Revision of New World Species of Shore Fly Genus Discomyza Meigen (Diptera: Ephydridae)

Transcription

1 SYSTEMATICS Revision of New World Species of Shore Fly Genus Discomyza Meigen (Diptera: Ephydridae) WAYNE N. MATHIS 1 AND TADEUSZ ZATWARNICKI 2 Ann. Entomol. Soc. Am. 98(4): 431Ð443 (2005) ABSTRACT Two species of Discomyza Meigen occur in the New World, one, D. u-signata Cresson, naturally and the other, D. maculipennis (Wiedemann), apparently as an introduction. These species are revised and their malacophagous breeding habits are documented. The species treatments include the Þrst detailed descriptions and illustrations of structures from the male terminalia, lectotype designations for Notiphila maculipennis Wiedemann and its New World synonym (D. balioptera Loew), as well as phylogenetic and biogeographic information, including maps. Although congeners, these two species are apparently not closely related, and their occurrence in the New World is independent of each other. D. maculipennis has a biogeographic connection with the Orient, and D. u-signata is linked with a group of Afrotropical species, D. eritrea Cresson speciþcally. KEY WORDS Diptera, Ephydridae, Discomyza, shore ßies, malacophagy 1 Department of Entomology, NHB 169, P.O. Box 37012; Smithsonian Institution, Washington, DC 20013Ð7012 ( mathis. wayne@nmnh.si.edu). 2 Department of Biosystematics, University of Opole, ul. Oleska 22, Opole, Poland ( zatwar@uni.opole.pl). AMONG GENERA OF SHORE FLIES (Ephydridae), only two, Discomyza Meigen and Platygymnopa Wirth, are known to breed in snails (Mollusca). Another shore ßy species, Allotrichoma simplex Loew, also has been reported from snails and has been reared from muskrat feces mixed with dead snails (Runyan and Deonier 1979). Platygymnopa is a monotypic genus that presently includes only P. helicis Wirth and has been reared from the snail Aplexa hypnorum (L.) (Mollusca: Physidae) in Montana (Wirth 1971, Foote 1995). Of the nine described species of Discomyza (Mathis and Zatwarnicki 1995), there is information available on the breeding habits of Þve. These species breed in a variety of both terrestrial and marine snails, although there is no obvious pattern of coevolution. Although the malacophagous habits for several species of Discomyza are known, their basic systematics, including phylogenetic relationships and zoogeography, are poorly understood. This article presents a revision of the New World species of the genus. As noted previously, Discomyza presently comprises nine species that are found primarily in the Old World. Only D. u-signata Cresson apparently occurs naturally in the New World where it is known thus far only from Texas. A second species, D. maculipennis (Wiedemann), also occurs in the New World, although it was apparently introduced there from the Australasian and/or Oriental regions (Wirth 1968). Although D. u-signata is a valid species (Wirth 1965, Mathis and Zatwarnicki 1995), its generic afþliation has been questioned, given the rather large geographic disjunction between Texas and the Old World, especially the Afrotropics and Orient. Thus, the question of whether D. u-signata is indeed a congener with Old World species of Discomyza has in part prompted this research, including our Þeldwork in Texas. If D. u-signata is a congener, then what is its sister species among Old World species? Resolving the latter question is important for establishing the biogeographic track. Another question concerns whether this species is malacophagous like Old World species of Discomyza. In this article, we report our research on New World species of Discomyza. The primary objectives of this research were to determine the generic placement of D. u-signata and to learn about its feeding habitats as a three-step process: 1) collect additional specimens of D. u-signata, males in particular; 2) conduct a preliminary phylogenetic study and analysis of closely related congeners, including males and females of D. u-signata; and 3) document comprehensively our results and conclusions in a well-illustrated and documented publication. Part of the documentation includes the Þrst detailed illustrations and descriptions of structures of the male terminalia. Previously, only Krivosheina (1987) provided illustrations of these structures as documentation for a new species she described (D. maritima Krivosheina) from Russia (Far East). Her illustrations included external structures only, such as the epandrium and presurstyli. A phylogenetic analysis and the improved generic placement of D. u-signata will undoubtedly provide evidence that will have signiþcant consequences on the historical biogeography of the group. For example, if this species is indeed a member of Discomyza, then how did it come to occur in Texas when the rest of its congeners are only found in the Old World subtropics /05/0431Ð0443$04.00/ Entomological Society of America

2 432 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4 and tropics, especially the Afrotropics? As already alluded, is the species truly a member of the tribe Discomyzini and of the genus Discomyza or does the species Þt better within the characterization of another discomyzine genus? Perhaps the species merits recognition at the generic level. In this article, we attempt responses to these questions. Specimens of D. u-signata are small (body lengths usually 4 mm), and specimens are rare in collections and perhaps in nature. Both conditions have impeded research on this species. However, a colleague, Robert A. Wharton (Texas A&M University, College Station, TX), discovered and provided us with some preliminary information on the biology of this species. His Þndings originate from his rearings of various invertebrates in an attempt to Þnd parasitoids of various Diptera. Methods and Materials The descriptive terminology, with the exceptions noted in Mathis (1986) and Mathis and Zatwarnicki (1990a), follows that published in the Manual of Nearctic Diptera (McAlpine 1981). Because specimens are small, usually 4 mm in length, study and illustration of the male terminalia required use of a compound microscope. We have followed the terminology for most structures of the male terminalia that other workers in Ephydridae have used (see references in Mathis 1986 and Mathis and Zatwarnicki 1990a,b), such as surstylus. Zatwarnicki (1996) suggested that the preand postsurstylus correspond with the pre- and postgonostylus and that the subepandrial plate is the same as the medandrium. The terminology for structures of the male terminalia is provided in the legends. The species descriptions are composite and not based solely on the holotypes. Four head and two venational ratios that are used in the descriptions are deþned below (all ratios are based on three specimens (the largest, smallest, and one other). 1. Head height-to-width ratio is the head height divided by the head width, where both measurements are the longest distances taken from the head in a lateral orientation. 2. Facial width-to-head width ratio is the narrowest width between the eyes across the face divided by the head width. 