18-0 18-1

Systematics of Eustylini - Reclassification of the Exophthalmus genus complex (Curculionidae) Guanyang Zhang & Nico Franz

School of Life Sciences, Arizona State University, Tempe, Arizona, USA gyz151@gmail.com nico.franz@asu.edu @GYZhang2 @taxonbytes

16—Rostrum, dorsal surface (0) plane or medially sulcate, not carinate (1) medially carinate17—Rostrum, dorso-lateral angle (0) smoothly curved, any angulation weak (1) conspicuously angulate18—Rostrum, medio-longitudinal sulcus (0) absent (1) present21—Rostrum, dorsolateral fovea (0) absent (1) present

28—Rostrum, occipital suture (0) short, not reaching eye (1) reaching middle of eye ventrally

16-0 16-1

17-117-0

21-0 21-1

45—Pronotum, surface (0) smooth or finely rugose (1) irregularly excavate

29—Rostrum, ventral surface (0) medially flat, not impressed (1) medially with triangular impression

79—Elytral vestiture, curled serrate setae (0) absent (1) present

79-180—Elytral vestiture, series of stripes (0) absent (1) present

80-1

60—Metatibial apex, vestiture (0) ventrally lacking linear, suberect setae (1) ventrally with sparse, suberect setae

116—Aedeagus, endophallus, sclerites (0) separate or contiguous, lacking bridge (1) connected through arched bridge 116-1

119—Aedeagus, endophallus, posterior sclerite (0) width constant, basally not enlarged (1) basally enlarged, arched 119-1

48—Pronotum, postocular vibrissae (0) absent (1) present

48-1

67—Elytra, apex (0) not projected, may be acute (1) distinctly projected

60-1

110—Aedeagus, endophallus, tubular sclerite (0) absent (1) present111—Aedeagus, endophallus, tubular sclerite (0) not divided into two regions (1) divided into anterior/posterior region 116-1

24—Rostrum, hypostomal-labial suture (0) reduced, short, or foveate (1) long, linear, reaching prementum

29-129-0

24-0 24-1

Figure 5. Core morphological characters (orange color in Fig. 2).

45-145-0

41—Pronotum, disc (0) convex (1) flattened

41-141-0

110-1

28-128-0

144—Vestiture, circular glossy metallic scales (0) absent; if metallic, not circular or glossy (1) present; often arranged as fasciae or stripes

144-1144-1

67-0 67-1

The New World tribe Eustylini Lacordaire, 1863, pertains to the broad-nosed weevils (Entiminae) and currently comprises 23 genera. Members of Eustylini include agriculturally important species, e.g., Diaprepes abbreviatus (Linnaeus, 1758), an introduced citrus pest in the continental U.S. Franz (2012) published the first phylogeny of Eustylini based on morphological characters. Eustylini were recovered as polyphyletic and re-circumscribed to include several genera previously placed in other tribes. As a result, all but two of the sampled eustyline genera formed a monophyletic clade. The Exophthalmus genus complex is positioned within that clade and contains eight sampled genera, the largest (with 95 species) being Exophthalmus Schoenherr, 1823. The 2012 analysis uncovered systematic problems that motivate the current study. Exophthalmus remains polyphyletic, with its species separated into at least three clades. Thus Exophthalmus needs to be redelimited and its current members reassigned to phylogenetically appropriate generic membership. The clade of continentals species also contains Rhinospathe Chevrolat, 1878, and Chauliopleurus Champion, 1911, warranting generic synonymy. Tropirhinus Schoenherr, 1823, Tetrabothynus Labram & Imhoff, 1852, Compsoricus Franz, 2012, and part of Exophthalmus exhibit ambiguous boundaries. These groups need to be either re-circumscribed or synonymized.

Systematics of the Exophthalmus genus complex – current status

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1. Test and delimit generic boundaries within the Exophthalmus genus complex based on both morphological and molecular phylogenetic inferences.

2. Revise generic classification within the Exophthalmus genus complex.3. Redefine the limit of Exophthalmus and reclassify its current constituent species.

Research objectives

Morphological phylogeny. Character matrix (144 characters, examples in Figs 4 & 5) was extracted and modified from Franz (2012). Thirty-eight species of eight genera in the Exophthalmus genus complex were sampled, along with 52 species of other eustylines or from other tribes. Phylogenetic trees were inferred with NONA and character optimizations with WinClada under parsimony. Molecular phylogeny. Seventy ingroup terminals were included, representing > 65 species and seven genera. The outgroup contained 105 terminals. Six gene fragments (COI, COII, Ef1-α, Arginine kinase, 12S, 28S) were sequenced, aligned, and concatenated to generate a 4787 bp data set. Phylogenetic reconstructions were performed using parsimony in TNT.

