Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Images: USNM syntype worker, face view (large); lateral view (large); dorsal view (large); pin with series (large); label (large). Worker from St. Croix, specimen JTLC000005414 (large). Queen from St. Croix, face view, specimen JTLC000005415 (large). Queen from Puerto Rico, face view, specimen JTLC000005419 (large). Queen from Santo Domingo, West Indies, face view, specimen JTLC000005427 (large). Queen from Dominican Republic, face view, specimen JTLC000005429 (large).
Range
Widespread on Caribbean islands.
Comments
Below is a summary of Myrmelachista taxa known from the Caribbean:
Myrmelachista kraatzii Roger 1863:162. Syntype worker(s): Cuba [Matanzas, C‡rdenas in Kempf 1972].
Myrmelachista rogeri Ern. AndrŽ 1887:288. Holotype worker: Cuba. Description of queen, redescription of worker: Wheeler 1934:190.
Myrmelachista rogeri var. manni Wheeler 1934:190. Syntype workers: Cuba, Oriente, Saetia, workers on tree trunk (Mann) [USNM] (examined). (= rogeri in the sense of Mann 1920:434).
Myrmelachista rogeri var. rubriceps Mann 1920:434. Syntype workers: Cuba, Pinares, numerous workers from trunks of pine trees (Mann) [USNM] (examined).
Myrmelachista ambigua Forel 1893:350. Holotype worker: Lesser Antilles, Saint Vincent, Upper Richmond Valley (H. H. Smith).
Myrmelachista ambigua ramulorum Wheeler 1908:155. Syntype workers, queens, males: Puerto Rico, Culebra Island (Wheeler); Puerto Rico, Arecibo, Utuado (Wheeler) [MCZC, USNM] (USNM syntype worker examined). Raised to species: Wheeler 1934:189.
Myrmelachista ramulorum subsp. fortior Wheeler 1934:189. Syntype workers: Puerto Rico, Mona Island (Lutz). "...described from nine specimens ..., seven from Mona Island (type locality) and two from Porto Rico, without more precise locality." (Wheeler 1934).
Myrmelachista gagates Wheeler 1936:204. Holotype worker: Haiti, La Visite, 6000-7000 ft (Darlington).
The above are all the species and subspecies known from Caribbean islands. My knowledge of the Caribbean fauna is limited, but I have examined 20 collections of ramulorum from Puerto Rico, St. Croix, USA (Florida, possibly introduced and then extirpated, see Deyrup 2003), Santo Domingo, St. Thomas, and the Dominican Republic; three collections of rogeri from Cuba; syntypes of rogeri manni from Cuba, and syntypes of rogeri rubriceps from Cuba. All appear to be similar to plebecula. All are bicolored or various shades of red brown. Unlike plebecula, all have long erect setae projecting from the sides of the head (workers and queens). Eight queens of ramulorum are very small with very narrow, rectangular heads. The largest of these have the narrowest heads, with HW around 0.70mm and CI around 74, a combination not found in any Costa Rican species except for the one small longiceps-like queen described under longiceps in Longino (2006). Unlike ramulorum, the longiceps-like queen lacks erect setae on the sides of the head. The smallest ramulorum queens and the queens of rogeri are in the same size range as plebecula queens, but with relatively narrow heads. All measured queens of plebecula have CI 85 or greater. The highest CI among the ramulorum and rogeri queens is 82. Myrmelachista kraatzii, ambigua, rogeri, and ramulorum are all older names than plebecula, and if plebecula proves to be an allopatric variant of a widespread polytypic Caribbean species it will no doubt be a synonym of one of these older names.
It is not clear that rogeri and ramulorum are distinct. When two Cuban rogeri queens I have measured are compared to eight ramulorum queens from other islands, they are at the small end of a continuum of measurements.
Myrmelachista ambigua was described from a single worker from St. Vincent. Given the relative uniformity of workers, the published description and even examination of the type will be of little use. Queen and male-associated collections of Myrmelachista from St. Vincent will be needed to compare with material from other parts of the Caribbean. Wheeler (1908) considered the worker of ramulorum close to ambigua.
Myrmelachista gagates, from Haiti, was described as being close to rogeri but solid black.
It will be important to examine multiple collection of Myrmelachista from Cuba, to ascertain whether there are multiple sympatric species there. It is unknown whether kraatzii and the forms of rogeri are distinct or represent one variable species. Myrmelachista kraatzii from Cuba and M. nigella from Venezuela are the two oldest names in the genus, kraatzii being a 9-segmented form and nigella a 10-segmented form. Thus kraatzii would have priority among all the 9-segmented forms.
One collection from El Yunque, Puerto Rico, is indistinguishable from M. longiceps. It is a collection of workers and alate queens, collected by Juan Torres. I am reluctant to identify it as longiceps until more Puerto Rican material is obtained, but there is a large size gap between the queen of this El Yunque collection and the various queens of ramulorum from elsewhere in Puerto Rico.
From these observations it is clear that more collections are needed from the Caribbean to better understand species boundaries in this group.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
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