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Zookeys. 2017; (665): 121–146.
Published online 2017 April 4. doi:  10.3897/zookeys.665.11609
PMCID: PMC5523170

A new species group in the genus Dichaetophora, with descriptions of six new species from the Oriental region (Diptera, Drosophilidae)

Abstract

The genus Dichaetophora Duda comprises 61 described species classified into four species groups: agbo, tenuicauda, acutissima and sinensis. This genus is distributed exclusively in the Old World, and is rich in species in the tropical and subtropical areas of the Oriental, Australasian, and Afrotropical regions. In this paper, a new species group, the trilobita group, is established for six new species discovered from the Oriental region. The delimitation of these species is firstly performed in light of morphology and further with the aid of DNA sequences of the mitochondrial COI and COII (cytochrome c oxydase, subunits I and II, respectively) genes, considering also their respective geographical origins. Then, the new species (trilobita Yang & Gao, sp. n., heterochroma Yang & Gao, sp. n., flatosternata Yang & Gao, sp. n., borneoensis Yang & Gao, sp. n., javaensis Yang & Gao, sp. n., and sumatraensis Yang & Gao, sp. n.) are described, and a key, based on not only morphological but also molecular information, is provided.

Keywords: DNA barcoding, geographical isolation, mitochondrial DNA, taxonomy

Introduction

The genus Dichaetophora is widely distributed in the Old World, especially its tropical and subtropical regions. This genus was originally established by Duda (1940) as a subgenus in the genus Drosophila Fallén, for the Seychellean species, Drosophila aberrans Lamb. Burla (1954) supplemented three African new species (including an informally named one) into Dichaetophora and revised its diagnostic characters. Since then, the species composition of this subgenus [genus since Grimaldi’s (1990) upgrading] had been altered time and again in relation to the genus Nesiodrosophila Wheeler & Takada (see Hu and Toda 2002). Hu and Toda (2002) examined the relationships among the genera Dichaetophora, Nesiodrosophila, the Lordiphosa tenuicauda species group and some presumably related genera by a cladistic analysis of morphological characters. As a result, the revised and enlarged genus Dichaetophora was proposed and subdivided into three species groups, i.e., the agbo, acutissima and tenuicauda groups. Hu and Toda (2005) established the forth (sinensis) species group for four species newly described from China, raising the number of known Dichaetophora species to 61. In the present study, a new species group is established for six new species of Dichaetophora recently discovered from the Oriental region, the trilobita group. The species delimitation is based on not only morphological but also geographical and DNA sequence data. A key to the six species is provided.

Materials and methods

Specimens

A summary of the specimens employed in the present study is shown in Table Table1.1. The flies were mostly captured by net sweeping on herbs growing along watersides in open forests or at forest edges. Specimens were preserved in either 70% (after fixing with Kahle’s solution for morphological observation) or 100% ethanol (for DNA sequencing).

Table 1.
Summary of new species and specimens of Dichaetophora employed in the present study.

Species delimitation

The specimens were first identified as of Dichaetophora in light of morphology referring to Hu and Toda’s (2005) diagnosis of this genus. Then, they were examined for external morphology, morphometric characters and detailed structures of some dissected organs by the same methods as in Li et al. (2014), and sorted into morpho-species. For each of these morpho-species, representative specimens suitable for DNA sequencing were selected, considering also the numbers, geographical origins, and genders of available specimens. For each of the selected specimens, the total DNA was extracted from a hind-leg (usually the right one) or small piece(s) of abdominal tissue picked from the dissection cut of terminalia, using the TIANamp® Genomic DNA Kit. DNA sequences of the 658-bp barcoding region of the mitochondrial COI (cytochrome c oxydase subunit I) gene were then amplified and sequenced with the Folmer primers (Folmer et al. 1994; Table Table2),2), using the same PCR cycle program as in Li et al. (2014). In addition, we determined the DNA sequences of the whole 688-bp region of the mitochondrial COII (cytochrome c oxidase subunit II) gene, using the primer pair designed by Simon et al. (1994; Table Table2),2), with the same PCR cycle program used in Gao et al. (2007). The sequences obtained were edited in the SeqMan module of the DNAStar package, version 7.1.0 (DNAStar, Inc., Madison, WI), and aligned in MEGA7 (Kumar et al. 2016). We performed a tree-based DNA barcoding with the COI and COII sequences, respectively, with Bayesian trees constructed using MrBayes 3.1 (Ronquist and Huelsenbeck 2003). For this, the sequence alignment of each gene was partitioned into two subsets (codon positions 1 plus 2, and codon position 3), with choice of substitution models justified via model testing (Srivathsana and Meier 2012) in MEGA7 using the Bayesian Information Criterion. In Bayesian inference, sampling frequency was set as every 1000 generations, and numbers of chains = 4. Two analyses were run simultaneously till the average deviation of split frequencies fell well below 0.01. Therefore, in all analyses, full runs of 5,000,000 generations were performed. In each analysis, 1000 early-phase samples were discarded as burn-in for each run, yielding a total of 8,002 trees to construct a 50% majority consensus tree with nodes characterized by posterior probability (PP). We then summarized the information of intra- and interspecific p-distances calculated without data partitioning. The morpho-species were then reconsidered by integrating information from the morphology, the geographical distribution (Fig. (Fig.1)1) and DNA barcodes.

Figure 1.
Geographical distribution of the Dichaetophora trilobita species group. See the text for the detailed information of the collection sites on the map.
Table 2.
Primer sequences for PCR/sequencing.

