A new species of Ripipteryx from Belize with a key to the species of the Scrofulosa Group (Orthoptera, Ripipterygidae)

Abstract A new species of the genus Ripipteryx (Orthoptera: Tridactyloidea: Ripipterygidae) from the Toledo District of southern Belize is described and illustrated. Ripipteryx mopana sp. n. is placed in the Scrofulosa Group based on its elaborately ornamented frons and is readily distinguished from its congeners by the fusion of the superior and inferior frontal folds to form a nasiform median process, the epiproct with both anterior and posterior margins emarginate, the subgenital plate with distinct lateroapical depressions either side of the median line, the basal plate of the phallus strongly bilobed apically, and the development of well-demarcated denticular lobes in the dorsal endophallic valves. A preliminary key to the species of the Scrofulosa Group is provided.


Introduction
Neotropical tridactyloids are both diminutive and cryptic, and being collected only rarely, are also underrepresented in collections. The tridactyloid fauna of Central America in particular is extremely diverse and yet simultaneously poorly documented. Indeed, only 19 tridactyloid species are recorded from Mesoamerica compared to over 100 known from South America (Otte 1997;Günther 1980;Eades et al. 2011). Work on Mesoamerican tridactyloids began with Saussure's (1859) description of Ripipteryx mexicana from Oaxaca, Mexico and continued with his contribution to Biologia Centrali-Americana (Saussure 1896) in which he described 17 additional species. These taxa were subsequently revised by Günther (1969Günther ( , 1975Günther ( -1977Günther ( , 1989) who added several species to the fauna and synonymized others. Despite Günther's work however, chronic under-sampling in the region means that very little is known about tridactyloid diversity in Mesoamerica and even less about their biology.
The genus Ripipteryx Newman, 1834 is exclusively Neotropical, with some 44 species distributed throughout South and Central America (Günther 1969(Günther , 1980Heads 2010). The majority of Ripipteryx species known from Mesoamerica belong to the Scrofulosa Group, a presumably monophyletic group comprised of small, variegated species characterized by their peculiar and elaborately ornamented frons and tuberculate or denticulate dorsal endophallic valvulae (Heads 2010). Here, we provide for the first time, a key to the Scrofulosa Group and describe a distinctive new species as the first record of the family Ripipterygidae from Belize.

Material and methods
The holotype is deposited in the Entomology Collection of the Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois, and was studied using an Olympus SZX12 zoom stereomicroscope with 1× and 2× objectives. Drawings were produced with the aid of a camera lucida. Photomicrographs were made using a digital SLR camera and 65 mm macro lens. To examine the terminalia and phallic complex, the abdomen was removed using Vannas' scissors and cleared in warm 10% KOH. The phallus was then dissected and subsequently stored together with the terminalia under glycerin in a glass microvial pinned beneath the specimen. Terminology generally follows that of Heads (2010) with modifications concerning structures associated with the highly modified male paraproct. In most tridactyloids, the paraproct bears two distinctive processes: [1] a well-sclerotized proximal hook-like structure, herein termed the uncus ("Hakensklerit" of Günther 1969); and [2] an elongate, cercus-like structure, herein termed the brachium ("Paraproctfortsatz" of Günther 1969). Description. Male: Body form small (length 4.54 mm from frons to apex of subgenital plate) and compact with coloration highly variegated (Figs 1-2). Vertex largely black, with crescent-shaped pale cream patches circumscribing the anterodorsal margins of the compound eyes. Interocular distance 0.73 mm. Compound eyes broadly subovoid, 0.86 mm high. Lateral ocelli very small, situated very close to the medial margin of the compound eyes. Median ocellus absent. Frons largely pale cream fringed with reddish brown and bearing numerous elaborate folds and lobes; comprising a central nasiform process formed through fusion of the superior and inferior folds, flanked by deep, sinuous furrows themselves bordered by broad ridges and lobes; frontoclypeal lobe present (Fig. 1). Antennae ten segmented, moniliform, inserted directly beneath the compound eyes. Scape twice as long as pedicel; flagellomeres densely pubescent and wider apically than at their base. Scape, pedicel and flagellomeres 1 and 2 pale cream dorsally and black ventrally; flagellomere 3 almost entirely black; flagellomere 4 with triangular-shaped pale cream patch dorsally and black ventrally; flagellomere 5 almost entirely pale cream; remaining flagellomeres entirely black. Pronotum somewhat tectate anteriorly (Fig. 2), 1.77 mm long, broadly rounded posteriorly; black with broad, pale cream lateral and posterior margins and a prominent orange-brown median patch dorsally that is obovate anteriorly and rhombiform posteriorly. Tegmen entirely black, 2.38 mm long. Hind wing remigium entirely black; posterior fan cream. Profemora 1.18 mm long, black to dark brown dorsally and pale brown to cream ventrally. Protibiae claviform and largely black with a pale cream longitudinal stripe. Mesofemora 1.91 mm long, subquadrate in section, black dorsally and pale cream ventrally. Mesotibiae black with a prominent pale cream longitudinal stripe along the dorsolateral margin. Metafemora large and robust, 3.28 mm long, reddish brown medially with broad pale cream bands dorsally and ventrally; geniculae well-developed, dark reddish brown with pale cream apices. Metatibiae 3.14 mm long, pale yellowish brown with prominent darker dorsal carinae; apical metatibial spurs blade-like with prominent apical hooks, more than twice as long as subapical spurs. Metatarsus sublanceolate, 0.66 mm long, marginally shorter than the apical metatibial spurs. Posterior margin of abdominal tergite 10 broadly emarginate with prominently bilobed membranous median region (Fig. 3). Epiproct with large, densely reticulate lateral lobes and emarginate anterior and posterior margins. Cerci fusiform, bearing numerous long and evenly spaced setae. Paraprocts with large, well-sclerotized and strongly hooked uncuses and robust, apically thickened brachia bearing numerous strong ventroapical setae; brachia only marginally longer than cerci (Fig. 3). Subgenital plate broadly rounded with prominent lateroapical depressions either side of the median line; densely pubescent apically (Fig. 4). Phallus with basal plate strongly bilobed apically; cingulum broad and furcate, thickened laterally and bearing elongate, gently curved apodemes; dorsal valves of the endophallus forming flexible lobes armed with numerous denticles; virga filiform with an uncinate basal articulating process (Fig. 5).

