A revision of the new world species of Polytrichophora Cresson and Facitrichophora, new genus (Diptera, Ephydridae)

Abstract The New World species of Polytrichophora Cresson and Facitrichophora new genus, are revised. Fifteen new species are described (type locality in parenthesis): Facitrichophora atrella sp. n. (Costa Rica. Guanacaste: Murciélago [10°56.9'N, 85°42.5'W; sandy mud flats around mangrove inlet]), Facitrichophora carvalhorum sp. n. (Brazil. São Paulo: Praia Puruba [23°21'S, 44°55.6'W; beach]), Facitrichophora manza sp. n. (Trinidad and Tobago. Trinidad. St. Andrew: Lower Manzanilla (12 km S; 10°24.5'N, 61°01.5'W), bridge over Nariva River), Facitrichophora panama sp. n. (Panama. Darien: Garachine [8°04'N, 78°22'W]), Polytrichophora adarca sp. n. (Barbados. Christ Church: Graeme Hall Nature Sanctuary [13°04.2'N, 59°34.7'W; swamp]), Polytrichophora arnaudorum sp. n. (Mexico. Baja California. San Felipe [31°01.5'N, 114°50.4'W]), Polytrichophora barba sp. n. (Cuba. Sancti Spiritus: Topes de Collantes [21°54.4'N, 80°01.4'W, 670 m]), Polytrichophora flavella sp. n. (Peru. Madre de Dios: Rio Manu, Pakitza [11°56.6'S, 71°16.9'W; 250 m]), Polytrichophora marinoniorum sp. n. (Brazil. Paraná: Antonina [25°28.4'S, 48°40.9'W; mangal]), Polytrichophora rostra sp. n. (Peru. Madre de Dios: Rio Manu, Pakitza [11°56.6'S, 71°16.9'W; 250 m]), Polytrichophora sinuosa sp. n. (Trinidad and Tobago. Trinidad. St. Andrew: Lower Manzanilla [12 km S; 10°24'N, 61°02'W]), Polytrichophora mimbres sp. n. (United States. New Mexico. Grant: Mimbres River [New Mexico Highway 61 & Royal John Mine Road; 32°43.8'N, 107°52'W; 1665 m]), Polytrichophora salix sp. n. (United States. Alaska. Matanuska-Susitna: Willow Creek [61°46.1'N, 150°04.2'W; 50 m]), Polytrichophora sturtevantorum sp. n. (United States. Tennessee. Shelby: Meeman Shelby State Park [Mississippi River; 35°20.4'N, 90°2.1'W; 98 m]), Polytrichophora prolata sp. n. (Belize. Stann Creek: Cockscomb Basin Wildlife Sanctuary [16°45'N, 88°30'W]). All known New World species of both genera are described with an emphasis on structures of the male terminalia, which are fully illustrated. Detailed locality data and distribution maps for all species are provided. For perspective and to facilitate recognition, the tribe Discocerinini is diagnosed and a key to included genera is provided.


Introduction
Polytrichophora Cresson occurs worldwide and now comprises 31 species, including 11 undescribed species that we treat in this revision of the New World fauna of this genus. Previously on a worldwide basis, 20 species were known (Mathis and Zatwarnicki 1995 and updates). We focus on the New World fauna, which for many years has been woefully in need of comprehensive revision. Cresson (1942Cresson ( , 1946 produced the last synopses of Polytrichophora for the Americas (North America and South America respectively) near the end of his distinguished research career on shore flies, but his series of synopses are now 70 years old and quite inadequate for recognizing the vast influx of newly discovered species. In his two synopses, for example, Cresson treated four species in the Nearctic Region (P. agens Cresson, P. conciliata Cresson, P. orbitalis (Loew), P. setigera (Cresson)) and three species in the Neotropical Region (P. desmata (Williston), P. pulchra Cresson, P. setulosa (Cresson)) with no apparent overlap of species between these two regions. Between Cresson and this revision, Mathis (1997a) described the only other New World congener, P. reginae, in a faunistic study of the shore flies of the Belizean Cays. Thus, the New World fauna, based on species reported in this revision, has increased dramatically from eight to 19 species, 11 being undescribed, which further documents the need for revising this biologically diverse genus.
Much of this increase has resulted from a greatly improved sampling of the New World fauna, especially the neotropics where the first author has focused much of his fieldwork for nearly four decades. Also contributing to this increase is our use of characters from structures of the male terminalia, which has revealed species complexes for what had been treated in some cases as a single, widespread species. The seven new species of the conciliata group are an example of this discovery process and taxonomic evolution.
In addition of a revision of Polytrichophora, we are also revising Facitrichophora, a new genus that includes four species, all undescribed, and that is related to Polytrichophora and other genera of the Discocerina group. The four species that we are describing in this genus all occur in the New World tropics.
Why study Polytrichophora or Facitrichophora? As alluded to previously, the New World fauna of Polytrichophora exhibits considerable diversity, and until this revision, most of the components of this diversity, the species, were unknown or had been misidentified. A basic component of this or any biodiversity study is a comprehensive, taxonomic treatment of the fauna wherein all included species are fully elaborated, including how they are differentiated (recognized), where they occur, the relevant literature, and a summary of their natural history, as this information is available. The importance of knowing a species' scientific name cannot be overly emphasized, as it provides an entrée into the literature on that species for those seeking further information (Thompson 1997).
Another reason for this study is to contribute to our understanding of the evolutionary and phylogenetic relationships among the included taxa. Discovering the complexity of a species group, for example, or determining the phylogenetic signal of character evidence that we discover and document, contribute significantly to clarifying the evolutionary history of the group, which in turn, becomes the backbone for other comparative, biological studies, such as behavioral studies or those on the historical biogeography of a group. Knowing the phylogeny of a group provides the necessary evolutionary context for other studies in comparative biology.
We know virtually nothing about the natural history of any species of Polytrichophora or Facitrichophora (see "Natural History" under generic heading, p. 26) and another objective of revision is to stimulate work on this invaluable component--understanding the natural history of this genus.
We cannot overly emphasize, however, that the primary stimulus and reason for this revision was to satisfy our own innate curiosity about these shore flies. The motivation generated by the process of discovery is compelling and greatly contributed to this study. Curiosity and discovery are basic to human nature and ought to be supported and otherwise fostered.