Descriptions

In species illustration, a DinoLite® Digital Eyepiece Camera was used to microphotograph some organs for representative specimens. McAlpine (1981) was followed for the morphological terminology, and Zhang and Toda (1992) for the definitions of measurements and indices. The examined specimens are deposited in the following institutes:

UMKL Zoological Museum, Institute of Biological Science, University of Malaya, Kuala Lumpur, Malaysia

KPSP Kinabalu Park, Sabah Parks, Sabah, Malaysia

ZSM Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia

MZB Museum Zoologicum Bogoriense, Bogor, Indonesia

SEHU Systematic Entomology, The Hokkaido University Museum, Hokkaido University, Sapporo, Japan

KIZ Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China

Results

Species delimitation

The specimens examined were first sorted into four morpho-species (Table (Table1).1). We got 23 COI and 26 COII sequences. The GenBank accession numbers are KY809802−KY809824 for the COI, and KY809825−KY809850 for the COII sequences. Table Table33 shows the result of model selection. The COI and COII Bayesian trees (both unrooted) are shown in Fig. Fig.2.2. Each of the morpho-species sp.K1 [from Peninsular Malaysia and Borneo (Sarawak and Sabah)], sp.K2 (Sabah) and sp.K2-like (Xishuangbanna, Yunnan, southwestern China) was strongly suggested to be monophyletic. Sp.K2 and sp.K2-like formed a well-supported clade (PPs = 1.00 in both of the COI and COII trees, respectively). Sp.K1, which is sympatric with sp.K2 in Sabah, formed a clade independent from the clade of sp.K2+sp.K2-like. Thus, these three morpho-species, spp.K1, K2 and K2-like, were recognized as independent species, i.e., trilobita sp. n., heterochroma sp. n. and flatosternata sp. n., respectively.

Figure 2.
Bayeisan trees deduced with COI (left) and COII (right) gene sequences. Label of each operational taxonomic unit (OUT) is given in the format of “voucher number (sex)”. Numbers beside nodes are posterior probabilities (when ≥ 0.90). ...
Table 3.
Models selected for sequence subsets a.

Specimens of the morpho-species sp.K3 clustered into three more or less diverged, allopatric lineages each endemic to Borneo (Sabah), West Java, or Sumatra (Jambi) in the COII tree (PP = 1.00 for each lineage). While the former two lineages were recovered in the COI tree (PPs = 0.99 and 1.00, respectively), the last one was not supported in this tree. Table Table44 shows the summary of intra- and interspecific p-distances for the six putative species. The interspecific mean p-distances for COI sequences among these three lineages of sp.K3 varied from 0.0349 (Java vs. Sumatra) to 0.0751 (Borneo vs. Java), coinciding with the smallest interspecifc distance variability of 5.9±4.1% (uncorrected divergence) for COI sequences in Diptera (Meier et al. 2008) and being larger than their intraspecific mean distances ranging from 0.0045 (Java) to 0.0185 (Sumatra). However, these lineages are morphologically very similar, differing from each other in so few morphological characters that it is hard to distinguish between them (see descriptions). On the other hand, comparison of the COI and COII nucleotide sequences among these lineages has revealed that there are fixed, lineage-specific nucleotides at more than one sites, where nucleotides remain unchanged in the other three species (Table (Table5).5). Such sites can therefore be used as pure molecular diagnostic characters (Sarkar et al. 2002, DeSalle et al., 2005) for respective lineages. Taking into account their geographically isolated situations as well, we regard these lineages as three independent, cryptic species, i.e., borneoensis sp. n., javaensis sp. n. and sumatraensis sp. n.

Table 4.
Summary of intra- and interspecific p-distances.
Table 5.
Selected diagnostic nucleotide sites for each of borneoensis sp. n., javaensis sp. n., and sumatraensis sp. n. in the COI and COII sequences. For nonsynonymous nucleotide substitutions, corresponding amino acid status are given in parentheses. Hyphens ...

Taxonomy

In the following descriptions of the new species group and new species, and also the key to species, some figures in Hu and Toda (2005) are referred to, with their original numbers given in double quotation marks.

The six new species to be described here certainly belong to the genus Dichaetophora, according to its diagnosis revised by Hu and Toda (2002): cibarium only slightly protruded at anterolateral corners; oviscapt with apical ovisensillum robust and largest, distinguishable from the others; basal lobe of palpus without setulae; hypopharyngeal apodeme expanded anteriorly; labellum with less than six pseudotracheae; ocellar setae outside triangle made by ocelli. Within Dichaetophora, they should be related to the sinensis group, sharing some characters regarded by Hu and Toda (2005) as diagnostic for the latter group: very large ocellar triangle (“Fig. 1”); large number (≥ 40 per side) of medial sensilla on cibarium (“Fig. 6”); ventral surface of prementum forming discrete bump (Fig. 4E, J, O, T, Y, D’; “Figs 8–11A”). However, they lack some other diagnostic characters of the sinensis group: foreleg tibia with stout apical seta distinctly thicker than preapical dorsal seta (“Fig. 2”); aedeagus apically with membranous, trumpet-like dilation (“Figs 8F, 9–11D”). And, three of them, trilobita sp. n., heterochroma sp. n. and flatosternata sp. n., share a particular character, i.e., 4 pseudotracheae varying in thickness (“Fig. 4”), with the agbo species group (Hu and Toda 2005). Furthermore, all the six new species possess some characters specific to themselves: there are two or three prominent setae on the anteromedial portion of cercus (Figs (Figs5510B); the cercus is strongly sclerotized along the anterior to caudoventral margin, which seems to be homologous with the strong sclerotization of the caudoventral portion of cercus seen in three species of the sinensis group (“Figs 9–11B”), but the sclerotized plates of cerci are fused with each other caudoventrally and to epandrium anteroventrally (Figs (Figs5510A,B). Based on these morphological characteristics, we establish a new species group, the trilobita species group, in Dichaetophora, for the six new species.

Figure 4.
Head (anterior view), postocciput, palpus, and prementum (ventral and lateral view, respectively). A−E Dichaetophora tirlobita sp. n. (#03877) F−J D. heterochroma sp. n. (#03879) K−O D. flatosternata sp. n. (#04172) P−T ...
Figure 5.
Dichaetophora trilobita sp. n. (A−H #03877 I−K paratype #03878). A Periphallic organs (posterior view), with red arrow indicating the median process on the caudoventral bridge of cerci B periphallic organs (posterolateral view), with ...
Figure 10.
Dichaetophora sumatraensis sp. n. (A−H #03890 I−K paratype #03891). A, B Periphallic organs (posterior and posterolateral view, respectively) C surstyli and ventral portions of cerci D tenth sternite (posteroventral view) E−G ...

Dichaetophora trilobita species group

Diagnosis. Cercus anteromedially with two or three prominent setae on anteromedial portion, strongly sclerotized along anterior to caudoventral margin; sclerotized plates of curci fused with each other caudoventrally and to epandrium anteroventrally (Figs (Figs5510A, B).

