New records of Clusiidae (Diptera: Schizophora), including three species new to North America

3.1 The Clusiidae of Florida

The Nearctic Sobarocephala (Sobarocephalinae) were last revised by Lonsdale and Marshall (2007a). Sobarocephala dreisbachi Sabrosky and Steyskal was later added to the Florida list by Halbert (2003) following detection by G. Steck (Florida Department of Agriculture and Consumer Services, Gainesville, Florida). Herein, two Neotropical Sobarocephala are recorded in the Nearctic region for the first time: S. lucibilis and S. oculata. Collection data and diagnoses of the two newly added species are as follows:

1. S. lucibilis Lonsdale & Marshall (Figure 1)

   New biogeographic region/country record: USA. Florida: Miami-Dade county, Coral Gables, Montgomery Botanical Garden, 25.6572917 °N, 80.2805500 °W, Malaise trap, 15–26.ix.2016, T. Magellan, CNC819985 (1♂, CNC).

   Diagnosis: This species has only one pair of lateral scutellar setae, which will differentiate it most easily from the similar S. setipes Melander & Argo. The scutum also has one pair of large postsutural stripes that do not connect basally, the scutellum is entirely yellow, the brown marking on tergite 2 is concave anteromedially, and the surstylus is very short with a very shallow medial emargination that may not be readily visible. It belongs to the S. interrupta species group, characterized by male cerci that are not produced past the distal margin of the epandrium.

2. Sobarocephala oculata Lonsdale & Marshall (Figure 2)

   New biogeographic region/country record: USA. Florida: Miami-Dade county, Coral Gables, Montgomery Botanical Garden, 25.6572917 °N, 80.2805500 °W, Malaise trap, 15–26.ix.2016, T. Magellan, CNC819970, CNC819998, CNC820011 (1♂ 2♀, CNC).

   Diagnosis: A brown scutellum and epandrium, and one pair of small, floating spots on the postsutural scutum are characteristic of this species. The surstylus is about as high as the epandrium, widest basally and broadly rounded apically, and male sternite 5 has a posteromedial comb of setae.

   To accommodate these new records in the key to Nearctic Sobarocephala provided by Lonsdale and Marshall (2007a), two sets of couplets must be emended, with newly added species in bold:

3. First emendation:

   8. Scutellum entirely brown. … 8b

   8′. –Scutellum yellow, at least in part. … 9

   8b. Scutal stripe large, fused posteriorly along posterior margin of scutum. Frons sometimes with orange tint. Male abdomen entirely yellow. Eastern North America … S. dreisbachi Sabrosky & Steyskal

   8b′. –Stripes on scutum limited to one pair of small floating spots (Figure 2). Frons always yellow. Male abdomen with dorsomedial stripe and epandrium brown. USA (Florida), Cayman Islands … S. oculata Lonsdale & Marshall

4. Second emendation:

   16. Postsutural stripe serrate on anterior margin. Scutellum brown laterally (rarely entirely yellow) (Lonsdale and Marshall [2007a: Figure 13]). Female tergite 6 yellow, sometimes with anteromedial spot. No small bristle in front of anterior dorsocentral. Surstylus deeply bifid (Lonsdale and Marshall [2007a: Figure 51]). Southeastern United States, Illinois … S. interrupta Sabrosky & Steyskal

   16′. –Postsutural stripe entire and rounded on anterior margin, if present. Scutellum usually entirely yellow, but if lateral corner brown (some S. setipes), small bristle present in front of anterior dorsocentral. Female tergite 6 brown, at least medially. Anterior lateral scutellar bristle not much smaller than posterior bristle, if at all. Surstylus rounded or with shallow, indistinct distomedial emargination. … 17

   17. One pair of lateral scutellar setae. Scutum with one pair of strong postsutural stripes (Figure 1). Fore tibia brownish. Tergite 2 with anteromedial margin of brown marking concave. Male sternite 5 without comb of setae. Surstylus with shallow, almost indistinct distomedial emargination (best viewed in posterior aspect). USA (Florida), Dominican Republic, Jamaica, Puerto Rico, and U.S. Virgin Islands, but also Brazil (Amazonas). … S. lucibilis Lonsdale & Marshall

