Allopodini

Johnston, M. Andrew, Naczi, Robert F. C. & Gimmel, Matthew L., 2024, Review of North American Scraptiidae (Coleoptera: Tenebrionoidea), with a Catalog of World Genera, The Coleopterists Bulletin 78 (2), pp. 171-200 : 173

Tribe Allopodini

Allopodini Franciscolo, 1964 ( Fig. 1 ) was established for Allopoda LeConte, 1866 as a tribe of Scraptiinae with little explanation ( Franciscolo 1964). Allopoda was originally erected by LeConte (1866: 144) for the single species Scraptia lutea Haldeman, 1848 ( Fig. 1A ). The genus was then synonymized in a catalog by Pic (1911: 4) with Scraptia Latreille, 1806 without further comment. The genus has been consistently treated as valid, and the prior synonymy never discussed, by later North American workers including Schaeffer (1917), who described two new species in the genus (see also Fender 1946; Hatch 1965; Pollock 2002). The tribe was subsequently expanded by Franciscolo (1972) to include the genera Evalces Champion, 1889 (from Central America) and Pseudoscraptia Wollaston, 1868 (from Cape Verde) on the basis of these genera having unlobed penultimate hind tarsomeres ( Fig. 1D ) in contrast to Scraptiini which have the penultimate hind tarsomeres lobed. This tribal distinction was further discussed and maintained by Watt (1987).

We examined over 200 specimens of Allopoda and found male genitalic characters useful for separating putative species. A number of cryptic and likely undescribed taxa exist in the United States and will need to be described when the appropriate types can be examined. The most abundant western species we observed in collections actually seem to be undescribed. Evalces was putatively diagnosed from Allopoda by Champion (1889) based upon his interpretation of LeConte’s (1866) description of the labial palpomeres of Allopoda . However, this interpretation was apparently erroneous, since all Allopoda examined by us, including type specimens, have triangular terminal labial palpomeres that are longer than wide, not “very transverse, with the apical side longer than the others” as surmised by Champion (1889: 93). No type species was established for Evalces , which we here address by assigning Evalces dentipes Champion, 1889 as the type species. We have examined specimens of Evalces and can confirm the labial palps are similar in form to those of Allopoda . Moreover, Champion’s (1889) illustrations of the labial and maxillary palps of Evalces griseus Champion, 1889 are a close match with the present concept of Allopoda . Additionally, the characteristic inner protibial spine of the male of E. dentipes is also found in Allopoda lutea (Haldeman) ( Fig. 1C ), the type species of Allopoda , as well as additional species of Allopoda occurring north of Mexico. We did not observe any other characters that would suggest two genera are represented. However, described species within each genus seem to be distributed among two putative species groups based upon male genitalic morphology: (1) species with flattened, blade-like parameres found in the type species of both Allopoda and Evalces and (2) species with inflated, tube-like parameres found in a number of taxa from Arizona south through Central America. Based on the above points, we consider Evalces a new junior synonym of Allopoda .

The monotypic genus Pectotoma Hatch, 1965 was described based on Pectotoma hoppingi Hatch, 1965 ( Figs. 1E, F, H ) from a single series of specimens from British Columbia, Canada and placed in Melandryidae : Tetratominae. It was later moved to Scraptiini by Young (1976: 266), who also reported the species from Alberta. Young (1976) coded several characters given by Franciscolo (1972) in sup- port of moving the genus to Scraptiini , though no in-depth discussion of other scraptiid tribes was presented; Franciscolo (1964, 1972) seemingly viewed Allopodini as intermediate between Scraptiinae and Anaspidinae based on tarsal characters. Pectotoma shares with Allopoda the penultimate tarsomeres lobed on the fore and middle legs but penultimate tarsomeres on the hind legs unlobed. Based on our examination of four specimens from the United States (from Arizona, Montana, and Utah; additional images available from New Mexico on BugGuide), we hereby transfer Pectotoma from Scraptiini to Allopodini . This now makes the two tribes, to our knowledge, consistently defined globally, though whether this tribal division based on tarsal characters alone is justified should be further investigated through comprehensive morphological and molecular studies.

Figures

Fig. 1. Allopodini, all scale bars = 1 mm. A) Allopoda lutea, dorsal habitus, B) A. dentipes, dorsal habitus, C) A. lutea, front leg, showing tibial spine (arrow) and lobed fourth tarsomere, D) A. lutea hind tarsus, showing lack of lobes on any tarsomeres, E) Pectotoma hoppingi, dorsal habitus, male, F) P. hoppingi, female, G) A. lutea, male genitalia, H) P. hoppingi, head in lateral view. bp = basal piece of tegmen; fp = fused parameres of tegmen; p = penis.