3. Eye-to-gena ratio is the genal height measured at the maximum eye height divided by the eye height. 4. Eye width-to-height ratio is the eye width divided by the eye height, where both measurements are the longest distances taken with the eye oriented laterally. 5. Costal vein ratio is the straight line distance between the apices of veins R 2 3 and R 4 5 divided by the distance between the apices of veins R 1 and R M vein ratio is the straight line distance along vein M between crossvein dm-cu and r-m divided by the distance apicad of crossvein dm-cu. Distribution maps were made using ESRI ArcView GIS 3.2. Longitude and latitude coordinates were obtained for the locality where each specimen was collected and entered into a FileMaker Pro database. If unavailable directly from specimen labels, longitude and latitude were estimated using gazetteers and maps to determine the geographical coordinates. Although many specimens examined for this study are in the National Museum of Natural History, Smithsonian Institution, Washington, DC. (USNM), we also borrowed and studied numerous specimens that are deposited in the following museums: American Museum of Natural History (AMNH), New York, NY; Academy of Natural Sciences of Philadelphia (ANSP), Philadelphia, PA; Museum of Comparative Zoology (MCZ), Harvard University, Cambridge, MA; Naturhistorisches Museum (NMW), Vienna, Austria; and Texas A&M University (TAMU). Systematics Subfamily Discomyzinae Acloque Diagnosis. The subfamily Discomyzinae is distinguished from other subfamilies by the following combination of characters: Fronto-orbital setae reclinate and/or proclinate; reclinate fronto-orbital seta usually inserted behind larger, proclinate fronto-orbital seta; medial facial area and ventral facial margin without setae; facial setae inserted in more or less vertical series, parallel with parafacial; subcranial cavity small to large. Prescutellar acrostichal setae large (subequal to posterior dorsocentral seta), inserted widely apart (distance between setae subequal to that between either prescutellar and the posterior dorsocentral seta on the same side) and usually inserted anterior of intra-alar seta; presutural or sutural dorsocentral seta inconspicuous or absent. Discussion. There are two tribes in the subfamily Discomyzinae: Discomyzini Acloque and Psilopini Cresson. The combined distribution for either tribe is essentially worldwide, although each has greater species diversity in the tropics and subtropics. The tribe Discomyzini presently comprises 11 genera and 49 species (Mathis and Zatwarnicki 1995). Six of these genera, including 26 species, occur in the New World. The two tribes and six New World genera can be distinguished by the following keys (in the key to genera, the two subgenera of the genus Guttipsilopa Wirth also are included). Key to Tribes of Subfamily Discomyzinae 1. Vein R 2 3 close to costal vein beyond end of vein R l ; crossvein dm-cu with sharp angle..... Discomyzini Acloque, in part - Vein R 2 3 well separated from costal vein; crossvein dm-cu nearly straight or shallowly arched, not angulate Face strongly and coarsely sculptured on at least lower one-half; facial setae short, the longest at most three-fourths as long as its distance from

3 July 2005 MATHIS AND ZATWARNICKI: REVISION OF GENUS Discomyza 433 opposite seta; R stem vein bearing two to four setulae on dorsum Discomyzini Acloque, in part - Face usually smooth, if Þnely striate the longest facial seta at least as long as the distance from opposite seta; R stem vein lacking setulae on dorsum...psilopini Cresson Key to New World Genera and Subgenera of Discomyzini 1. A postsutural supra-alar seta much reduced (no larger than surrounding setulae) or absent A postsutural supra-alar seta present, size subequal to presutural seta Pseudopostocellar setae well developed, length approximately one-half that of ocellar setae, orientation divergent at usually Clasiopella Hendel - Pseudopostocellar setae weakly developed, length considerably less than one-half that of ocellar setae, orientation variable Face conspicuously and deeply, transversely rugose; only the reclinate fronto-orbital seta well developed...discomyza Meigen - Face at most with shallowly impressed, transverse striae; at least one proclinate frontoorbital seta in addition to reclinate seta well developed Eye seeming bare; one well-developed proclinate fronto-orbital seta (second seta greatly reduced), inserted anterior to reclinate seta; presutural supra-alar seta weakly developed, length less than anterior notopleural seta (except in M. cressoni Lizarralde de Grosso); legs bicolored...mimapsilopa Cresson - Eye conspicuously setulose; two well-developed proclinate fronto-orbital setae, anterior proclinate seta at about same level as large, reclinate seta, posterior proclinate seta inserted posterior of reclinate seta; presutural supra-alar seta well developed, length longer than anterior notopleural seta; legs unicolorous, blackish brown... Helaeomyia Cresson 5. Mesofrons bearing strong pair of intrafrontal setae inserted well in front of ocellar setae; fronto-orbital setae with one large and one small upper, lateroclinate setae and two large proclinate lower setae; wing hyalin Paratissa Coquillett - Mesofrons lacking intrafrontal setae; frontoorbital setae proclinate and reclinate, but not lateroclinate; wing with at least anterior margin infumate, sometimes mostly brown with white spots (Guttipsilopa Wirth) Wing guttate, mostly dark with white spots; eye only slightly higher than wide (subgenus Guttipsilopa)... G. haydeni Wirth - Wing with at most infuscation along anterior one-half, posterior portion hyaline; eye conspicuously higher than wide subgenus Nesopsilopa Genus Discomyza Meigen Discomyza Meigen 1830: 76. Type species: Psilopa incurva Fallén 1823, monotypy. Cresson 1939: 1Ð6 [review]; Wirth 1968: 12 [Neotropical catalog]; Mathis and Zatwarnicki 1995: 23Ð25 [world catalog]. Diagnosis. Moderately small to moderately large shore ßies, length 2.2Ð4.5 mm; generally dark-colored species, many surfaces subshiny to shiny. Head. Normally developed, not triangular or with bulging eyes; antenna inserted at dorsal one-third of head height; frons rectangular, conspicuously wider than long, mostly bare, shiny, sometimes with anterior or lateral patches of dense microtomentum, vertex distinctly to somewhat angulate, not broadly rounded; intrafrontal setae absent; only reclinate fronto-orbital seta well developed, two proclinate setae evident but much smaller than reclinate seta, inserted anterior of reclinate seta; ocellar setae well developed, insertion variable, usually behind level of anterior ocellus, orientation usually proclinate and slightly divergent; pseudopostocellar setae usually weakly developed, divergent and very slightly proclinate; both inner and outer vertical setae well developed, outer seta shorter than inner seta. Antennal shape variable; arista pectinate, bearing Þve to 11 dorsal rays. Eye irregularly elliptical, higher than wide, interfacetal setulae sparse, seeming bare. Face generally wide, shiny, mostly bare of