   17′. –Two pairs of lateral scutellar setae. Scutum yellow postsuturally or with one pair of postsutural stripes that are usually strong. Fore tibia yellow. If brown marking on tergite 2 present, then anterior margin convex. Male sternite 5 with posteromedial comb of setae. Surstylus rounded … 17b

   17b. Notopleuron brown posteriorly (females sometimes with most of notopleuron and postpronotum brown) and scutum usually with one pair of wide brown postsutural stripes (Lonsdale and Marshall [2007a: Figure 15]). Acrostichal bristle absent. Length 2.4–2.9 mm. Female abdomen with wide brown stripe on tergites 2–6. Eastern North America … S. setipes Melander & Argo (in part)

   17b′. –Scutum yellow with dark brown quadrate spot on notopleuron (sometimes faded in males and teneral specimens) (Lonsdale and Marshall [2007a: Figure 16]). Acrostichal bristle present. Length 3.9–4.9 mm. Female abdominal pattern as follows: tergite 2 sometimes brown along posterior margin, tergites 3 and 4 with wide central stripe, tergite 5 with narrow central stripe, and tergite 6 dark brown. Eastern and central North America … S. lachnosternum Melander & Argo

Figure 1:

Sobarocephala lucibilis Lonsdale & Marshall, Florida male; A: left lateral; B: dorsal; C: head, frontal. D–F: S. lucibilis, male genitalia (from Lonsdale and Marshall [2012: Figures 375–377]): D: external components, left lateral; E: same, posterior; F: internal components, left lateral.

Figure 2:

Sobarocephala oculata Lonsdale & Marshall, Florida male; A: left lateral; B: dorsal; C: head, frontal. D–F: S. oculata, male genitalia (from Lonsdale and Marshall [2012: Figures 515–517]): D: external components, left lateral; E: same, posterior; F: internal components, left lateral.

Of the 19 Sobarocephala species now known from the Nearctic region, all but six have been collected in Florida. The absentees include Sobarocephala texensis Sabrosky & Steyskal, a Texas endemic, Sobarocephala pengellyi Lonsdale & Marshall from Georgia and Alabama, and the mostly or entirely northeastern species Sobarocephala atricornis Sabrosky & Steyskal, Sobarocephala lachnosternum, Sobarocephala latifacies Sabrosky & Steyskal, and Sobarocephala latifrons (Loew). Of these species, S. latifrons is widespread in the south and likely also occurs in Florida, and S. pengellyi likely also occurs in Florida because it is known from two adjacent states.

Nine species of Sobarocephala known from Florida are restricted to the Nearctic. Only Sobarocephala cruciger Sabrosky & Steyskal is known exclusively from Florida. Three other Florida species are known from other eastern coastal states: S. affinis, S. muesebecki (also Texas), and Sobarocephala wirthi Lonsdale & Marshall. More widespread eastern species are S. dreisbachi, Sobarocephala flava Melander & Argo, and Sobarocephala setipes, which extend as far north as Ontario and Quebec. Sobarocephala flaviseta (Johnson) is quite widespread in the Nearctic except for the western states and the continental north. Most records of Sobarocephala interrupta Sabrosky & Steyskal are from the southeastern United States, but one apparent outlier has been found in Illinois.

Four species known in Florida also occur in the Neotropics. Sobarocephala atrifacies Sabrosky & Steyskal is known from the Dominical Republic. Sobarocephala quadrimaculata Soós is known from Central America, the Caribbean, Alabama, Georgia, and Texas. S. lucibilis was previously known mostly from the Caribbean (Dominican Republic, Jamaica, Puerto Rico, and U.S. Virgin Islands) but it also has been recorded from Brazil (Amazonas). S. oculata was previously known from the Cayman Islands (Lonsdale and Marshall 2012).

The New World species of Clusiinae are represented by three species of the genus Clusia Haliday, one of which is western and two of which are northeastern. While none of these are known from Florida, the distribution of Clusia lateralis Walker extends relatively far south and may be found in or close to Florida following focused collecting. The species of Clusia are keyed in Lonsdale et al. (2011).