The taxonomic and nomenclatural history of the New World species of Polytrichophora is both short and simple, especially as there were relatively few species and contributors involved. Loew (1861) described the first New World species, P. orbitalis (Loew), in the genus Discocerina and then Cresson transferred it to Polytrichophora (Cresson 1924) when he first proposed Polytrichophora as a genus-group taxon. That same sequence of description in another genus then transfer to Polytrichophora was followed by the next three species now included in the genus: (1) Williston (1896) described P. desmata (Williston) in the genus Psilopa and then Mathis and Edmiston (1991) transferred it to Polytrichophora; (2) Cresson (1916) described P. setigera (Cresson) in Discocerina and then transferred it to Polytrichophora (Cresson 1924); and (3) Cresson (1918) described P. setulosa in Discocerina and then transferred it to Polytrichophora (Cresson 1924). The other previously described, New World species were all originally described as congeners in Polytrichophora: Cresson (1924) described P. agens P. conciliata, and P. pulchra and Mathis (1997b), in a review of the shore flies of Belizean Cays, described P. reginae. The only other New World species proposed is P. boriqueni Cresson (1930) from specimens collected on Puerto Rico. Cresson's species was later discovered to be conspecific with P. desmata. The latter species had been described 34 years earlier in Psilopa, a genus in the subfamily Discomyzinae, not Gymnomyzinae, which is the subfamily in which genera of the tribe Discocerinini are currently placed (Mathis and Zatwarnicki 1995).
Virtually nothing is known about the natural history of Polytrichophora except for brief descriptions of habitats where adults have been collected (Deonier 1965), and these, perhaps, are suspect because we now know that three species occur in the Midwest (so far as we have records, however, only P. sturtevantorum is currently known to occur in Iowa).

Methods and materials
The methods used generally in this study were explained previously (Mathis 1986, Mathis andZatwarnicki 1990a). Because specimens are small, usually less than 3.5 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, 1990b, and the terminology for these structures provided directly on Figs 1-4 (Facitrichophora atrella sp. n.) and is not repeated for comparable illustrations of other species.
Dissections of male terminalia were performed following Clausen and Cook (1971) and Grimaldi (1987). Abdomens were removed with microforceps and macerated in a sodium hydroxide solution. Cleared genitalia were then transferred to glycerin for observation, description, and illustration. The dissected abdomen was placed in a plastic microvial filled with glycerin and attached to the pin supporting the remainder of the insect from which it had been removed.
Three ratios (two are venational) are used commonly in the descriptions and are defined here for the convenience of the user (ratios are averages of three specimens).
1. Gena-to-Eye ratio: Genal height/eye height. Measurements are taken from the head in lateral view.
2. Costal vein ratio: The straight line distance between the apices of R 2+3 and R 4+5 / distance between the apices of R 1 and R 2+3 .
3. M vein ratio: The straight line distance along vein M between crossveins (r-m and dm-cu)/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 Microsoft Excel© spreadsheet. If unavailable directly from specimen labels, longitude and latitude were estimated using gazetteers and maps to determine the geographical coordinates. Localities of specimens were plotted on a world land projection, presented within ESRI ArcView layouts and exported as encapsulated postscript (EPS) files.
Although we do not include a rigorous cladistic analysis as part of this revision, we do provide some discussion on the phylogeny of some groups, especially the conciliata group. We include character evidence, usually synapomorphies, for these groupings, and it is understood that this evidence is putative and further, that the phylogenetic inferenc-inferences are hypotheses. We have not done a cladistic analysis in part because Polytrichophora is a worldwide genus and herein we treat only the New World fauna. In the Old World there are numerous species, including some that are undescribed. At the generic level, the discussions of phylogeny provided here are written within the perspective of an earlier paper on the phylogeny of Discocerinini (Zatwarnicki and Mathis 2001).
Although this study was based in large part on specimens in the National Museum of Natural History (USNM), numerous others were borrowed, particularly type specimens of the species previously described. To our colleagues and their institutions listed below who loaned specimens, we express our sincere thanks. Without their cooperation this study could not have been completed.
Head: Frontal vitta (or ocellar triangle) mostly bare of setulae, not conspicuously setulose; pseudopostocellar setae well developed, length greater than distance between either posterior ocellus and anterior ocellus, generally with proclinate orientation and slightly divergent; ocellar seta inserted anterior to lateral alignment of anterior ocellus, sometimes only slightly so; reclinate fronto-orbital seta inserted in front of proclinate fronto-orbital (if 2 proclinate fronto-orbital setae present, reclinate seta inserted in front of the larger proclinate seta); proclinate fronto-orbital seta subequal to length of reclinate seta. Pedicel bearing a large seta anterodorsally; arista with 5-7 dorsally branching rays evenly along aristal length. Compound eye bearing numerous, interfacetal microsetulae. Face generally smooth, not conspicuously pitted or rugose, in lateral view shallowly carinate between antennal bases and/or very shallowly conically produced, convex. Gena generally short (secondarily high in some species), bearing setulae (including midportion) and 1 large seta, its posterior (postgenal) margin rounded, not sharp. Oral opening and clypeus narrow; mouthparts generally dark colored; clypeus generally microtomentose, similar to microtomentum of face.
Thorax: Mesonotum generally microtomentose, usually densely so; supra-alar seta usually evident although sometimes reduced; acrostichal setulae arranged in about 8 irregular rows; prescutellar acrostichal setae approximate and inserted behind level of posteromost dorsocentral setae; scutellum usually moderately densely setulose, bearing more than 20 setulae, these evenly scattered; both anterior and posterior notopleural setae inserted at about the same level from notopleural/anepisternal suture; anepisternum with 2 equal setae along posterior margin. Wing with vein R 2+3 long, extended nearly to level of apex of vein R 4+5 . Foreleg normally developed, not raptorial with greatly enlarged femur.
Abdomen: Five tergites visible, usually not covered with microtomentum. Male terminalia: Structures symmetrical; cerci paired, hemispherical, setose, bearing sides of rectum, sometimes fused with posteroventral margin of epandrium; epandrium Ushaped, encircling cerci, anterior margin rounded, in lateral view with setae mainly on dorsum and along anteroventral margin; presurstylus lacking or fused indistinguishably with epandrium; posterolateral arms of epandrium attached with ventral apex of gonites, middle of posterior margin a base for phallapodeme; phallapodeme situated under aedeagus, associated with hypandrium and with ventral part of base of aedeagus, ventral margin with lobate appendix providing attachment for genital muscles that move aedeagus, sometimes fused with base of aedeagus; gonites paired, connecting sides of base of aedeagus and laterodorsal margin of epandrium, bearing 1 or some setulae; subepandrial plate reduced; aedeagus tubular, tapered anteriorly; ejaculatory apodeme usually lacking, if present as a spatula against background of ductus ejaculatorius.
Discussion. Starting with Cresson (1925), who first described Discocerinini, and including all students of the family until Mathis and Zuyin (1989), the diagnoses, descriptions, and catalogs of this tribe included some taxa that are not closely related phylogenetically, rendering the tribe polyphyletic. Mathis and Zuyin (1989) recharacterized Discocerinini using synapomorphies and resulting in a monophyletic tribe under which Mathis and Zatwarnicki (1995) included eight genera and 143 species in their world catalog. Zatwarnicki and Mathis (2001) added two additional genera, Galaterina and Orasiopa, and altered the status of some subgenera in their phylogenetic study of the tribe.
