A new species of Lohmannia ( Acari : Oribatei : Lohmanniidae ) from mangroves at Quintana Roo ( Mexico )

A new species of Lohmannia, L. maya n. sp., from mangrove soils in Mexico is described and illustrated. It is morphologically similar to L. similis Balogh, 1962, L. jornoti Mahunka, 1985 and L. lanceolata Grandjean, 1950 but differs from these species in having lateral and posterior setae wide in their proximal half and thin in their distal half, ending in a sharp tip, and a continuous notogastral band S8. It also has a smaller body size (727 μm) compared with the three aforementioned species (790, 810 and 840 μm respectively). The 11 species of the genus Lohmannia recorded from the Americas were compared, a key for them is included, and some ecological notes for the new species are also provided.


INTRODUCTION
Data on taxonomy and ecology of oribatid mites from Mexico have been increasing in the last two decades (Palacios-Vargas & Iglesias, 2004) and ecological contributions have been published recently (García et al. 2014). Six genera of the family Lohmanniidae are known from Mexico, among which the genus Lohmannia is represented by three recorded species: L. banksi Norton et al., 1978 from Veracruz, Campeche and Hidalgo states;L. juliae Mahunka, 1984 from Veracruz and L. lanceolata Grandjean, 1950 from Quintana Roo (Vázquez, 2001).
Much later after the review of the Lohmanniidae by Granjean (1950), that of Sengbusch (1984) included the description of a new species from Micronesia and a comparison with most of the known taxa belonging to the genus Lohmannia. Recently, Norton and Ermilov (2014) did a historical review of immature oribatids where they include members of Lohmannia.
In this contribution we describe a new species of Lohmannia from Mexico and a key for those known from the Americas is provided and some new ecological data for the new taxon is given.

MATERIALS AND METHODS
Mites were collected from mangrove soil and litter samples from Chetumal Island and fixed in 75% ethanol. Only 34 specimens of Lohmannia were found, and some were mounted under smooth slides in Hoyer's solution and other were kept in 75% ethanol. Four specimens were dissected and mounted. Observations and measurements were undertaken under a phase-contrast Carl Zeiss microscope Axiostar plus and drawings were done with the aid of a "camera lucida". In the description, all body measurements are in micrometers (µm) and indicated between parentheses after each morphological character. Setal nomenclature follows those of Grandjean (1950) and Norton (1977).
Paratypes -All specimens are females, 15 on slide and 18 stored in 75% ethanol. Original labels. 04/sep/2011, ex mangrove litter of littoral marine sand, A. García col. All the material will be deposited in the acarological collection of Laboratorio de Ecología y Sistemática de Microartrópodos, Facultad de Ciencias, UNAM.
Notogaster -( Figure 1A) Lateral margins parallel in anterior half, posteriorly rounded. Transverse bands weekly developed, bands S 3 -S 7 and S 9 incomplete and interrupted medially; S 6 incomplete on each side. Band S 8 complete. Lyrifissures hardly discernible: ia located laterally, at the level epimeral setae 3c; im located dorsally, next setae e 2 ; ip laterally, in the middle part of notogaster; ips ventrally, next to preanal plate and ih between setae h 3 and p 3 ( Figures 1A-B).
Preanal plate wide, width equal to that of genital plate. Adanal setae phylliform with serrated margins tapering distally. The 4 th pair of adanal setae slightly thinner. Measurements of setae: ad 1 = 79, ad 2 = 81, ad 3 = 81, ad 4 = 79. Anal setae setiform and smooth; the second pair of anal setae reaching the insertion first pair. Measurements of anal setae: a 1 = 49, a 2 = 59. One additional adanal seta was observed in one specimen.

Material Examined
Distribution -Known only from the type locality, at Cozumel, Quintana Roo, México.
Ecology -It seems that species of this genus are quite well adapted to salinity, as several specimens of L. similis Balogh, 1962 were collected from mangrove in Bermuda Islands (Schatz & Schuster, 2012) and Galápagos (Schatz, 1993), L. jornoti Mahunka, 1985 described from Marie-Galante (Antilles), was collected from the beach pebbles and L. maya n. sp. comes from Laguna Chuc Chacaab, Cozumel, Quintana Roo, in mangrove litter close to marine littoral where A. germinans tree was dominant. It may be a quite rare species as it was only found in three of the four months sampled: March, September and November but not in April. Relative humidity was 59 and 91 % during dry and rainy season, respectively. Temperature was 29.69 -24.67°C at noon; soil salinity was 36.8 -32.3%, while pH very alkaline (7.5-8.7). A total of 200 samples were col-    II  II  II  VII VIII II  II  III  I  I  II  I  I  III  III  930  390  L. jornoti Mahunka, 1985  II  II  II  V VIII II  II  III  I  II  II  VI  II  I  II  826 410 L. vulcania Schatz, 1993 II II  II  V VIII II  II  III  I  II  II  I  II  I  II  1125 500 L. (Carolohmannia ) carolensis Norton et al ., 1978 IV IV  II  II VIII IV  IV  III  I  II  II  I  I  I  IV  1025  631 L. maya n.sp .  II  II  II  VII VIII  I  II  III  I  II  II  III  II  III  II  751  lected and processed using by Berlese funnels. Only 34 specimens of Lohmannia were found, which represent a very low percentage among the Oribatid mites (García et al. 2014).
Remarks -Schatz (1993) made a comparison of several neotropical species from the "lanceolate" group and studied the variation of specimens of L. lanceolata from two localities: Peru and Galapagos Islands. Lohmannia maya n. sp. is very close to L. lanceolata Grandjean, L. jornoti Mahunka, and L. similis Balogh, as they share the following characteristics: they have similar shape and length of rostral setae, lateral margins of notogaster in the anterior part are parallel; both, rostral setae and marginal setae on notogaster are phylliform; however, these last setae are very thin on the second half of notogaster of the new species. Differences to other species are that the length of setae exp in L. maya n. sp. is twice its width, lateral setae of notogaster are wider and bent at the proximal half and are very thin in distal half; first half of setae p 1 is wide and thin at the end, the band S 8 is continuous; from subcapitulum, seta m 2 is setiform and thinner than seta h, besides that the new species is the smallest in length among all Lohmannia known from Americas (table 2). Also, other members that occur in Americas are compared in table 2 and a key to the Lohmannia species from Americas is presented herein.