The Floridian Clusiodinae belong to three genera. Czernyola is known in Florida from C. concinna (Williston), which is widespread in the Neotropics, and C. weemsi (Lonsdale & Marshall), which also occurs in Jamaica, Mexico, and Peru. Czernyola annulipes (Johnson) likely occurs in Florida as it ranges from the Neotropics north to Maryland, Mississippi, North Carolina, and Texas. The New World Czernyola were revised by Lonsdale and Marshall (2006). Three Heteromeringia occur in Florida: Heteromeringia czernyi Kertész, which is widespread in the Neotropics; Heteromeringia flavipes Williston, which is known from Costa Rica, St. Vincent, and Nicaragua; and Heteromeringia nitida Johnson, which is widespread in the eastern Nearctic from northern Mexico to southern Ontario, but also occurs in parts of the southwestern USA. The New World Heteromeringia were revised by Lonsdale and Marshall (2007b). Clusiodes Coquillett is only represented in Florida by C. gracilolobus Caloren & Marshall, but the known distribution of C. johnsoni Malloch suggests that it may occur in Florida. The genus was revised in the New World by Caloren and Marshall (1998).

3.2 Other new global geographic records

3.3 On the identity of S. muesebecki

The differences between S. affinis and S. muesebecki are slight, and females can be difficult to identify since the only unambiguous character differentiating them is the color of the epandrium, being yellow in S. affinis and dark brown in S. muesebecki. S. muesebecki sometimes also differs having slightly darker pigmentation on the wing, hind legs and setae, the anterior margin of the frons is sometimes whitish, and the gena and postgena are more frequently pilose (Lonsdale and Marshall 2007a). Alabama populations of S. muesebecki are additionally unique in having one pair of faded brownish spots anterolateral to the anterior dorsocentral setae in all examined females and some males, and a few of these spotted specimens also have a similar faded spot dorsomedially on the scutellum.

Despite the above differences, the two may be synonymous because their male genitalia are essentially identical and known distributions largely overlap. Additionally, specimens of both species within Alabama localities share a unique and previously unnoted character: an anteromedial abdominal stripe attaining the anterior extreme of tergite 1. The geographically restricted occurrence of this character suggests the possibility of localized variation within a single species.

Support for the separate specific status of these two species is still present in the subtle and variable differences listed above, however, as well as in the more striking difference of epandrium color. This strong binary feature of epandrium color is not seen elsewhere in the family, although some Sobarocephala exhibit more subtle color variants with intermediate forms. The collection of new material of both species across their distributions is recommended to obtain sequence data that may better establish species limits.

Material examined (affinis): USA. Alabama: Baldwin county, Bon Secour N.W. Ref. T9S.R2E, Sec. 24, Malaise trap, 13–14.x.1991, T. Schiefer & G. Eickwort, CNC1865983–1865990, CNC1865995–1865997 (3♂ 8♀, MEMU), Baldwin county, Bon Secour N.W. Ref. T9S.R2E, Sec. 25, on dunes, Malaise trap, 12–16.x.1991, T. Schiefer & G. Eickwort, CNC1865991, CNC1865992 (2♀, MEMU), Baldwin county, Bon Secour N.W.R., 30.2119444 °N, 87.8308333 °W, in fore dunes, black light, 8–9.viii.1994, R.L. Brown, CNC1865994 (1♀, MEMU).

Material examined (muesebecki): USA. Alabama: Baldwin county, Bon Secour N.W. Ref. T9S.R2E, Sec. 24, Malaise trap, 13–14.x.1991, T. Schiefer & G. Eickwort, CNC1866003 (1♀, MEMU), Baldwin county, Bon Secour N.W. Ref. T9S.R2E, Sec. 25, on dunes, Malaise trap, 12–16.x.1991, T. Schiefer & G. Eickwort, CNC1865998–1866002, CNC1866004–1866010 (7♂ 5♀, MEMU), Baldwin county, Oyster Bay, 1 mile E, T9S.R4E, Sec. 6, black light, 4.ix.1988, A.L. Brown & J. MacGown, CNC1866012, CNC1866013 (2♀, MEMU).