Common characters. Head (Fig. (Fig.4):4): Eye red, with dense interfacetal setulae; longest axis nearly orthogonal to body axis. Frons, face, gena, occiput, postgena and clypeus glossy black; facial carina blackish brown. Ocellar very large, nearly rectangular, anteriorly reaching to ptilinal fissure; frontal vitta narrow, without interfrontal setulae. Pedicel grayish brown; arista with 6−7 dorsal and 2−3 ventral branches in addition to terminal fork. Subvibrissal seta not differentiated, as small as other orals. Palpus slender, apically with one prominent ventral and one subprominent dorsal setae. Cibarium not thickened on anterior margin, with four anterior sensilla arranged square; dorsal wall pear-shaped, anteriorly somewhat dilated in dorsal view and strongly convex in lateral view; anterior portion of hypopharynx shorter than posterior tubular portion. Prementum with 5–6 (one proximal, one central, 2–3 lateral, and one distal longest) pairs of setae. Labellum with four pseudotracheae per side.

Thorax (Fig. 3A, B, E, F, H, I, K, L, N, O, Q, R): Scutum and scutellum matt, entirely black. Postpronotum, thoracic pleura and notopleural portion blackish brown to black. Acrostichal setulae in six rows. Mid katepisternal seta minute, indistinguishable from a few underneath others.

Figure 3.
Left lateral habitus, head and thorax (dorsal view), wing (left, ventral view), and abdomen (dorsal view). A−D Dichaetophora tirlobita sp. n. (#03877) E−G D. heterochroma sp. n. (#03879) H−J D. flatosternata sp. n. (#04172) K−M ...

Legs (Fig. 3A, E, H, K, N, Q): Preapical dorsal setae present on all tibiae; foreleg apical seta as thick as preapical dorsal one. Foreleg first tarsomere slightly shorter than total length of four succeeding tarsomeres; all tarsi narrowing distally, with small, apical claws.

Abdomen (Fig. 3A, D, E, H, K, N, Q): Tergites blackish brown. Sternites grayish yellow.

Male terminalia (Figs 5A–H, 6A–I, 7A–I, 8A–G, 9A–G, 10A–H): Surstylus basally narrowly fused to epandrium, with 8–10 peg-like prensisetae on caudal margin. Hypandrium pale brown, submedially with a pair of small, pubescent lobes apically bearing short paramedian seta. Paramere broad, plate-like, not pubescent, partly fused to hypandrium, articulated with aedeagus, with two sensilla. Aedeagus apically without pale, membranous trumpet-like dilation; basal processes absent; aedeagal guide present, apically fused to hypandrium; apodeme as long as aedeagus.

Figure 6.
Dichaetophora heterochroma sp. n. (A−I #03879 J−L paratype #03881). A, B Periphallic organs (posterior and posterolateral view, respectively) C surstyli and cerci, with red arrow indicating the caudoventral bridge of cerci D, E tenth ...
Figure 7.
Dichaetophora flatosternata sp. n. (A−I #04172 J−L paratype #04177). A, B Periphallic organs (posterior and posterolateral view, respectively) C surstyli and cerci D, E tenth sternite (ventral and anterior view, respectively) F−H ...
Figure 8.
Dichaetophora borneoensis sp. n. (A−G #03895 H−J paratype #03894). A, B Periphallic organs (posterior and posterolateral view, respectively) C surstyli and cerci, with red arrow indicating the median, elongated process on the caudoventral ...
Figure 9.
Dichaetophora javaensis sp. n. (A−G #03892 H−J paratype #03888). A, B Periphallic organs (posterior and posterolateral view, respectively) C surstyli and ventral portions of cerci D−F phallic organs (ventral, ventrolateral and ...

Female terminalia (Figs 5I–K, 6J–L, 7J–L, 8H–J, 9H–J, 10I–K): Oviscapt valve yellowish brown, apically pointed and slightly bent outward, with four (three dorsal, one ventral) subterminal, trichoid ovisensilla.

Included species. trilobita Yang & Gao, sp. n., heterochroma Yang & Gao, sp. n., flatosternata Yang & Gao, sp. n., borneoensis Yang & Gao, sp. n., javaensis Yang & Gao, sp. n., and sumatraensis Yang & Gao, sp. n.

Key to the species

In the following key, not only morphological characters but also the selected pure diagnostic nucleotide sites of COI and COII sequences (Table (Table5)5) are used to identify the three cryptic species, borneoensis sp. n., javaensis sp. n. and sumatraensis sp. n.