Phylogenetic relationships. On a worldwide basis, Zatwarnicki and Mathis (2001) proposed a phylogenetic hypothesis for higher-level lineages within the tribe Discocerinini and the discussion to follow is written within the context of the hypothesis and supportive evidence they then proposed. Discocerinini, according to their proposed phylogeny, is divided into three sublineages: the Gymnoclasiopa, Diclasiopa, and Discocerina groups. Other genera in addition to Facitrichophora and Polytrichophora that are included in the Discocerina group are: Discocerina Macquart, Galaterina Zatwarnicki and Mathis, Hydrochasma Hendel, Lamproclasiopa Hendel, and Orasiopa Zatwarnicki and Mathis. Facitrichophora and Polytrichophora along with other genera of the Discocerina group form a monophyletic lineage within the Discocerinini that is corroborated thus far by two synapomorphies that we have identified. The first is the setulose notopleuron. In other genera of the subfamily Gymnomyzinae, including many in the tribe Discocerinini, the notopleuron is bare except for a larger anterior and a posterior setae that are inserted near the ventral margin of the notopleuron. In taxa of the Discocerina group, however, the notopleuron bears a few additional setulae that are usually inserted slightly dorsad and toward the anterior portion of the notopleuron, usually around the anterior notopleural seta. The second synapomorphy confirming the monophyly of the Discocerina group is the shape of the gonite, which is narrowly elongate, bar-like, and often essentially parallel sided. In other genera of Discocerinini outside of the Discocerina group, the gonite is elongate, variously swollen medially, and tapered toward both apices. Within the Discocerina group, an elongated male terminalia (hypopygium) that is at least 2.5× longer than wide (the plesiomorphic condition is for the hypopygium to be of moderate length) occurs almost exclusively in three genera: Galaterina, Hydrochasma, and Polytrichophora. The genera Hydrochasma and Polytrichophora are characterized by a deeply incised posterior margin of the hypandrium (the plesiomorphic condition is a hypandrium with a moderately concave posterior margin). Polytrichophora and Facitrichophora are distinguished from other New World genera by the characters provided in the key and generic diagnoses that follow (characters being discussed are synapomorphies unless specified otherwise (Zatwarnicki and ). Face with 2 or more conspicuous rows of setae/setulae on each side, paralleling facial suture setal row medial, row(s) of setulae between setal row and parafacial (Figs 10- 11,[28][29] Diagnosis. Small to moderately small shore flies, length 1.8-3.20 mm; generally densely microtomentose, dull species . Head : Frons lacking anterior, proclinate, fronto-orbital seta; face substantially prominent at level of dorsal facial seta; antennal grooves generally sharply defined ventrally; facial setae comprising at least 2 vertical to verticolateral rows , 5 setae of medial row larger than those of lateral row, these not arising from shiny papilla and with similar, mostly inclinate to ventroinclinate orientations; face lacking a distinctly dorsoclinate seta at ventral extremity; parafacial moderately wide, bearing conspicuous, vertical row of large setulae; gena variable but moderately high. Eye generally oval, conspicuously microsetulose, bearing numerous interfacetal setulae; maxillary palpus yellow. Thorax (Fig. 13): Acrostichal setulae in 6-8 rows; a presutural and postsutural supra-alar setae moderately well developed, both about 1/2 length of postalar seta; notopleuron bearing several setulae in addition to 2 larger setae; anterior notopleural seta inserted conspicuously closer to posterior notopleural seta than to postpronotal seta; anepisternum bearing 2 prominent, subequal setae along posterior margin. Wings faintly infuscate, more so toward anterior margin; costa bearing 3-5 long, dorsal setae between humeral and subcostal breaks. Forefemur normally developed, lacking row of short, stout setae along anteroventral or posteroventral surfaces; hindtibia lacking a preapical, ventral, spur-like seta. Abdomen: Tergites variable, but mostly unicolorous; tergite 2-4 of ♂ becoming progressively longer. Male terminalia (Figs 1-4): Epandrium thinly connected dorsally above cerci, in posterior view more or less elliptical, 2× longer than wide, in ventral half gradually tapered, or pyriform, broader basally and tapered irregularly to apex, on whole surface bearing distinct setae, in lateral view apical half slightly widen by extension of its ventral portion, apical section of ventral margin often with setae; cerci fused ventrolaterally to medial margin of epandrium, in posterior view generally slightly elongate or hemispherical; gonites rod-shaped without setae, rarely lobate; aedeagus strongly elongate, about 4-6× longer than wide, in dorsal view base generally narrowly triangular, apex rounded, in lateral view trunk of aedeagus with uniform thickness, apex pointed and generally bearing subapically a narrow, membranous flap that generally folds back under aedeagus with about 2/3 length of aedeagus to battered tape 2× as long as aedeagus; phallapodeme separate from aedeagus, in posterior view elongate with extension at base and bifurcate anteriorly, in lateral view narrowly subtriangular, with extension toward aedeagal base narrow, parallel sided or tapered, keel usually evident toward hypandrial extension, but sometimes reduced; ejaculatory apodeme absent; hypandrium in dorsal view U-or V-to Y-shaped with thickened stem or base, anterior margin narrowly to broadly rounded, posterior arms either straight or oriented posterolaterally, if straight then with a lateral and medial pair of arms, in lateral view hypandrium generally flattened or broadly and shallowly pocket-like.

Key to new world genera of Discocerinini
Distribution. Species of Facitrichophora have only been found in the Neotropical Region.
Natural history. Specimens of Facitrichophora are usually associated with mudshore and sand-shore habitats associated with brackish water in backwater areas of maritime coasts.
Discussion. Facitrichophora, along with Discocerina, Hydrochasma Hendel (New World), and Polytrichophora, form a monophyletic lineage within the tribe Discocerinini (see Zatwarnicki and Mathis 2001 for background on this node). Facitrichophora may be distinguished from Discocerina, Hydrochasma, or Polytrichophora by the two series of facial setae (see generic description and  with an inclinate to ventroinclinate orientation; medial facial series larger and numbering 5. These characters are unique to the species of this genus (synapomorphies) and are evidence of its monophyly. Facitrichophora is perhaps most closely related to Polytrichophora and a synapomorphy establishing this relationship is the fusion of the ventral portion of the cerci with the epandrium.
