Drosophila (Sophophora) narragansett Sturtevant and Dobzhansky, 1936

Grimaldi, David A., 2024, The Drosophila (Sophophora) obscura species group in the Americas (Diptera: Drosophilidae): review, revisions, and three new species, American Museum Novitates 2024 (4015), pp. 1-44 : 25-30

publication ID	https://doi.org/ 10.1206/4015.1
DOI	https://doi.org/10.5281/zenodo.12173693
persistent identifier	https://treatment.plazi.org/id/0387351B-FFE5-FFA4-F63A-5DCDFC9AFCBC
treatment provided by	Felipe
scientific name	Drosophila (Sophophora) narragansett Sturtevant and Dobzhansky
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Treatment

Drosophila (Sophophora) narragansett Sturtevant and Dobzhansky View in CoL

Figures 2C, D View FIG ; 5A–C View FIG , 7F View FIG , 9J View FIG ; 12A, B View FIG ; 15A, D View FIG

Drosophila (Sophophora) narragansett Sturtevant and Dobzhansky, 1936: 577 View in CoL .

Drosophila (Sophophora) seminole Sturtevant and Dobzhansky, 1936: 577 View in CoL . NEW SYNONYMY.

DIAGNOSIS: Males immediately recognized among North American species of the group by the silvery frons, best seen in frontal view in dried/fresh specimens. Distinguished from D. olmeca , n. sp. (Chiapas Mexico), also with a silvery male frons, as discussed under that species below. D. narragansett further distinguished by the following: male ta1 with 4–5 teeth and ta2 with 1; ta1 1.3× length of ta2; base of inner ventral epandrial lobe with furrows, no microtrichia; surstylus with 9–10 prensisetae. Spermatheca distinctive, roughly cup-shaped, apical indentation short; sleeve large, conical, with fine annulations.

REDESCRIPTION: Coloration: Frons in ♂ silvery in frontal view, especially frontal vittae (fronto-orbital plates and ocellar triangle slightly less so); in dorsal view of ♂ this silvery shagreenation diminished; ♀ frons pollinose, slightly olive but not silvery, ocellar triangle and pair of spots at vertex lateral to ocelli without pollinosity; portion of frons near ptilinal suture dull, dark yellow. Antenna with pedicel light brown, flagellomere 1 darker brown; face, cheeks, and palps dull, tan; clypeus light brown. Scutum, scutellum, postpronotal lobe very light brown, dull, with dusting of pruinescence; notopleural area, anepisternum and anepimeron slightly darker brown, katepisternum lighter. Legs and halter knob dark yellowish tan; abdomen uniformly brown in both sexes, darker in ♂.

Head: Arista with 4 dorsal, 2 ventral branches, plus terminal fork; pedicel with 4 larger setae. HD/HW 0.74 (mean of 4♂). Anterior reclinate orbital seta slightly posterolateral to the proclinate orbital; posterior reclinate slightly closer to proclinate than to inner vertical seta; proclinate 1.65× length of anterior reclinate, posterior reclinate 1.14× length of anterior reclinate. Ipsilateral vertical setae close together, sockets separated by distance ~2× their diameter; inner vertical in line with proclinate and posterior reclinate; vertical setae long, IV/OV 0.96. Ocellar seta socket on tangent between median and posterolateral ocelli; postocellars of medium length, parallel to convergent, pointing backward, shorter than ocellars (OC/POC 1.30); ~6 small setulae in ocellar triangle. Frons with 2–8 minute setulae near anterior margin. FL/LFW 0.94, UFW/LFW 1.47. Frontal W-index 2.85; carina very small, thin, short (half the length of face); vibrissa long, 1st genal seta small, GS1/VL 0.56, gena with 5–6 setae, decreasing in length posteriad. Cheek fairly narrow, ED/CD 7.5. Palp with 1 long preapical seta. Eye broadly oval in lateral view, EW/ED 0.81.

Thorax: Length 0.88 mm (mean of 4♂). Acrostichals in 6 even rows between anterior dorsocentrals, lengths slightly increasing posteriad; acrostichals in front of scutellum or anterior dorsocentrals not enlarged. Anterior dorsocentrals 0.72× length of posterior ones; distance between ipsilateral dorsocentrals less than that between contralateral ones. Postpronotum with 2 strong setae, h-index 0.77; 2 strong notopleural setae near notopleural suture, plus 1 dorsally, another, short postsutural; katepisternum with 2 large setae, posterior one about 2× the size of other (S-index 0.57), sclerite with 5–7 small setulae. Anterior scutellar setae convergent, posterior ones crossing for about 0.2× their length, both pairs approximately equal in length (scut-index 0.96). Legs: Profemur with ventral row of 3–4 long setae on distal half (lengths approximately equal to femur width); mid and hind tibiae each with stout, ventroapical seta, thinner dorsal-preapical seta; ♂ protarsus ta1 1.3× length of ta2; ta1 with 4–5 teeth, ta2 with 1; teeth stout, touching, length 1.3× tarsomere width. Wing of moderate length and width, ThL/WL 0.44, WL/WW 2.28, C-index 2.65, hb-index 2.49, 4V-index 2.23, 5X-index 2.15.