microtomentum, but conspicuously, transversely rugose, sometimes deeply and with some vertical lines; moderately developed facial setae 4Ð5, these in more or less vertical alignment, inclinate and usually slightly upcurved, inserted more remote from parafacial than other genera of tribe; proboscis normally developed, not elongate; palpus black. Thorax. Generally black; mesonotum, including postpronotum and notopleuron granulose and sparsely microtomentose, thereafter ventrally, including most of pleural area, mostly bare of microtomentum, shiny black; scutellum more or less trapezoidal, posterolateral angle rounded. Chaetotaxy as follows: prescutellar acrostichal setae lacking; presutural supra-alar seta evident but not well developed; postsutural supra-alar seta generally lacking; postalar seta 1; scutellar disc moderately setulose; basal scutellar seta over one-half length of apical seta; notopleuron lacking setulae but bearing anterior and posterior setae, these equidistant from notopleural suture; anepisternum with two large setae at posterior margin, ventral seta only slightly longer to nearly twice length of dorsal seta; katepisternum with one large seta. Halter with knob white to yellowish white. Wing variable, although generally with some infuscation, often with distinct pattern; vein R 2 3 extended normally to costal margin, well separated from costa, lacking a stump vein, moderately long, making section II 1.5

4 434 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4 length of section III; R stem vein bearing two to four setulae dorsally; crossvein dm-cu straight. Foreleg, including basitarsomere, usually black; basitarsi of mid- and hindleg white to yellow, contrasted sharply from dark colored tibiae and femora; forefemur with dorsal surface uneven, slightly emarginate. Abdomen. Mostly shiny, blackish, microtomentum generally sparse; Þfth tergite of male shinier than preceding tergites 1Ð4, almost devoid of microtomentum, anterior margin with broad, shallow emargination dorsomedially, bearing longer setae along posterior margin. Male terminalia: Epandrium heavily sclerotized, generally of two shapes, wide with high cercal cavity and narrow with short cercal cavity; presurstylus at ventral margin of epandrium, varying considerably in shape; postsurstyli symmetrical or asymmetrical, generally elongate; subepandrial plate as a single structure or divided medially; aedeagus tubular, elongate, wider basally; phallapodeme in lateral view with shallow keel, usually skewed toward articulation with hypandrium; pregonite small, usually longer than wide, bearing two apical setulae; hypandrium wide, pocket-like, depth of pocket varying from pouch-like to shallowly concave. Natural History. Species of Discomyza for which feeding habits are known have an association with snails, although details, such as whether malacophagy is obligate or restricted to a single species, are lacking. Data range from general information such as ex. mollusks to more speciþc, such as now available for D. u-signata breeding in Rabdotus alternatus (Say), a terrestrial snail. Discomyz incurva, which only occurs in the western Palearctic Region, has been reported many times to breed in helicid snails, especially Helix pomatia L. (Bergenstamm 1864). Other terrestrial snail breeders are D. similis Lamb and D. maculipennis of which both are known to breed in species of Achatina Lamarck, but neither shows an obligate preference to this snail, being known to breed in a host of other organisms (Disney 1970, Bohart and Gressitt 1951). For example, D. maculipennis has been collected from several land snails but also from trochid shells, as has D. eritrea Cresson. Trochus L. is a marine snail that lives in the intertidal zone. Discussion. Most structures of the male terminalia vary in shape and size and are of diagnostic value at the species level. The postsurstyli are unusual in sometimes being asymmetrical, a condition that is known only for this genus and Mimapsilopa Cresson. Perhaps the asymmetry of these structures indicates a close phylogenetic relationship between these two genera. In neither genus, however, is the asymmetry universal, i.e., each genus has species with symmetrical postsurstyli. The epandrium in species of Discomyza is very heavily sclerotized and is generally represented by two shapes (species noted in parentheses are those for which we have access to males for dissection): 1) very wide with the lateral margins greatly extended (D. africana Cresson, D. eritrea, and D. u-signata); and 2) narrow to gently rounded, mostly like an inverted U (D. incurva, D. maculipennis, D. maritima, and D. similis). In the New World, only two species have been discovered, and as noted in Introduction, one occurs naturally and the other is probably an introduction. Based on our study, which includes particular focus on structures of the male terminalia, we conclude that although these species are congeners, they are not especially closely related phylogenetically. Key to New World Species of Discomyza 1. Wing with large, somewhat irregular, inverted U-shaped maculation on apical half and toward anterior margin (Fig. 21); anepisternum with maze of several thin, horizontal rows of silvery white microtomentum; foreleg entirely black... D. maculipennis (Wiedemann) - Wing with crossvein dm-cu infuscate and sometimes cell R1, but otherwise hyaline (Fig. 22); anepisternum coarsely granulose but lacking several thin rows of silvery white microtomentum; foretarsus, especially the basitarsomere, yellow.. D. u-signata Cresson Discomyza maculipennis (Wiedemann) (Figs. 1-19, 21) Notiphila maculipennis Wiedemann 1824: 57. Homalura maculipennis: Wiedemann 1830: 574 [generic combination]. Discomyza maculipennis. de Meijere 1908: 166 [generic combination]; Cresson 1946: 163 [review]; Wirth 1968: 12 [Neotropical catalog]; Soans and Adolph 1971: 847 [breeding]; Campos and Peña 1973: 227 [list, Easter Island]; Cogan 1980: 661 [Afrotropical catalog]; Mathis and Zatwarnicki 1995: 24Ð25 [world catalog]. Discomyza balioptera Loew 1862: 140; Cresson 1925: 242 [synonymy]. Diagnosis. This species is readily distinguished from congeners by the following combination of characters: small- to medium-sized shore ßies, body length 2.4Ð 3.9 mm. Head: Pseudopostocellar setae weakly developed, length far less than one-half outer vertical seta, completely divergent; frons faintly sculpted and with lateral, linear, oblique areas of brown microtomentum; parafacial and genal areas with silvery white microtomentum present around compound eyes; face generally elongate, deeply and transversely rugose, lateral margins pitted. Thorax: Foretarsus unicolorous, black; anepisternum with distinctive maze of several silvery white, horizontal rows of microtomentum; microtomentum of scutum silver to gray with distinct pattern of straight to curved short lines; scutellum wider than long, trapezoidal, apex truncate. Abdomen: Epandrium narrowly rounded and genital opening reduced; presurstylus enlarged, well developed, nearly rectangular though basal portion narrowed and medioapical aspect slightly structure.

