Phloeodes LeConte, 1862

Foley, Ian A. & Ivie, Michael A., 2008, A phylogenetic analysis of the tribe Zopherini with a review of the species and generic classification (Coleoptera: Zopheridae), Zootaxa 1928 (1), pp. 1-72 : 37-41

Genus Phloeodes LeConte

Figs. 32 , 35–53

Phloeodes LeConte, 1862: 216 . LeConte, 1853: 235. Horn, 1870: 272–273. LeConte and Horn, 1883: 364. Champion, 1884: 44. Casey, 1907a: 42–43. Casey, 1907b: 471–473. Leng, 1920: 223. Essig, 1926: 429. Bradley, 1930: 183,322. Böving and Craighead, 1931: 41. Gebien, 1936: 667–668. Arnett, 1973: 651. Doyen, 1976: 267–272; fig. 1–11. Doyen and Lawrence, 1979: 341–345. Powell and Hogue, 1979: 295,297. Doyen and Miller, 1980: 3. White, 1983: 250, fig.107. Arnett, 1985: 350. Costa et al., 1988: 213. Hogue, 1993: 296,298. Ṡ lipi ń ski and Lawrence, 1999: 19, fig. 69–82. Ivie, 2002: 458–461. Caterino, 2004: 7. García-París et al., 2006: 215–230. (Type species Nosoderma diabolicum LeConte, 1851 , designated by Casey 1907b).

Noserus LeConte, 1862: 216 . Horn, 1870: 273. LeConte and Horn, 1883: 365. Champion, 1884: 44. Casey, 1907a: 43– 44. Casey, 1907b: 473–474. Leng, 1920: 223. Bradley, 1930: 183,322. Böving and Craighead, 1931: 41. Gebien, 1936: 668. Arnett, 1960: 651,668. Arnett, 1968: 651,668. Arnett, 1973: 668. Arnett, 1983: 16. Doyen and Lawrence, 1979: 345. Doyen, 1980: 3. Arnett and Jacques, 1981: 145. Arnett, 1985: 350. Ṡ lipi ń ski and Lawrence, 1999: 19. García-París et al., 2000: 473. García-París et al., 2001: 151–153. Ivie, 2002 c: 461. Foley et al. 2003: 103. García- París et al., 2006: 215–230. (Type species: Nosoderma plicatum LeConte, 1859 , by monotypy). (Synonymy by Ṡ lipi ń ski and Lawrence 1999).

Ageonoma Pascoe, 1866: 478 . Horn, 1870: 272. (Type species: Nosoderma diabolicum LeConte, 1851 , by monotypy). (Synonymy by Horn 1870).

Phoeodes Arnett, 1962: 668 (lapsus calami).

Noserosus Doyen and Lawrence, 1979: 345 (lapsus calami).

Noserodes [in part] Gebien, 1936: 670.

Diagnosis: This genus is supported based on the well-developed glabrous tarsal strip ( Fig. 43 ) and at least partial, broad, well developed antennal cavities on the prothoracic hypomeron. The glabrous tarsal strip also occurs as a homoplasy in the distantly related Zopherus , and weakly in some Verodes , but Zopherus has 9-segmented antennae (10 in Phloeodes ) and Verodes has no hint of an antennal cavity (well developed in Phloeodes , Figs. 39–42 ). This genus is very closely related to the genus Verodes , and can be further distinguished from that genus (Ṡ lipi ń ski and Lawrence 1999) by the lack of a mandibular prostheca, the broad mentum, and the laterally inserted labial palps. The presence of a tomentose whitish vestiture on the humeri and apical declivity in many specimens of Phloeodes diabolicus , and covering a large portion of the body in Phloeodes venustus will separate those two species from all other Zopherini with 10-segmented antennae that lack a scutellum (golden vestiture present in some Sesaspis species ). The third member of the genus, Phloeodes plicatus is usually uniformly colored, but rarely has whitish patches of scale-like setae on the body.

