A new genus of Macrotomini ( Coleoptera , Cerambycidae , Prioninae )

A new genus of Macrotomini (Coleoptera, Cerambycidae, Prioninae). Allomallodon gen. n. is erected to accommodate Mallodon hermaphroditum Th omson, 1867, and M. popelairei Lameere, 1902. Th e assignment of this new genus to Macrotomini, and the validity of Mallodontini are discussed. As result, Mallodontini is considered a synonym of Macrotomini. A key to species of the new genus is included as well.

A new genus of Macrotomini (Coleoptera, Cerambycidae, Prioninae) Introduction Th omson (1867) described Mallodon hermaphroditum, noting that it was the only species known in the genus whose male lacks impunctate and shining facets on the pronotum, in contrast with the remainder of the surface.Th us, the pronotum is simi-lar to that of the female.Later, Lameere (1902) transferred M. hermaphroditum to Stenodontes (Mallodon), described Stenodontes (Mallodon) popelairei, and noted that this species shows diff erent characters, than Th omson's species.Some characters as, for example, body slender, labrum tumid, and prothorax in male without evident sexual dimorphism, allow to allocate these species in a new genus.
Since Lameere (op.cit.), both species were simply included in catalogues, and were not fi gured until Fragoso and Monné (1995) studied the lectotype male of M. hermaphroditum, and Santos-Silva (2005) examined the lectotype male and the paralectotypes (two males and one female) of M. popelairei.Neither of the latter two authors questioned the generic assignment of these species.
During the study of another genus (Nothopleurus Lacordaire, 1869), which included a cursory analysis of several species of Mallodon, it became evident that both M. hermaphroditum and M. popelairei exhibited an exclusive set of characters that would permit them to be assigned to a new genus.Further evidence is presented to support the inclusion of this new genus in Macrotomini, which includes Mallodontini, sensu Monné and Hovore (2006) and Monné (2006).
Female (Figs 2,4).Eyes proportionally larger than in male.Distance between upper ocular lobes equal to length of scape; distance between lower ocular lobes just greater than the length of scape or subequal.Antennae (Figs 2, 4) slightly shorter than in male.Lateral margins of pronotum crenulate (Figs 11,13), more acute and projected than in male.Proepisterna and proepimera (Figs 21,23) rugose or slightly rugose, not punctate or with coarse punctures near the prosternum.Punctation of prosternum similar to that of male.Prosternal process, metasternum and metepisterna (Figs 21,23) as in male.
Diagnosis and Discussion.Allomallodon gen.n. diff ers from Mallodon Lacordaire, 1830 by the following characters: body (Figs 1-4) slender; mandibles of male (Fig. 29), at most, as long as the head; base of labrum (Figs 6,10,29) distinctly visible in dorsal view, coplanar or nearly so with the clypeus; labrum (Fig. 10) tumid; lateral angles of prothorax of male (Figs 12,14) distinctly more elevated than posterior angles in line; pronotum (Figs 12,14), proepimera and prosternum (Figs 22,24) of male without evident sexual dimorphism; prosternal process (Figs 21-24) distinctly narrowed medially.In Mallodon body, in general, more robust (Fig. 5); mandibles of major male (Figs 30, 31) longer than the head; base of labrum (Fig. 7) not visible in dorsal view or when visible (Fig. 8), more distinct laterally, with its basal margin placed, in general, distinctly lower than the edge of clypeus (Fig. 9), and always strongly concave at middle region; lateral angles of prothorax of male (Figs 16,18) placed in the same line or almost in the same line of posterior ones (sometimes, similar to the species of Allomallodon (Fig. 20)); pronotum, proepimera and prosternum of male (Figs 26,27) with sexual dimorphism very distinct; prosternal process (Figs 25-28) wide and not or, slightly narrowed medially (in female of some species, narrowed medially, but always moderately wide).
From the species of Physopleurus Lacordaire, 1869 with unarmed tibiae, Allomallodon diff ers, mainly, by the prosternal suture straight or substraight, and by the prosternum not tumid.In all species of Physopleurus the prosternal suture is distinctly curved, and the prosternum is tumid or strongly tumid.