Abdomen: Male terminalia: epandrium height slightly greater than width; cercus relatively narrow, with narrowed ventral lobe; outer lobes of ventral epandrial lobe relatively short (tips reaching to level of about midway to surstylus); margin of inner lobe of ventral epandrial lobe not well defined from surstylus, base of inner lobe with furrows; surstylus with row of 9–10 prensisetae; aedeagus and valves slightly shorter than (0.9× the length of) postgonites; gonites with faint elbow near middle of lateral margin. Aedeagal valves without ornamentation; membrane of aedeagus with very fine microtrichia. Hypandrium length 1.3× the width. Female terminalia: spermatheca distinct, width 1.5× the height; sleeve very large, funnel shaped, with fine annulations, extended into capsule 0.9× the capsule height, with small apical indentation protruding into end of sleeve. Oviscapt of moderate depth in lateral view, apex slightly narrowed; with ~13 ovisensilla pegs along margins.

TYPE: Lectotype, ♂, selected by myself from a series of 9♂, 14♀ specimens, all labeled as: “WoodsHole, Mass [printed]/stock 25 [written]/ A.H. Sturtevant Collection, 1970 [printed.” Steyskal did not apply a note to any specimen as the type. 1 ♂, 1♀ paralectotype dissected. In the USNM.

SPECIMENS EXAMINED: Besides the lectotype and the paralectotype series (above), the holotype of seminole and several specimens identified as seminole (see in Comments below).

DISTRIBUTION: Currently a very rare species that historically extends from southern Alabama (Hartsell, Kushla), Mississippi (Corinth), and mid-Florida (St. Petersburg) north to Massachusetts (Amherst, Woods Hole), northern Michigan (University of Michigan Biological Station), and in the west to Nebraska (Lincoln, Chadron St. Forest), Missouri (St. Louis) ( Miller, 1958), as well as Indiana (locality not specified) and Texas (Bastrop St. Park) ( Barrio et al., 1992). The record and figures in M. Miller et al. (2017) of D. narragansett from Maine are incorrect. These are based on a series of specimens in the AMNH: “SE Guarette Maine, July 1948 / M.R. Wheeler collector,” which were misidentified by Marshall Wheeler as narragansett . The specimens are actually D. athabasca , with a spermathecal capsule that is especially flat and broad.

In a study of abundances of D. affinis , D. algonquin , D. athabasca , and D. narragansett ( Miller, 1958) , the last one was not found at most of the localities, and when present was less than 1% of the abundance of these four species, except at two sites: Corinth, Mississippi (3%) and Hartshell, Alabama (7%). Astonishingly, narragansett has to my knowledge been collected only once within the past 60 years, despite its broad range: a male swept from over compost in May 2017 in Rochester New York ( Werner et al., 2020a, 2020b). I have never collected it, nor have many other drosophilists.

COMMENTS: The holotype of seminole , a male, is labeled: “Kushla, Ala[bama], My.14.22, oak trunk [in Sturtevant’s writing] / A.H. Sturtevant collection, 1970 [printed].” In USNM. This is the sole specimen from the type locality (Kushla), it has a penciled note by Steyskal (in his writing) “seminole type”; it was labeled 12 June 2023 by myself as the holotype; glue on the tip of the abdomen prevented it from being dissected for the genitalia. The glue also embedded the foretarsi, but fortunately it is clear and four long teeth are visible on protarsomere-1. The type of D. seminole is darker than specimens in the type series of D. narragansett and the specimen from Virginia, but in all other respects it is identical to those others, including measured proportions of body structures and setae. The putative differences between D. narragansett and D. seminole in the silvery frons, reported by Sturtevant and Dobzhansky (1936) and cited by Sulerud and Miller (1966), are incorrect and one basis for confusion that D. seminole could be a separate species. The silvery male frons may not be apparent in specimens preserved in alcohol.

Two other specimens in the USNM collection identified as D. seminole are the following: one mentioned in the original publication (Sturtevant and Dobzhansky, 1936) labeled as: “Whistler Ala[bama] Oc[t.].20.24 [written in Sturtevant’s hand] / A.H. Sturtevant Collection 1970 [printed]/ Drosophila seminole [written].” This specimen, a male with the genitalia everted, is not D. seminole (i.e., D. narragansett ); it lacks the distinctive silvery frons. A third specimen is a male with a silvery frons, labeled: “Mountain L[ake], Va., 22-VII-’ 40 W. H. #2, L.J. & M.J. Milne / Drosophila seminole det. Steyskal ‘[19]44.” This specimen is D. narragansett , although it has some interesting distinctions from other measured specimens of D. narragansett : upper seta of postpronotal lobe smaller than lower one (h-index 0.62, vs. 0.80–0.87 for others), smaller anterior scutellars (Scut-index 0.88, vs. 0.97–1.02 for others), C-index smaller (2.48, vs. 2.65–2.71), and hb-index smaller (2.18, vs. 2.42–2.75). The male genitalia of the type series of D. narragansett and the Virginia specimen are identical.