Two new species of Meropidia Hippa & Thompson, 1983 (Diptera, Syrphidae) from the Andes Mountains

Two new species of Meropidia Hippa & Thompson, 1983 (Diptera, Syrphidae) are described, Meropidia nitida Morales, sp. n. and M. flavens Hippa & Ståhls sp. n., from Bolivia and Colombia respectively. A key to all described Meropidia species is provided.


Two new species of Meropidia
(Diptera, Syrphidae) from the Andes Mountains

Introduction
The Neotropical region has a very high diversity of flower flies (Diptera, Syrphidae), comprising just over 30% of the currently recognized species in the world (Thompson et al. 2010) and many species new to science have continuously been described for genera confined to this region (e.g.Rotheray et al. 2007, 2009, Carvalho Filho and Esposito 2009, Morales et al. 2009, Ricarte et al. 2012).However, few studies on re-gional Syrphidae fauna in the Neotropical region exist, particularly on South America (see Thompson andMarinoni 2003, Montoya et al. 2012 for a review).The genus Meropidia was described by Hippa and Thompson in 1983, comprising three species: Meropidia nigropilosa Thompson, M. neurostigma Hippa and M. rufa Thompson.All described species are confined to the Neotropical region, specifically occurring on Tropical Andes (Hippa andThompson 1983, Montoya et al. 2012).
Besides the simple metafemur, Meropidia is recognized as a moderately pilose taxa, with sexually dimorphic face (male with a broad, low, medial tubercle and female concave), with pollinose pattern on mesonotum and pilose metasternum.It has eye bare and male is very narrowly dichoptic.The wing has variable numbers of stigmatic crossveins; cell r1 open; vein R4+5 slightly sinuate, with a short petiole; vein r-m strongly oblique and long, ending at outer ¼ of discal cell, vein A1+CuA2 very long.The male sex is known only for one species, M. neurostigma (Hippa and Thompson 1983).The authors of this genus suggest that Meropidia is sister group of Orthoprosopa and Paratropidia Hull, 1949, being these three taxa the plesiomorphic sister group to the other genera of Tropidiina (Hippa and Thompson 1983).
The most appropriate identification key to run for the genus Meropidia is that published in Thompson (1999).Because Meropidia is a small genus with species confined to a very particular region, there is no information about biology of its species, neither about immature stages.In addition to the original description work (Hippa and Thompson 1983) and the identification key for Neotropical genera (Thompson 1999), Meropidia is also cited by Montoya et al. (2012), where is presented a review for flower flies fauna of Colombia and a comprehensive review of the literature concerning Colombia and the Neotropical region.It is noteworthy that in a previous work presenting a faunal list of Colombia, Gutierrez et al. (2005) had omitted the genus Meropidia from that list, but Montoya et al. (2012) included the omitted species Meropidia neurostigma Hippa, 1983 andrecorded M. nigropilosa Thompson, 1983 as new to Colombia.
No additional species have been described for Meropidia since 1983, and in the present work two new species, Meropidia nitida Morales, sp. n. and M. flavens Hippa & Ståhls, sp. n., from Bolivia and Colombia respectively, are described.

Material and methods
Terminology follows Thompson (1999).The identification key was constructed based on the key from Hippa and Thompson (1983).
Type localities and holotype holding institutions are specified for each species.Location and identifications labels are indicated with quotation marks (" "), and which line on the label separated by a forward slash (/).Handwritten information on labels is indicated in italics.The acronyms used for collections follow the standard of the Systema Dipterorum (Thompson 2013), and their equivalents are listed below: AMNH American Museum of Natural History, New York, USA.MNHN Muséum National d'Histoire Naturelle, Paris, France.
All measurements are in millimeters and were taken using a reticule in a Nikon SMZ1000 stereomicroscope.Photographs of all new species were provided and were composed using the Combine ZP software based on images of pinned specimens.
In addition, were also provided photographs of the M. nigropilosa holotype, which is deposited at Natural History Museum, London, UK, and has no images available in an online source.

