Scraptiini

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 : 174-177

Tribe Scraptiini

The North American components of Scraptiini Gistel, 1848 ( Fig. 2 ) have not been comprehensively studied and most of the taxonomic concepts date back to LeConte and Champion in the 19th century. The taxonomic history of the species from north of Mexico, which have moved in and out of synonymy with each other and back and forth among genera, is summarized in the catalog presented below. The present-day tribe was first recognized as the single genus Scraptia ( Figs. 2A, E ). Haldeman (1848: 100) reviewed the Nearctic species, slightly modified in the checklist of Melsheimer (1853: 143), where Scraptia comprised six valid species plus two synonyms. The works of LeConte (1854, 1866) included many species-level rearrangements in which the species were ultimately assigned among the genera Scraptia , Allopoda , and Canifa LeConte, 1866 . LeConte (1878: 619) briefly described one more species and made no further rearrangements within this group.

Pic (1911) provided a catalog to the world species of Scraptiidae at the time, now considered to represent the Scraptiinae . In this catalog, he considered Canifa and Allopoda to be synonyms of Scraptia and provided several new combinations for North American species. The next work on this group was that of Schaeffer (1917), who described one new species in Scraptia and two new species in Allopoda but, as noted above, gave no discussion of Pic’s (1911) synonymies and instead continued to follow the previous generic concepts of LeConte. No other rearrangements in this group were made through the completion of the Leng (1920: 239) checklist, which recognized the three genera Scraptia , Allopoda , and Canifa as valid. Fender (1946) added the monotypic Neoscraptia Fender, 1946 ( Figs. 2B, F ) to the North American fauna and was the last author to treat any part of the group taxonomically until Young (1976) added Pectotoma (see Tribe Allopodini above). Thus, upon the transfer of Pectotoma above, the Scraptiini north of Mexico are presently assigned to the genera Scraptia , Canifa , and Neoscraptia ( Pollock 2002) .

The Scraptiini of Central America were treated largely in parallel to the above-cited works in the collective works of Champion. Similar to his treatment of Allopodini discussed above, Champion’s interpretation of LeConte’s species descriptions led him to describe three scraptiine species from Central America in Canifa ( Champion 1889: 90–92) . Following the synonymization of Canifa under Scraptia by Pic (1911), Champion (1916) subsequently described many additional species in Scraptia from around the world and clearly considered his Canifa species from Central America to belong among those he treated in Scraptia . Subsequent workers have continued to recognize the Central American species as belonging to Scraptia (e.g., Blackwelder 1945).

Recognition of Canifa ( Fig. 2C ) as distinct from Scraptia is problematic. The genus was separated based on the presence of a strongly cultriform terminal maxillary palpomere ( Fig. 2G ). We can add to this that, in Canifa , the elytral epipleuron ends abruptly near the hind margin of the metacoxa ( Fig. 2L ). Among Nearctic taxa this combination of character states is diagnostic. However, we have also observed this in a number of Mexican taxa (presently placed in Scraptia , though not yet compared with type specimens) and several unidentified taxa from elsewhere around the world. A cultriform palpomere is also approached in other described genera such as Cteniacantha Quedenfeldt, 1886 ( Figs. 2D, H ) and Trotommidea Reitter, 1883 . Thus, either recognition or synonymization of Canifa leads to worldwide taxonomic implications beyond the scope of this study. We consider it valid until future studies can account for worldwide scraptiine diversity. All current nominal species of Canifa are Nearctic, although the species Scraptia cribriceps Champion, 1916 from southeastern China and Japan was transferred to Canifa by Hatayama (1985: 398). However, this species was later listed in Scraptia by Leblanc et al. (2008: 459). We have not seen the type nor any specimens of this species but its placement should be investigated in the future.

