Flies from L.A., The Sequel: A further twelve new species of Megaselia (Diptera: Phoridae) from the BioSCAN Project in Los Angeles (California, USA)

Abstract Background Presented are continued results from the BioSCAN Project, an urban biodiversity study sampling primarily from private backyards in Los Angeles, California (USA). Presented are continued results from the BioSCAN Project, an urban biodiversity study sampling primarily from private backyards in Los Angeles, California (USA). New information Twelve new species of Megaselia (Diptera: Phoridae) are described: M. baileyae, M. friedrichae, M. gonzalezorum, M. joanneae, M. losangelensis, M. phyllissunae, M. pongsaiae, M. shatesae, M. stoakesi, M. studentorum, M. voluntariorum, M. wongae.


Introduction
In spite of extensive taxonomic work, urban biodiversity is still largely unknown in most metropolitan areas. This makes big finds inevitable, and big finds are big news; the description of 30 new species and one new Nearctic record from the BioSCAN project in urban Los Angeles (Hartop et al. 2015) prompted extensive media coverage. Major news outlets worldwide, from NBC to The New Yorker, picked up on the news. On social media, the story "went viral". Suddenly, three dipterists working on an obscure group of flies were catapulted into the closest thing they may ever know to fame. It was clear from all the "buzz" (pun intended) that there is a lot of public interest in the biodiversity of the urban environments. The authors hope that this interest, and the corresponding media hulaballoo, helps get the message out: there is an enormous taxonomic deficiency, including (or, perhaps, especially) in rapidly changing urban environments, and we need people, funding, and institutions to get behind identifying, describing, and monitoring new species now. Baseline collections of urban fauna must be established in the present if there is hope for understanding the introductions and extinctions that will occur in the future. The BioSCAN Project, an ongoing urban biodiversity study of insects in Southern California, is doing just that (Brown et al. 2014, Hartop 2014. Truthfully, the authors were not surprised to find dozens of new species in Los Angeles: this was a predicted problem and opportunity (Hartop et al. (2015). The original paper did not tell the whole story, however, as it was based on only 10,000 phorids collected over the first 3 months of the BioSCAN project. After an entire year of sampling, the project yielded a total of 43,651 phorids and 68 species of Megaselia. 43 of those species, 68%, were (or are herein) described as new to science from the BioSCAN project.
Describing the final twelve species from year one of BioSCAN required the authors to dig deeper into the collections of old, poorly preserved type material: a persistent thorn in the side of the Megaselia taxonomist. Sorting out all of the errors and misidentifications is a slow, frustrating process (Disney 1983). Dedication to photographing, dissecting, and slide mounting historic types is the only way to make progress on this genus. Often paratype series are found to be useless for anything beyond demonstrating the limitations of historical definitions of species complexes. The series are often composed of any number of radically different species, with some being the opposite sex of the holotype and matched to the species based only on superficial characters. Despite the frustrations of study of this genus, the remarkable diversity of biologies of these flies makes them a varied and essential group to document in any ecosystem (Disney 1994).

Materials and methods
Specimens were collected by Townes lightweight style Malaise traps (Townes 1972) purchased from Sante Traps, Lexington, Kentucky. Traps were set up at thirty sites in Los Angeles (CA: USA) (Hartop et al. 2015: table 1). Specimens were captured and preserved in 95% ethanol. Methods for dissection and specific mounting protocol followed those recommended for this genus (Disney 2009). Specimens selected as holotypes, and some of the paratypes, were dissected and slide mounted by first clearing in clove oil and then mounting in Canada Balsam. Some paratypes and additional material were mounted directly in Berlese's fluid purchased from D. J. & D. Henshaw, Waltham Abbey, England and then sealed with dammar varnish (a commercially available product used for preserving artwork).
Unlike the first set of new species described from the project, hypandria were not dissected out and photographed. The species herein described are all rare flies in the survey and are represented sometimes only by a single specimen, and never more than ten (out of over 43,000 specimens). This led the authors to decide against sacrificing specimens to potentially damaging genital dissection. Also due to the rarity of specimens, habitus photos of dried specimens are not available for all species, as some of the flies were slide mounted for identification before they were determined to be new.
Specimens were examined using a Leica M205C stereo microscope and an Olympus BX40 compound microscope. Photography was done with a Keyence VHX-5000 digital microscope. Specimens are deposited in the Natural History Museum of Los Angeles County, USA (LACM) and the Cambridge University Museum of Zoology, UK (CUMZ).
Following the authors' previously established system, descriptions are presented as tables supplemented by habitus and wing photographs, genitalia drawings, and additional images of any salient features (Hartop and Brown 2014). Clarification of some of the characters for this system can be found in Hartop et al. (2015), along with the first thirty new species described from the BioSCAN project. With this manuscript, we present a single change to our system: we are removing the "relative posterior setation" character from our description tables. Relative posterior setation is often so close in length that a curved seta can cause discrepancies between two viewers of the same genitalia, so we think it better to let the genitalia illustrations (that clearly show all setae, including those on T6) inform the reader.