Materials & methods

(1) Pachnaeus Schoenherr, 1826Synapomorphies: Hypostomal-labial suture long, reaching prementum (24-1, Figs. 2 & 4); postocular vibrissae present (48-1); anterior endophallic sclerite membranous, posteriorly tubular (113-1).Distribution: Cuba & Jamaica.(2) Tropirhinus Schoenherr, 1823Taxonomic amendments: Tetrabothynus Labram & Imhoff, 1852, and Compsoricus Franz, 2012, placed as junior synonyms. Exophthalmus species in clade 2 transferred to Tropirhinus. Synapomorphies: Pronotal disc flattened or impressed (41-1); elytral apex projected (67-1); circular metallic scales forming fasciae (144-1). Distribution: Cuba, Hispaniola & Puerto Rico.

(3) Rhinospathe Chevrolat, 1878 Taxonomic amendments: Chauliopleurus Champion, 1911, placed as junior synonym. Continental Exophthalmus spp. transferred to Rhinospathe.Diagnosis: Rostrum with dorsolateral fovea (21-1); rostrum ventrally with a short, deep, triangular impression (29-1). Distribution: Southern Mexico, Central America & northern South America.

(4) Diaprepes Schoenherr, 1823 Synapomorphies: Rostrum dorsolaterally carinate (17-1); occipital suture extends to middle part of eye (28-1); pronotum irregularly excavate (45-1). Distribution: Lesser Antilles & Puerto Rico.

(5) Exophthalmus Schoenherr, 1823 Taxonomic amendments: Exophthalmus re-circumscribed to refer to a clade containing its type species E. quadrivittatus (Olivier, 1807). More than 50 species transferred to other genera.Synapomorphies: Rostrum dorsally plane, lacking carina or groove (15-1, 16-0); Pronotum and elytra with curled, serrate scales (79-1), arranged into stripes or patches (80-1). Distribution: Cuba, Jamaica & Hispaniola.

Figure 1 (left). Proposed new generic classification within the Exophthalmus genus complex, and habitus images of select species. Five genera are recognized (Figs. 2 & 3). Three are placed in synonymy. Exophthalmus is redefined. Habitus image (current, unchanged names): (1-3) Pachnaeus spp., Cuba (4) Pachnaeus marmoratus (5) Pachnaeus sp., Jamaica (6) Compsoricus maricao (7) Exophthalmus humeridens (8) E. regalis (9) E. roseipes (10) E. quindecimpunctatus (11) Tetrabothynus spectabilis (12) Tropirhinus elegans (13) Tropirhinus nr. lepidus (14) Tropirhinus Cuba GZ48 (15) T. lepidus (16) E. agrestis (17) E. impositus (18) E. jekelianus (19) E. lunaris (20) Exophthalmus Mexico (21) Exophthalmus nr. annulonotatus (22) E. opulentus (23) Exophthalmus PA[Panama].GZ65 (24) Exophthalmus CR[Costa Rica].GZ147 (25) Exophthalmus CR.GZ163 (26) E. triangulifer (27) E. verecundus (28) Exophthalmus nr. vermiculatus (29) E. sulcicrus (30) Rhinospathe v-album (31) Diaprepes abbreviatus (32) D. boxi (33) D. doublierii (34) D. maugei (35) D. rohrii (36) E. cinerascens (37) E. hieroglyphicus (38) E. pictus (39) E. similis (40) E. scalaris (41) E. quadrivittatus (42) Exophthalmus DR[Dominican Republic] sp. nov. (43) Exophthalmus DR6 (44) Exophthalmus nr. sulphuratus (45) E. vittatus.

Both morphological and molecular phylogenies recover the monophyly of the Exophthalmus genus complex and the polyphyly of Exophthalmus. They are broadly congruent in five clades, although the relationships among the clades differ between the two analyses. Five genera can be delimited within these clades (Fig. 1). Two (Clades 1 & 4 in Figs. 2 & 3) correspond to Pachnaeus and Diaprepes. Clade 2 contains Tetrabothynus, Tropirhinus, Compsoricus, and Exophthalmus spp. Tropirhinus is considered the valid name for this clade, hence the other two genera are synonymized. A large continental clade (3) is obtained, now referred to as Rhinospathe. The genus Exophthalmus is narrowed to include only West Indian species with a "stripy look" (Figs. 1 & 5). Future work will focus on increasing species sampling, expanding the character range, combining morphological and molecular data in phylogeny reconstructions, and describing new species.

Results, taxonomic proposals & conclusions

Figure 2 (above). Morphological phylogeny of the Exophthalmus genus complex, with character optimizations.

Figure 3 (above). Molecular phylogeny reconstructed using parsimony.

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Franz N.M. 2012. Phylogenetic reassessment of the Exophthalmus genus complex (Curculionidae: Entiminae: Eustylini, Geonemini). Zoological Journal of the Linnean Society 164: 510–557. This work is supported by the National Science Foundation (DEB-1155984) and the United States Department of Agriculture (USDA) (Agreement No. 58-1275-1-335). Dr. Charles W. O'Brien assisted with species identifications. Lin Pan, Will Sides, Julian Jones, and Joseph Hunter captured habitus or head images.

Reference & acknowledgements

Figure 4 (left).Morphological diversity of the rostrum (dorsal view).

Orange numbers denote "core characters" (see Fig. 5).

Numbers shown above branches are jackknifing resampling values.

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