Taxonomy and phylogeny of a new Central American beetle genus : Catrachia ( Coleoptera : Scarabaeidae )

A new genus and two species of Melolonthinae from Honduras and Nicaragua are described. A phylogenetic analysis, carried out using morphological characters, suggests that Catrachia is a strongly supported monophyletic group. Catrachia is therefore established as a new genus, constituted by two new species, Catrachia mariana and Catrachia nica. Rev. Biol. Trop. 54(1): 000-000. Epub 2006 Mar 31.

The aim of this work is to contribute to a better understanding of the biodiversity of the Melolonthinae in the Neotropical Region.A new genus and two species from Honduras and Nicaragua are described and established with phylogenetic support.
The phylogenetic analysis was based on external morphology, mouthparts and genitalic characters.
The mouthparts and genitalia (male and female) were removed and cleared in a hot solution of 5% KOH.After clearing, they were studied under immersion in distilled water.Additionally, the female genitalia were dehydrated in a progressive ethanol series (70%, 90%, 95% and 100%) and mounted in Euparal.
Phylogenetic analysis was carried out using PAUP 4 (Swofford 2003).A heuristic search was used to find the most parsimonious trees.Support for the clades in the tree was assessed with bootstrapping (Felsenstein 1985).
Diplotaxis tristis Kirby 1837 was selected as the outgroup because the genus Diplotaxis is a sister group of the Phyllophaga.
The genera Trichesthes and Phyllophaga are represented by the type species T. tristis (F.1781) and P. hirticula (Knoch 1801).In addition, representative species belonging to other subgenera in the Phyllophaga were selected to reflect the variation within the genus (Table 1).
The data set comprises 26 characters scored across 23 taxa.The characters include 16 from the external morphology (including mouthparts) and 10 from the genitalia (6 male, 4 female).Characters were polarised using the outgroup method as described by Nixon and Carpenter (1993).The multistate characters were treated as non-additive (Fitch 1971).In unordered multistate characters, the distance between all pairs of states was treated as a single step.The character state matrix used in the phylogenetic analysis may be seen in Table 1.
(0) Semi-circular; (1) bi-lobed; (2) rectangular.Head: Antenna with 9 segments; antennal club with three segments and shorter than the stem; mandible with edge of the incisor lobe straight (Figs. 1 and 3); moderately wrinkled molar lobe (Fig. 2); galea of the maxilla with very poorly developed teeth (Figs. 4 and 5); labrum gently depressed in the middle (Fig. 6 and 7) with very little pubescence; clypeus shorter than frons, clypeus abruptly widens from base and then quickly narrows; lateral sides arcuate and elevated in relation to the eye edge, anterior margin not sinuate at the middle; head coarsely and closely punctated ; head coarsely and closely punctated and with conspicuous, with not very abundant pubescence; frontal carina highly developed; depressed vertex with punctures more densely distributed than on the frons; small and flat ocular carina; small eyes hidden by the anterior angle of the pronotum.
Prothorax: In dorsal view, glabrous pronotal surface with scattered punctures; anterior angles of the pronotum very sharp and prolonged towards the eyes; anterior margin of the pronotum thick, elevated and with a row of pubescence; posterior angles obtuse with rounded apex; softly serrated lateral margins, with scarce and short pubescence.Elytra: Glabrous elytral surface with shallow punctures; smooth, not striated.
Legs: Fore tibia with three teeth; meso and meta tibia with developed lateral carina.Cleft tarsal claws.
Male genitalia (Fig. 8): With parameres short (1/3 phallobase, approximately), ventrally separated.Endophallus long and thin (but not flagello-shaped); joined to the parameres by simple temones having two dorsal structures of differing shape and size.Epithelium of the endophallus covered with scattered sensillae.Genital segment with reduced vestigial sternite.
Etymology: General Florencio Xatruch led the defense of Honduras in 1857 against an attempted invasion by North American William Walker.The complimentary nicknames "catracho" or "catracha" (derived from Xatruch) refer to people of Honduran descent.This genus is named to honour the people of Honduras who endeavour to preserve the biodiversity of Central America for the benefit of all.Description: Habitus as in Figures 9 and 10.In addition to the generic features, this species can be characterized by: antennal clubs about the same size in both sexes.Pronotal surface with wide and deep punctures; punctures more densely distributed on the anterior edge than on the remaining part of the pronotum.Pygidium with wide and deep punctures of indistinct outline and inconspicuous pubescence on the surface.Dorsal surface of the metatibia with an edge.
Male genitalia (Fig. 8) with highly developed and spear-like, dorsal structures of the temones which are recumbent when the endophallum is at rest, and raised when the endophallum is projected.Endophallum with a raspullae in the ventral position.
Female genitalia very little sclerotized.Large, deep genital chamber with the distal edge sclerotized, thick integument, well developed sternites, dorsal genital palpi and two thin and long tergites.Median oviduct without sclerotized structures and with membranous integument.Pedunculated bursa copulatrix with a proximal duct (ductus bursae) and a slightly dilated distal blister (corpus bursae).Spermatheca inserted directly on the median oviduct and twice as short as its gland.Two accessory glands.
Material examined: All specimens of the type series were trapped in Zamorano, Honduras between May 27 and June 6, 1996 in a sex attractant trap.
Etymology: This species is named to honor Maryann Robbins, wife of the junior author, whose enthusiasm for, and willingness to participate in numerous beetle adventures has made the life work of the junior author pleasant indeed.
Description: Habitus as in Figure 11.In addition to the generic features, this species can be characterized by: pronotal surface with homogeneously distributed thin and shallow punctures.Pygidium with thin, deep and outlined punctures; conspicuous surface pubescence.Dorsal surface of the metatibia scarcely dentate and with an edge.
Male genitalia with the dorsal structures of the temones relatively undeveloped and drumstick shaped.Endophallum without raspullae in ventral position Material examined: type specimen trapped in Estelí, Nicaragua, 5/28/00 in a sex attractant trap.
Etymology: This species is named in honor the people of Nicaragua who endeavor to preserve the biodiversity of Central America for benefit of all.12 13 14 15 Phylogenetic analysis A maximum parsimony analysis (heuristic search) using equal weights yielded 18 equally parsimonious cladograms, each with 67 steps.The consistency (CI) and retention (RI) indices were 0.567 and 0.803, respectively.All consensus trees displayed the same topology except in the terminal taxa .
The results of character weighting were stable in three successive iterations, yielding 6 trees of length 314 steps, a CI of 0.732 and an RI of 0.887 All weighted consensus trees displayed the same topology (Fig. 16).
The bootstrapping analysis (Fig. 17   node, one comprised of Catrachia mariana and Catrachia nica, and the other composed of species from Phyllophaga, Chlaenobia, Chirodines, Cnemarachis, Listrochelus, Phytalus and Trichesthes . The bootstrap analysis provides considerable support for the clade established by the two species included in the new genus Catrachia (97% bootstrap) (Fig. 17).This clade is supported by unambiguous synapomorphic characters (CI=1 and RI=1) such as the lateral edges of the clypeus strongly elevated over the eyes (character 2) and a well developed frontal carina (character 3).The second major clade also has considerable support (75% bootstrap) but there is, however, a basal conflict that leaves unresolved the relationships of the taxa in question.

