Resurrection of Dryotomicus Wood and description of two new species from the Amazon River Basin (Coleoptera, Curculionidae, Scolytinae, Phloeotribini)

Abstract A cladistic analysis based on 20 morphological characters was conducted for 11 species representing two valid and two synonymized Phloeotribini genera. One hundred-eighty most-parsimonious trees were recovered and the Dryotomicus Wood species were monophyletic in a mostly unresolved strict-consensus tree. The unusual antennal morphology, with the length of the first two funicular segments equal to the last three segments and a scape which is twice the length of the funicle, distinguish Dryotomicus from the other Phloeotribini genera. Hence this genus is resurrected because of monophyly and diagnostic characters. Dryotomicus oenophilis sp. n. and Dryotomicus woodrex sp. n. are described from Guyana and Peru, respectively. In the male specimen of Dryotomicus oenophilis, the frons has one median and two large lateral carinae and in the male specimen of Dryotomicus woodrex, the frons has three smaller median tubercles arranged transversely. Phloeotribus puberulus Chapuis and Phloeotribus tuberculatus (Eggers) were monophyletic with the new Dryotomicus species and thus are transferred to this genus. Keys to the Phloeotribini genera and Dryotomicus species are given.


Introduction
Th e most diverse and unknown scolytine fauna lies in the tropics. Although a recent monograph of the South American scolytines has been published, approximately another 2500 species remain undiscovered in the Neotropics (Wood 2007). Among these species, are lineages with previously unobserved morphologies, some of which represent undescribed genera. For example, Dole and Cognato (2007) described Akrobothrus ecuadoriensis because of the elytral depression around the scutellum, which is a rare character among scolytines. Similarly, we recently discovered two morphologically interesting species of the Phloeotribini collected from primary wet forests in Guyana and Peru. Although the pseudo-lamellate antennal club places these new species in Phloeotribus Latreille, the unusually long funicle and scape suggests the placement of these species in a diff erent genus. Phloeotribini currently contains two genera: Phloeotribus which is represented by ~100 species distributed in the Holarctic, South America (with highest diversity), and Australia and Aricerus Blandford which is represented by three Australian-New Guinea species (Wood 1986). However, as many as nine previously recognized genera have been synonymized with Phloeotribus and, of these, the Neotropical genera Eulytocerus Blandford and Dryotomicus Wood resemble the recently collected specimens based on previous descriptions (Chapuis 1869;Blandford 1897;Schedl 1962;Wood 1962).
In this study, we assembled specimens of Neotropical, Nearctic, and Australian Phloeotribini and conducted a cladistic analysis, which justifi ed the resurrection of Dryotomicus and the description of two new species.
Using this data matrix (Table 2), most parsimonious trees (mpts) were reconstructed by a branch and bound search in PAUP* 4.0 b10 PPC using default settings (Swofford 2002). Bootstrap values were determined by performing 500 pseudo-replicates in a heuristic search with simple stepwise addition replicates. Bremer support was calculated with TreeRot v.2 (Sorenson 1999).

Results and discussion
One hundred-eighty mpts where reconstructed for the 13 taxa. Th e strict consensus tree of the mpts was mostly unresolved except for the monophyly of Dryotomicus species (Fig. 1). Th is clade has a high bootstrap value (100), is supported by a relatively high Bremer value (4) and has several diagnostic characters (Fig. 1). Th e antennal funicle, in which the length of the fi rst two funicular segments equals the last three segments, and the scape, which is twice the length of the funicle, are the most striking features. Antennal morphological variation is taxonomically important because these features diagnose Aricerus as well as species of Phloeotribus (Wood 1982, Wood 1986). Hence, given monophyly and the diagnostic characters, Dryotomicus is removed from synonymy with Phloeotribus and includes four species D. puberulus (Chapuis, 1869), D. tuberculatus (Eggers, 1943), D. oenophilis sp. n., and D. woodrex sp. n. Exclusion of P. ovatus (Egg -Table 1. Characters and their states used in the phylogenetic analysis.

Table 2.
Character states used for the reconstruction of the Phloeotribini phylogeny ( Fig. 1).
Characters and states are in Table 1.  (Wood and Bright 1992). Although the relationship of the Phloeotribus spp. is unresolved, many of the mpts suggest that this genus is potentially paraphyletic. Th e inclusion of more Phloeotribus spp. and data, especially DNA sequences, in future phylogenetic analyses would help to solidify the relationships among the genera.
Th e relationship of the four Dryotomicus species is mostly unresolved (Fig. 1). Low support values indicate a potential sister-relationship between D. oenophilis and D. tuberculatus. However this is a likely spurious result caused by missing character data for D. tuberculatus; the only known specimen representing this species is missing its head. However, the distinct morphology of the male frons and elytral declivity distinguish the new species from D. tuberculatus (Fig. 1). Diagnosis. Dryotomicus oenophilis is distinguished from the other Dryotomicus species by a large medial tubercle and lateral carina with acute proximal tips on the male frons, interstriae 2 without long uniserial setae, and by raised interstriae of the elytral declivity having tubercles on interstriae 3, 5, and 7 (Fig. 3B). Description. Holotype, male, total length 4.5 mm (3.8-4.5 mm, n=7), 2× longer than wide, color reddish-black (Fig. 2).

Systematics
Head. Frons shagreen with s etae as long as or longer than the large median tubercle, longest setae close to epistoma and frontal margins; a large median tubercle between antennal insertions and dorsal margin of eye; lateral carinae from epistoma to dorsal end of eye thicker at antennal insertion and ending acutely (Fig. 3A ). Vertex, shagreen with setae approximately as long as or longer than large median tubercle; slightly concave with distinct slightly carinate lateral margins; obtuse median carina from median frontal tubercle to epistoma. Antennae, scape expanded distally and curved proximally beyond the anterior edge of pronotum, funicle fi ve segmented, segments 1 and 2 about equal length and each as long as the combination of segments 3, 4, 5, club pseudo-lamellate, asymmetric, basal segment 1 expanded at base (j-shaped). Eyes oval, ventrally acute (Fig. 3A).
Type material. Holotype and 6 paratypes (3 males and 3 females) bear two collection data labels, First: "GUYANA: Iwokrama Forest, GPS N 04,40.486', W 58.41.028', 4-9 March 2007, Cognato, Hulcr, Smith, Dole, McCall Colls";Second: "Collected with ethanol trap". Th e holotype is deposited in the Biodiversity Center at the University of Guyana and 4 paratypes are deposited in the A. J. Cook Arthropod Research Collection, Michigan State University, East Lansing; 2 paratypes are in the U.S. National Museum of Natural History, Washington D.C.
Notes. In Guyana, we collected all specimens from 20 plastic cups fi lled with 100 ml of 90% ethanol and nailed to trees 1.5 meters above ground.
Etymology. Th e name "woodrex" honors Dr. Stephen L. Wood's kingly contribution to the knowledge of scolytine and platypodine taxonomy. It is used as a noun in apposition.