Oplodontha minuta ( Fabricius, 1794 )

Tkoč, Michal & Rozkošný, Rudolf, 2014, New synonymy of Oplodontha minuta (Diptera: Stratiomyidae) with its first record from Socotra Island, Acta Entomologica Musei Nationalis Pragae 54, pp. 429-439 : 431-436

Oplodontha minuta ( Fabricius, 1794)

( Figs 1–14 )

Stratiomys minuta Fabricius, 1794: 268 . Oxycera indica Brunetti, 1907:119 . Odontomyia ochracea Brunetti, 1907: 129 . Odontomyia submutica Brunetti, 1907: 130 . Eulalia oasina Lindner, 1925: 150 , syn. nov.

Type localities. Stratiomys minuta : India, Tranquebar [= Tharangambadi]. Oxycera indica : India, Kolkata. Odontomyia ochracea : India, Kolkata. Odontomyia submutica : India, Kolkata. Eulalia oasina : Egypt, Khârgha Oasis.

Type material examined. Stratiomys minuta : SYNTYPE: 1 ♀, labelled: ‘p.86·32 [hw] // minuta [hw]’ ( ZMUC, only the head of this specimen is preserved, see Figs 12, 13 ).

Eulalia oasina : SYNTYPE: 1 ♀, labelled: ‘Cotype [hw] // Min. Agr. Egypt / Khârgha Oasis. / 9.v. [hw] 1918 [p] / Coll. [p] Storey [hw] // Eulalia / oasina / Lind. [hw]’ ( SMNS).

Odontomyia ochracea : PARATYPES: 1 J, labelled: ‘Type [p, round label with red edge] // Odonto / ochracea / n. s. J 28 / type [hw] // Pres.by / E.Brunetti. / Brit.Mus. / 1927–184. [p] // BRUNETTI / Calcutta / environs [p] / 26.vii.[hw]190[p]4[hw] // BRUNETTI / COLLECTION [p] // PARATYPE / (HOLOTYPE?) / Odontomyia ochracea Brunetti / det. J.E.CHAINEY 1982 [hw] // BMNH(E) / 1237759 [p]’ ( BMNH); 1J, labelled:‘BRUNETTI / Calcutta / environs [p] / 26.vii.[hw]190[p]4[hw] // Pres.by / Brunetti. / B.M. 1927–184 [p] // BRUNETTI / COLLECTION [p] // PARATYPE / Odontomyia ochracea Brunetti / det. J.E.CHAINEY 1982 [hw] // BMNH(E) / 1237763 [p]’ ( BMNH).

Odontomyia submutica : SYNTYPES: 1 ♀, labelled: ‘Type [p, round label with red edge] // O. submutica / mihi[?] sp. non / type exemp [hw] // Pres.by / E.Brunetti. / Brit.Mus. / 1927–184. [p] // India / Calcutta / 1. 2. ʼ07. [hw] // Calc / 1.II.07 [hw] // SYNTYPE / Odontomyia / submutica Brunetti / det. J.E.CHAINEY 1982 [hw] // BMNH(E) / 1237760 [p]’ ( BMNH). 1 ♀, labelled: ‘ India / Calcutta / E. Brunetti / 5. III. ʼ05. [hw] // Calc / 5.III.05 [hw] // Pres. by / E.Brunetti. / Brit.Mus. / 1927–184. [p] // BMNH(E) / 1237761 [p] // SYNTYPE / Odontomyia / submutica Brunetti / det. J.E.CHAINEY 1982 [hw]’ ( BMNH).

