Santarosamyia Fleming & Wood, 2025

Fleming, A. J., Smith, M. Alex, Hallwachs, Winnie & Janzen, Daniel, 2025, A new genus and a new species in the tribe Eryciini (Diptera, Tachinidae) from Area de Conservación Guanacaste in north-western Costa Rica, Biodiversity Data Journal 13, pp. e 161853-e 161853 : e161853-

Santarosamyia Fleming & Wood gen. nov.

erecta Coquillett, 1902: 112 ( Phorocera ). Holotype female ( USNM: USNMENT 01789077 ) (examined by AJF). Type locality: USA, Arkansas, Camden. comb. nov.

loxostegeae Reinhard, 1922: 331 ( Exorista ). Syntypes, 14 males and 10 females ( CNC) (examined by AJF). Type localities: USA, Texas, College Station.

unipilum Aldrich & Webber, 1924: 83 ( Phorocera ( Neopales) ). Holotype male ( USNM: USNMENT 01789003 ) (examined by AJF). Type locality: USA, Oregon, Hood River. Nearctic species. comb. nov.

woodorum Fleming & Wood, 2025 . Holotype male ( CNC: DHJPAR 0019111 ). Type locality: Costa Rica, Guanacaste, Area de Conservacíon Guanacaste, Sector Santa Rosa. sp. nov.

Santarosamyia woodorum Fleming & Wood, 2025 . Type species.

Description

Male, Head: head slightly wider than thorax; vertex 1 / 4–1 / 3 head width; gena 1 / 6 of head height, approximately 1 / 5 of eye height; head width approximately 1 / 2 of height at widest point, giving it a slightly protruding character when viewed laterally, with one row of frontal setae, these extending well below base of pedicel and one pair of reclinate orbital setae, nearly in line with frontal row; frontal vitta at least as wide as either parafrontal, ocellar setae present and proclinate; eye densely setulose; parafacial bare and narrow; fronto-orbital plate ranging from shining silver to gold, with a sparse vestiture of short black irregularly inserted setulae; lower margin of face level with vibrissa; facial ridge with strong robust setae, along at least 1 / 3–2 / 3 its length almost reaching height of lowest frontal seta; pedicel black; postpedicel black, 6 x as long as pedicel in males and 4 x as long as pedicel in females; arista bare, usually distinctly-thickened on basal 4 / 5 almost to tip, palpus black to dark brown and setulose.

Thorax: scutum ranging from dark grey-back to brilliant gold; 4–5 dorsal vittae, these can often be bold and unbroken to only scarcely present under certain angles of light, outer pair broken at suture; prosternum setose; postpronotum bearing 4–5 setae, middle basal seta in line with outer and inner basal setae; anterior margin of anepisternum setulose with long hair-like black setulae. Thoracic chaetotaxy: acrostichal setae 3: 3; dorsocentral setae 3: 4; intra-alar setae 3: 3; supra-alar setae 2: 3; 3–4 katepisternal setae often widely spaced such that anterior katepisteral seta is closely paired with anterior ventral katepisternal seta; scutellum ground colour black with tomentosity ranging from nearly glabrous black to gold tomentose, with one pair of discal setae and three pairs of long flat marginal setae of subequal length; apical setae strong and crossed, inserted on the same plane as marginal setae, in some cases, at an upward angle from the plane of the rest of the scutellar marginal setae. Legs: black, with yellow pulvilli of varying length; hind coxae bare. Anterodorsal row of setae on hind tibia ciliate with up to 3–4 longer setae emerging above the rest. Wing: mostly pale translucent, to slightly hyaline; wing vein R 4 + 5 setose, bearing only 1–3 setulae at base; calypters ranging from white to slightly yellow infuscate, almost amber coloured.

Abdomen: ground colour black dorsally with some orange laterally, tomentosity ranging from greyish – brown to nearly glabrous black; abdominal tomentosity ranging from strikingly gold to dull grey, often forming conspicuous anterior bands on dorsal surfaces of tergites, bisected by a narrow median black stripe; mid-dorsal depression on ST 1 + 2 ranging from halfway across tergite to almost reaching to hind margin; one pair of median marginal setae present on ST 1 + 2 – T 3 and a complete marginal row on T 4 and T 5; median discal setae present on T 3 – T 5.

