Research Article |
Corresponding author: Alessandra Rung ( alessandra_rung@hotmail.com ) Academic editor: Ralph Holzenthal
© 2018 Alessandra Rung.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Rung A (2018) A new species of Aulacigaster Macquart from Zurquí de Moravia, a Costa Rican cloud forest (Diptera, Aulacigastridae). Zoologia 35: 1-6. https://doi.org/10.3897/zoologia.35.e13047
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A new species of Aulacigaster Macquart, 1835 A. zurqui sp. nov., is described from Costa Rica. The new species, which is classified in the plesiomorphica species group following a cladistics analysis, can be separated from all congeners by having a triangular 1st flagellomere and stout body that is uniformly dark-brown to black. An expanded diagnosis of the plesiomorphica group and a modified key to the Neotropical Aulacigaster are provided to accommodate the new species.
Acalyptrate, Aulacigaster zurqui , Central America, Neotropical Region, taxonomy
Two species of the dipteran family Aulacigastridae were collected as part of the ZADBI project (
Aulacigastridae are a small family of acalyptrate flies with two extant genera, Aulacigaster Macquart, 1835, distributed worldwide, and Curiosimusca Rung et al. (
In this paper, I describe a new species of Aulacigaster from Zurquí. Since the genus has already been revised (
The descriptive terminology is from
The following ratios are used in the new species’ description and appended key: 1) scutal ratio: the greatest length of scutum divided by the greatest width of scutum; 2) head ratio: the greatest length of head divided by the greatest height of head.
Specimens are small and study and illustration of the male terminalia required the use of a compound microscope. Photographs were taken with a Nikon Coolpix Ds-Fi1 digital camera through a Nikon SMZ1500 dissecting scope and were assembled using Combine Z. The photographs were enhanced, formatted, and arranged in Adobe Photoshop 7.
Drawings of the male terminalia were traced over pictures assembled using Combine Z, taken using a Nikon Coolpix Ds-Fi1 digital camera through a Nikon Eclipse 600 compound microscope.
The consensus cladogram was drawn in Adobe Illustrator CS6.
A phylogenetic analysis was performed to ascertain where the new species fits the phylogeny provided by
Adding A. zurqui sp. nov., to the matrix of
Strict consensus cladogram obtained from 17 optimum trees, summarizing a cladistics analysis of Aulacigaster. The optimum trees were obtained with a branch-and-bound search, characters unordered and equally weighted, and have 41 steps, consistency-index (CI) 0.78 and retention index (RI) 0.91. The number on the nodes indicate the species-groups as follows: 1. The leucopeza group; 2. The plesiomorphica group; 3. The bromeliae group; 4. The grimaldii group; 5. The femorata group; 6. The minuta group; 7. The ecuadoriensis group.
The strict consensus cladogram of the 17 trees obtained in this analysis (Fig.
Given the results of the cladistics analysis, I have decided to place the new species in the plesiomorphica group, despite some taxonomic ambiguity. Aulacigaster zurqui sp. nov., lacks some of the striking characters that are used to diagnose the plesiomorphica group, such as the lunate silver stripe on the frons, and the characteristic shape of the face, which often bears a facial band. It is possible that, in the future, as new taxa are collected and new character systems are explored, a better placement for A. zurqui sp. nov. will be found.
The new species keys out to couplet 6 in the “Key to the Neotropical Species Groups and Species of Aulacigaster Macquart” (
6 | Frons mostly brown, at most with anterior margin pale, yellowish ( |
7 |
6’ | Frons with anterior 1/2–1/3 often yellowish in ground color (yellowish portion of frons invested with dense microtomentum, silver under certain angles) ( |
16a |
16a | Frons completely black; 1st flagellomere triangular (Figs |
A. zurqui sp. nov. |
17b | Frons with anterior 1/2–1/3 yellowish in ground color; 1st flagellomere rounded | 18 |
Diagnosis of the plesiomorphica group, adapted from
Figs
The plesiomorphica group is distinguished from other species groups by the following combination of characters: Stout, medium-sized flies, body length 2.4–3.5 mm. Coloration and vestiture: Frons often with anterior1/3–1/2 yellowish in ground color, rarely completely black; anterior portion of frons densely microtomentose, often with microtomentum forming a wide, lunate, silvery stripe; facial band often present. Anepisternum mostly dull microtomentose. Abdomen in a few cases with a large, white to yellowish region on syntergite 1+2. Morphology: Head: Head higher than long (head ratio less than 0.9); 1st flagellomere often rounded, rarely triangular; face strongly convex on ventral 2/3, easily visible in lateral view; ocellar seta minute; fronto-orbital setae with posterior seta slightly internal to and almost transversely aligned with anterior seta. Thorax: Subcosta partially fused with vein R1 apically but terminated at costa. Male abdomen and terminalia: Surstylus a short, posteroventral lobe in lateral view; cerci often partially fused; subepandrial sclerite typically forming a single, platelike structure; gonopods often with 2 posterior processes; one bearing 4–5 strong, stout setae.
