Megachile (Xanthosarus) latimanus Say, 1823

Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M. & Delphia, Casey M., 2025, A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification, Zootaxa 5683 (1), pp. 1-51 : 34

Megachile (Xanthosarus) latimanus Say, 1823

Megachile latimanus Say, 1823: 81 .

Megachile (Xanthosarus) latimanus ; Mitchell 1936: 130; 1962: 157. Hurd 1979: 2067. Ivanochko 1979: 268. Fultz 2005: 134. Scott et al. 2011: 56. Sheffield et al. 2011: 79. Reese et al. 2018: 23 . Delphia et al. 2019a: 25 . Engel 2020: 11.

Megachile (Delomegachile) vidua Smith, 1853: 192 . Mitchell 1935b: 200.

Megachile latimanus / perihirta ; Pearce 2008: 57.

Diagnosis. The females of M. latimanus cannot be reliably separated from M. perihirta in Montana based on morphology (see Taxonomic Challenges). Megachile latimanus / M. perihirta have 5-toothed mandibles with the deepest emargination between the 3 rd and 4 th teeth, emargination strongly angled towards the 4 th tooth ( Fig. 7F ), and medially incomplete apical setal bands on T3–5. Females are most similar to M. dentitarsus , which has T3–5 apical setal bands consistently wide, as wide medially as laterally. The male of M. latimanus can be identified by its widely expanded and ventrally excavated probasitarsus ( Fig. 8B ), the wide, rounded, ventral protuberance of the mesobasitarsus basally (viewed anteriorly) ( Fig. 8C ), and the widely depressed ventral side of the mesofemur. Males are most similar to M. perihirta , which has mesobasitarsus with narrowly rounded, ventral protuberance basally ( Fig. 8D ) and the smooth, convexly rounded ventral side of mesofemur.

Notes. Megachile latimanus has been recorded in a few scattered localities across Montana ( Fig. 1Q ). Photographs, a full morphological description (but see Taxonomic Challenges), and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).

Figures

FIGURE 1. County-level distribution of each Megachile species in Montana. Females identified as Megachile latimanus/ Megachile perihirta (and data without recorded specimen sexes) are counted here as M. perihirta as they are not distinguishable from one another in Montana. Males identified as Megachile lapponica/Megachile relativa (and data without recorded specimen sexes) are counted here as M. relativa as they are not distinguishable from one another in Montana. Mitchell county records are included on maps but not in specimen counts. Two specimens did not have county-level localities and are not included in maps but are included in specimen counts.

FIGURE 7. Female Megachile characters. (A–H) Anterolateral view of mandible, (I–N) Lateral view of metasoma, tergites 4–6, (O) Lateral view of tergites on M. dakotensis, and (P) Lateral view of head with pronounced tooth on the posterior genal margin on M. pugnata.

FIGURE 8. Male Megachile characters. (A) Probasitarsus not expanded or excavated ventrally, (B) Probasitarsus widely expanded and excavated ventrally, (C–E) Anterior view of mesobasitarsus and mesotibia, (F) Lateral view of triangular metatarsomeres on M. manifesta, (G) Lateral view of quadrate metatarsomeres on M. wheeleri, (H) Ventral view of procoxal spine, longer than wide, (I) Ventral view of procoxal spine, wide and spatulate, (J–L) Dorsal view of vertex of head: (J) Ocelloccipital distance longer than ocellocular distance, (K) Ocelloccipital distance equal to ocellocular distance, and (L) Ocelloccipital distance shorter than ocellocular distance.