5 July 2005 MATHIS AND ZATWARNICKI: REVISION OF GENUS Discomyza Figs. 1ⴚ5. Structures of the male terminalia of D. maculipennis (Surinam. Paramaribo). (1) Epandrium, cerci, and presurstylus, posterior view. (2) Same, lateral view. (3) Internal genitalic structures (aedeagus [shaded], phallapodeme, subepandrial plate, postsurstylus, pregonite, and hypandrium), ventro-oblique view. (4) Same, lateral view. (5) left postsurstylus, lateral view. Scale bar, 0.1 mm. Description. Head: Head height-to-width ratio 0.76 Ð Frons black; ocellar triangle and frontoorbits conspicuously sculptured, raised in relief, with some metallic luster; area between ocellar triangle and fronto-orbits smooth, with matte to subshiny surface; vertex sharply marginate; ocelli forming an equilateral triangle, distance between posterior ocelli greater than between either posterior ocellus and anteromedial ocellus. Chaetotaxy: ocellar setae proclinate and slightly inclinate, widely separate, inserted laterad of anterior ocellus; pseudopostocellar setae tiny, hair- like, well separated, completely divergent; ocellar triangle bearing some tiny setulae; inner and outer vertical setae well developed, outer vertical seta slightly shorter than inner vertical seta; frontal-orbital setae 2, posterior seta reclinate, slightly longer than proclinate, anterior seta. Pedicel bearing two well-developed setae; more apical seta proclinate, basal seta reclinate; basal ßagellomere longer than combined length of pedicel and scape; arista unipectinate, with seven to eight dorsal branches. Facial width-to-head width ratio 0.35Ð 0.40; face (Fig. 19) striking, black,

6 436 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no Figs Internal structures of the male terminalia of D. maculipennis (Surinam. Paramaribo). (6) Aedeagus and phallapodeme, ventral view. (7) Same, lateral view. (8) Subepandrial plate, ventral view. (9) Same, lateral view. (10) Left postsurstyli, ventral view. (11) Same, lateral view. (12) Right postsurstyli, ventral view. (13) Same, lateral view. (14) Pregonite, ventral view. (15) Same, lateral view. (16) Hypandrium, ventral view. (17) Same, lateral view. Scale bar, 0.1 mm. shiny, with some metallic luster, deeply and conspicuously rugose but lacking pattern of silvery white microtomentum; facial setae 4Ð5, all relatively short, arranged in vertical line, all inclinate, none nearly touching, insertions of facial setae in rugose areas; area at base of antennae and parafacial silvery white microtomentose, also with a silvery white genal spot at venter of eye in line with microtomentum from parafacial. Compound eyes bearing sparse, interfacetal setulae; eye shape elliptical, much higher than wide; eye width-to-height ratio 0.56Ð0.59; eye-to-gena ratio 0.16Ð0.18. Palpus dark brown. Thorax. Dull to subshiny black in coloration with some silvery white microtomentum; mesonotum with interrupted, thin lines of microtomentum, entirely and conspicuously microsculptured, bearing densely seriate, numerous, irregular rows of short setulae; scutellum broadly produced, posterior margin rounded. Chaetotaxy: posteriormost dorsocentral seta, presutural supra-alar seta, postpronotal seta, and postalar seta well developed. Anepisternum, except anteroventral corner, with numerous, oblique, irregular rows of dense, silvery white microtomentum; dorsal margin of katepisternum with silvery white microtomentum; otherwise remainder of pleural area mostly subshiny, smooth, lacking silvery white microtomentum. Wing (Fig. 21) mostly hyaline to very faintly infumate; with an irregular inverted U-shaped infuscate area on apical one-third of wing with open area posterior; costal vein ratio 0.66Ð0.69; M vein ratio 0.72Ð0.98. Halter

7 July 2005 MATHIS AND ZATWARNICKI: REVISION OF GENUS Discomyza 437 Fig. 18. Distribution map for D. maculipennis in the New World. knobs mostly whitish or yellowish white. Legs all brownish black to black except for yellow to yellowish brown tarsi, especially basitarsi of mid- and hindleg, apical 1Ð2 tarsomeres becoming darker, with apical tarsomere black; foreleg entirely black with forefemur somewhat swollen, shiny; forecoxa with dorsal onefourth with silvery white microtomentose area. Abdomen. Fourth male sternite rectangular, longer than wide, slightly wider posteriorly; Þfth male sternite wider than long, posterior margin deeply and broadly emarginate, forming a U-shaped concavity. Male terminalia (Figs. 1Ð17): Epandrium in posterior view (Fig. 1) as high as wide, cercal cavity relatively small with distance between dorsal margin of cavity and dorsum of epandrium much greater than height of cercus, uniformly and rather densely setulose; cercus in posterior view (Fig. 1) lunate, narrower ventrally than dorsally, bearing several, long setulae; presurstylus in posterior view (Fig. 1) with base moderately narrow then ventrally becoming broader and somewhat quadrate; presurstylus in lateral view (Fig. 2) hexagonal, higher than wide, obtusely pointed ventrally; subepandrial plate (Figs. 3 and 8) as a broad, U-shaped single plate; aedeagus in ventral view (Figs. 3 and 6) with base moderately wide and then abruptly narrowed to elongate, tapered apex; in lateral view (Figs. 4 and 7) only slightly narrower apically than basally; phallapodeme in lateral view (Figs. 4 and 7) with short keel that extends away from aedeagal attachment, in ventral view T-shaped with vertical portion much wider than horizontal piece and becoming wider toward attachment with base of aedeagus; postsurstyli asymmetrical, right postsurstylus in lateral view (Figs. 4 and 13) gradually becoming wider apically, apex broadly