Canifa comprised four valid species prior to this study. An additional name, Canifa pallipes minuta ( Melsheimer, 1846) , has apparently been forgotten in the literature since its description. The name stems from a nomen nudum in an earlier catalog of insects from Pennsylvania ( Melsheimer 1806) and was made available as a variety of what was then known as Scraptia pallipes Melsheimer, 1846 . The Melsheimer collection in the Museum of Comparative Zoology at Harvard University (MCZ) contains two series of Canifa . The first is labeled as Canifa pallipes ( Melsheimer, 1846) and the second as Canifa pusilla ( Haldeman, 1848) . The latter series should not be considered primary type material since Haldeman described his species from the J. L. LeConte collection. Indeed, MCZ holds at least one genuine syntype of C. pusilla . We consider the series labeled as C. pallipes to be the syntype series. There are no additional labels or data to indicate which of these specimens may have referred to the typical or varietal taxa and we were unable to clearly associate any particular specimens with the limited original descriptions. We found no other specimens potentially belonging to the original type series of these varieties. Therefore, to promote stability and to resolve any ambiguity in these names, we propose the following typifications: (1) we hereby designate a lectotype for Scraptia pallipes Melsheimer, 1846 and (2) also designate this same specimen as the neotype for both Scraptia pallipes minuta Melsheimer, 1846 and Scraptia pallipes plagiata Melsheimer, 1846 . This is the first specimen ( Figs. 12C, D ) from the type series which appears on the upper point of a pin containing two pointed individuals. The pin bears several labels, the first on white paper typewritten with “Melsh.”, the second being a torn scrap of red paper presumed to be added by later curators to denote one of the type series, the third label is the catalog number “MCZ-ENT 0079595867” which bears a machine-readable 2-D barcode, and the final label is a piece of white paper handwritten with “pallipes ”. To this we added a red label indicating the lectotype and neotype designations. The result of this are three objective synonyms: S. pallipes , S. pallipes minuta , and S. pallipes plagiata . We further designate S. pallipes as the type species of Canifa .

Early workers distinguished Canifa species on the basis of elytral coloration, pronotal depressions, and general body coloration. We also observed notable variation in the relative lengths of antennomeres 2 and 3 as well as the depth of emargination in ventrite 5 of males, but observed no differences in aedeagal structure across several dissections representing these disparate morphs. Additionally, none of these characters seemed to co-vary in our examination of 160 specimens and images of primary types for all valid names; however, our sampling was not robust enough to justify subjective synonyms. This array of diversity nevertheless supports our typification proposed above to objectively anchor synonyms for nomina with uncertain types in a cryptically diverse lineage whose species concepts may ultimately be defined based on molecular data.

The monotypic Neoscraptia was described as distinct from Scraptia and Canifa by having fusiform terminal labial palpomeres ( Fig. 2F ) while the latter two genera have expanded and lunulate terminal labial palpomeres ( Figs. 2E, G ). This character, along with the truncate ventrite 5 in males, readily differentiates Neoscraptia among North American Scraptiini . This former character state is also present in both Allopodini genera from the region but Neoscraptia bears distinct lobes on the hind penultimate tarsomeres, placing it within Scraptiini under the current tribal definitions.

The three scraptiine genera in North America pose additional taxonomic problems when the worldwide fauna is considered. The worldwide variation seen in Scraptia appears to include many of the other described genera which are likely at best characterized by autapomorphies. However, assigning species to monophyletic units may be problematic due to the relative homogeneity of Scraptiini . We here leave the genera as valid since the characters seem to be as reliable as those for most other recognized scraptiid genera of the world.

Figures

Fig. 2. Scraptiini, all scale bars = 1 mm.A) Scraptia sericea, dorsal habitus, B) Neoscraptia testacea, dorsal habitus, C) Canifa cf. pallipes, dorsal habitus, D) Cteniacantha marginata, dorsal habitus, E) Scraptia cf. speciosa, mouthparts, arrow indicating lunulate labial palpomere, F) Neoscraptia testacea, mouthparts, arrow indicating fusiform labial palpomere, G) Canifa sp., mouthparts, arrow indicating cultriform maxillary palpomere, H) Ct. marginata, mouthparts, arrow indicating lunulate labial palpomere, I) S. cf. speciosa, male tegmen, penis removed, J) S. sericea, hind tarsus showing lobed third tarsomere, K) Scraptia sp., left epipleuron, arrow roughly indicating termination near elytral apex, L) Canifa sp., left epipleuron, arrow roughly indicating termination near position of metacoxa.

Fig. 12. Scraptiidae, type specimens and labels.A) Allopoda dentipes [Evalces], lectotype, dorsal habitus, B) Same, labels, C) Canifa pallipes [Scraptia], lectotype, dorsal habitus, D) Same, labels, E) Sphingocephalus ovalis, holotype, dorsal habitus, F) Same, labels. Images C and D by Whit Farnum, Museum of Comparative Zoology, copyright President and Fellows of Harvard College, images E and F by K. Taro Eldredge, University of Michigan Museum of Zoology.