1Postocellar setae absent; ocellar plate granulose; posteromost pseudotrachea of labellum thicker than the others; mid-leg first tarsomere with one subproximal and one apical, short, blackish brown spines, and hindleg first tarsomere with one apical, short spine; prensisetae on surstylus apically blunt (Figs (Figs557C); cercus with three prominent setae on anteromedial portion (Figs (Figs557B); sclerotized, caudoventral bridge of cerci with a pair of lateral, broad, apically rounded lobes (Figs (Figs5A,5A, ,6C,6C, ,7C);7C); aedeagus apically hooked (Figs (Figs5G,5G, ,6H,6H, ,7H);7H); spermathecal capsule pale brown, spherical, slightly broader than long, without apical indentation (Figs (Figs5K,5K, ,6L,6L, ,7L7L) 2
Postocellar setae present (Fig. (Fig.4W);4W); ocellar plate smooth, glossy; posteromost pseudotrachea of labellum as thick as the others; first tarsomeres of mid- and hindlegs without short, blackish brown spines; prensisetae on surstylus apically somewhat pointed (Figs (Figs8810C); cercus with two prominent setae on anteromedial portion (Figs (Figs8810B); sclerotized, caudoventral bridge of cerci without lateral lobes (Figs (Figs8810C); aedeagus apically not hooked (Figs (Figs8F,8F, ,9F,9F, 10G); spermathecal capsule small, less sclerotized, with apical indentation (Figs (Figs8J,8J, ,9J,9J, 10K) 4
2Wing nearly entirely, lightly fuscous, without distinct cloud (Fig. (Fig.3C);3C); sclerotized, caudoventral bridge of cerci with small, narrow, apically pointed, median process (Fig. (Fig.5A);5A); aedeagus apically curved, hook-like, and finely wrinkled all over, subapically with numerous, coarse serrations, submedially not swollen dorsally (Fig. (Fig.5G);5G); spermatheca without distinct introvert (Fig. (Fig.5K5K) Di. trilobita Yang & Gao, sp. n.
Wing largely clouded, except for central pale patch around dm-cu vein and periphery (Fig. 3G,J); sclerotized, caudoventral bridge of cerci without median process (Figs (Figs6C,6C, ,7C);7C); aedeagus apically bearing a pair of strongly recurved, smooth hooks, subapically densely spinose, submedially swollen dorsally (Figs 6F,H, 7F,H); spermatheca with introvert 1/5–1/4 as deep as capsule height (Figs (Figs6L,6L, ,7L7L) 3
3Dorsolateral tentorial apodemes nearly parallel in basal half but strongly divergent in distal half (Fig. (Fig.4H);4H); tenth sternite mediolaterally with a pair of round depressions (seen in anterior view; Fig. Fig.6E);6E); oviscapt valve 2/5 as broad as long (Fig. (Fig.6J6J) Di. heterochroma Yang & Gao, sp. n.
Dorsolateral tentorial apodemes slightly divergent in basal half but strongly divergent in distal half (Fig. (Fig.4M);4M); tenth sternite nearly flat (Fig. (Fig.7E);7E); oviscapt valve half as broad as long (Fig. (Fig.7J7J) Di. flatosternata , Yang & Gao, sp. n.
4Spermathecal capsule somewhat cylindrical, apically flat; introvert 7/10 as deep as capsule height (Fig. (Fig.8J);8J); COI = C, C, T, T, C and C at sites 235, 499, 519, 532, 541 and 544, respectively; COII = G, T, C, A and G at sites 309, 389, 441, 513 and 636, respectively (Table (Table55) Di. borneoensis Yang & Gao, sp. n.
Spermathecal capsule somewhat dome-shaped, apically roundish; introvert 2/5 as deep as capsule height (Figs (Figs9J,9J, 10K); COI = T, T, C, A, T and T at sites 235, 499, 519, 532, 541 and 544, respectively; COII = A, C, T, G and A at sites 309, 389, 441, 513 and 636, respectively (Table (Table55) 5
5Hypandrium sparsely pubescent in small, medial patch on caudolateral plate (Fig. (Fig.9G);9G); COI = C and T at sites 142 and 205, respectively; COII = T, C, C, C, G and C at sites 18, 69, 270, 303, 381 and 393, respectively (Table (Table55) Di. javaensis Yang & Gao, sp. n.
Hypandrium without pubescence on caudolateral plate (Fig. 10H); COI = T and C at sites 142 and 205, respectively; COII = C, T, T, T, A and T at sites 18, 69, 270, 303, 381 and 393, respectively (Table (Table55) Di. sumatraensis Yang & Gao, sp. n.

Description of new species

The characters described above for the genus, the species group, and the key are not referred to in the following descriptions.

Dichaetophora trilobita

Keywords: Animalia, ORDO, FAMILIA

Yang & Gao sp. n.

http://zoobank.org/BAF11C36-EB50-4E98-A8A1-537AE7AD715A

Figs 3A–D , 4A–E , 5

Type material.

Holotype ♂ (#03877): MALAYSIA: Ulu Gombak, Selangor, 8.xii.2013, MJ Toda (UMKL).

Paratypes: same data as holotype (1♀: #03878, UMKL); Kubah, Sarawak, Malaysia, 19.i.1999 (1♂, 1♀, SEHU); Park Headquarters, Mt. Kinabalu, Sabah, Malaysia, 11.iii.2008, MJ Toda (1♂: #03876, KIZ); Poring, Mt. Kinabalu, Sabah, Malaysia, 20.iii.2008, MJ Toda (1♀: #03882, KIZ).

Diagnosis.

Postocellar setae absent; wing without distinct cloud (Fig. (Fig.3C);3C); sclerotized, caudoventral bridge of cerci with small, narrow, apically pointed, median process and a pair of lateral, broad, apically rounded lobes (Fig. (Fig.5A);5A); aedeagus apically curved, hook-like, and finely wrinkled all over, subapically with numerous, coarse serrations, submedially not swollen dorsally (Fig. (Fig.5G);5G); spermatheca without distinct introvert (Fig. (Fig.5K5K).

Description.

Head (Figs 3A, B, 4A–E): First flagellomere grayish yellow. Dorsolateral tentorial apodemes slightly divergent in basal 2/5 but strongly divergent in distal 3/5; supracervical setae 21−23 per side; postocular setae 22–23 per side. Palpus with two subprominent, lateromedial setae. Cibarium with ca. 70 medial and ca. 8 posterior sensilla per side.

Wings (Fig. (Fig.3C):3C): Veins pale brown to brown. Halter pale gray; stem darker.

Legs (Fig. (Fig.3A)3A) pale grayish yellow; mid- and hindleg femora distally, foreleg tibia and tarsi proximally to medially darker. Apical setae present on all tibiae; hindleg apical seta short, stout. Mid-leg first tarsomere longer than total length of four succeeding tarsomeres; hindleg first tarsomere as long as total length of four succeeding tarsomeres.

Male terminalia (Fig. 5A–H): Epandrium pubescent except for anterior to ventral margin, with 1–3 dorsal and ca. 22 ventral, long setae per side. Surstylus with peg-like prensisetae in sinuate row on caudal margin, 2–5 apically pointed spines and medial patch of pubescence on outer surface and ca. 26 apically pointed spines (ventral ones shorter, thicker and straight, but medial to dorsal ones trichoid and recurved) on inner, caudal portion. Tenth sternite nearly flat. Cercus pubescent except for caudal margin, with 11–12 long setae near dorsal to posterior margin and 7–11 short setae in cluster on ventral portion of sclerotized marginal plate. Paramere with sensilla apically.

Female terminalia (Fig. 5I–K): Oviscapt valve dorsomedially narrowly extended, with 3−4 lateral and 9−13 marginal, peg-like ovisensilla.