Four species have been discovered in this genus thus far, and each can be distinguished by external characters. Reference to characters of the male terminalia, however, may be needed to confirm a species' identity. Two posterior dorsocentral setae, anterior seta slightly smaller than posterior seta (Argentina, Brazil, Costa Rica Tergite 4 of male long, conspicuously longer than tergite 3 and subequal to tergite 5; tergite 3 with ventrolateral margin produced into a curved, narrow, parallel-sided process; tergite 5 with anteroventral angle projected slightly, acutely pointed (Costa Rica, Cuba, Mexico, Trinidad and Tobago Head: Frons mostly black, generally very sparsely grayish microtomentose, becoming denser and tannish on and around ocellar triangle; fronto-orbits with silvery gray microtomentum. Antennal scape and pedicel black; basal flagellomere black or becoming tannish to brownish apically; arista bearing 5 dorsal rays. Face wide, microtomentum dull to subshiny, tannish gray to silvery. Parafacial concolorous with fronto-orbit. Gena moderately high, height equal to length of scape; gena-to-eye height ratio 0. 20-0.28. Thorax: Mesonotum subshiny to shiny, black, with sparse, whitish to grayish microtomentum; a single pair of posterior dorsocentral setae; no evident prescutellar acrostichal setae; scutellum trapezoidal in dorsal view with posterior margin truncate, lateral margins very slightly bowed, bearing 2 primary scutellar setae along lateral margins but also with several larger setae between primary setae, especially posteriorly. Wing uniformly faintly infuscate; costal vein ratio 0.57-0.60; M vein ratio 0.60-0.62.
Type material. The holotype male is labeled "BRAZIL.  Zatwarnicki, DZUP [red]." The holotype is double mounted (minuten pin in Etymology. The species epithet, carvalhorum, is a plural genitive Latin patronym to honor and recognize the contribution of the A. Bernardo Carvalho family (Bernardo, Monica, Elisa) to this study of the shore flies of Brazil. Remarks. This species is distinguished externally from congeners most notably by having two posterior dorsocentral setae (in other species there is a single seta), and the anterior dorsocentral seta is slightly smaller than the posterior seta. Facitrichophora manza sp. n. urn:lsid:zoobank.org:act:A85B0B69-12D0-4D0C-AF17-11447AB1E979 http://species-id.net/wiki/Facitrichophora_manza  Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.90-2.55 mm.
Etymology. The species epithet, manza, is an abbreviated reference to the general area, Lower Manzanilla, where this species was first discovered on Trinidad.
Remarks. Discovery of this species along the coast of Trinidad was our first indication of this genus. Some specimens were initially classified as an undescribed species of Polytrichophora and others within the genus Discocerina. Additional species were discovered and with careful study of them, including characters of the male terminalia, we became aware of a monophyletic group that is somewhat between these two genera.
Although similar to F. panama, this species is distinguished by having a grayish brown to bronzish brown mesonotum, by having two lateral, scutellar setae, and in males, by having an elongated tergite four (conspicuously longer than tergite three and subequal to tergite five). In addition, the ventrolateral margin of tergite three is produced into a curved, narrow, parallel-sided process, and the anteroventral angle of tergite five is slightly projected and acutely pointed. Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to medium-sized small shore flies, body length 1.84-3.20 mm.
Type material. The holotype male is labeled "PANAMA[.] DarienProv[incia] [,] Garachine/Feb 1953 [,] FSBlanton/USNM ENT 00285973 [plastic bar code label]/HOLOTYPE ♂ Facitrichophora panama Mathis & Zatwarnicki, USNM [red]." The holotype is double mounted (glued to a paper triangle), is in moderate condition (arista missing; some head setae missing or misoriented), and is deposited in the USNM. One male paratype (dissected; USNM) bears the same label data as the holotype. Other paratypes are as follows: PANAMA. Canal Zone: San Lorenzo (9°07.9' N, 79°32 Etymology. The species epithet, panama, refers to the country where this species was collected and is a noun in apposition. Remarks. Although similar to F. manza (similarities include having a single dorsocentral seta, the mesonotum grayish brown to bronzish brown, and having two lateral scutellar setae), it is distinguished by having male tergites three and four subequal in size (tergite four not unusually longer as in F. manza); male tergite three is not produced ventrolaterally; and male tergite five is rounded or angulate (not projected anteroventrally and acutely pointed as in F. manza). Diagnosis. Small to moderately small shore flies, length 1.4-3.5 mm; generally densely microtomentose, dull species (Figs 29-31). Head (Figs 29-30): Frons lacking anterior, proclinate, fronto-orbital seta; face substantially prominent at level of dorsal facial seta; antennal grooves generally sharply defined ventrally; facial setae usually comprising 8 setae, these not arising from shiny papilla and generally decreasing in size from dorsum to venter, appearing as 2 series (Figs 29-30) due to divergent orientation of setae in series; setae of primary series inclinate (setae 1, 2, 5, and 7), generally larger than setae of secondary series except for seta 2, which is much reduced and inserted laterad and sometimes slightly ventrad of seta 1, seta 1 largest of all facials, inclinate (cruciate with opposite seta), but not arising from shiny papilla; setae of secondary series oriented dorsolaterally to laterally (setae 3, 4, 6, and 8), usually smaller series than primary series; face lacking a distinctly dorsoclinate seta at ventral extremity; parafacial narrow to moderately wide, generally bearing setulae although sometimes fine and pale or lacking; gena variable but generally short to moderately high. Eye generally oval, conspicuously microsetulose, bearing numerous interfacetal setulae; maxillary palpus yellow. Thorax (Fig. 31): Single presutural and postsutural supra-alar setae well developed; postsutural supra-alar seta reduced, about 1/2 length of postalar seta; acrostichal setae present; notopleuron bearing several setulae in addition to 2 larger setae; anterior notopleural seta inserted conspicuously closer to posterior notopleural seta than to postpronotal seta. Wings transparent; costa bearing 3-5 long, dorsal setae between humeral and subcostal breaks. Forefemur normally developed, lacking row of short, stout setae along posteroventral surface; hindtibia lacking a preapical, ventral, spurlike seta. Abdomen: Tergites variable, but mostly unicolorous, if bicolorous, bearing pale colored areas laterally, but these not distinctly wedge-shaped; 4th tergite of ♂ only slightly longer than 3rd. Male terminalia : Epandrium complete or separate dorsally, in posterior view more or less elliptical, 2× longer than wide, in ventral half gradually tapered, or pyriform, broader basally and tapered irregularly to apex, on whole surface bearing distinct setae, in lateral view apical half slightly widen by extension of its ventral portion, apical section of ventral margin often with setae; cerci fused ventrolaterally to medial margin of epandrium, in posterior view generally slightly elongate or hemispherical; gonites rod-shaped without setae, rarely lobate; aedeagus strongly elongate, about 4-6× longer than wide, in dorsal view base generally narrowly triangular, apex rounded, in lateral view trunk of aedeagus with uniform thickness, apex pointed and generally bearing subapically a narrow, membranous flap that generally folds back under aedeagus with about 2/3 length of aedeagus to battered tape 2× as long as aedeagus; hypandrium in dorsal view H-shaped, with transverse cross-bar, anterior arms arcuate, approximate to each other, with narrow arms with uniform thickness or unequal lobate broadened, sometimes to different degree at apex interrupted or/and with reduced cross-bar, in lateral view hypandrium flat, slightly directed dorsally; phallapodeme separate from aedeagus, in posterior view elongate with extension at base and bifurcate anteriorly, in lateral view subtriangular or subrectangular, with dorsal margin slightly bent ventrally, ventral margin irregularly U-shaped, middle part of apodeme with ventral broad appendix, sometimes slightly directed anteriad; ejaculatory apodeme absent.

