Camponotus yogi Wheeler, 1915

Ward, Philip S. & Boudinot, Brendon E., 2021, Grappling with homoplasy: taxonomic refinements and reassignments in the ant genera Camponotus and Colobopsis (Hymenoptera: Formicidae), Arthropod Systematics & Phylogeny 79, pp. 37-56 : 37

3.2.1. Camponotus yogi Wheeler Figs 5 , 6

Camponotus yogi Wheeler, 1915: 420. Two syntype workers, Point Loma, California, USA (P. Leonard) ( AMNH) [examined via image supplied by Christine Lebeau].

Colobopsis apostemata Mackay, in Mackay and Mackay, 2018: 100. Holotype major worker, Tecate, Baja California, Mexico ( LACM) [not examined]. Syn. nov.

Colobopsis cavibregma Mackay, in Mackay and Mackay, 2018: 107. Holotype dealate queen, Skinner Reservoir, Riverside Co. , California, USA (T. Prentice) ( LACM) [not examined]. Syn. nov.

Camponotus (Colobopsis) yogi Wheeler; Wheeler, 1917: 562. Placement in Camponotus (Colobopsis) .

Camponotus (Myrmaphaenus) yogi Wheeler; Emery, 1925: 156. Placement in Camponotus (Myrmaphaenus) .

Camponotus (Myrmaphaenus) yogi Wheeler; Creighton and Snelling, 1967. Taxonomic and biological notes.

Colobopsis yogi (Wheeler); Mackay and Mackay, 2018: 215. Combination in Colobopsis .

Camponotus yogi Wheeler; present study. Combination in Camponotus (comb. rev., see above).

Camponotus apostemata (Mackay); present study. Combination in Camponotus (comb. nov., see above).

Camponotus cavibregma (Mackay); present study. Combination in Camponotus (comb. nov., see above).

Based on the original description and figures ( Mackay and Mackay 2018: 111-113), the holotype of Camponotus cavibregma appears to be simply a queen of Ca. yogi . Its supposedly distinctive feature-a concave genal area, free of the short spatulate hairs that are common on surrounding anterior regions of the head-is observed also in queens of Ca. yogi (Fig. 5D ). The description and illustrations of the paratype minor worker of Ca. cavibregma ( Mackay and Mackay 2018: 109-111) similarly place it within the range of variation exhibited by minor workers of Ca. yogi .

Camponotus apostemata , described from a series of workers collected in northern Baja California (specimens from this series examined in LACM), is scarcely distinguishable from Camponotus yogi , and is here treated as part of the geographical variation of the latter species. The head of the major worker is a bit more strongly truncate than in populations farther north, but no consistent differences are seen in the minor workers. Johnson & Ward (2002) referred to these and other samples of Ca. yogi from Baja California as Camponotus sp. cf. yogi .

Camponotus yogi is closely related to Ca. clarithorax Creighton. The major worker of the latter species lacks a pitted, obliquely truncate head, but is otherwise structurally similar. The two species can be distinguished by differences in scape and leg length, with Ca. yogi having consistently shorter appendages than Ca. clarithorax (Fig. 6 ), although very small workers may be difficult to distinguish. The median clypeal notch or concavity is better developed, on average, in Ca. clarithorax workers than in those of Ca. yogi , a feature which led to the placement of Ca. clarithorax in the subgenus Camponotus Myrmentoma , but neither species belongs in that subgenus. They are here treated as Camponotus (Camponotus) since genetic data indicate a fairly close relationship to other species in that subgenus ( Wernegreen et al. 2009; Ward, unpublished). In addition to Ca. clarithorax and Ca. yogi , there are two other species in the Ca. yogi group: Ca. keiferi Wheeler, endemic to Isla Guadalupe, Mexico (and already placed in the nominate subgenus), and an undescribed species from the California Channel Islands (Ward, unpublished).

Camponotus yogi is endemic to California and northern Baja California, where it occurs in coastal sage scrub, chaparral, oak woodland, and oak-juniper woodland. Nests are located in dead branches or stumps of various plants, always near the ground and often extending into live plant tissue. Creighton & Snelling (1967) reported this species nesting in live beetle-bored stems of Ericameria pinifolia , and tending pseudococcids in the stems.

Figures

Figure 5. Camponotus yogi, full-face dorsal views of head (A, B, D) and lateral view of body (C); scale bars = 0.5 mm. A: Minor worker (CASENT 0249398). B, C: Major worker (CASENT 0249399). D: Dealate queen (CASENT 0923092). Images from AntWeb (www. antweb. org); photographers Will Ericson (A-C), and Wade Lee (D).

Figure 6. Plot of scape length (SL) against head width (HW) for workers of Camponotus clarithorax (n = 12) and Camponotus yogi (n = 27). Samples of Camponotus yogi from northern Baja California (BC) fall within the same cluster of points as those from California (CA).