Measurements (in mm): BL (straight distance from anterior edge of pedicel to tip of abdomen) = 2.03 in holotype (1♂ paratype: 2.00; range in 2♀ paratypes: 2.00−2.21), ThL (distance from anterior notal margin to apex of scutellum) = 0.84 (0.82; 0.86−0.88), WL (distance from humeral cross vein to wing apex) = 1.62 (1.69; 1.72−1.73), WW (maximum wing width) = 0.71 (0.72; 0.74−0.79).

Indices: FW/HW (frontal width/head width) = 0.53 (range in 1♂, 2♀, or less if noted, paratypes: 0.38−0.50), ch/o (maximum width of gena/maximum diameter of eye) = 0.18 (0.19−0.26), prorb (proclinate orbital seta/posterior reclinate orbital seta in length) = 0.72 (2♀: 0.71−0.80), rcorb (anterior reclinate orbital seta/posterior reclinate orbital seta in length) = 0.30 (2♀: 0.31−0.33), orbito (distance between proclinate and posterior reclinate orbital setae / distance between inner vertical and posterior reclinate orbital setae) = 0.60 (0.58−0.68), dcl (anterior dorsocentral seta/posterior dorsocentral seta in length) = 0.78 (2♀: 0.64−0.74), sctl (basal scutellar seta/apical scutellar seta in length) = 0.67 (1♀: 0.60), sterno (anterior katepisternal seta/posterior katepisternal seta in length) = 0.51 (0.57−0.60), dcp (distance between ipsilateral dorsocentral setae/distance between anterior dorsocentral setae) = 0.49 (0.53−0.60), sctlp (distance between ipsilateral scutellar setae/distance between apical scutellar setae) = 0.79 (0.68−0.77), C (2nd costal section between subcostal break and R2+3/3rd costal section between R2+3 and R4+5) = 1.57 (1.35−1.53), 4c (3rd costal section between R2+3 and R4+5/M1 between r-m and dm-cu) = 1.54 (1.46−1.66), 4v (M1 between dm-cu and wing margin/M1 between r-m and dm-cu) = 2.19 (2.11−2.33), 5x (CuA1 between dm-cu and wing margin/dm-cu between M1 and CuA1) = 2.19 (2.00−2.38), ac (3rd costal section between R2+3 and R4+5/distance between distal ends of R4+5 and M1) = 3.58 (3.66−3.76), M (CuA1 between dm-cu and wing margin/M1 between r-m and dm-cu) = 0.72 (0.66−0.70), C3F (length of heavy setation in 3rd costal section/length of 3rd costal section) = 0.70 (0.66−0.68).

Etymology.

Referring to the trilobed, caudoventral bridge of cercal sclerotized plates.

Distribution.

Malaysia (Peninsular Malaysia, Sarawak, Sabah).

Dichaetophora heterochroma

Keywords: Animalia, ORDO, FAMILIA

Yang & Gao sp. n.

http://zoobank.org/4C4A707B-EFFC-474D-A485-381B40B879E8

Figs 3E–G , 4F–J , 6

Type material.

Holotype ♂ (#03879): MALAYSIA: Poring, Mt. Kinabalu, Sabah, 20.iii.2008, MJ Toda (KPSP).

Paratypes: same data as holotype (1♂, 1♀: #03880, #03881, KIZ; 1♂, SEHU); same data as holotype except for 13.iii.2008 (1♀: #03883, KIZ); same data as holotype except for 19.iii.2008 (1♂, SEHU); same data as holotype except for 3.x.1999 (1♂, SEHU); Mahua, Crocker Range, Sabah, Malaysia, 14.x.1999, MJ Toda (1♀, KPSP; 2♀, SEHU); Ulu Senagang, Crocker Range, Sabah, Malaysia, 18.x.1999, MJ Toda (1♂, 2♀: #03884–3886, ZSM).

Diagnosis.

Wing largely clouded, except for central pale patch around dm-cu vein and periphery (Fig. (Fig.3G);3G); dorsolateral tentorial apodemes nearly parallel in basal half (Fig. (Fig.4H);4H); tenth sternite mediolaterally with a pair of round depressions (seen in anterior view; Fig. Fig.6E);6E); oviscapt valve 2/5 as broad as long (Fig. (Fig.6J6J).

Description.

Head (Figs 3E, F, 4F–J): First flagellomere grayish yellow. Supracervical setae 15−22 per side; postocular setae 17–21 per side. Palpus with one subprominent lateromedial seta. Cibarium with 78–79 medial and ca. 8 posterior sensilla per side.

Wings (Fig. (Fig.3G):3G): Veins pale brown to dark brown, but pale within central pale patch. Halter pale gray; stem darker.

Legs (Fig. (Fig.3E)3E) pale grayish yellow; foreleg coxa, tibia and tarsus, except for fifth tarsomere, dark brown. Mid-leg first tarsomere longer than total length of four succeeding tarsomeres; hindleg first tarsomere as long as total length of four succeeding tarsomeres.

Male terminalia (Fig. 6A–I): Epandrium pubescent except for anterior portion, with 3–4 dorsal and 9–12 ventral, long setae per side. Surstylus with prensisetae in nearly straight row on caudal margin, 2–4 apically pointed spines but no pubescence on outer surface and ca. 20 apically pointed, recurved spines on inner, caudal portion. Cercus pubescent except for caudal margin, with 6–12 long setae near dorsal to posterior margin and 6–7 short setae in cluster on ventral portion of sclerotized marginal plate. Paramere with sensilla subapically.

Female terminalia (Fig. 6J–L): Oviscapt valve with ca. five lateral and 12–14 marginal, peg-like ovisensilla. Introvert of spermathecal capsule 1/5 as deep as capsule height.

Measurements (in mm): BL = 2.18 in holotype (range in 2♂ paratypes: 1.99 –2.21; range in 4♀ paratypes: 2.31–2.77), ThL = 0.79 (0.81–0.85; 0.92 –0.97), WL = 1.64 (1.60–1.64; 1.80 –2.30), WW = 0.68 (0.69–0.70; 0.75 –0.97).