biþd, in ventral view (Figs. 3 and 12) with apical portion twice as wide as basal portion, with subapical bulge; left postsurstylus in ventral view (Figs. 3 and 10) longer than right postsurstylus, apex narrowed to a single digitiform process, in lateral view (Figs. 4 and 11) with apex becoming narrower as an angulate, two-step process; pregonite short (Figs ), bearing two apical setulae; hypandrium (Figs ) shallowly pocket-like, narrow at basal attachment, becoming broadly oval. Type Material. The lectotype female of Notiphila maculipennis Wiedemann, here designated to preserve stability and make more universal the use of this name, is labeled TYPE [red]/ind. Orient. Coll. Winth. [ Ind. Orient. handwritten]/homalura maculipennis Wid Ind. Orient [handwritten]/maculipennis det. Wied [all but det. handwritten]/lectotype Notiphila maculipennis Wiedemann By Mathis & Zatwarnicki [handwritten except for LECTOTYPE and By ; black sub-border]. The lectotype is double mounted (minuten in a rectangular block of cork; red

8 438 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4 Figs (19Ð20) Faces of species of Discomyza. (19) D. maculipennis. (20) D. u-signata. (21Ð22) Wings of species of Discomyza. (21) D. maculipennis. (22) D. u-signata. square below specimen), is in good condition, and is deposited in the NMW. The lectotype male of Discomyza balioptera Loew (designated by Mathis and Zatwarnicki 1995: 25) is labeled [a silver square label]/ [handwritten]/ Loew Coll./balioptera [handwritten]/type [red; number handwritten]/lectotype Discomyza balioptera Loew By Mathis & Zatwarnicki [handwritten except for LECTOTYPE and By ; black sub-border]. The lectotype is directly pinned, is in poor condition (seeming dirty and partially covered with fungal growth), and is deposited in the MCZ (11138). The lectotype was designated in 1995 when we listed the only known specimen of the type series as the holotype ( HT ) under the assumption of holotype article (74.6) in the International Code of Zoological Nomenclature. Even though we later learned that there may be additional specimens in Cuba (Poey collection), the 1995 designation remains valid, and we are now treating this specimen as the lectotype. Loew listed F. Poey as the collector of this specimen. Type Locality. India Orient. Other Specimens Examined from New World. Nearctic: UNITED STATES. California. San Diego: San Diego, Lemon Grove (conch shell), 6-X-1961, R. Buckner (1, USNM). Neotropical: BAHAMAS. North Bihimi Island: May 1951, M. Cazier (1 ; AMNH). BELIZE: Belize City, August 1959; K.L.H. Krauss (1 ; USNM). CUBA: (1 ; lectotype of D. balioptera; MCZ). HAITI: Boroderes (in dead shell), 10-IV-1930, W. M. Perrygo (1 ; USNM). PUERTO RICO: San Juan (intercepted, pantry on ship Santo Domingo), 18-V-1932, Anderson (1 ; USNM). SURINAM: Paramaribo (herring barrel), 3-VIII-1940, D. C. Giejskes (5 3 ; USNM). VIRGIN ISLANDS: St. Croix: Christiansted, 4-VI-1911 (2 3 ; AMNH, USNM). Distribution (Fig. 18; in the New World). Australasian/Oceanian: Belau, Easter Island, Fiji, French Polynesia (Society Islands), Guam, Hawaiian Islands (Lisianski, Maui, Oahu), Marshall Island, Micronesia, Northern Marianas, Papua New Guinea, Samoa, Solomon Islands, Vanuatu. Nearctic: USA (California,?Florida). Neotropical: Bahamas, Belize, Brazil, Surinam, West Indies (Cuba, Haiti, Puerto Rico, St. Croix). Oriental: Celebes, India, Malaysia, Philippines (Luzon), Singapore, Sri Lanka, Taiwan, Vietnam. Palearctic: Japan. Natural History. Cresson (1939) reported that larvae are apparently necrophagous in land snails, particularly those occurring near saline water. Bohart and Gressitt (1951) found larvae of this species breeding in small carrion, especially mollusks. Four specimens were collected in the Malay States from Achatina

9 July 2005 MATHIS AND ZATWARNICKI: REVISION OF GENUS Discomyza 439 fulica Bowdich, the giant African snail (Cresson 1939). Specimen labels in the USNM indicate malacophagy encompassing a variety of mollusks that include: on dead giant snails, ex. A. fulica, rotten snails, in package of sea shells, on Trochus shell, ßy trap (snail baited), and ex. dead mollusks. This species, which is frequently associated with highly organic debris, such as garbage, has apparently been introduced to the Caribbean from the Old World, probably from the Orient and probably through human commerce. Its current status in the West Indies, however, is unknown, and perhaps it no longer occurs there. We did not collect this species, for example, while conducting Þeldwork on the West Indies during the past 15 yr, although our collecting was not comprehensive geographically or chronologically. Remarks. Specimens are comparatively robust; palpus very large, blackish; foretarsus black (variable); forefemur enlarged; mid- and hindtarsus with only apical tarsomere black, other tarsomeres yellowish; proclinate setae on pedicel short; vertex not as sharp as in other species; frons variable (some specimens black and shiny, others with microtomentum on parafacial). Discomyza u-signata Cresson (Figs. 20 and 22Ð37) Discomyza u-signata Cresson 1926: 250; 1942: 128 [review]; Wirth 1965: 740 [Nearctic catalog]; Mathis and Zatwarnicki 1995: 25 [world catalog]. Diagnosis. This species is readily distinguished from congeners by the following combination of characters: Medium-sized shore ßies, body length 3.3Ð3.5 mm. Head: Face with silvery white microtomentum in distinctive U- and W-shaped pattern (pattern easily seen as well as paired median parallel lines that diverge apically); frons faintly sculpted, microtomentum present; length of pseudopostocellar seta subequal