DISCUSSION
Catrachia constitutes a monophyletic group that is well supported (Fig. 17  Morphological and genitalic features which distinguish Catrachia from allied genera and subgenera (lateral sides of clypeus strongly elevated over the eyes, strong frontal carina and temones with two dorsal structures), together with its phylogenetic position as sister group of the genus Phyllophaga, allow us to establish Catrachia as a group with the same taxonomic rank as the genus Phyllophaga.Therefore, the genus Catrachia is hereby established with two species: Catrachia mariana and Catrachia nica.
Catrachia mariana Coca-Abia and Robbins (NEW SPECIES) Types: Holotype: A male specimen in the collection of the Museo Nacional de Ciencias Naturales, Madrid (Spain) (MNCN), is the designated Holotype, labelled as: 1) white and printed label: Honduras, VI 1996, pheromone trap 100/0 valine/isoleucine; 2) red and printed label: Holotype, Catrachia mariana Coca-Abia and Robbins, 2005.Paratypes: A male and four female specimens in the collection MNCN are designated Paratypes, labelled as: 1) white and printed labels: Honduras VI 1996, pheromone trap 100/0 valine/isoleucine; 2) red and printed label: Paratype, Catrachia mariana Coca-Abia and Robbins, 2005.Other specimens of C. mariana were deposited in the following collections: Cornell University, Ithaca, NY, USA; Florida State Collection of Arthropods, Gainesville, Florida, USA; Escuela Agrícola Panamericana de Zamorano, Apartado Postal No. 93, Tegucigalpa, Honduras; University of Nebraska State Museum, Systematics Research Collections, Lincoln, Nebraska, USA, and the personal collection of the junior author (PSR).
) provided considerable support for the basal clade (87% bootstrap).Triodonyx gigantissima occupies a basal position outside the main clade.Two clades emerge above the T. gigantissima
) by autapomorphic characters which clearly distinguish it from Phyllophaga, Chlaenobia Blanchard 1850, Chirodines Bates 1888, Cnemarachis Saylor 1942, Listrochelus Blanchard 1850, Phytalus Erichson 1847 and Trichesthes Erichson 1847.These allied genera and subgenera form a monophyletic group, but this analysis does not resolve their phylogenetic relationships.The cladogram does, however, provide clear evidence that Catrachia and its allied genera and subgenera are sister clades (Fig.17 ).