Indices: FW/HW = 0.59 (2♂, 4♀, or less if noted, paratypes: 0.50–0.54), ch/o = 0.20 (0.25–0.28), prorb = 0.74 (2♂, 1♀: 0.76–0.87), rcorb = 0.29 (2♂, 3♀: 0.31–0.36), orbito = 0.54 (0.48–0.76), dcl = 0.71 (1♂, 2♀: 0.60–0.73), sctl = n/a (1♂, 3♀: 0.88–0.94), sterno = 0.54 (0.50–0.61), dcp = 0.55 (0.55–0.65), sctlp = 0.62 (0.75–0.95), C = 1.69 (1.99–2.08), 4c = 1.54 (1.41–1.54), 4v = 2.50 (2.28 –2.51), 5x = 1.79 (1.25–1.56), ac = 2.86 (2.38–3.09), M = 0.70 (0.62–0.64), C3F = 0.78 (0.73–0.87).

Etymology.

Referring to the heterochromatic legs.

Distribution.

Malaysia (Sabah).

Dichaetophora flatosternata

Keywords: Animalia, ORDO, FAMILIA

Yang & Gao sp. n.

http://zoobank.org/2BAD2A68-B183-4781-AF74-A103DEF614F4

Figs 3H–J , 4K–O , 7

Type material.

Holotype. ♂ (#04172), CHINA: Mengyuan Substation, Mengla Station, Xishuangbanna National Nature Reserve, Guanlei, Mengla, Xishuangbanna, Yunnan, 14–15.xi.2012, JJ Gao (KIZ).

Paratypes: same data as holotype (5♂, 2♀: #04171, #04173–4178, KIZ, SEHU).

Diagnosis.

Wing largely clouded, except for central pale patch around dm-cu vein and periphery (Fig. (Fig.3J);3J); dorsolateral tentorial apodemes slightly divergent in basal half (Fig. (Fig.4M);4M); tenth sternite nearly flat (Fig. (Fig.7E);7E); oviscapt valve half as broad as long (Fig. (Fig.7J7J).

Description.

Head (Figs 3H, I, 4K–O): First flagellomere grayish yellow. Supercervical setae 17−18 per side; postocular setae 20–22 per side. Palpus with one subprominent lateromedial seta. Cibarium with 77–79 medial and ca. 10 posterior sensilla per side.

Wings (Fig. (Fig.3J):3J): Veins pale brown to dark brown, but pale within central pale patch. Halter pale gray; stem darker.

Legs (Fig. (Fig.3H)3H) pale grayish yellow; foreleg tibia and tarsus, mid-leg femur and distal portion of hindleg femur darker. Hindleg tibia lacking apical seta. Mid-leg first tarsomere longer than total length of four succeeding tarsomeres; hindleg first tarsomere as long as total length of four succeeding tarsomeres.

Male terminalia (Fig. 7A–I): Epandrium pubescent except for anterior portion, with ca. three dorsal and 10–11 ventral, long setae per side. Surstylus with prensisetae in slightly concave row on caudal margin, 2–3 apically pointed spines but no pubescence on outer surface and ca. 16 apically pointed, recurved spines on inner, caudal portion. Cercus pubescent except for caudal margin, with 10–13 long setae near dorsal to posterior margin and 8–10 short setae in cluster on ventral portion of sclerotized marginal plate. Paramere with sensilla subapically.

Female terminalia (Fig. 7J–L): Oviscapt valve with ca. four lateral and 12–13 marginal, peg-like ovisensilla. Introvert of spermathecal capsule 1/4 as deep as capsule height.

Measurements (in mm): BL = 2.10 in holotype (range in 5♂ paratype: 2.08–2.32; range in 2♀ paratypes: 2.21 –2.31), ThL = 0.87 (0.83–0.88; 0.83 –0.93), WL = 1.78 (1.67–1.81; 1.71 –1.81), WW = 0.81 (1.79–1.82; 0.81–0.83).

Indices: FW/HW = 0.54 (5♂, 2♀, or less if noted, paratypes: 0.49–0.54), ch/o = 0.23 (0.27–0.29), prorb = 0.71 (0.79–0.87), rcorb = n/a (0.33–0.39), orbito = 0.54 (0.55–0.74), dcl = 0.64 (0.62–0.78), sctl = n/a (4♂, 2♀: 0.89–0.97), sterno = 0.65 (0.54–0.63), dcp = 0.55 (0.54–0.62), sctlp = 0.73 (0.74–0.80), C = 1.53 (1.63–1.71), 4c = 1.45 (1.22–1.36), 4v = 1.96 (1.42–1.60), 5x = 1.89 (1.79–1.94), ac = 3.04 (2.53–2.76), M = 0.64 (0.57–0.64), C3F = 0.69 (0.62–0.71).

Etymology.

Referring to the flat male tenth sternite.

Distribution.

China (Yunnan).

Dichaetophora borneoensis

Keywords: Animalia, ORDO, FAMILIA

Yang & Gao sp. n.

http://zoobank.org/20778512-6C3C-4BC2-99A6-83A02C6FBCC4

Figs 3K–M , 4P–T , 8

Type material.

Holotype ♂ (#03895), MALAYSIA: Park Headquarters, Mt. Kinabalu, Sabah, 16.viii.2011, K Akutsu (KPSP).

Paratypes: same data as holotype except for 17.viii.2011 (1♂: #03896, KIZ); same data as holotype except for 11.iii.2008 (2♀: #03893, #03894, KIZ); same data as holotype except for 2.i.1999, MJ Toda (8♂, 2♀, SEHU; 1♀, KPSP; 1♀, ZSM); Poring, Mt. Kinabalu, Sabah, Malaysia, 28.xii.1998 (1♂); Mahua, Crocker Range, Sabah, Malaysia, 14.x.1999, MJ Toda (1♂, ZSM).

Diagnosis.

Postocellar setae present; spermathecal capsule somewhat cylindrical, apically flat; introvert 7/10 as deep as capsule height (Fig. (Fig.8J);8J); COI = C, C, T, T, C and C at sites 235, 499, 519, 532, 541 and 544, respectively; COII = G, T, C, A and G at sites 309, 389, 441, 513 and 636, respectively (Table (Table55).

Description.

Head (Figs 3K, L, 4P–T): First flagellomere grayish brown. Dorsolateral tentorial apodemes slightly divergent in basal 2/5 but strongly divergent in distal 3/5; supracervical setae 21−25 per side; postocular setae 23−24 per side. Palpus with one subprominent, lateromedial seta. Cibarium with ca. 80 medial and 9−12 posterior sensilla per side.