Neotropical: Belize, Brazil, Costa Rica, Ecuador, Guyana, Panama, Peru, Venezuela.
There is sparse biological information on species of this group. Exemplars that were hand collected in the rainforest were captured on tree trunks and other aerial portions of large Ceiba trees with no visible, wound-exuding sapfluxes (
Species of the plesiomorphica group are distinguished by the presence/absence of a facial band, the shape of the face, and coloration of the legs. In some cases, species can only be identified with certainty by referring to the shape of the surstylus and other structural characters of the male, such as the shape of sternite 5, presence/absence of setae on the hind trochanter and hind tibia.
With the addition of the species described herein, the plesiomorphica group includes 11 species. The group is exclusively Neotropical.
The holotype is mounted on a pin together with three labels as in Fig.
COSTA RICA. Prov. San José. Moravia. Zurquí de Moravia (10°02’58”N, 84°00’57”W).
This species can be separated from all congeners by having a triangular 1st flagellomere and body stout, uniformly dark-brown to black.
Coloration and vestiture: Vertex mostly polished, with a densely microtomentose stripe posterior to ocellar tubercle, with a shiny spot extended from ocellus to eye margin; ocellar tubercle dull microtomentose; frons uniformly microtomentose, silver under certain angles; antenna pale yellow to yellowish, infuscate on dorsal margin; face dark-brown to black, yellowish ventrally; gena mostly yellowish; facial band absent, face entirely glossy; palpus white. Pleural region uniformly black; scutum mostly completely microtomentose; scutellum dull microtomentose; postpronotum yellowish to pale brown, scarcely microtomentose, subshiny; anepisternum mostly dull; katepisternum subshiny to dull; halter mostly white; wings hyaline. Fore coxa brown to black, fore femur brown, apical 1/4 yellow, fore tibia yellowish, fore tarsus yellowish; mid coxa brown to black, mid femur brown or brown to black, apical 1/4 yellow, mid tibia yellowish, mid tarsus mostly yellowish; hind coxa brown, hind femur brown or brown to black, apical 1/4 yellow, hind tibia yellowish, hind tarsus yellowish. Abdomen completely dark brown to black; female abdomen uniformly microtomentose medially.
Body robust, scutal ratio 1.1–1.2. Head: Head higher than long (head ratio 0.7–0.8); 1st flagellomere triangular; face convex, at level of pseudovibrissal seta approximately 2/3 times the width of the longest axis of 1st flagellomere; medial vertical seta 1/2–3/4 length of lateral vertical seta; 3 strong peristomal seta present, following pseudovibrissal seta, posteriormost seta the longest.
Thorax. Acrostichal setae in 2 rows; scutellum strongly raised (angle with scutum less than 135°), approximately triangular, apex rounded, disk of scutellum convex; basal scutellar seta a little less than 1/2 length of posterior seta; wings with one row of stronger setae on Coastal vein.
Male abdomen and terminalia: Surstylus inconspicuous in lateral view in unprepared specimens, folded beneath the epandrium and appearing as a strongly setose postero-ventral region. After preparation, an approximately triangular sheath can be observed in lateral view, bearing 2 long setae, one pre-apical and one apical; subepandrial sclerite with 2 lateral arms on each end, nearly parallel, well sclerotized; anterior dorsal process of gonopod subequal in size to anterior dorsal process; gonopod subrectangular, wider than high in profile, with posteriormost ventral process pointed, at base as wide as base of anterior dorsal process; anteriormost ventral process bearing 5 strong, strong setae; cerci lost during preparation.
Measurements: Body length 2.5 (male)–2.6 (female) mm. Wing (female only) length 3 mm, wing width 1.1 mm.
The specific epithet, zurqui, is the cloud forest where the species was collected. The name is a noun in apposition.
Neotropical: COSTA RICA (San José and Cartago).
Nothing is known about the habits and biology of this new species.
Including this contribution, 14 species of Aulacigaster are known from Costa Rica. The new species, A. zurqui, belongs to the plesiomorphica species-group according to a cladistic analysis and is united with the other species of that group by one homoplasious synapomorphy: the presence of a process on the posterior portion of the gonopod bearing long, strong setae.
This research was partly funded by US National Science Foundation grant DEB 1145890 to B. Brown and A. Borkent.