Data resources
An annotated list of literature necessary for the identification of Nearctic Megaselia is given in Hartop et al. (2015). A single addition to the Nearctic fauna is found in . Primary keys used for Nearctic Megaselia are those of Borgmeier (Borgmeier 1964, Borgmeier 1966 in his revisions of the North American fauna, although all world literature was considered when identifying these species.
A web-based key for Megaselia is in progress by authors Hartop and Brown. With a group as large and taxonomically difficult as this genus, dichotomous keys are often cumbersome, frustrating, and largely useless to anyone not well versed in the group. The online key that is being created will include a system to rapidly narrow down potential matches based on key characters, and then allow the user to further narrow species choices visually based on high quality habitus and wing photos and clear illustrations of the male genitalia. This key should be available online by the end of 2016.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. baileyae keys to M. pygmaeoides [now considered to be M. berndseni (Schmitz 1919)], to which it is very similar. The most notable difference between these similar species is in the overall lighter coloration of M. baileyae, which has legs that are clearly yellow, not light brown like M. berndseni. This subtle difference in coloration is easily confirmed by looking at the hind femur, which is largely yellow but has a dark brown spot apically. This contrasts with the femur of M. berndseni which, although it does darken slightly apically, is clearly a light, mottled brown throughout. Details of the genitalia also differ between the species although there, too, they are quite similar. In contrast to the brown, rounded left process of the hypandrium found in M. berndseni, M. baileyae has a left lobe that is large, pale and ends abruptly, appearing almost as if it has been broken or cut (Fig. 4a). This lobe is so light, in fact, that you can see parts of the penis-complex through the lobe (visible as darkened areas in Fig. 4a).

Etymology
Named in honor of Kelsey Bailey, BioSCAN Photographer, for her hard work on all our publications and outreach.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. friedrichae keys to couplet 9 where it differs from M. berndseni by the presence of a notopleural cleft and cannot be taken further in the key due to its short costal index (0.34-0.35). If one assumes a margin of error and takes M. friedrichae further in the key despite the short costal index, at couplet 11 it differs from M. globipyga by having a notopleural cleft and from M. brevicostalis by having a very small notopleural cleft (Fig. 2d) versus the large cleft on M. brevicostalis.

Etymology
Named by BioSCAN Phase I Project Manager Dean Pentcheff in honor of Kristin Friedrich whose effective work on behalf of this project brought a wide audience into an appreciation of the richness of urban biodiversity.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. gonzalezorum keys to couplet nine, where its costal index of 0.35-0.36 differentiates it from either the very short (0.33) costal index of M. pygmaeoides [now considered to be M. berndseni (Schmitz 1919)] or the longer costal index (0.38-0.43) for continuing in the key. It also differs from M. berndseni in details of the genitalia (Fig. 4c), and if taken further in the key (by assuming that with more specimens the costal index might sometimes reach 0.38), details of the genitalia including the "nose-like" shape of the epandrium, would quickly differentiate it from species listed further down.

Etymology
Named by BioSCAN employee Lisa Gonzalez in honor of her family; parents Armando and Aida Gonzalez, and sister Rita Gonzalez.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. joanneae keys to couplet 11 where it differs from M. globipyga Borgmeier by lacking the globose genitalia of that species and from M. brevicostalis Wood 1910 by having unequal supraantennals and lacking the large notopleural cleft of that species. It should be noted that in order to key to M. globipyga, you must say that the first costal division is at most as long as second (couplet 10), which is not always accurate (but the alternative, of the first costal division being three-times as long as second, is much less accurate). Otherwise, the species simply fails to key at couplet 10. Within the Los Angeles fauna, this species is quite similar to M. mikejohnsoni, but differs in details of the genitalia, most noticeably with M. joanneae lacking the prominent trio of setae on the posterior of the epandrium (Fig. 83 in Hartop et al. 2015 versus Fig. 4d).

Etymology
Named by Adam and Jenessa Wall in honor of their mother, JoAnne Kay Wall.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. losangelensis keys to couplet 10 where it fails the key by having costal division one greater than two-times, but not as long as three times, costal division two. Assuming a margin of error, if one continues to couplet 11 M. losangelensis differs from M. globipyga by having a cleft, and from M. brevicostalis by having a small cleft (Fig. 2e) as opposed to the large cleft on M. brevicostalis.

