Synonyms

Gymnocalycium marsoneri ssp. megatae, Gymnocalycium brevistylum, Gymnocalycium eytianum, Gymnocalycium fricianum, Gymnocalycium hamatum, Gymnocalycium matoense, Gymnocalycium marsoneri ssp. matoense, Gymnocalycium onychacanthum, Gymnocalycium tortuga, Gymnocalycium tudae

Distribution

Bolivia (Santa Cruz, Tarija), Brazil (Mato Grosso do Sul), Paraguay (Alto Paraguay, Boquerón)

Conservation status

(5)   Least Concern, LC

Comments

At present the relationship between Gymnocalycium megatae Y. Itô and Gymnocalycium marsoneri Fric ex Y. Itô does not appears so evident to us. G. megatae is considered in Anderson (2001, 355) to be a synonym of G. marsoneri, in Hunt et al. (2006, text: 130) a synonym of Gymnocalycium marsoneri ssp. matoense (Buining & Brederoo) P. J. Braun & Esteves, and in Charles (2009, 241) subspecies of G. marsoneri. It is our opinion that G. megatae was probably a widespread species, which starting from the line Charagua-Boyuibe-Palos Blancos in the Bolivian Chaco, and crossing the Chaco Boreal (i.e. the Dptos of Boquerón and Alto Paraguay in Paraguay, where there are still populations of the taxon), it arrived in the area of Porto Murtinho, Mato Grosso do Sul (BR) where the Chaco becomes Pantanal. The taxon known as Gymnocalycium matoense Buining & Brederoo, which we could not to locate, and that is probably near extinction (Braun & Esteves 2001, 63), was at the edge of the area, to the east of the populations of G. megatae. The photographic documentation available (ibid., 123; Charles 2009, 239-240) confirms that the two taxa are closely related. On the contrary, in addition to the distance of the distribution area, which by itself might be weak data [as in populations of Gymnocalycium pflanzii (Vaupel) Werdermann]; when not also supported by a real diversity between the taxa, in habitat the appearance of G. megatae (A&M 656, photos 1-21; A&M 664, photos 22-30) is completely different from G. marsoneri (A&M 509, photo 1-26). The first has acute, sharp, angular ribs (a character which unites it with G. matoense), the second has ribs that are divided into large rounded tubercles. The first has thin spines spreading from the stem, the second has large spines, wide at the base, appressed on the stem surface. We do not understand where the idea that these two taxa are related came from. Concerning the distribution of G. megatae, we must stress that the taxon currently occupies a strip of land between the Charagua-Boyuibe-Palos Blancos line, in Bolivia, and the Mennonite colonies, in the Paraguayan Chaco. As highlighted in the comment on Gymnocalycium anisitsii (K. Schumann) Britton & Rose, the populations known as Gymnocalycium pseudomalacocarpus Backeberg and Gymnocalycium anisitsii ssp. holdii Amerhauser, attributed by Charles (2009, 244-245, 285) to G. megatae, are to be attributed to G. anisitsii. (Quoted from: Anceschi & Magli 2013b, 59-60)

Genus

Gymnocalycium

Other species

alboareolatum
andreae
anisitsii
baldianum
bayrianum
bodenbenderianum
borthii
bruchii
buenekeri
calochlorum
capillaense
cardenasianum
castellanosii
chiquitanum
denudatum
eurypleurum
ferrarii
fischeri
glaucum
horridispinum
horstii
hossei
kieslingii
marsoneri
megatae
mesopotamicum
mihanovichii
monvillei
mostii
nigriareolatum
oenanthemum
paediophilum
paraguayense
pflanzii
reductum
ritterianum
robustum
saglionis
schickendantzii
schroederianum
spegazzinii
stellatum
stenopleurum
uebelmannianum
uruguayense