Allomallodon diff ers from Mallodonhoplus Th omson, 1861 by the unarmed tibiae (distinctly spinose, mainly the protibiae, in Mallodonhoplus).It can be separated from the species of Stenodontes Audinet-Serville, 1832 by the shorter antennae that do not reach the middle of elytra.In males of Stenodontes the antennae surpass the middle of the elytra, and in females they reach the middle.It diff ers from Neomallodon Linsley, 1957 by the pronotum of male being distinctly and abundantly punctate laterally (slightly rugose in Neomallodon).From the species of Olethrius Th omson, 1861 it diff ers, mainly, by the scape not surpassing the posterior edge of eye (distinctly surpassing in Olethrius).Fragoso and Monné (1995) noted the following on the pronotum of A. hermaphroditum: "Besides the inappropriate epithet, the male pronotal disc shows a large, subcircular "tache luisante", with a cluster of points in the middle, as well as a few other points scattered at the periphery of the disc (latero-posteriorly more numerous); the sex-points are limited to lateral areas, close to pronotal bordes (including the "oreilletes")".Th ese statements, however, are not consistent with the lectotype and specimens examined by us.In fact, the epithet chosen by Th omson is quite appropriate, as the sexual dimorphism in the pronotum is minimal and, above all, there is no the sexual punctation as noted by Fragoso and Monné (op.cit.).Th e entire sculpture of pronotal disc is quite similar in both sexes of A. hermaphroditum (Figs 13,14), as well as in A. popelairei (Figs 11,12), and very diff erent from what occurs in other species of , in which the sexual dimorphism is strongly evident.

On the placement of Allomallodon gen. n.
Allomallodon belongs to the group that some authors (primarily European) exclude from Macrotomini, and include in Mallodontini.Although it may seem obvious that a genus carved out of Mallodon belongs to that group, such an assertions, in some cases, can be misleading.Prioninae is a small subfamily in comparison with other cerambycid subfamilies, but the relationship and placement of the genera and species, frequently, are complex.Th at, in our opinion, is the reason by which Mallodontini is not a well defi ned group, as suggested by some authors, for example Vitali (2008): "Th e systematics of the Macrotomini, already partially cleared by European authors (Th omson, Lameere, Quintin [sic], Villiers), still shows uncertainties due to the fact that the American authors (Monné and Hovore 2005;Silva-Santos [sic] and Martins 2005) still consider Macrotomini, Mallodontini and others only one tribe".
Th omson (1861) erected the group "Mallodonitae" (currently considered Mallodontini) and defi ning it by the following: head wide, not elongated behind eyes; antennae short, fi liform or submoniliform, with the antennomere III short, and barely longer or equal to IV; mandible subvertical or horizontal, robust, frequently elongated; lateral margins of prothorax crenulated or multi-spinose; elytron elongated, subdepressed; prosternum distinct; mesosternum fl at; legs cylindrical; protibiae unarmed (except in Mallodonhoplus); tarsi mediocre, with the tarsomere V usually not longer than I-IV together.Th omson (op.cit.)According to Th omson (op.cit.), the characters of "Macrotomitis" that allow separation from "Mallodonitae" are: antennae longer, with antennomere III distinctly longer than IV; upper ocular lobes closer; mandibles not transversal; protibia often with spines and diff erent.Th e genera that were included in "Mallodonitae" make the group an amalgam of tribes, as currently accepted, be they by European or American authors: Macrotomini, Macrotomini/Mallodontini, Notophysini, Eurypodini, Platygnathini.Th us, the only merit of Th omson's (op.cit.)regarding "Mallodonitae" was to attribute a name to the group, without contributing substantively to the classifi cation of Prioninae, as noted by Vitali (2008).
Following his previous classifi cation, Th omson (1864) redefi ned "Mallodonitae" with the following changes sensu Th omson (1861): body wide, mainly in males; antennae just surpassing the middle of elytron (sometimes, shorter); scape thick, longer or as long as the antennomere III; pronotum in male with smooth facets, and scabrous or punctate in female; prosternal process slightly projected; mesosternal process laminiform; legs never with spines [mainly modifi cation]; tarsomere V as long as I-IV together; integument always brownish, shining.Th omson (1864) included in this group the genera recorded in Th omson (1861), except Mallodonhoplus (transferred to "Mac-rotomitae"), and added Opheltes Th omson, 1864.Again, this concept joins genera that currently are included in many tribes of Prioninae.