Genus
Distribution. This is one of the few genera of Ephydridae that occurs worldwide and in temperate or tropical environments. The New World, with 23 species, currently has greater species diversity. Worldwide there are 35 species.
Natural history. Specimens of Polytrichophora are usually associated with mudshore and sand-shore habitats (Deonier 1965) or rarely with a marsh-reed habitat (Scheiring and Foote 1973). We usually found greatest diversity and abundance while collecting on mud and sandy shores that had a mat-like covering of algae. Some species, as will be noted with their individual treatment, are tolerant of mildly saline conditions and occur on mud and sandy shores where the water is brackish.

Key to species of Polytrichophora from the New World
The second assemblage, which includes P. adarca, P. arnaudorum, P. conciliata Cresson, P. marinoniorum, P. sinuosa, is characterized by a small H-shaped hypandrium in ventral view, and the relationships of its included species in parenthetic notation are: P. arnaudorum (P. adarca ((P. conciliata Cresson, P. marinoniorum) P. sinuosa))). An apomorphy for P. arnaudorum is the long anterior process of the aedeagus (basiphallus). For other species of this group, there is a narrow ventral epandrial process (surstylus). Specimens of P. adarca have a shortened ventral epandrial process (surstylus). For other species, there is a lateral projection on the distiphallus and a narrowed anterior process of the aedeagus (basiphallus). Specimens of P. conciliata Cresson and P. marinoniorum have a digitiform ventral epandrial process (surstylus), and P. sinuosa has an elongated ventral epandrial process (surstylus). Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.45-2.10 mm.
Head: Frons dull, heavily microtomentose, 2-toned, mostly tan with some faint golden reflections on posterior 2/3, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, anterior portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with shiny to pearly luster, mostly white but with considerable gold coloration in antennal grooves and extended laterally onto parafacial; parafacial not markedly differing from midfacies in color, more golden dorsally, becoming whiter ventrally; parafacial with slight to considerable ventral dilation, 2-3 times wider ventrally than dorsally; gena relatively short, subequal to height of basal flagellomere, gena-to-eye ratio 0.12-0.14.
Remarks. Although similar to P. conciliata and P. marinoniorum in having a row of setulae along the anteroventral surface of the forefemur and in having a small Hshaped hypandrium in ventral view, this species is distinguished from these congeners in having a shortened ventral epandrial process (Fig. 24). Diagnosis. This species is distinguished from congeners by the following combination of characters: Moderately small shore flies, body length 2.30-2.90 mm (comparatively large and robust in comparison to congeners). Head (Figs 29-30): Frons dull, heavily microtomentose, 2-toned, mostly tan with some faint golden reflections on posterior 2/3, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, anterior portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose with subshiny to pearly luster, mostly white but with considerable gold coloration in antennal grooves and extended laterally onto parafacial; parafacial color not markedly differing from midfacies; parafacial becoming much wider ventrally and with slight to considerable ventral dilation, 2-3 times wider ventrally than dorsally; gena moderately high, height about equal to combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.20-0.23.
Natural history. All specimens that we have examined are from localities that are associated with marine or at least brackish-water shorelines, indicating a tolerance and perhaps an affinity for these habitats.
Remarks. Specimens of this species are usually relatively large and robust, especially the abdominal tergites. Unlike most congeners, there is some asymmetry in some structures of the male terminalia (similar to P. flavella; Figs 32, 35). From similar congeners, this species is distinguished by the shortened apical arms (apparently secondarily shortened) of the H-shaped hypandrium. Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.90-2.40 mm.
Head: Frons largely dull, moderately microtomentose, 2-toned, posterior 2/3 mostly grayish to whitish tan, anterior 1/3 (from level of fronto-orbital setae anteriad) yellow to yellowish gray. Antenna mostly yellow to yellowish orange, basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with faint shiny to pearly luster, mostly tannish white; parafacial and gena becoming more whitish than face; parafacial becoming much wider ventrally with slight to considerable ventral dilation; parafacial 2-3 times wider ventrally than dorsally; gena moderately high, height about equal to combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.21-0.24.
Type locality. Mexico. Baja California. San Felipe (31°01.5' N, 114°50.4'W). Distribution (Fig. 42). Nearctic: Mexico (Baja California). Etymology. The species epithet, arnaudorum, is a plural genitive patronym to recognize and honor Paul H. Arnaud, Jr. and his wife, Madeline (nee Milliet), who contributed greatly to our careers in entomology and specifically to the study of Diptera. Paul was the collector of the type series.
Remarks. This species is similar and probably closely related to P. conciliata, P. adarca, and P. sinuosa but is distinguished from these species and other congeners in having a long anterior process of the aedeagus (basiphallus) (Figs 40-41). Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.65-2.10 mm.
Head: Frons largely dull to faintly subshiny, moderately microtomentose, mostly grayish to brown, extreme anterior portion yellowish orange. Antenna mostly yellow to yellowish orange, arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with faint shiny to pearly luster, mostly yellow to faintly whitish yellow; parafacial and gena becoming slightly more whitish than face; parafacial becoming much wider ventrally with moderate ventral dilation; gena moderately short, height less than combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.16-0.17.
Abdomen: Tergites widely subshiny gray medially, laterally tan to tannish gray. Male terminalia (Figs 43-47): Epandrium in posterior view (Fig. 43) moderately broadly rounded dorsally, thereafter tapered ventrally to narrowly rounded ventral apex, in lateral view (Fig. 43) with posterior margin curved with slight prominence at ventral fourth that bears a more dense tuft of setulae, anterior margin irregularly straight; cerci moderately sized, relatively narrowly fused with epandrium; aedeagus in lateral view (Fig. 47) elongate, narrow, folded back on itself, basiphallus shallowly curved, parallel sided, distiphallus twisted, deeply recurved subapically; phallapodeme in lateral view rod-like, oriented almost perpendicular to general plane of terminalia, keel barely evident at hypandrial end, almost parallel sided, very shallowly angular, in ventral view (Fig. 46) as a small rounded structure with short dorsal and ventral knobs; gonite in lateral view (Fig. 47) narrow, elongate, nearly straight, rod-like, in ventral view (Fig.  46) slightly asymmetrical, elongate, more curved toward hypandrial end; hypandrium in lateral view (Fig. 47) nearly flat, very narrow and elongate, margins irregularly sinuous, in ventral view (Fig. 47) slightly asymmetrically H-shaped with bar situated much closer to posterior portion, anterior arms slightly longer than bar, pointed apically, posterior short, about half length of bar and slightly flared laterally. Type material. The holotype male is labeled "CUBA. Sanc [ti].Spiritus [,] Topes de Collantes [,] 21°54.4' N, 80°01.4'W, 670m, 9-11Dec1994[,]   Etymology. The species epithet, barba, is Latin word for beard and refers to the distinctive tuft of setulae, the beard, on the ventral portion of the epandrium of this species.