to that of outer vertical seta, weakly divergent; silvery white microtomentum circumocular, especially well deþned on parafacial; face lacking deep rugosity as in some congeners, but under high magniþcation transverse rugose striae evident between two medial parallel lines. Thorax: Scutellum wider than long, widest at base, trapezoidal, apex blunt; both anepisternum and scutum with patches of microtomentum; foretarsus bicolored, basitarsomere yellow, remaining tarsomeres brown to black. Abdomen: Epandrium of male with lateral margins broadly expanded and cercal cavity high; presurstylus moderately developed, L- shaped. Description. Head: Head height-to-width ratio 0.75Ð0.80. Frons black with faint though conspicuous spot of microtomentum anterolateral of ocellar triangle, with shallow rugose lines evident under high magniþcation; vertex sharply marginate; ocelli forming an equilateral triangle, distance between posterior ocelli greater than between either posterior ocellus and anteromedial ocellus; ocellar triangle only slightly shinier than rest of frons, ocellar triangle and frontoorbits slightly raised in relief from frons. Chaetotaxy: ocellar setae proclinate and slightly inclinate, widely separate, inserted laterad of anterior ocellus; pseudopostocellar setae well developed, slightly divergent and reclinate, aligned with medial margin of posterior ocelli; ocellar triangle bearing some tiny setulae; inner and outer vertical setae well developed, outer seta slightly longer than inner seta; frontal-orbital setae three as follows: posteromedial seta well developed, reclinate, with a small proclinate seta laterad, and a large anterior proclinate seta. Pedicel bearing two well-developed setae; more apical seta proclinate, basal seta reclinate; basal ßagellomere longer than combined length of pedicel and scape; arista unipectinate, with seven dorsal branches. Facial width-tohead width ratio 0.42Ð0.44; face (Fig. 20) striking, black, shiny, with distinctly contrasting pattern of silvery white microtomentum; facial pattern as follows: face outlined with thin line of microtomentum, with two vertical microtomentose lines medially, these becoming slightly convergent near oral margin then subventrally angled ventrolaterally to form a horizontal, lunate shiny area medially along oral margin just dorsad of microtomentose margin, laterad of vertical lines with open pattern of horizontally directed Us and Ws extended along lateral facial height with open ends oriented laterally toward parafacial; facial setae 3Ð4, arranged in vertical line, all inclinate; dorsal pair nearly touching, second almost touching and third and fourth fairly separate, insertions of facial setae in open areas of horizontal Us and Ws. Compound eyes bearing sparse, interfacetal setulae; eye shape elliptical, much higher than wide with a circum-ocular band of whitish microtomentum; band more deþned around ventral margin eye; eye width-to-height ratio 0.46Ð 0.54; eye-to-gena ratio 0.16Ð0.20. Palpus dark brown. Thorax. Dull to subshiny black, entirely microsculptured with shallow rugosity; mesonotum densely seriate with numerous irregular rows of short setulae. Chaetotaxy: posteriormost dorsocentral seta, presutural supra-alar seta, postpronotal seta, and postalar seta well developed. Posterodorsal corner of anepisternum microsculptured as a ventral extension from mesonotum and speciþcally notopleuron; remainder of pleural area mostly subshiny, smooth, lacking distinct rows or pattern of silvery white microtomentum. Wing (Fig. 22) faintly infumate; distinctly infuscate at crossveins and along costa in cell r1; costal vein ratio 0.51Ð0.55; M vein ratio 1.0Ð1.1. Halter knobs mostly whitish or yellowish white. Legs all brownish black to black except for yellowish tarsi, especially basitarsi, apical one to two tarsomeres becoming darker with apical tarsomere black; forefemur somewhat swollen. Abdomen. Black, setose, not shiny. Patches of microtomentum covering abdominal tergum. Male terminalia (Figs ): Epandrium in posterior view (Fig. 23) conspicuously wider than high, with cercal cavity relatively large with distance between dorsal margin of cavity and dorsum of epandrium less than height of cerci, uniformly and rather densely setulose;

10 440 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no Figs. 23ⴚ26. Structures of the male terminalia of D. u-signata (United States. Texas. Bexar: San Antonio). (23) Epandrium, cerci, and presurstylus, posterior view. (24) Same, lateral view. (25) Internal genitalic structures (aedeagus (shaded), phallapodeme, subepandrial plate, postsurstylus, pregonite, and hypandrium), ventro-oblique view. (26) Same, lateral view. Scale bar, 0.1 mm. cercus in posterior view (Fig. 23) rod-like, almost parallel sided, slightly projected dorsomedially, ventral margin narrowly rounded, bearing several, long setulae, especially ventrally; presurstylus in posterior view (Fig. 23) irregularly L-shaped, basal arm widened medially, ventral arm tapered, narrowly pointed apically; presurstylus in lateral view (Fig. 24) only slightly higher than wide, shallowly and broadly bilobed ventrally, posterior lobe more sharply pointed than anterior lobe; subepandrial plate in ventral view (Figs. 25 and 29) as two symmetrical structures, narrowed to point medially; aedeagus in ventral view (Figs. 25 and 27) hourglass shaped, constricted medially, basal and apical margin broadly rounded, in lateral view (Figs. 26 Ð28) with bulge sub-basally then tapered to narrow, slightly pointed apex; phallapodeme in lateral view (Figs. 26 and 28) with keel long, moderately deep, irregular, broadly T-shaped in ventral view (Figs. 25 and 27) with horizontal piece especially elongate; postsurstylus symmetrical, in ventral view (Figs. 25 and 31) elongate, wider basally, gradually tapered to narrow but rather bluntly rounded apex, in lateral view (Figs. 26 and 32) with basal one-half roundly quadrate, apical process as a narrow, gradually tapered extension; pregonite narrow, short, longer than wide, rod-like, bearing two apical setulae; hypandrium (Figs ) deeply pocket-like, in