Th is concept of Mallodontini, based mainly on the absence of spines on the legs, is very unsatisfactory, and usually does not allow to reliably separat included genera.For example, in Physopleurus there are species with spines on tibiae as well as species with the tibiae unarmed.Many other characters are shared by these two species groups of Physopleurus (apex of antennal tubercles sub-horizontal and backward; prosternal suture absent or present and distinctly curved in males, etc), which does not allow the division in two genera, much less the inclusion of these species in diff erent tribes.It is important highlight that the species of Physopleurus show a general appearance similar to that of the species of Mallodon and often have facets on pronotum of males, mentioned by Th omson (1864), as well as all other characters pointed out by Th omson (1861, 1864).In the description of Mallodon hermaphroditum, a species that does not have facets on the pronotum of males, demonstrates that Th omson was deliberately modifying the description of Mallodontini in each of his works, including and excluding genera.Th is exposes the fragility of the classifi cation of this group that, as previously seen by the concept of Th omson (1867), diff ers from Macrotomini only by the unarmed legs.Lameere (1919) summarized his previous works ("Révision des prionides") and divided Macrotomini in several groups that currently are considered subtribes by some authors, and tribes by others: Archetypi; Basitoxi; Stenodontes; Cnemoplites; Macrotomae; Rhaphipodi; and Xixuthri.According to him, the subgroup "Stenodontes" is characterized: body, in general, large, more or less depressed; eyes not emarginated; antennal tubercle distinct and acute; scape elongated and longer than the antennomere III; mandibles with dorsal carina; ligulae small and weakly whole (almost undivided); prothorax wide, with the sides wide and a little bent down, lateral edge present and crenate, more parallel in male than in female; males with sexual punctation on prothorax; pronotum of males with callosities shining; legs robust, with or without spines; last urosternite of males more or less emarginated.As shown above, Lameere (op.cit.)modifi ed the concept of Macrotomini and Mallodontini established in the works of Th omson considerably.In particular, the main character used by Th omson (1867) to separate these two groups, was not accepted by Lameere (op.cit.), because the subgroup "Stenodontes", that included Mallodon, has species with legs that are spinose or not.
As in the divisions established in Th omson's works, the division proposed by Lameere maintains separate genera that share many characters (e.g.Xixuthrus Th omson, 1864 and Mecosarthron Buquet, 1840), and combined other genera with notably diff erent characters (e.g.some species of Nothopleurus, and Mallodon).
Despite showing inconsistencies in his descriptions of tribes, in which were included genera that contradict the characters that were noted (e.g.body more or less depressed in "Archetypi", in relation to Strongylaspis Th omson, 1861, whose species has body distinctly not depressed), the concept of "Stenodontes" proposed by Lameere is more consistent than that of Th omson, because it unites genera with generally similar shared characters (body form, length of scape in relation to the antennomere III, prothorax form, etc).Quentin and Villiers (1975) considered Macrotomini and Mallodontini as distinct and, in their key to the tribes that occur in Madagascar, separated these groups in the following manner: pronotum fl at, with sides explanate in Mallodontini, and convex and with the sides bent down in Macrotomini; presence of shining facets on pronotum of males, occupying almost the whole surface in Mallodontini, and without facets or with small facets in Macrotomini.Th at key, if applied to American genera, would separate into distinct tribes species in the same genus, including species that at that time were in Mallodon, as well as genera included in the subgroup "Stenodontes" by Lameere (1919).According to Quentin and Villiers (op.cit.),Mallodontini is characterized by: general form wide and depressed; eyes not or slightly emarginated, coarsely faceted, weakly protruding, not surpassing the antennal tubercles; antennae with eleven segments, fi liform, rarely surpassing the middle of elytra; scape, at least, as long as antennomere III; prothorax transverse, explanate laterally; pronotal disc, mainly in males, with facets or callosities fl at and shining; prothoracic episterna very wide; legs, in general, short and always unarmed.It is important to note that Quentin and Villiers (op.cit.)characterized the tribe not only for the single species present in Madagascar.Th is defi nition of Mallodontini distinctly modifi es, again, the limits of the group, resulting in the mandatory exclusion of genera included by Lameere (1919): Nothopleurus (part); Physopleurus; Mallodonhoplus; Olethrius; and Allomallodon gen.n. (originally included in Mallodon).Moreover, it may include species in genera that, by the defi nition of European authorities, could not belong to Mallodontini, as for example, Physopleurus rugosus (Gahan, 1894) and P. longiscapus Lameere, 1912, in which the proepisterna is not notably reduced and has all the other characters listed by Quentin and Villiers (op. cit.).Seemingly contradictory, Villiers (1980) allocated Nothopleurus in Mallodontini, without realizing that the type species of this genus, Nothopleurus ebeninus Lacordaire, 1869, does not fi t to his description of the tribe, primarily, by the pronotum of males is without impunctate and shining facets in contrast with the remainder of surface.
As shown above, the divisions proposed, in part by European authors, affi rmed the opinion of Vitali (op.cit.)(Mallodontini diff erent from Macrotomini), and did not "clear [up]" the classifi cation of Macrotomini.In fact it has made it more chaotic, mainly by contradicting the vastly diff erent concepts of Th omson (1861,1864,1867), Lameere (1919) and Quentin and Villiers (1975).
It is probable that Macrotomini is not a monophyletic group, but the divisions proposed up to now are inconsistent.Th us, we believe that the prudent action is to maintain Macrotomini as a single tribe, including and disregarding the subdivisions presented in Lameere (1919).Monné and Hovore (2006) listed the American genera of Macrotomini, following the concept of American authors.