Description of new species
The species described here do not have a concave face, neither a wholly pollinose face as defined in Hippa and Thompson 1983 as diagnostic characters for Meropidia females; but, it is flat with a sub-medial and sub-developed tubercle, and shiny medially.A full generic description of Meropidia is not necessary here, but it is necessary to record that concavity and pollinosity of female face are not diagnostic characters for the genus Meropidia.Otherwise we have no additions or changes to the generic description.Paratype.Adult female.BOLIVIA.Deposited at AMNH, New York City, USA.Labels: same data as Holotype; "COBIMI0011826"; "PARATYPE / Meropidia nitida / Morales, 2013".
Legs: simple, coxae and trochanters dark brown, mostly yellow pilose, intermixed with brownish pile.Pro and mesofemora brownish on basal half and yellow on apical half, yellow pilose, with longer pile ventrally; metafemur mostly dark brown, but apically yellow (Fig. 5), yellow pilose, ventral pile shorter than anterior and posterior surfaces, but longer than dorsal surface, longest pile on anterior and posterior surfaces erect, tilted apically elsewhere.Tibiae yellow, except metatibia slightly brownish medially (Fig. 5), yellow pilose.Metatarsus dark brown (Fig. 5), mostly brownish pilose, with few scattered yellow pile on anterior and posterior surfaces; pro and mesotarsus brown, lighter than metatarsus, yellow pilose.
Wing: completely microtrichose; vein CuP long, almost reaching the level of posterior apex of cell bm (Fig. 5); alula shorter than anal lobe; Abdomen.Tergum I black (Figs 3, 4), lateral corners brownish yellow, with long yellow erect pile laterally, shortest black tilted backward pile elsewhere; tergum II mostly black, with yellow pile on the yellow maculae region (Figs 3, 4), laterally they are erect and longer, on anteromedial 1/3 yellow pilosity tilted backward, pile black and tilted backward elsewhere, scattered pale pollinose on anterior half; tergum III mostly black, with yellow pile on lateral corners and on the yellow macula region (Figs 3, 4), black, posteriorly inclined pile elsewhere, whitish pollinose on anterior half; tergum IV black (Figs 3, 4), black pilose, except white pilose on anterior corners, whitish pollinosity forming two anterior triangular-like macula.Sterna dark brown, slightly pale pollinose; sterna I-III yellow pilose, IV yellow pilose intermixed with brownish pile; sternum V brownish pilose.
Wing: completely microtrichose; slightly brownish along veins, wing veins brownish-yellow; four stigmatic crossveins; vein CuP long, almost reaching the level of posterior apex of cell bm (Fig. 11); alula shorter than anal lobe.
Abdomen.Tergum I yellow (Fig. 11), yellow pilose anteriorly, black short pilose posteriorly; tergum II yellow with brown spot antero-medially and posterior brownish stripe (Fig. 11), with long yellow pile at anterior corners and triangular area with short black pile; tergum III with antero-lateral corners broadly yellow (Fig. 11) and with yellow pile, with posterior brownish stripe with short black pile; tergum IV brown with antero-lateral corners yellow (Fig. 12) with short black pile.Sterna brownish, long pale pilose; sternum II with lateral areas yellow.
Comments.Only type known.

Discussion
The Tropical Andes, including parts of Venezuela, Colombia, Ecuador, Peru, Bolivia and Argentina, is the biologically richest and most diverse of Earth's biodiversity hotspots areas, mainly for vertebrates and plants (Myers et al. 2000).Although that area retains about 25% of its primary vegetation, is believed to contain, at least, 20,000 known plant endemics and probably thousands of species remain to be discovered there (Myers et al. 2000).Because many insects are associated with plants, the extreme plant endemism of the Tropical Andes suggests a similar high level of insect diversity and endemism (Larsen et al. 2011).
The high altitudes of the Andes (above 3000 masl) include the most endangered and vulnerable ecosystem in South America and it is one of the three areas where the largest changes in fauna are predicted as a result of climate change (e.g.Lawler et al. 2009, Larsen et al. 2011).Montoya et al. (2012) found that the Colombian Andes has the highest diversity and number of endemic species of Syrphidae.Species in the Neotropical genera Macrometopia Philippi, 1865, Meropidia, Talahua Fluke, 1943and Tuberculanostoma Fluke, 1943 were in their study found to be restricted to the high altitudes above 3000 masl of the Colombian Andes.
Therefore, these taxa might be considered focus groups in future conservation projects due to the predictions of the impact of the climate change.The species described here also occur at altitudes between 2000-3000 masl and are thus important additions to the knowledge of the biodiversity of the high Andes flower fly fauna.
Of the five Meropidia species now known for the science, the male sex is still only known for M. neurostigma.The hitherto described Meropidia species are distributed in Bolivia, Colombia and Ecuador.