Remarks. This species is similar to and has been confused with P. orbitalis (see synonymy). Structures of the male terminalia are very distinctive, however, especially the tuft of short, setulae, which is apparently an autapomorphy, on the ventral portion of the epandrium (Figs 43-44). This tuft can often be seen in preserved specimens without dissection. Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.70-2.15 mm. Head: Frons dull, heavily microtomentose, 2-toned, mostly tan with some faint golden reflections on posterior 2/3, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, anterior portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with shiny to pearly luster, mostly white but with considerable gold coloration in antennal grooves and extended laterally onto parafacial; parafacial not markedly differing from midfacies in color, more golden dorsally, becoming whiter ventrally; parafacial with slight to considerable ventral dilation, 2-3 times wider ventrally than dorsally; gena relatively short, less than 1/4 eye height; gena-to-eye ratio 0.10-0.16. Thorax: Mesonotum mostly dull, densely microtomentose, concolorous with posterior 2/3 of frons; pleural area blackish gray. Stout setae on apical half; anterior margin of wing lacking large, spine-like setae; costal vein ratio 0.45-0.55; M vein ratio 0.55-0.59. Forefemur lacking row of 9-10 short, stout setae along apical half of anteroventral surface; forefemur with posteroventral row of 7-10 short setulae, each equal to width of femur; tibiae mostly yellowish; basal tarsomeres yellow, apical 1-2 brown.
Remarks. This species is similar to P. adarca and P. marinoniorum in having a row of short setulae along the anteroventral surface of the forefemur and subtlety differs from these two species in structures of the male terminalia, especially the ventral processes of the epandrium (perhaps equaling fused surstylus). Although there is some variation in the shape of these processes, males from the Atlantic coast of the United States have the apex in lateral view slightly enlarged apically (Fig. 49). Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.85-2.25 mm.
Head: Frons largely dull to faintly subshiny, brown with moderate investment of gray to yellowish gray microtomentum, anterior margin with some orange coloration; fronto-orbits narrow, gray to whitish gray. Antenna mostly yellow; basal flagellomere tannish yellow apicodorsally; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face more densely microtomentose than frons, microtomentum with faintly shiny, mostly gray to whitish gray; parafacial and gena becoming slightly more whitish to silvery white than face; parafacial becoming wider ventrally with moderate ventral dilation; gena moderately high, height less than combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.17-0.21.
Remarks. This species, like P. agens, has some asymmetry in structures of the male terminalia. Unlike P. agens, however, this species has yellow legs, including most of the coxae, and the epandrium is rounded ventrally and has a subapical, anterior process (Figs 53-55). Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.75-2.25 mm.
Head: Frons generally blackish brown, dull, moderately heavily microtomentose, mostly tan with some faint golden reflections on posterior 2/3, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, dorsal portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with subshiny to pearly luster, mostly white but with considerable gray to bluish gray coloration in antennal grooves and extended laterally onto parafacial; parafacial not markedly differing from midfacies in color, more golden dorsally, becoming whiter ventrally; parafacial with considerable ventral dilation; parafacial color not markedly different from that of middle of face, usually silvery white; parafacial 2-3 times wider ventrally than dorsally; gena relatively short, less than 1/4 eye height; gena-to-eye ratio 0.18-0.20.
Etymology. The species epithet, marinoniorum, is a plural genitive patronym to recognize and honor Renato C. (1939Renato C. ( -2011 and Neuza (nee Fonseca) Marinoni, who were gracious hosts and greatly fostered our field work in southern Brazil.
Remarks. This species and P. conciliata are very similar externally (forefemur with row of short, stout setulae along anteroventral margin). Characters of the male terminalia are likewise similar, but in detail, there are subtle differences in structures of the male terminalia (compare Fig 59 with 48), such as the more rounded epandrium in posterior view and the slightly thinner ventral epandrial processes. Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.80-2.25 mm.
Head: Frons dull, moderately heavily microtomentose, partially2-toned, mostly grayish tan to grayish black with some faint golden reflections on posterior 3/4, anterior 1/4 becoming orange immediately along ptilinal suture. Antenna mostly yellow to yellowish orange, dorsal portion of pedicel and to a lesser degree basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with subshiny to pearly luster, mostly yellowish white but with considerable gold coloration in antennal grooves and extended laterally onto parafacial; parafacial not markedly differing from midfacies in color, becoming silvery white ventrally and posteriorly; parafacial with slight ventral dilation; gena relatively short, less than 1/4 eye height; gena-to-eye ratio 0.18-0.19.
Abdomen: Tergites subshiny to shiny medially, grayish black, becoming grayer laterally; tergite 5 of male somewhat pointed posteriorly, lacking distinctive row of setulae apically. Male terminalia (Figs 64-67): Epandrium in posterior view ( Fig  64) as an inverted tear drop, wide basally, at midheight, tapered ventrally to form a narrowly pointed ventral margin, connected dorsally around cerci, in lateral view (Fig 65) with most of posterior margin mostly straight, angled anteriorly and either end, ventral portion forming a beak-like extension that tapers to a narrow point, anterior margin shallowly zigzagged, apical portion bearing numerous short setulae; cerci prominent, moderately well developed; aedeagus complex, in lateral view (Fig  67) elongate, doubly folded back on itself, basiphallus elongate, narrow, pointed apically, distiphallus more narrowly developed than basiphallus, folded back twice with apical segment oriented in same direction as general plane of terminalia, with complicated smaller folds and lines, in ventral view (Fig 66) with basiphallus tubular, elongate, distiphallus twisted and irregularly curved; phallapodeme in lateral view (Fig 67) elongate, clavate, narrowed toward aedeagal base, keel only slightly extended, in ventral view (Fig 66) appearing aforeshortened as small irregularly rounded structure with short knobs; gonite in lateral view (Fig 67) rod-like, narrow, elongate, irregularly parallel sided, in ventral view (Fig 66) angularly curved, like a boomerang; hypandrium in lateral view (Fig 67) elongate, very narrow, sinuous, in ventral view (Fig 66) irregularly H-shaped with bar shallowly curved and posterior arms subequal to each other, anterior arms, narrow, left arm considerably shorter than right arm, both narrowly developed.
