesarma tetragonum: Miers, 1879: 490 ; Ortmann, 1894a: 720; Doflein, 1904: 130 [not Cancer tetragona Fabricius, 1798: 341 ].

Sesarma rotundifrons: De Man, 1880: 24 View in CoL [not Sesarma rotundifrons A. Milne-Edwards, 1869 View in CoL ; see Davie, 1994].

Sesarma meinerti: De Man, 1887: 648 View in CoL , 668–669 (in part); Haig, 1977: 127.

Neosarmatium meinerti: Serène & Soh, 1970 View in CoL (localities not listed); Serène, 1977: 51; Davie, 1994: 35 (in part).

Material examined. — Lectotype: 1 male (34.00 × 39.30 mm) (MNHN-IU-2011-278), Ile de France (Mauritius), coll. M. Mathieu (1837 or earlier) (identified as Sesarma tetragona , ex-MNHN- B3688) ; Paralectotypes: MAURITIUS: 2 females (28.20 × 33.90 mm; 30.60 × 36.00 mm) (MNHN-IU-2011-279 ex-MNHN-B3688) same data as lectotype . Other material: SEYCHELLES: 2 males, 1 female ( ZRC 1972.8.25.2), Mahé Island , coll. R. Serène, May 1972 ; 1 male (40.26 × 35.60 mm) ( MZUF 2931 View Materials ), Mahé Island: Port Launary , coll. S. Fratini, 11 Dec.2005 ; 1 male (15.34 × 12.35 mm) ( MZUF 2940 View Materials ), Mahé Island, Port Launary , coll. M. Fusi, 4 Dec.2005 ; REPUBLIC OF MAURITIUS: 1 male (27.00 × 22.00 mm) ( RMNH D 17503), Barkley Island , Port Louis, coll. C. Miquel, Feb.1960 ; 1 male (34.5 × 28.83 mm) ( MZUF 3661 View Materials ), Rodrigues, coll. M. Vannini, 8 Jul.1987 ; 1 male (15.74 × 12.85 mm) ( MZUF 3662 View Materials ), Rodrigues, coll. M. Vannini, 8 Jul.1987 ; 1 male (12.70 × 10.35 mm) ( MZUF 3660 View Materials ), Mauritius , coll. M. Vannini, 1 Sep.1989 ; male (20.47 × 17.00 mm) ( MZUF 3665 View Materials ), Mauritius , coll. M. Vannini, 1 Sep.1989 .

Diagnosis. — Carapace gently concave posteriorly, without any indication of second anterolateral tooth ( Fig. 2b View Fig ). Male chela characterised by presence of single prominent line of tubercles along inner palm surface ( Fig. 3f View Fig ), with palm height 1.58 (± 0.18; n = 8) times maximum chelar width. Descending slope of palm (with parallel prominent ridge) at articulation with dactylus oblique ( Fig. 3b View Fig ). Lower margin of chela straight. Dorsal surface of dactylus covered with tubercles until three-quarters of length ( Fig. 4b, f View Fig ). Male abdomen triangularly shaped; somite 6 with proximal width 1.29 (± 0.124; n = 8) times length; telson length 1.15 (± 0.141; n = 8) times width ( Fig. 5b View Fig ).

Colour. — All specimens examined correspond to the morph with red-orange chelae, with the colouration extending to two-thirds of the proximal part of the outer margin of the palm and the fingers fading to yellow.

Remarks. — Regarding the missing holotype of this species, Peter Ng, Danièle Guinot, and Charles Fransen offered useful and extensive information based on the nomenclatural rules and material to be found in the collections of Paris and Leiden. Davie (1994: 57) noted that the holotype of this species was “unidentifiable”, with the type locality being Mauritius. The same paper (p. 56) does not list any specimens from H. Milne Edwards, A. Milne-Edwards, or De Man under the material examined; although the author notes later (p. 57) that in the Paris Museum there is a bottle with three female specimens (MNHN-B 10887) from Mauritius that had been labeled as S. meinerti , but dated 10 Jun.1890, three years after De Man’s (1887) paper. As such, he argued that these could not be the types. Davie thus considered the types to be lost, but deferred from designating a neotype because at that time, there was no confusion over the identity of N. meinerti and the stability of the nomenclature was not threatened.

According to article 72.4.1 of the International code of Zoological Nomenclature (ICZN) “the type series of a nominal species-group taxon consists of all the specimens included by the author in the new nominal taxon (whether directly or by bibliographic reference)”. This means that all the material De Man (1887: 648) had in his hands at the time of the description or the specimens listed by the given bibliographic reference (i.e., H. Milne Edwards, 1853 and A. Milne-Edwards, 1873) are syntypes. Now H. Milne Edwards (1853: 184, 185) did not have any figure or material listed for “ Sesarma tetragona ”, and only noted that the species in his report was found in “Ile de France ” (= Mauritius). Alphonse Milne-Edwards (1873: 304–305) gave a longer account and indicated the species occurred in New Caledonia, Mauritius and Madagascar. However, A. Milne-Edwards (1873) also did not indicate how many specimens he had from each location or provide any other data. Presumably, most, if not all the material used by both H. Milne Edwards (1853) and A. Milne-Edwards (1873) were in Paris.