Notes: The genera Phloeodes LeConte and Noserus LeConte were originally described for species

described in Nosoderma sensu Solier 1841 . The taxonomic histories of those species have followed separate paths since 1862. These paths recently converged when Noserus was synonymized with Phloeodes (Ṡ lipi ń ski

and Lawrence 1999). This synonymy was not recognized by García-París et al. (2000, 2001) who described a

Mexican species, Noserus doyeni García-París et al. 2001 , in the old sense of Noserus which returned the genus to independent status. Ivie (2002) restored it to synonymy following Ṡ lipi ń ski and Lawrence (1999),

but little actual analysis of this question has been conducted.

The genus Phloeodes originally included two California species, Nosoderma diabolicum LeConte 1851 , and Nosoderma pustulosum LeConte 1859 ( LeConte 1862) . This genus was differentiated from Zopherus Gray and Phellopsis LeConte by having 10-segmented antennae and from Noserus LeConte by the degree of closure of the prothoracic antennal cavity. Verodes ( Nosoderma Solier not Guérin-Méneville), occurring in Central America, was not included in LeConte's generic key (1862), but he did mention that it differed from Phellopsis in the number of antennal segments (10 vs. 11). He did not comment on any differences between the three genera with 10-segmented antennae.

Casey described 6 new species of California Phloeodes : P. latipennis Casey 1907a , P. ovipennis Casey 1907a , P. elongatus Casey 1907a , P. scaber Casey 1907a , P. angustus Casey 1907a , and P. remotus Casey 1907b . Casey’s (1907a) contention was that the two LeConte Phloeodes species were divided into a northern species ( Phloeodes diabolicus ) and a southern species ( Phloeodes pustulosus ) separated by the presence of a dense pale whitish vestiture on the apical declivity of the elytra. To this interpretation, Casey (1907a, 1907b) then described his 6 new Phloeodes species from few or single specimens. These specimens were distinguished in typical Casey key format based on variations in sculpture, body proportions, velvety spots on the elytra, and vestiture of the apical declivity. All of these characters have been observed to be highly variable within the genus, frequently because the external appearance of individuals is concealed by the accumulation of exudate and collected environmental debris. Casey had some inkling of this condition when he commented that some of his species may prove to be subspecies (1907a) and that some of his previously described Phloeodes species seemed doubtful (1907b). Despite these reservations, he concluded after examining additional specimens, that all of the species were valid and proceeded to described Phloeodes remotus from a single specimen ( Casey 1907b). LeConte did not recognize a type species when he erected the genus, therefore Casey (1907b) designated Phloeodes diabolicus as the type species. The first Casey name to be synonymized was Phloeodes latipennis , which was listed as a junior synonym of Phloeodes pustulosus by Gebien (1936). The tradition of synonymy recently continued when García-París et al. (2006) synonymized the remainder of the Casey names with either, P. diabolicus or P. pustulosus .

LeConte (1862) described the genus Noserus , in the same paper that he described Phloeodes , with Nosoderma plicatum LeConte 1859 from California as the sole member of the genus. Noserus emarginatus Horn 1878 was added from Texas, considerably expanding the geographic range of the genus.

In a situation similar to his treatment of Phloeodes, Casey (1907a, 1907b ) also revised Noserus . In addition, he recognized the close relationship between Phloeodes and Noserus and noted that in both groups the species forms were difficult to define ( Casey 1907b). However, Casey described several new California Noserus species based on single or a few specimens as he had done in Phloeodes : Noserus torvus Casey 1907a , Noserus collaris Casey 1907a , Noserus corrosus Casey 1907b , and Noserus convexulus Casey 1907b . In describing these taxa, Casey primarily used differences in the strength of elytral ridges and tubercles as well as degree of body convexity; these characters are highly variable in most members of the tribe and are not useful in defining species limits. All of these Casey species were recently synonymized with P. plicatus (García- París et al. 2006).