Additional material examined. AFGHANISTAN: 1 J, East Afghanistan, Jalalabad, Kunartal , 30.iii.1953, J. Klapperich lgt. ( HNHM) ; 2 JJ 3 ♀♀, Jalalabad , 580 m, 13.iv.1966, D. Povolný & F. Tenora lgt. ( MMBC) ; 1 ♀, Jalalabad , 580 m, 17.iv.1966, D.Povolný & F.Tenora lgt. ( MMBC) ; 1♀, Jalalabad , park, 560 m, 17.iv.1974, L. Papp ( HNHM, published as O. oasina by ROZKOŠNÝ (1982b)) . EGYPT: 1 J, Khârgha Oasis , 12.vi.1926, coll. Efflatoun ( SMNS) . INDIA: 4 ♀♀, Andra Pradesh, Hyderabad , 29.x.1971, A. C. Pont lgt .; 1 ♀, same locality, 4.xi.1971, A. C. Pont lgt .; 4 ♀♀, Tamil Nadu, Dohnavur, Tinnevelly [= Tirunelveli], 28.ix.1938, B.M.-C.M. Expedition ; 1 J 1 ♀, same locality, 7.iii.1936, B.M.-C.M. Expedition ; 1 ♀, Gujarat, Banaskantha, Deesa , 1.vii.1901, C. G. Nurse lgt .; 1 J, Madhya Pradesh, Jabalpur distr., Jubbulpore [= Jabalpur], 1.ix.1907, C. G. Nurse lgt .; 1 ♀, West Bengal, Kolkata distr., Calcutta [= Kolkata], 15.viii.1907 ; 1 ♀, same locality, 26.vii.1904 ; 1 ♀, same locality, 28.v.1907 ; 1 J, same locality, 17.viii.1907 ; 1 J, same locality, 31.x.1907 (all Indian material from BMNH) . ISRAEL: 1 J, 35 km N Elat Iddan , 30°47′N, 35°17′ E, Malaise trap, 8.v.1996, M. Hauser leg. et det. ( CSCA) ; 1 J, Jericho , 19.vii.1976, A. Freidberg lgt. ( SMNS) ; 1 ♀, Shivta , 23. vi. 1976, M. Kaplan lgt. ( SMNS) . SRI LANKA: 1 ♀, Trincomalee distr., Trincomali [= Trincomalee], 29.xii.1891, Lt. Col.Yerbury lgt.( BMNH) ; 1♀, Periakulam [= Periyakulam], 1.iii.1891, Lt. Col. Yerbury lgt. ( BMNH) . UNITED ARAB EMIRATES: 1 J, Khor al-Khwairi, 25°57′N, 56°03′E, light trap, 2.–13.v.2007 ; 1 ♀, Al-Ajban , 24°36′N, 55°01′E, Malaise trap, 17.–24.iv.2006 ; 1 J, same locality, 15.–22.v.2006, all van Harten leg., M. Hauser det. ( CSCA) ; 1 ♀, Wadi Maidaq , 25°31′N, 56°13′E, 11.–19.iii.2009, Schmid-Egger lgt., M. Hauser det. ( CSCA). (All UAE material published as O. pulchriceps by HAUSER (2007)) . YEMEN: 1 ♀, Socotra Island, Homhil , 330 m a.s.l., 12.587°N, 54.302°E, 20.–21.xi.2000, V. Bejček & K. Šťastný lgt. ( NMPC) ; 1 ♀, Socotra Island, Wadi Faar , 69 m a.s.l., 12.433°N, 54.195°E, 1.iv.2001, V. Bejček & K. Šťastný lgt. ( NMPC) ; 6 ♀♀, Socotra Island, Dixam plateau, wadi Zerig , 655 m a.s.l., 12°29.6′N, 53°59.5′E, Juncus marsh, open Dracaena cinnabari woodland, 13.–14.vi.2012, I. Malenovský, P. Kment, J. Bezděk, J. Hájek, V. Hula, J. Niedobová & L. Purchart lgt. (1 ♀ in NMPC, 5 ♀♀ in MMBC) ; 1 J, wadi Zerig , 650–670 m a.s.l., 12°29′35ʺN, 53°59′28ʺE, 30.vi.2010, L. Purchart lgt. ( NMPC) ; 1 ♀, Socotra Island, Scant area , 1300–1500 m a.s.l., 12°34′33ʺN, 54°01′31ʺE, 31.i.–2.ii.2010, L. Purchart lgt. ( NMPC) .