Male terminalia: sternite 5 with a deeply excavated median cleft along posterior edge, approximately 1.4 x as wide as long, V-shaped, inner margins covered in dense tomentum; posterior lobes flattened somewhat apically, 2–3 strong setae surrounded by many shorter, weaker setulae; unsclerotised " window " on anterior plate of sternite 5 almost entirely translucent, shape ranging from rectangular to almost indistinct directly basal to posterior lobes. Epandrium setulose, cercus triangular, slightly longer than surstyli; cercus apically pointed, completely separate along most of its entire length. Cercus in lateral view, with a slight downward curve at apex, appearing slightly clubbed appearance to sharp and smoothly curved almost beak-like appearance, densely setulose along basal 2 / 3. Surstylus in lateral view, wide and robust, round medially, rounded and blunt at apex, not tapering to a point, giving the structure a wide digitate appearance; surstylus not fused with epandrium; when viewed dorsally, surstyli wide, slightly divergent, bearing a slight outward bend at apices. Pregonite broad, well-developed, apically rounded, blunt, with 6–7 setae along margin. Postgonite, slightly narrowed, up to 1 / 3 as wide as pregonite, sharply curved at apex. Basiphallus with a well-developed narrow elongate epiphallus; distiphallus broad with a thickened median process of the dorsal sclerite on its posterior surface pointed with a distinctive downward curve at apex and a broad, lateroventral sclerite, on the anterior surface also curving downwards at the apex.

Female, as in male, differing in the following traits: Head: bearing two pairs of proclinate orbital setae, frons wider than males. Abdomen: often slightly more globose than males. In those cases where sexual dimorphism is observed, the differing character states are mentioned in the species description.

Diagnosis

The genus Santarosamyia can be recognised by the combination of the following character states. Head, frons with a single row of frontal setae, parafacial bare, facial ridge strongly setose along lower 1 / 2–5 / 8, ocellar setae well developed and proclinate, eyes setulose, with distinct ommatrichia present and distance between eye and facial margin greater than 1 / 6 head height. Thorax, postpronotum with middle basal seta in a straight line, first postsutural supra-alar seta, as long and stout as first postsutural dorsocentral seta, 4 katepisternal setae, apical scutellar setae long and crossed often angled upwardly, but sometimes flat. Legs, hind coxa bare on postero-apical margin, tibia of last leg ciliate along posteroventral margin. It can be distinguished from Lespesia by the presence of both median discal and median marginal abdominal setae on tergites 2–4; it is distinguished from Nilea by its DNA barcode and the distinctive curvature at the apex of the median process of the dorsal sclerite, which is straight in both Nilea and Lespesia and presents as a distinctive character of the postabdomen in the new genus.

The phylogeny of 181 BINS from 12 genera of tachinid flies reared in ACG Costa Rica from the Eryciini was estimated using the Maximum Likelihood method and General Time Reversible model ( Nei and Kumar 2023) in MEGA 11 ( Tamura et al. 2021) (Fig. 3 ). Santarosamyia is, on average, 12 % divergent from other genera within the ACG Eryciini and the average divergence between genera was 12 %. Sequence divergence between genera was estimated using the Maximum Composite Likelihood model in MEGA 11. Sample information is provided in Suppl. materials 1, 2.

A phylogeny of 71 public sequences of Santarosamyia ( woodorum and unipilum ) and of public sequences of Nilea was estimated using the Maximum Likelihood method and General Time Reversible model ( Nei and Kumar 2023) in MEGA 11 ( Tamura et al. 2021) (Fig. 4 ). Our results suggest Santarosamyia is, on average, 10 % divergent from Nilea and the average divergence within Nilea is 5 %. Sequence divergence between genera was estimated using the Maximum Composite Likelihood model in MEGA 1 (associated data provided in Suppl. material 3). Within Costa Rican Santarosamyia collected in ACG, there was only one specimen that posessed a single base-pair of variation in the DNA barcode region (an asynonymous A / G transition variation) and is 10 % divergent from species of Nilea . S. woodorum DNA barcode sequences are AT rich, as is characteristic for insect mitochondrial DNA (AT content is 70.02 %).

Etymology

The prefix of the compound name Santarosamyia refers to the locality where the holotype of the type species was collected (“Parque Nacional Santa Rosa” which is today Sector Santa Rosa of ACG). The suffix “myia” is in reference to the Greek word for fly.

Distribution

Widespread throught the Nearctic and Mesoamerican Regions, its range including Canada and USA, south to Costa Rica.

Ecology

To date, Santarosamyia has been reared from Lepidoptera larvae in the families: Crambidae , Geometridae , Olethreutidae and Pyralidae .

Taxon discussion

Santarosamyia keys out in the Manual of Nearctic Diptera ( Wood 1987) with couplets 43 and 46 along with Nilea . However, Santarosamyia does not consistently possess horizontally directed apical scutellar setae, nor the diagnostic placement of the katepisternal setae, both features used to distinguish Nilea from Lespesia . In the Manual of Central American Diptera ( Wood and Zumbado 2010) , it keys out with Lespesia in couplet 57. It is distinguished from these closely-related genera by the presence of discal setae on tergites 3 and 4.

Figures

Figure 3. Phylogeny of 181 BINS from 12 genera of tachinid flies reared in ACG Costa Rica from the Eryciini. Santarosamyia gen. nov. shown in red.

Figure 4. Phylogeny of 71 public sequences of Santarosamyia (woodorum and unipilum) and of public sequences of Nilea. Santarosamyia in yellow and public sequences of Nilea available on BOLD in purple.