Neotypification of M. virens Linnaeus, 1766

The name Contopus virens (Linnaeus) has been used for the Eastern Wood Pewee for more than 200 years, and is recognised as the type species of Contopus Cabanis, 1855. However, Brisson’s (1760) measurements match a specimen in the genus Empidonax, unidentifiable to species, and Catesby’s (1731) plate and description exhibit an inconsistent suite of characters, precluding identification. The bird in Catesby’s original painting lacks prominent wingbars, and therefore resembles Sayornis phoebe more than C. virens. Furthermore, Linnaeus (1766) evidently miscopied a conspicuous plumage character—a white supercilium (‘ superciliis albis ’)—from a species in a different family (Vireonidae), the ‘Red-eyed Fly-catcher’ (= Vireo olivaceus), which appeared on the same plate as Catesby’s (1731: 54) ‘little brown Fly-catcher’. Therefore, despite its long use, the original description of M. virens Linnaeus, 1766, is not unambiguously identifiable. Its known type material evidently consisted of specimens from multiple passerine families and genera (Tyrannidae: Empidonax, Sayornis; and Vireonidae: Vireo, or Icteriidae: Icteria) and no specimen is extant or traceable. None of the type material can be unambiguously identified as the species now known as Eastern Wood Pewee. To my knowledge, this situation has not been previously discussed in literature, nor has any previous author designated a lectotype or neotype of M. virens.

Therefore, to fix the taxonomic identity of Eastern Wood Pewee C. virens (Linnaeus), in accordance with prevailing use, I hereby designate a neotype for M. virens Linnaeus, 1766. The neotype is an adult female (DMNH 85602) in the collection of the Delaware Museum of Nature & Science, Wilmington, DE, USA (Fig. 9). This action stabilises nomenclature and prevents confusion arising from alternative identifications. It satisfies the requirements for neotype designation in the Code (ICZN 1999) by clarifying the taxonomic application (status) of the name (Art. 75.3.1), describing, illustrating and referencing the defining characters of C. virens and its neotype (Art. 75.3.2), providing data sufficient to ensure recognition of the neotype specimen (Art. 75.3.3), providing grounds for believing that all original type material has been lost and is untraceable (Art. 75.3.4), showing that traits of the neotype are included in the original description (Art. 75.3.5), choosing a neotype collected on the breeding grounds of C. virens, in eastern North America, where the syntypes that served as the models for Brisson (1760) and Catesby (1731) were presumably collected (Art. 75.3.6), and depositing the neotype in a recognised scientific institution (Art. 75.3.7).

Collection of the neotype.— DMNH 85602 is an adult female (study skin and spread left wing) collected on private property (‘Stoffa Cabin’) at 274 Freedom Road, Drums, Luzerne County, Pennsylvania, USA (41°1’0.62”N, 75°56’29.86”W). At 08.00 h, on the morning of 29 August 2022, I captured the bird in a mist-net. I drew approximately 50 ΜL of blood via brachial venipuncture into a microhematocrit capillary tube. I immediately smeared blood droplets on two glass slides, then fixed them in pure methanol. I also applied blood drops to an FTA card, which I stored in a sealed plastic bag with silica desiccant beads. I euthanised the bird via cardiac compression, then transported the body on ice to DMNH, where I placed it in a storage freezer (‒20 oC) until I prepared the specimen.

The type locality (‘Stoffa Cabin’) is a mixed deciduous-conifer woodland with a colonial history of human disturbance including residential development and selective logging. It is located near the headwaters of the Little Nescopeck Creek, and named for a cabin constructed there in the 1980s by my grandfather, Francis J. Stoffa, Sr. (1931–99). Eastern Wood Pewee is a common summer resident and breeder in the woods at Stoffa Cabin, and I heard its familiar song during field work there on 13 August 2022 (one singer), 28 August (two) and 29 August 2022 (two, both singing after I collected DMNH 85602). On those dates, I did not detect any species except those that breed regularly on the property. I did not hear C. virens when I returned to the site for several hours of field work on 24 September. Therefore, it is likely that DMNH 85602 was a member of the breeding population at Stoffa Cabin, collected just prior to its migration, and not a southbound migrant collected at a stopover site, although this is not known for certain. In this case, choosing a breeder for the neotype is not imperative because no geographic variation is known or described in the monotypic C. virens (Watt et al. 2020) nor is there evidence that Catesby’s (1731) or Brisson’s (1760) original descriptions were based on breeding birds.

Preparation of the neotype.—Four days later (2 September 2022), I prepared the study skin and sampled tissues (Fig. 10, prep. = MRH459). The bird was undergoing general body moult, most pronounced on the breast and neck. I did not find any parasites, despite fumigation with ethyl acetate and ruffling of each feather tract. I measured the wings and tail from the fresh (pliable) body with a metric ruler or dial callipers, as noted. Max. wingspan was 243 mm (ruler); the length of the closed and flattened right wing from the carpal joint to the tip of the longest primary was 79 mm (ruler); with the wing closed, the distance between the tips of the longest primary and first secondary (‘Kipp’s distance’; Kipp 1959) was 22.7 mm (callipers); the length of the tail, from the insertion point of the two central rectrices to the tip, was 58 mm (ruler). I measured the wing length again on 22 March 2023, by which time the study skin had been dried for over six months; it had decreased slightly to 78.5 mm.

The ovary measured 5 × 1 mm (ruler), was an orangey colour and had a granular texture. The oviduct was straight and <1 mm wide (ruler). The skull was 100% pneumatised. No bursa was found. The stomach was saved and refrozen for a forthcoming dissection. There was a small amount of fat in the dorsal tract and around the furcula. Measured with dial callipers, the widest diameter of the (wet) left eye was 8.8 mm, after removal from the skull, and the diameter of the corneal ‘bulge’ was 4.9 mm. I collected samples of the breast muscle, liver, and heart tissue (DMNH P10371) in 95% ethanol and placed them in the storage freezer (‒20 oC). I also deposited backup tissues at the Academy of Natural Sciences of Drexel University (Philadelphia, PA).

Diagnosis.—Eastern Wood Pewee C. virens (Linnaeus) is distinguished morphologically from the five Empidonax (Tyrannidae) that regularly occur in eastern North America (see above) by its combination of a longer wing and shorter tarsometatarsus (Fig. 11, Pyle 2022: 257), and, from Sayornis phoebe, by its shorter tarsometatarsus (Fig. 11) and pale mandible (vs. black in S. phoebe).