Etymology. The species epithet, rostra, is the Latin word for beak and refers to the shape of the beak-like epandrium as viewed in lateral view. Remarks. Like P. setulosa, this species has asymmetry in the anterior hypandrial arms, which is probably a synapomorphy that indicates a close relationship with that species. This species is distinguished by the beak-like apical process of the epandrium, best seen in lateral view (Fig 65), which is unmistakable and is the primary character that distinguishes this species from congeners within the conciliata group. ( Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.70-2.60 mm. Head: Frons dull, heavily microtomentose, 2-toned, mostly tan to brown with some faint golden reflections on posterior 2/3, especially medially, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, anterior portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face and clypeus densely microtomentose, especially ventrally, less so dorsally, microtomentum with shiny to pearly luster, mostly white but with considerable gold coloration in antennal grooves and extended laterally onto parafacial; parafacial not markedly differing from midfacies in color, more golden dorsally, becoming whiter ventrally; parafacial with moderate ventral dilation, 2-3 times wider ventrally than dorsally; gena moderately short, about equal to height of basal flagellomere; gena-to-eye ratio 0.19-0.21.
Abdomen: Tergites dorsally 2-toned, laterally lightly gray, becoming distinctly darker and subshiny medially; tergite 5 of male mostly gray medially, with whitish gray areas laterally, broadly pointed posteriorly. Male terminalia (Figs 69-72): Epandrium in posterior view (Fig 69) mostly oval with relatively elongate, narrow, tapered, pointed ventral extensions, ventral extension in lateral view (Fig 70) robustly developed, curved and tapered apically to acute point, bearing secondary point at midlength of extension that bears setulae; aedeagus complex, narrow, elongate, with distinct basiphallus and distiphallus, distiphallus with twisted, partially coiled, very elongate bands (Figs 71-72) very shallowly arched, almost straight and parallel sided, apex bluntly rounded; phallapodeme in lateral view (Fig 72) relatively short, clavate with larger end toward hypandrium, sinuous, in ventral view (Fig 71) asymmetrical, especially shallow keel at more clavate end; gonite in lateral view (Fig 72) elongate, shallowly sinuous, slightly larger toward hypandrium, in ventral view (Fig 71) asymmetrical with gonite on left side larger than right one, left gonite more angulate, right gonite more shallowly and evenly curved; hypandrium in lateral view (Fig 72) moderately elongate, narrowly elliptical, in ventral view H-shaped but with anterior arms of differing lengths and much shorter posterior arms.
Remarks. Among congeners of the conciliata group, this species is very similar to P. rostra as evidenced by both species having a crescent-shaped ventral epandrial process and pronounced asymmetry of the anterior hypandrial arms. This species is distinguished from P. rostra, however, in the lateral view by the shape of the epandrium (Fig 70), which has a secondary prong and has more gradual curvature of the ventral epandrial process, not abrupt as in P. rostra (Fig 65). Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.65-2.10 mm.

Polytrichophora sinuosa
Head: Frons dull, heavily microtomentose, 2-toned, mostly tan with some faint golden reflections on posterior 2/3, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, anterior portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face densely microtomentose, microtomentum with shiny to pearly luster, mostly yellowish to golden white but with considerable gold coloration in antennal grooves and extended laterally onto parafacial; parafacial not markedly differing from midfacies in color, more golden dorsally, becoming whiter ventrally; parafacial with slight to considerable ventral dilation; parafacial color not markedly different from that of middle of face, usually silvery white; parafacial 2-3 times wider ventrally than dorsally; gena moderately short, less than 1/4 eye height, subequal to height of basal flagellomere; gena-to-eye ratio 0.18-0.20.
Remarks. This is a species of the conciliata group and is distinguished from other congeners of that group by the following combination of characters: Parafacial and gena not greatly dilated and high; forefemur lacking row of setulae along anteroventral surface, and setae along posteroventral surface are not elongate; tibiae yellowish (often with dorsal surface silvery white), and ventral epandrial extensions elongate, thinly developed, and sinuous in lateral view (Fig 75).
Discussion. This species group is distinguished from the other groups by the following combination of characters: Parafacial color contrasted sharply with the much darker midfacies; parafacial with little or no ventral dilation; and abdomen mostly shiny, brownish black to black. ( Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.60-2.05 mm. Head: Frons mostly black with moderate dusting of gray to whitish gray microtomentum; ocellar triangle slightly lighter in color; fronto-orbits creamy white, narrow. Antenna mostly yellow; basal flagellomere darkened apicodorsally; arista bearing 5 dorsal rays. Face, especially ventrad of antennal grooves, narrow, width less than combined length of scape and pedicel; facial color mostly dark but with investment of gray microtomentum medially; parafacial creamy to yellowish white, contrasted with the much darker midfacies; parafacials with little or no dilation ventrally; gena very short, height much less than height of basal flagellomere; genato-eye ratio 0.06-0.08.
Type material. The holotype male of Psilopa desmata is labeled "Type [round label with a red border]/Windward side St. Vincent, W.I. H. H. Smith./W.Indies. 1907-66./Psilopa desmata Will [handwritten, two red submarginal borders]." The holotype is double mounted (pin in a rectangular piece of cardboard), is in poor condition (head missing; mesonotum cracked anteriorly), and is deposited in the BMNH.
Diagnosis. This species is distinguished from congeners by the following combination of characters: Small shore flies, body length 1.45-1.90 mm.
Head: Frons mostly black with moderate dusting of gray to whitish gray microtomentum; ocellar triangle slightly lighter in color; fronto-orbits creamy white, narrow. Antenna mostly yellow; basal flagellomere darkened apicodorsally; arista bearing 5 dorsal rays. Face, especially ventrad of antennal grooves, narrow, width less than combined length of antennal scape and pedicel. Midfacies with broad vitta extended from oral margin to antennal bases, gray to yellowish gray, sharply contrasted with blackish brown, vertical laterofacies; parafacial yellowish white to entirely silvery white, contrasted with the much darker laterofacies; parafacials with little or no dilation ventrally; gena very short, height much less than height of basal flagellomere; gena-to-eye ratio 0.05-0.07.
Type material.   Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.40-2.10 mm. Head: Frons largely dull to faintly subshiny, brown with moderate investment of gray to yellowish gray microtomentum, anterior margin with some orange coloration; fronto-orbits narrow, gray to whitish gray. Antenna mostly yellow; basal flagellomere tannish yellow apicodorsally; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face more densely microtomentose than frons, microtomentum with faintly shiny, mostly gray to whitish gray; parafacial and gena becoming slightly more whitish to silvery white than face; parafacial becoming wider ventrally with moderate ventral dilation; gena moderately high, height less than combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.11-0.13.
Thorax: Mesonotum mostly dull to faintly subshiny, moderately densely microtomentose, mostly tan to brown, becoming gray laterally and anteriorly; pleural area mostly gray. Anterior margin of wing lacking spine-like setae; costal vein ratio Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.70-2.30 mm.