Wings (Fig. (Fig.3M)3M) slightly fuscous; veins yellowish brown to brown. Halter and stem gray.

Legs (Fig. (Fig.3K):3K): All femora blackish brown; foreleg coxa, tibia and tarsus (except 5th tarsomere) grayish brown; rest grayish yellow. Apical setae present on foreleg and mid-leg tibiae. Mid-leg first tarsomere as long as total length of four succeeding tarsomeres; hindleg first tarsomere longer than total length of four succeeding tarsomeres.

Male terminalia (Fig. 8A–G): Epandrium pubescent except for anterior margin, with 1–2 dorsal and 7–11 ventral, long setae per side. Surstylus with 1–3 short spines and medial patch of pubescence on outer surface and 7–10 recurved spines on inner, caudal portion. Tenth sternite lingulate, slightly curved. Cercus pubescent except for dorsal to caudal margin, with 15–17 long setae distributed nearly all over; sclerotized, caudoventral bridge of cerci medially with narrowly elongated process. Paramere somewhat triangular in lateral view, apically round, with sensilla on inner surface. Aedeagus apically trilobed, densely hirsute on outer lobes, dorsosubapically with a pair of small, marginally serrated flaps.

Female terminalia (Fig. 8H–J): Oviscapt valve dorsomedially narrowly extended, with 4−5 lateral and 12−15 marginal, peg-like ovisensilla. Spermathecal capsule with fine spinules on distal half of outer surface.

Measurements (in mm): BL = 2.42 in holotype (1♂ paratype: 2.10; range in 2♀ paratypes: 2.34–2.57), ThL = 1.01 (0.87; 0.93–0.96), WL = 2.19 (1.84; 1.82–2.14), WW = 0.97 (0.85; 0.92–0.94).

Indices: FW/HW = 0.50 (1♂, 2♀, or less if noted, paratypes: 0.48–0.51), ch/o = 0.19 (0.25–0.29), prorb = 0.66 (1♂, 1♀: 0.63–0.73), rcorb = 0.23 (1♂, 1♀: 0.24–0.30), orbito = 0.62 (0.53–0.60), dcl = 0.76 (1♀: 0.77), sctl = 0.86 (0.84–0.87), sterno = 0.59 (1♂, 1♀: 0.58–0.62), dcp = 0.49 (0.49–0.52), sctlp = 0.90 (0.84–0.89), C = 1.82 (1.82–2.01), 4c = 1.47 (1.31–1.51), 4v = 2.51 (2.22–2.70), 5x = 2.16 (2.11–2.32), ac = 2.81 (2.88–3.15), M = 0.79 (0.71–0.87), C3F = 0.59 (0.57–0.63).

Etymology.

Pertaining to the type locality.

Distribution.

Malaysia (Sabah).

Dichaetophora javaensis

Keywords: Animalia, ORDO, FAMILIA

Yang & Gao sp. n.

http://zoobank.org/09DA1C1A-C0A2-4025-99FB-6AAAC123F295

Figs 3N–P , 4U–Y , 9

Type material.

Holotype. ♂ (#03892), INDONESIA: Cikaniki, Mt. Halimun, West Java, 7.x.2009, MJ Toda (MZB).

Paratypes: same as holotype except for 6.xi.2009 (1♀: #03887, MZB; 2♀: #03888–9, KIZ); same as holotype except for 10.xi.2009 (1♀, SEHU); Cibodas, West Java, Indonesia, 16.xi.2013, MJ Toda (1♂, SEHU); Mt. Patuha, Sugihmukti, West Java, Indonesia, 13.x.2004 (1♂, SEHU).

Diagnosis.

Postocellar setae present; spermathecal capsule somewhat dome-shaped, apically roundish; introvert 2/5 as deep as capsule height (Fig. (Fig.9J);9J); hypandrium sparsely pubescent in small, medial patch on caudolateral plate (Fig. (Fig.9G);9G); COI = C and T at sites 142 and 205, respectively; COII = T, C, C, C, G and C at sites 18, 69, 270, 303, 381 and 393, respectively (Table (Table55).

Description.

Head (Figs 3N, O, 4U–Y): First flagellomere grayish brown. Dorsolateral tentorial apodemes slightly divergent in basal 2/5 but strongly divergent in distal 3/5; supercervical setae 18−22 per side; postocular setae 19 per side. Palpus with one subprominent, lateromedial seta. Cibarium with ca. 90 medial and 10−12 posterior sensilla per side.

Wings (Fig. (Fig.3P)3P) slightly fuscous; veins yellowish brown to brown. Halter and stem gray.

Legs (Fig. (Fig.3N):3N): All femora blackish brown; foreleg coxa, tibia and tarsus (except 5th tarsomere) grayish brown; rest grayish yellow. Apical setae present on foreleg and mid-leg tibiae. Mid-leg first tarsomere as long as total length of four succeeding tarsomeres; hindleg first tarsomere longer than total length of four succeeding tarsomeres.

Male terminalia (Fig. 9A–G): Epandrium pubescent except for anterior margin, with 2–3 dorsal and 9–10 ventral, long setae per side. Surstylus with 2–3 short spines and medial patch of pubescence on outer surface and 10–11 recurved spines on inner, caudal portion. Tenth sternite lingulate, slightly curved. Cercus pubescent except for dorsal to caudal margin, with 14–17 long setae; sclerotized, caudoventral bridge of cerci medially with narrowly elongated process. Paramere somewhat triangular in lateral view, apically round, with sensilla on inner surface. Aedeagus apically trilobed, densely hirsute on outer lobes, dorsosubapically with a pair of small, marginally serrated flaps.

Female terminalia (Fig. 9H–J): Oviscapt valve dorsomedially narrowly extended, with 4−5 lateral and 12−15 marginal, peg-like ovisensilla. Spermathecal capsule without spinules on outer surface.

Measurements (in mm): BL = 1.94 in holotype (range in 3♀ paratypes: 2.08–2.50), ThL = 0.86 (0.97–1.03), WL = 1.81 (1.99–2.07), WW = 0.82 (0.86–0.92).