When Noserus LeConte was synonymized with Phloeodes LeConte by Ṡ lipi ń ski and Lawrence (1999) in their review of the genera of Zopherinae , the synonymy was based on the fact that there are no distinguishing characters between the taxa besides the extent of the antennal cavity. All available evidence supports that Phloeodes diabolicus and Phloeodes plicatus , the respective type-species of the genera Phloeodes and Noserus , belong to the same genus, and that synonymy is recognized here.

The problems with the classification of Phloeodes in this sense comes from the described species that occur outside of California, Noserus emarginatus from Texas, New Mexico and Northern Mexico (García- París et al. 2000)], and Noserus doyeni García-París et al. , from Nuevo Leon, Mexico. Casey, who divided the Zopherini ( sensu Ṡ lipi ń ski and Lawrence 1999) into several genera that were later synonymized ( Triplehorn 1972, Doyen and Lawrence 1979) was the first to acknowledge that true Phloeodes would probably be confined to California (1907b). Even though Casey did not examine specimens of Noserus emarginatus , he stated that it would prove to be generically different and possibly belong to the genus Nosoderma Solier (not Guérin- Méneville) of Central America (now Verodes ). The independent status of the genus Phloeodes was recently questioned by García-París et al. (2001, 2006). Based on previous difficulties assigning a species to the appropriate genus ( Noserus doyeni ), and perhaps realizing the problematic generic concepts in the Zopherini, García-París et al. (2006) , lumped the genera Phloeode s and Noserus into Nosoderma (= Verodes ). Little support was found for this conclusion, and three independent monophyletic lineages of this group are here recognized at the generic level.

The two species of old “ Noserus ” differ from the current diagnosis of Phloeodes in having setiferous punctures on the ventral body surfaces, a different type of antennal cavity, a poorly defined tarsal strip, variation in the male nodules, and the generally dense setose vestiture. They also differ from species of Verodes in lacking a membranous mandibular prostheca, in the presence of ventral setose punctures and laterally inserted labial palps. Therefore, these two species are removed from the genus Phloeodes , and added to the genus Sesaspis

Phloeodes ( sensu stricto) is here restricted to the two California species ( Phloeodes diabolicus and Phloeodes plicatus ) and the Central American Phloeodes venustus (Champion) NEW COMBINATION, which was discovered to be a member of Phloeodes during the course of this study. The species here considered members of Phloeodes LeConte represent quite distinct forms. While the habitat and geographic range of the California species seem to overlap entirely, the two species are easily distinguishable. Phloeodes venustus , moved into Phloeodes from Nosoderma Solier (not Guérin-Méneville), was called the “finest and most distinct” of all the Central American species ( Champion 1884), so it is also readily identifiable.

The inclusion of Phloeodes venustus in this genus is based on the absence of a membranous mandibular prostheca (which excludes it from Verodes ), presence of tubercles on all body surfaces (which excludes it from Sesaspis ), a well defined tarsal strip, broad apical margin of the mentum, and laterally inserted labial palps. The whitish vestiture that is seen in many specimens of Phloeodes diabolicus , and was the historical distinction between that species and Phloeodes pustulosus , is exactly the same vestiture that covers nearly the entire surface of the body in Phloeodes venustus . This whitish vestiture is seen in no other species of Zopherini with tuberculate sculpture, 10-segmented antennae, and hidden scutellum.

A general evolutionary trend towards wood boring larvae has been suggested in the Zopherini ( Triplehorn 1972, Doyen 1976, Doyen and Lawrence 1979, Ṡ lipi ń ski and Lawrence 1999, Ivie 2002). The larval morphology of Phloeodes diabolicus is obviously modified for a wood-boring habitat possessing an enlarged thoracic region and reduced legs ( Doyen 1976). The larva of Phloeodes diabolicus was described from cottonwood logs ( Populus sp. ), oak logs ( Quercus sp. ), and mulberry roots ( Morus sp. ) and was suggested as a nonspecific decomposer that utilizes a variety of tree species ( Doyen 1976). While for many larval Zopherinae the associated substrate is rotting wood, the nutritive source may be associated fungi ( Doyen 1976, Ivie 2002), possibly white rot fungi (Lawrence 1991).