Etymology
Named by BioSCAN Phase I Co-Principal Investigator Regina Wetzer in honor of our "City of Angels", the place that made BioSCAN possible.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. phyllissunae keys to couplet 11 where it differs from M. globipyga Borgmeier by lacking the globose genitalia of that species (Fig. 3 in Hartop et al. 2016 versus Fig. 4f) and from M. brevicostalis Wood by having unequal supraantennals and lacking the notopleural cleft of that species.

Etymology
Named in honor of Phyllis Sun for her many contributions to phase I of the BioSCAN project.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. pongsaiae keys to couplet 19 where it keys to M. polyporicola Borgmeier. These species differ in a number of ways, but most easily M. pongsaiae has a long seta at the base of vein R on the wing, and M. polyporicola lacks a seta in this position.

Etymology
Named by Kathy Omura in honor of USC work study student Jean Pongsai for her hard work training and supervising students.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. shatesae keys to couplet 19 where it differs from both M. perplexa Malloch and M. polyporicola Borgmeier by its very long costal setae (0.18 mm). This species is superficially similar to some other species found in Los Angeles, but the combination of dark halters, very long costal setae, 5 alular setae, and a strong, complete subcosta make this species easily separated from any potential lookalike.

Etymology
Named in honor of Tessa Shates whose volunteer work with author Hartop helped in identifying these twelve new species.

Biology
Unknown.

Diagnosis
Male. In the keys of Borgmeier (1964) , this species can be taken through either the group III or group V key, depending on whether one takes the stronger setae on the posterior edge of the anepisternum as strong hairs or weak bristles. In the key to group III, it keys to couplets 13 or 14 (depending on whether the setation on the epandrium is judged to be bristles or bristlelike hairs), and in the key to group V it keys to couplets 6 or 7 (depending on whether the brown palps are considered to be black or yellow). It can easily be differentiated from any of the species found at these couplets by the presence of dense fields of short, blunt spines on f3 basally (Fig. 2g).

Etymology
Named in honor of Ralph Stoakes, the collector of the holotype.

Distribution
Los Angeles, California and Larimer County, Colorado (USA).

Biology
Unknown.

Diagnosis
Male. In the group VII key of Borgmeier (1966), M. studentorum keys to M. inornata Malloch at couplet 41. Megaselia studentorum differs from both M. inornata and most others species by its costal ratio of 2.40: 1.85: 1; costal segment 2 is longer relative to the other two segments than is usual. Megaselia inornata, for instance, has a ratio of 2.78: 1.44: 1 (25: 13: 9), this is more typical in Megaselia.

Etymology
Named in honor of the many USC work study students who continue to do countless hours of work on every aspect of the BioSCAN project. Without them, BioSCAN would not be possible.

Biology
Unknown.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. voluntariorum keys to couplet 19. At this couplet, M. perplexa Malloch is described only from the female and thus ruled out, and M. polyporicola lacks a seta at the base of R on the wing, while M. voluntariorum has a short seta. Compared to other Megaselia from the Los Angeles area with a complete subcosta, M. voluntariorum has a short wing (just over 1mm) and short costal index (0.38).

Etymology
Named in honor of the many people that have, are, and will volunteer for the BioSCAN project. These volunteers are critical to our operation, and have contributed to everything from public outreach in the NHM Nature Lab to specialized work on phorid flies.

Diagnosis
Male. In the group VIII key of Borgmeier (1966), M. wongae keys to M. bovista [now considered to be M. agarici (Lintner, 1895)], from which it can easily be differentiated by the absence of M. agarici's characteristic pale protrusion from the posterior of the epandrium. This species is similar to M. lombardorum Hartop et al. (2015), also from the L.A. region, but differs in having much longer setae on T6, and hypandrial lobes that appeared cupped (Hartop et al. 2015: fig 81 versus Fig. 5f).

Etymology
Named in honor of BioSCAN volunteer Maria Wong whose help identifying Megaselia for BioSCAN Phase I contributed to the discovery of these twelve new species.

Biology
Unknown.

Discussion
The authors continue to stress that the field of species-level taxonomy, especially in urban environments, must continue to grow. Taxonomists and their funding agencies must give time, attention and money to the environments surrounding their towns and cities. Poor quality type material continues to be an obstacle to identification of Megaselia. Dissecting and slide mounting old type specimens has proven to be the only method for any sort of definitive identification. Redescription of historic type material ) will likely prove to be an enormous help to those not working in close proximity to these definitive collections.
dedication to the project; we hope that naming these new species of flies in their honor properly conveys our gratitude. This is contribution number eleven of the BioSCAN project.