Diagnosis. A small species with hyaline wings and ivory white to yellow (or greenish) pattern on head, thorax and abdomen. Eyes with microtrichia, scutellar spines slender but distinct. Discal cell fused with Rs along a short upper part. At least middle third of all femora and hind tibia darkened. Male terminalia species-specific, gonostylus pointed apically and posteromedial process of genital capsule relatively low and trapezoid-shaped.

Redescription. Male. Body length (without antennae): 3.5–6.2 mm, wing 3.4–5.0 mm.

Head almost hemispherical, somewhat swollen at middle of face. Postocular area narrow, visible only in lower fourth of head in profile. Antenna brown (3 apical flagellomeres often more darkened), about 0.7 times length of head, basal antennal segments subequal, scape slightly longer than pedicel; flagellum spindle-shaped, consisting of 6 flagellomeres, two apical flagellomeres form short style. Flagellomere V very short, apical flagellomere barely longer than broad, rounded apically. Proboscis relatively long (as in other species visiting flowers), with black labella. Setae on head usually pale greyish to white, short and inconspicuous on upper frons but dense and partly appressed on face, longer on lower postocular area and beyond ocellar triangle.

Thorax black in ground colour, with pale ivory spots, minimally on postpronotal lobe, anterior and posterior parts of anepisternum and anepimeron. Thorax completely covered with dense greyish setae. Setae on scutum often more brown, mostly erect, about as long as antennal pedicel and partly appressed along notopleura and above wing base. Setae on pleura usually paler, long and partly curled, often covering ivory spots. Scutellum blackish basally and usually with broadly ivory distal margin, scutellar spines ivory, barely as long as erect setae on scutum.

Wing hyaline, stronger veins yellowish, medial and cubital veins often indistinct or lacking, upper part of discal cell fused to Rs. Calypter white, with sparse whitish fringe, halter white with basally darkened stem.

Legs pale yellow (ivory) in ground colour but all coxae and broad median rings on all femora and hind tibia blackish.

Abdomen ( Fig. 4 ) rounded, rarely more oval, ivory. Dorsal side with black pattern consisting of middle row of transverse black spots which may be confluent in different ways. Venter usually ivory. Abdominal pilosity usually white and inconspicuous, only on posterior margin of tergite IV + V longer and mostly erect, setae on black spots partly darkened.

Male terminalia ( Figs 6–8 ). Genital capsule rounded proximally, gonostylus pointed apically. Posteromedial process of genital capsule trapezoidal ( Fig. 7 ).

Female. Body length (without antennae): 4.2–6.6 mm, wing 3.8–5.8 mm.

Head ( Figs 1–3 , 12–14 ) semi-globular but eyes much smaller than in male, with pilosity sparser and shorter. Postocular area as broad as length of pedicel and broadly separated by wide frons. Ground colour of head bright ivory with black pattern. Occiput entirely black as well as transverse band at level of ocellar triangle on frons, pair of frontal spots and pair of facial spots; facial medial tubercle black at apex, as well as narrow anterior margin of swollen oral opening. Antenna usually somewhat longer and darker than in male, predominantly dark brown, at most scape somewhat paler. Slender and long proboscis entirely black. Head pilosity mostly inconspicuous and short, pale.

Thorax ( Figs 1–2 ) black in ground colour, ivory spots conspicuous and shining, extended on to postpronotal lobe, propleura, anterior third of anepisternum, narrow subnotopleural stripe, broad spot along posterior margin of anepisternum, spots on upper corner of katepisternum and on anepimeron ( Fig. 2 ). Thoracic pilosity usually less distinct than in male, also pale and dense, at least partly appressed. Scutellum usually ivory with semicircular, narrow, basal black spot. Wing and legs as in male.

Abdomen ( Figs 1 , 5, 9, 11 ) usually somewhat longer than in male and darker dorsally. Colour pattern very variable, consisting of transverse black stripes on tergites but often reduced, especially on tergites I and II, and along posterior and lateral margins of tergites ( Figs 5, 9, 11 ). Venter pale ivory.