Head: Frons dull, moderately to heavily microtomentose, mesofrons grayish brown to grayish black, more grayish anteriorly and on ocellar tubercle; parafrons black with gray microtomentum, slightly grayer anteriorly; fronto-orbits silvery gray microtomentum. Antenna short, mostly yellowish orange but black dorsally, basal flagellomere short, length subequal to height of pedicle, slightly darker, more brownish yellow; arista with 5 dorsal rays. Face wider than combined length of pedicel and basal flagellomere; face densely microtomentose, seriaceus, yellowish to lightly golden white; parafacial and gena mostly faintly golden white, becoming silvery white; parafacial with moderate ventral dilation; gena moderately short, height subequal to height of basal flagellomere, eye-to-cheek ratio 0.19-0.22.
Remarks. This species is distinguished from congeners of the orbitalis group externally by having the row of stout setae along the posteroventral surface of the forefemur short (length less than width of foretibia) and male tergite five is bluntly rounded to truncate. Among characters of the male terminalia that distinguish this species are the following: Epandrium in posterior view (Fig 99) generally as an inverted pear, pyriform, widest a midheight; both ventral epandrial extensions are robustly developed, with short, acute point apicomedially; hypandrium in ventral view (Fig 101) H-shaped with anterior extensions abutting anteriorly, posterior arms as digitiform projections that are slightly flared laterally. ( Diagnosis. This species is distinguished from congeners by the following combination of characters: Small shore flies, body length 1.60-1.95 mm.

Polytrichophora setigera
Head: Frons largely dull to faintly subshiny, brown with moderate investment of gray microtomentum, anterior margin mostly concolorous, some specimens faintly orange; fronto-orbits narrow, gray to whitish gray. Antenna mostly yellow; basal flagellomere tannish yellow apicodorsally; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face more densely microtomentose than frons, microtomentum with faintly shiny, mostly gray to whitish gray; parafacial and gena becoming slightly more whitish to silvery white than face; parafacial becoming wider ventrally with moderate ventral dilation; gena moderately high, height less than combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.13-0.16.
Head: Frons largely dull to faintly subshiny, brown with moderate investment of gray to yellowish gray microtomentum, anterior margin with some orange coloration; fronto-orbits narrow, gray to whitish gray. Antenna mostly yellow; basal flagellomere tannish yellow apicodorsally; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and basal flagellomere; face more densely microtomentose than frons, microtomentum with faintly shiny, mostly gray to whitish gray; parafacial and gena becoming slightly more whitish to silvery white than face; parafacial becoming wider ventrally with moderate ventral dilation; gena moderately high, height less than combined length of pedicel and basal flagellomere; gena-to-eye ratio 0.09-0.12.
Etymology. The species epithet, sturtevantorum, is a plural genitive patronym to recognize and honor a father and son. The father, Alfred H. Sturtevant (1891Sturtevant ( -1970, was a world-renowned geneticist who also conducted taxonomic research on shore flies (Sturtevant and Wheeler 1954) and was an indefatigable collector of acalyptrate Diptera. Most of A. H. Sturtevant'S shore-fly collection is deposited in the USNM, where his son, William C. Sturtevant (1926Sturtevant ( -2007; see Merrill and Goddard 2002 for biographical information), was a colleague and distinguished scholar in the Department of Anthropology (USNM). Remarks. Among species of the orbitalis group, this species is distinguished by characters of the male terminalia as follows: Area between anterior arms of the hypandrium is partially sclerotized; the ventral epandrial processes are relatively wide until small, digitiform, ventral projections (Fig 109); the posteroventral edge of the epandrium in lateral view is evenly curved; and the taper toward the apex is more gradual and acute (Fig 110).

The reginae Group
Species included: P. prolata sp. n. and P. reginae Mathis. Discussion. Externally, this species group is recognized by having male tergite five bearing a distinct row of six to ten longer setae along the extreme posterior margin. These setae have a posterodorsal orientation.
The monophyly of this group is questionable. Although the male tergite five is somewhat similar, structures of the male terminalia are remarkably different and may indicate that the two included species are not that closely related. In P. reginae, the ventral portion of the epandrium in posterior view is pointedly rounded, which is unique within the genus. In P. prolata, the ventral portion of the epandrium is as two, elongated, and narrow processes, more typical of many other congeners.
Head: Frons largely dull, gray to dark brown with moderate investment of gray to yellowish gray microtomentum, anterior margin with some yellowish to orange coloration; fronto-orbits moderately narrow, whitish gray to yellowish white. Antenna mostly yellow; dorsum of pedicel blackish; basal flagellomere tannish yellow apicodorsally; arista with 5 dorsal rays. Face relatively narrow, at narrowest point width less than combined length of pedicel and basal flagellomere; face more densely microtomentose than frons, microtomentum with shiny luster, midfacies mostly grayish tan to brown; parafacial yellowish gold, becoming more whitish gray; gena becoming slightly more whitish to silvery white than face; parafacial becoming slightly wider ventrally with little ventral dilation; gena moderately short, height less than height of basal flagellomere; gena-to-eye ratio 0.09-0.10.
Abdomen: Abdomen, including tergite 5 of male, entirely black, shiny dorsally, slightly grayish and very sparsely microtomentose ventrally; sternites 4-5 of male partially setulose but not as dense patches. Male terminalia (Figs 114-117): Epandrium in posterior view (Fig 114) narrowly connected dorsally, dorsum bluntly rounded, each lateral half very narrowly triangular, tapered ventrally, ventral extensions well separated on ventral 1/3, but extended parallel to each other, each tapered to narrowly rounded point, extensions bearing short setulae, in lateral view (Fig 115) as a bent turkey leg, ventral extension moderately well developed, mostly parallel sided, subapically shallowly sinuous, apex pointed; cerci evident in lateral view, moderately well developed; aedeagus in lateral view (Fig 117) very robustly developed, relatively very broad, length slightly more than twice length, broadly truncate apically, in ventral view (Fig 116) wedge-like, robust, basal half with lateral margins parallel sided, tapered to point on apical half; phallapodeme in lateral view (Fig 117) elongate, clavate, keel forming club, in ventral view (Fig 116) narrowly T-shaped with short, robust bar basally; gonite in lateral view (Fig 117) elongate, rod-like on most of length, end toward aedeagal base Diagnosis. This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.70-2.40 mm.
Head: Frons dull, heavily microtomentose, 2-toned, mostly tan with some faint golden reflections on posterior 2/3, anterior 1/3 (from level of fronto-orbital setae anteriad), gray. Antenna mostly yellow to yellowish orange, anterior portion of pedicel and basodorsal area of basal flagellomere with some blackish coloration; arista with 5 dorsal rays. Face at narrowest point about equal to combined length of pedicel and Remarks. This species is distinguished from P. prolata in having a smaller body (body length of 2.40 mm or smaller). In addition, male tergites one through four are bicolored (mostly blackish brown dorsally in contrast with the lateroventral surface being gray), male tergite five is truncate and is gray on the posterior one-third, and male sternites three and four have a dense patch of setulae along the posterior margin. Structures of the male terminalia (Figs 119-122) are unique within the genus in having the ventral margin pointedly rounded, without two apical processes.