Adults of Phloeodes diabolicus and Phloeodes plicatus are most commonly collected under bark of decaying oak ( Quercus sp. ) and cottonwood ( Populus sp. ) trees, but have also been found associated with woody material of willow ( Salix sp. ), alder ( Alnus sp. ), sycamore ( Platanus sp. ), walnut ( Juglans sp. ), eucalyptus, cedar ( Cedrus sp. ), pine ( Pinus sp. ), madrone ( Arbutus sp. ), and laurel ( Umbellularia sp. ), as well as under several shrubs (including Salicornia sp. and Baccharis sp. ), on fungi, in leaf litter, and under rocks. Multiple individuals of both species were found in the same microhabitat, with both species being relatively abundant under the same standing dead oak trees in Monterey Co., California in 2005 (pers. obs.).

Typically species of Zopherini are covered in a waxy cuticular secretion that accumulates environmental debris. Such secretions have been hypothesized to be mechanisms to protect against water loss, for sexual attraction, and defense ( Lawrence and Hlavac 1979). All three functions seem reasonable within the Zopherini . The secretions in Phloeodes probably serve at least some sexual attractant function, this is attributed to the apparent secretory pores on the secondary sexual character of the male ( Figs. 50–53 ). These waxy secretions would also provide a useful barrier against water loss in the dry summer months that occur in the southwestern United States and Central America, where many members of the tribe are found.

Many Zopherinae have the ability to feign death (thanatosis), a behavior documented in several groups of beetles ( Chemsak and Linsley 1970, Allen 1990, Oliver 1996, Miyatake 2001, and Miyatake et al. 2004) and specifically in the Zopherini ( Evans and Hogue 2004) . Both species of the genus Phloeodes in California when disturbed will drop from an attached substrate and become immobile for an extended period of time, probably as a defense mechanism (pers. obs.).

Individuals have also been reported (label data) to have the ability to survive long periods of time without food or water. This potential has also been documented in members of Zopherus (Sallé 1849, Triplehorn 1972).

Distribution: As defined here, the genus occurs in two disjunct geographic areas with two species ( P.diabolicus , P. plicatus ) occurring in the California Floristic Province and one ( P.venustus ) in Central America.

Figures

FIGURES 32–34. Dorsal view of left mandibles. 32. Phloeodes diabolicus; 33. Sesaspis sylvatica; 34. Verodes aequalis. Scale bar = 1mm.

FIGURES 35–38. Dorsal habiti. 35. Phloeodes diabolicus, California, San Diego Co.; 36. Phloeodes diabolicus, California, Napa Co.; 37. P. plicatus, California, Los Angeles Co.; 38. P. venustus, Costa Rica.

FIGURES 39–41. 39–40. Ventral surface of pronotum. 39. Phloeodes diabolicus; 40. P. plicatus. 41. Lateral view of P. diabolicus hypomeron.

FIGURES 42–46. 42. Lateral view of P. venustus hypomeron. 43. Ventral view of tarsus of P. venustus. 44–46. Male genitalia. 44. P. diabolicus; 45. P. plicatus; 46. P. venustus.

FIGURES 47–49. 47–48. Labial palp insertions. 47. Phloeodes diabolicus; 48. P. plicatus. 49. SEM of tarsal claw of P. plicatus.

FIGURES 50–51. Femora of male Phloeodes diabolicus. 50. Male nodule. 51. Cuticular pores.

FIGURES 52–53. Femora of male Phloeodes plicatus. 52. Male nodule. 53. Cuticular pores.