Indices: FW/HW = 0.56 (3♀, or less if noted, paratypes: 0.49–0.52), ch/o = 0.21 (0.34–0.41), prorb = 0.76 (0.72–0.79), rcorb = 0.24 (0.29–0.31), orbito = 0.60 (0.54–0.69), dcl = 0.74 (1♀: 0.71), sctl = 0.81(1♀: 0.81), sterno = 0.60 (0.50–0.54), dcp = 0.52 (0.53–0.60), sctlp = 0.71 (0.52–0.71), C = 1.85 (1.78–1.98), 4c = 1.54 (1.35–1.40), 4v = 2.62 (2.26–2.28), 5x = 2.28 (1.73–1.91), ac = 3.03 (2.95–3.24), M = 0.76 (0.71–0.90), C3F = 0.58 (0.50–0.60).

Etymology.

Pertaining to the type locality.

Distribution.

Indonesia (West Java).

Dichaetophora sumatraensis

Keywords: Animalia, ORDO, FAMILIA

Yang & Gao sp. n.

http://zoobank.org/8F7EB4F2-3B81-4D2F-9AAC-3ABD144F8BC7

Figs 3Q–S , 4Z–D ’, 10

Type material.

Holotype ♂ (#03890): INDONESIA: Mt. Kerinci., Jambi, Sumatra, 7.x.2004, MJ Toda (MZB).

Paratypes: same as holotype (1♀: #03891, MZB); same as holotype except for 6.x.2004 (1♀, SEHU).

Diagnosis.

Postocellar setae present; spermathecal capsule somewhat dome-shaped, apically roundish; introvert 2/5 as deep as capsule height (Fig. 10K); hypandrium without pubescence on caudolateral plate (Fig. 10H); COI = T and C at sites 142 and 205, respectively; COII = C, T, T, T, A and T at sites 18, 69, 270, 303, 381 and 393, respectively (Table (Table55).

Description.

Head (Figs 3Q, R, 4Z–D’): First flagellomere grayish brown. Dorsolateral tentorial apodemes slightly divergent in basal 2/5 but strongly divergent in distal 3/5; supercervical setae 19−22 per side; postocular setae 20−24 per side. Palpus with one subprominent, lateromedial seta. Cibarium with numerous (> 60) medial and 8−9 posterior sensilla per side.

Wing (Fig. (Fig.3S)3S) slightly fuscous; veins yellowish brown to brown. Halter and stem gray.

Legs (Fig. (Fig.3Q):3Q): All femora blackish brown; foreleg coxa, tibia and tarsus (except 5th tarsomere) grayish brown; rest grayish yellow. Apical setae present on foreleg and mid-leg tibiae. Mid-leg first tarsomere as long as total length of four succeeding tarsomeres; hindleg first tarsomere longer than total length of four succeeding tarsomeres.

Male terminalia (Fig. 10A–H): Epandrium pubescent except for anterior margin, with three dorsal and 11–13 ventral, long setae per side. Surstylus with 9–10 prensisetae caudal margin, 2–3 short spines and medial patch of pubescence on outer surface and ca. 15 recurved spines on inner, caudal portion. Tenth sternite lingulate, slightly curved. Cercus pubescent except for dorsal to caudal margin, with 20–21 long setae; sclerotized, caudoventral bridge of cerci medially with narrowly elongated process. Paramere somewhat triangular in lateral view, apically round, with sensilla on inner surface. Aedeagus apically trilobed, densely hirsute on outer lobes, dorsosubapically with a pair of small, marginally serrated flaps.

Female terminalia (Fig. 10I–K): Oviscapt valve dorsomedially narrowly extended, with 5−6 lateral and 14−17 marginal, peg-like ovisensilla. Spermathecal capsule without spinules on outer surface.

Measurements (in mm): BL = 2.33 in holotype (1♀ paratype: 2.70), ThL = 1.04 (1.13), WL = 2.17 (2.46), WW = 1.10 (1.00).

Indices: FW/HW = 0.36 (1♀ paratype: 0.40), ch/o = 0.39 (0.33), prorb = n/a (n/a), rcorb = n/a(n/a), orbito = 0.75 (0.78), dcl = 0.72 (n/a), sctl = n/a (n/a), sterno = n/a (0.61), dcp = 0.62 (0.60), sctlp = 0.80 (0.75), C = 1.90 (2.00), 4c = 1.29 (1.34), 4v = 2.18 (2.23), 5x = 2.18 (1.84), ac = 2.37 (2.57), M = 0.79 (0.75), C3F = 0.58 (0.60).

Etymology.

Pertaining to the type locality.

Distribution.

Indonesia (Sumatra).

Remarks.

The last three species somewhat resemble trilobita sp. n. in having the following morphological characters: wing without distinct, dark cloud; surstylus with medial patch of pubescence on outer surface; sclerotized, caudoventral bridge of cerci with narrow, median process; and oviscapt valve dorsomedially narrowly extended. However, the three species are very hard to distinguish from each other because of their least morphological differentiation. To overcome this difficulty, we employed 19 nucleotide sites of COI and COII genes as molecular diagnostic characters to identify these cryptic species (Table (Table5).5). Nucleotide substitutions at two of these sites are nonsynonymous, i.e., causing changes of amino acids, and specific to borneoensis sp. n. (Table (Table5),5), thus providing more reliable (less changeable) characters for this species.

Supplementary Material

XML Treatment for Dichaetophora trilobita :
XML Treatment for Dichaetophora heterochroma :
XML Treatment for Dichaetophora flatosternata :
XML Treatment for Dichaetophora borneoensis :
XML Treatment for Dichaetophora javaensis :
XML Treatment for Dichaetophora sumatraensis :

Acknowledgments

We thank Dr Maklarin B. Lakim and Dr Maryati Bte Mohamed for their help in field works in Sabah, Malaysia under research permissions (UPE:40/200/19 SJ. 732 and UPE: 40/200/19 SJ.1194 and 1195) of Economic Planning Unit of Malaysian Government. This work was supported by NSFC (Nos 31160429, 31572238), the fund of the Ministry of Science and Technology of China (No. 2011FY120200 and 2012FY110800).

Notes

Citation

Yang J-H, Toda MJ, Suwito A, Hashim R, Gao J-J (2017) A new species group in the genus Dichaetophora, with descriptions of six new species from the Oriental region (Diptera, Drosophilidae). ZooKeys 665: 121–146. https://doi.org/10.3897/zookeys.665.11609

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