11 July 2005 MATHIS AND ZATWARNICKI: REVISION OF GENUS Discomyza Figs Internal structures of the male terminalia of D. u-signata (United States. Texas. Bexar: San Antonio). (27) Aedeagus and phallapodeme, ventral view. (28) Same, lateral view. (29) Subepandrial plate, ventral view. (30) Same, lateral view. (31) Postsurstyli, ventral view. (32) Same, lateral view. (33) Pregonite, ventral view. (34) Same, lateral view. (35) Hypandrium, ventral view. (36) Same, lateral view. Scale bar, 0.1 mm. ventral view broadly ovate with base more truncate and with a medial, shallow notch. Type Material. The holotype female is labeled S[a]n.Antonio V.10Ð06 [10 May 1906 not 18 Apr as in the original description and on a male paratype] Tex [date handwritten]/fcpratt Collector/Holo-TYPE Discomyza U-SIGNATA E. T. Cresson Jr [dark maroon; gender symbol and the generic and species names handwritten]/type No USNM [red; handwritten]. The holotype is double mounted (glued to a paper point), is in good condition (slightly dusty), and is deposited in the USNM (29455). Paratypes are 1) a male (ANSP) bearing the same locality and collection date as the holotype; 2) a male (USNM), designated as an allotype, is topotypical and was collected on 18-IV-1908 by Hunter and F. C. Pratt. Type Locality. UNITED STATES. Texas. Bexar: San Antonio ( N, W). Other Specimens Examined. UNITED STATES. Texas. Bexar: San Antonio, 28-III-1942, A. L. Melander (1 ; USNM). Brazos: Bryan (Malaise trap), 29Ð30-V- 1976, H. R. Burke (1 ; TAMU). Cameron: Boca Chica (10.7 km west; beach on Highway 4), 31-X-1991, T. Carlow, E. G. Riley (1 ; TAMU). Jim Wells: Mathis (7.5 km south; Nueces River; N, W; 18 m; 15 m), 6-VI-2004, T. Zatwarnicki (1 ; USNM). Kerr: Center Point (Malaise trap), 30-VIÐ6-VIII-1987, L. Praetorius, R. A. Wharton (1, 4 ; TAMU). Kleberg: Kingsville, 8Ð9-VI-1936, R. H. Painter (1 ; ANSP). San Patricio: Mathis (6.5 km south; Nueces River; N, W; 18 m), 6-VI-2004, W. N. Mathis (1, 1 ; USNM). Travis: Austin, 14-IV-1951, M. R. Wheeler (1 ; USNM); Austin (Zilker Park), 24-IX-1988, J. M. Edwards, P. S. Fiuza F. (2, 3 ; TAMU, USNM); Heep Farm (17.5 km south Austin), 2-VIII-1972, E. E. Grissell (1[ ; TAMU). Texas (without further speciþcation), May (1 ; USNM). Distribution (Fig. 37). Nearctic: United States. Texas (Bexar, Brazos, Cameron, Jim Wells, Kerr, Kleberg, San Patricio, and Travis counties).

12 442 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4 Fig. 37. Distribution map for Discomyza u-signata. Natural History. Robert A. Wharton, a hymenopterist at Texas A&M University, reared several specimens from the terrestrial snail Rabdotus alternatus (snail species determined by Robert Hershler). The snails were collected in Zilker Park within the city of Austin, TX (Travis County) in early September, and the imagos emerged 24 September Wharton noted that reared D. u-signata emerged in small numbers compared with those of ßesh ßies (Sarcophagidae) or blue and green bottle ßies (Calliphoridae) that were also in the same snail host. Wharton collected both living and dead snails, looking for holes in the mucous door or other evidence that the snail had been parasitized. Remarks. Although deþnitely a congener, evidence from structures of the male terminalia indicates that this species is not particularly closely related to D. maculipennis, which was probably introduced to the New World from the Oriental Region. Instead, this species seems to be more closely linked to a group of species from the Afrotropical Region that, like D. u-signata, has an epandrium that is greatly expanded laterally. Apparently a laterally expanded epandrium is a synapomorphy that links D. u-signata with some but not all Afrotropical species, such as D. africana and D. eritrea. The epandrium of D. maculipennis, in contrast, is narrowly rounded, somewhat like an inverted U, being almost parallel sided. The narrowly rounded epandrium is probably a synplesiomorphy that is shared with the following congeners: D. incurva, D. maritima, and D. similis. Among congeners in the Afrotropics, D. u-signata is apparently most closely related to D. eritrea. Both species share the following synapomorphies, primarily from structures of the male terminalia, that establish the sister-group relationship: 1) presurstyli weakly developed (Fig. 23), not well developed as in other congeners; 2) postsurstyli symmetrical (Figs. 25Ð26, 31Ð32) (As noted previously, other congeners, similar to some species of Mimapsilopa, have asymmetrical postsurstyli.); and 3) postsurstylus lacking a postsurstylar process. The shape of the aedeagus of each species clearly distinguishes between D. u-signata and D. eritrea, as among other species of Discomyza. Given the morphological evidence just presented, we are of the opinion that D. u-signata is more closely related to a group of Afrotropical species with broadened epandriums and to D. eritrea speciþcally. This phylogenetic relationship indicates that D. u-signata shares a biogeographic track between Texas and Africa, perhaps similar to species of Paratissa Coquillett (Mathis 1993), which has species in the Caribbean and Africa, particularly East Africa.