Female terminalia ( Fig. 10 ). Posterior corners of tergite IX pointed, apical segment of female cerci oval, twice as long as broad.

Variability. Colour characters in this species are remarkably variable as in the other Stratiomyidae with aquatic larvae. The antennae range from brownish to predominantly yellow with darkened tip of flagellum. The ivory ground colour of the face may be considerably reduced in both sexes. Medial dark spots on the facial tubercle and the anterior margin of the oral cavity of males may be extended and ivory parts reduced to ivory spots along eye margins. The variable pattern is even more striking on the female frons and face ( Figs 3 , 12–14 ). The ivory pleural spots may serve as an important species-specific character ( Fig. 2 ). They are mostly shining and striking but covered by dense pale setae in some specimens and thus often overlooked. The scutellum is mostly ivory with a narrow black basal part but sometimes almost entirely black with only a narrowly ivory posterior margin. The extensive black rings on all femora and the hind tibia are usually well developed but sometimes only pale or partly reduced. The dark pattern on the ivory abdomen is fairly stable in males ( Fig. 4 ), consisting of blackish medial spots on tergites that may be separated or fused. On the contrary, the abdominal pattern in females may be extremely variable within the same population ( Figs 5, 9, 11 ). The vestiture of the thorax is usually longer and denser in males and sparser in females but some females with relatively dense pilosity were examined as well.

Comparison with O. viridula . The common Palaearctic species O. viridula (Fabricius, 1775) is distributed from Europe and Israel, Afghanistan, Iraq, Kazakhstan, Kyrgyzstan, and Mongolia to the Pacific shore of Russia and China ( WOODLEY 2001). Its detailed redescription and a discussion of extensive variability is given by ROZKOŠNÝ (1982a). The distinguishing characters of O. minuta and O. viridula are summarized in Tab. 1. Females may be easily separated by their different head, pleural and abdominal colour pattern, but distinguishing of males may be difficult in some cases when ivory facial and pleural spots are only weakly distinct. Such a case is demonstrated by papers of LINDNER (1974) and LINDNER & FREIBERG (1978). In the first paper, three males from Israel were identified as O. viridula and in the second the identification was corrected to ‘ O. pulchriceps ’ [= O. minuta in present sense] as a result of the ‘augmented extension of the black pattern of the head, the nearly black scutellum and abdomen, with remainders of narrow light stripes on the posterior borders of the tergites’ (LINDNER & FREIBERG 1978: 55).

Distribution. Palaearctic, Afrotropical and Oriental Region ( Fig. 15 ). According to the material we studied: Afghanistan, Egypt, India, Sri Lanka, United Arab Emirates, Yemen: Socotra Island. First record from Socotra Island.

Figures

Figs 1–2.Oplodontha minuta (Fabricius, 1794), female from Socotra Island: 1 – habitus in dorsal view; 2 – habitus in lateral view.

Figs 3–11. Oplodontha minuta (Fabricius, 1794). 3 – frontal view of female head showing the black facial colouration (specimen from Afghanistan); 4 – dorsal view of male abdomen; 5 – dorsal view of female abdomen showing colouration (Afghanistan); 6 – dorsal part of male genitalia; 7 – ventral part of male genitalia; 8 – aedeagal complex in dorsal and lateral view; 9 – dorsal view of female abdomen showing colouration (Afghanistan); 10 – female terminalia in dorsal view; 11 – dorsal view of female abdomen showing colouration (Socotra Island).

Figs 12–13. Head of syntype female of Stratiomys minuta Fabricius, 1794, from India: 12 – frontal view; 13 – lateral view. Photos by M. H. Post.

Fig. 14. Female heads of Oplodontha minuta (Fabricius, 1794) from Socotra Island. Variability of black colour pattern of five different specimens.

Fig. 15. Distribution of Oplodontha minuta (Fabricius, 1794) based on material studied herein and detailed distribution on Socotra Island.