Genus
Female Etymology. The specific epithet honors the Mopan, a Mayan people that live primarily in the southern part of Belize where the new species was collected. There is considerable ethno-historic and toponymic evidence to suggest that the Mopan have lived in this region since before the Spanish conquest (Jones 1998;Wainwright 2009). The Mopan people are recognized by their eponymous language (a form of Yucatec Mayan), spoken by 11,800 people in Belize and Guatemala (Lewis 2009). The gender of the epithet is feminine.
Remarks. Ordinarily, we would hesitate to describe a new species based on a single specimen. However, given the number of robust morphological apomorphies there can be no doubt that R. mopana is a distinct species. Within the Scrofulosa Group, R. mopana is most similar to R. biolleyi Saussure, 1896 sharing with this species the loss of the median ocellus and the distinctive nasiform frontal process. The nasiform process in R. biolleyi is formed by the upturned apex of the inferior fold strongly overlapping that of the superior fold. Ripipteryx mopana differs in that the apex of the inferior fold is completely fused to the underlying superior fold (Fig. 1). The frontal ornament of R. mopana further differs from that of R. biolleyi in the presence of carinulated pits on the lateral lobes of the inferior fold and deep, sinuous furrows (rather than ovoid cavities as in R. biolleyi) flanking the nasiform process. Both species possess a furcate cingulum with long, slender apodemes, though the apex of the basal plate is strongly bifurcated in R. mopana and undivided in R. biolleyi. Together, R. biolleyi and R. mopana appear to be most closely related to R. saltator Saussure, 1896 andR. saussurei Günther, 1969 sharing with these species a deep invagination of the inferior fold above the frontoclypeal lobe and the development of well-sclerotized denticles in the dorsal valves of the endophallus. These denticles are directed posteriorly and arranged in rows along valvular axial lobes, which are particularly well developed in R. mopana (Fig. 5). Denticular lobes are not present in R. mediolineata Saussure, 1896, R. mexicana Saussure, 1859, R. scrofulosa Günther, 1969and R. tricolor Saussure, 1896 all of which instead possess rows of weakly sclerotized, tubercle-like rugosities (Günther 1969). Of these species, R. mediolineata and R. scrofulosa are apparently the most primitive of the group having the frontal folds poorly developed and lacking a frontoclypeal lobe.
Preliminary key to species of the Scrofulosa Group