13 July 2005 MATHIS AND ZATWARNICKI: REVISION OF GENUS Discomyza 443 Acknowledgments We acknowledge the assistance and cooperation of many organizations and individuals who contributed to the Þeldwork and production of this article. To Jon K. Gelhaus and Jason D. Weintraub (ANSP), Michael S. Engel (KU), Philip D. Perkins (MCZ), Peter Sehnal (NMW), and Robert A. Wharton and Edward G. Riley (TAMU), and their institutions, who loaned specimens, we express our sincere thanks. We are especially grateful to Robert A. Wharton, who graciously and freely allowed us to publish information on the rearing of D. u-signata from snails in Texas. Hollis B. Williams provided technical support and produced the maps; Guilherme C. Ribeiro and Lucrecia Rodriguez helped with the production of the facial and wing photographs. James F. Edmiston advised on the production of the maps and reviewed the manuscript. We also thank B. A. Foote and Stephen D. Gaimari for reviewing a draft of this article and F. C. Thompson for advice on nomenclatural issues. Fieldwork in Texas in 2004 was funded by a grant from the Biodiversity Program (Biotic Surveys and Inventories), National Museum of Natural History, and Smithsonian Institution (George R. Zug). References Cited Bergenstamm, J. von Ueber die Metamorphose von Discomyza incurva Fall. Verhandlungen der kaiserlichköniglichen zoologisch-botanischen Gesellschaft in Wien 14: 713Ð716. Bohart, G. E., and J. L. Gressitt Filth-inhabiting ßies of Guam. Bulletin of the Bernice P. Bishop Mus. 204: 1Ð152. Campos, S. L., and G.L.E. Peña Los insectos de Isla de Pascua (Resultados de una prospección entomologica). Rev. Chilena Entomol. 7: 217Ð229. Cogan, B. H Family Ephydridae, pp. 655Ð669. In R. W. Crosskey [ed.], Catalogue of the Diptera of the Afrotropical Region. British Museum (Natural History), London, United Kingdom. Cresson, E. T., Jr Studies in the dipterous family Ephydridae, excluding the North and South American faunas. Trans. Am. Entomol. Soc. 51: 227Ð258. Cresson, E. T., Jr Descriptions of new genera and species of Diptera (Ephydridae and Micropezidae). Trans. Am. Entomol. Soc. 52: 249Ð274. Cresson, E. T., Jr Description of a new genus and ten new species of Ephydridae, with a discussion of the species of the genus Discomyza (Diptera). Notulae Naturae. Acad. Nat. Sci. Phila. 21: 1Ð12. Cresson, E. T., Jr Synopses of North American Ephydridae (Diptera) I. The subfamily Psilopinae, with descriptions of new species. Trans. Am. Entomol. Soc. 68: 101Ð128. Cresson, E. T., Jr A systematic annotated arrangement of the genera and species of the Neotropical Ephydridae (Diptera) I. The subfamily Psilopinae. Trans. Am. Entomol. Soc. 71: 129Ð163. de Meijere, J.C.H Studien über südostasiatische Dipteren II. Tijdschrift Entomol. 51: 105Ð180. Disney, R.H.L A note on Discomyza asimilis Lamb (Diptera, Ephydridae) and other ßies reared from dead snails in Cameroon. Entomol. Mon. Mag. 105[1969]: 250Ð 251. Foote, B. A Biology of shore ßies. Annu. Rev. Entomol. 40: 417Ð442. Krivosheina, M. G K faune mukh-beregovushek (Diptera, Ephydridae) Dalnego Vostoka [On the fauna of shore-ßies (Diptera, Ephydridae) of the Far East], pp. 116Ð123. Taksonomia nasekhomych Sibirii i Dalnego Vostoka SSSR, Vladivostok. Loew, H Monographs of the Diptera of North America. Part 1. Smithson. Misc. Collect. 6: 1Ð221. Mathis, W. N Studies of Psilopinae (Diptera: Ephydridae), I: a revision of the shore ßy genus Placopsidella Kertész. Smithson. Contrib. Zool. 430: 30. Mathis, W. N A revision of the shore-ßy genera Hostis Cresson and Paratissa Coquillett (Diptera: Ephydridae). Proc. Entomol. Soc. Wash. 95: 21Ð47. Mathis, W. N., and T. Zatwarnicki. 1990a. A revision of the western Palearctic species of Athyroglossa (Diptera: Ephydridae). Trans. Am. Entomol. Soc. 116: 103Ð133. Mathis, W. N., and T. Zatwarnicki. 1990b. Taxonomic notes on Ephydridae (Diptera). Proc. Biol. Soc. Wash. 103: 891Ð906. Mathis, W. N., and T. Zatwarnicki A world catalog of the shore ßies (Diptera: Ephydridae). Mem. Entomol. Int. 4: vi. McAlpine, J. F Morphology and terminologyñ Adults. In J. F. McAlpine, B. V. Peterson, G. E. Shewell, H. J. Teskey, J. R. Vockeroth, and D. M. Wood. [eds.], Manual of Nearctic Diptera, 1: 9Ð63. Ottawa. [Volume 1 is Monograph 27 of Research Branch Agriculture Canada.] Meigen, J. W Systematische Beschreibung der bekannten europäischen zweißügeligen Insekten. 6: 401 xi pp. Schulz-Wundermann, Hamm, Germany. Runyan, J. T., and D. L. Deonier A comparative study of Pseudohecamede and Allotrichoma, pp. 123Ð137. In D. L. Deonier [ed.], First Symposium on the Systematics and Ecology of Ephydridae (Diptera). 147 iii pp. North American Benthological Society, Oxford, OH. Soans, A. B., and C. Adolph A note on the occurrence of Discomyza maculipennis Wiedemann (Diptera: Ephydridae) on dried Fish. J. Bombay Nat. Hist. Soc. 68: 847Ð 848. Wiedemann, C.R.W Munus Rectoris in Academia Christiana Albertina aditurus Analecta entomologica ex Museo Regio Havniensi maxime congesta profert iconibusque illustrat. 60 pp., 1 plate. Kiliae, Germany. Wiedemann, C.R.W Aussereuropäische zweißügelige Insecten. Volume 2, 648 xii pp., 5 plates. Schulz, Hamm, Germany. Wirth, W. W Ephydridae, pp. 734Ð759. In A. Stone, C. W. Sabrosky, W. W. Wirth, R. H. Foote, and J. R. Coulson [eds.], A catalog of the Diptera of America north of Mexico. United States Department of Agriculture, Agriculture Handbook No Wirth, W. W Family Ephydridae, pp. 1Ð43. In N. Papavero [ed.], A catalogue of the Diptera of the Americas South of the United States. Departamento de Zoologia, Secretaria da Agricultura. São Paulo, Brazil. Wirth, W. W Platygymnopa a new genus of Ephydridae reared from decaying snails in North America (Diptera). Can. Entomol. 103: 266Ð270. Zatwarnicki, T A new reconstruction of the origin of Eremoneuran hypopygium and its classiþcation implications (Insecta: Diptera). Genus 7: 103Ð175. Received 14 October 2004; accepted 22 March 2005.