Unfortunately, even De Man (1887) did not list which specimens were studied by him, and he also did not indicate a holotype for Sesarma meinerti . Peter Ng brought to our attention (personal communication) an important and very revealing comment made by De Man in the introduction which he wrote in Jan.1887. De Man (1887: 640) thanked Milne Edwards (presumably Alphonse-Milne Edwards) for his kindness in letting him examine material from the Paris Museum. He also noted that he examined material from Leiden Museum ( De Man, 1887: 641). According to article 72.4.1.1 of the ICZN, for all the taxa established before 2000, “any evidence, published or unpublished, may be taken into account to determine what specimens constitute the type series”. Taking these facts into account, all the material of “ Sesarma tetragona ” of H. Milne Edwards that were examined or seen by De Man up to Jan.1887 from Mauritius can be regarded as types. The same applies for all the material of “ Sesarma tetragona ” from Mauritius, Madagascar, and New Caledonia that A. Milne-Edwards (1873) had up to Jan.1887. As noted above, there is also a good chance that De Man had, in fact, examined this material from the Paris Museum. Whether this material was renamed as S. meinerti or it kept the original identification, we do not know. Moreover, the fact that De Man listed Zanzibar, even though it was not mentioned by H. Milne Edwards (1853) or A. Milne-Edwards (1873), is interesting and suggests that De Man had examined material from this location as well.

It is also possible that any specimens in the Leiden Museum which may have been labeled as S. meinerti up to Jan.1887, would have been examined by De Man and can be regarded as syntypes. Charles Fransen, the curator of Crustacea at RMNH, noted that: “apart from the material of Mauritius ( RMNH D 17503) we also have two specimens from Madagascar ( RMNH D 171 About RMNH ) that were collected in 1863–1866 by F. P. L.Pollen & D. C. van Dam and are indicated as syntypes.” These two specimens were collected from Nosy Bé, northwestern Madagascar. However, according to Ragionieri et al. (2009), all the samples genetically and morphometrically examined from Nosy Bé belong to the African clade, which is named N. africanum , new species, in the present paper. The material from Mauritius now present in the Leiden Museum was collected in 1960, so it could not have been seen by De Man and cannot be considered a syntype .

Fortunately, Danièle Guinot from MNHN was able to relocate the material presumably examined by De Man. She, together with Tohru Naruse and Peter Ng, clarified the origin of the type of N. meinerti as follows: there is a strong presumption that the material initially used by H. Milne Edwards (1837) for Sesarma tetragona (indicated from Indian Ocean) was collected by Mathieu M. in Ile de France (= Mauritius), because the dates of Mathieu’s life correspond to this period. Also, the fact that H. Milne Edwards in 1853 used the same material is indicative of Ile de France as the locality. Thus, the Sesarma tetragona of H. Milne Edwards, 1837, is the same as that of 1853. Alphonse Milne-Edwards (1873: pl. 16, Fig. 4 View Fig ) depicted the Sesarma tetragona specimens of H. Milne Edwards (1837) and (1853). They correspond to the specimens, which De Man (1887) described as new under the name “ Sesarma meinerti ” and hence they are also types of Sesarma meinerti .

Consequently, here we have designated a male (34.00 × 39.30 mm) from the series collected by M. Mathieu in Mauritius (MNHN-IU-2011-278) as the lectotype of Sesarma meinerti De Man, 1887 . The two remaining specimens of this series are to become paralectotypes. The lectotype of N. meinerti (MNHN-IU-2011-278) has similar morphological characteristics as other studied specimens of N. meinerti from the western Indian Ocean islands: carapace shape without any indication of second anterolateral tooth ( Fig. 7a View Fig ); frontal border straight with the postfrontal margin separated into four well-defined lobes, with median lobes much more prominent than external ones, and separated by a deep concavity ( Fig. 7d View Fig ); inner palm of the chela characterised by the presence of a single prominent line of tubercles ( Fig. 7b View Fig ), dorsal surface of dactylus covered with tubercles until three-quarters of its length ( Fig. 7b View Fig ), and descending slope of palm at articulation with dactylus oblique ( Fig. 7c View Fig ). This lectotype selection conclusively fixes the name Sesarma meinerti De Man, 1887 , for the Mauritius taxon.

With regard to the specimens from New Caledonia mentioned by A. Milne Edwards in 1873, all previously identified specimens of N. meinerti from the western Pacific Ocean (such as Guam and Fiji; see Ragionieri et al., 2009) and Papua New Guinea (unpublished data) have been morphologically and genetically identified as N. fourmanoiri . Therefore, we assume that the specimens collected in New Caledonia previously identified as N. meinerti by De Man (1887) and others belong to N. fourmanoiri Serène, 1973 .

Habitat. — Similar to N. africanum , new species (M. Vannini pers. obs.).

Ecology. — Similar to N. africanum , new species (M. Vannini pers. obs.).

Distribution. — The range of distribution of this species extends into the western Indian Ocean from Mauritius (type locality) to Rodrigues, including the islands Aldabra and Mahé Island belonging to the Seychelles.