Tachytes mirus Kohl

Pulawski, Wojciech J., 2022, New Synonymy in the Afrotropical Tachytes Panzer, 1806 (Hymenoptera: Crabronidae), Proceedings of the California Academy of Sciences 67 (10), pp. 269-279 : 269-272

Tachytes mirus Kohl

Tachytes mirus Kohl, 1894:295 , ♀ (as mira, incorrect original termination). Holotype or syntypes: ♀, Mozambique: Delagoa Bay, now Maputo Bay ( TMP), not seen. – Dalla Torre, 1897:691 (in catalog of world Hymenoptera ); nec R. Turner, 1916:445 and 1917d:11 (= Tachytes danae ); Arnold, 1923a:188 (similar to Tachytes observabilis ), 1930:4 (in checklist of Afrotropical Sphecidae ); Berland, 1942:3 ( Central African Republic: Fort Sibut); van Vondel, 1995:25 (specimens from Malawi in Natuurmuseum Rotterdam). – As Tachytes mirus : R. Bohart and Menke, 1976:266 (in checklist of world Sphecidae ).

Tachytes observabilis Kohl, 1894:295 , ♂. Holotype or syntypes: ♂, Tanzania: Zanzibar: no specific locality ( TMP), not seen. New synonym. – Dalla Torre, 1897:692 (in catalog of world Hymenoptera ); R. Turner, 1917:12 (in revision of Afrotropical Tachytes ; description of ♀; Angola, Kenya, Malawi, Uganda); Arnold, 1923a:184 (in revision of southern African Tachytes ), 1930:4 (in checklist of Afrotropical Sphecidae ); Schouteden, 1930:92 ( Zaire); Arnold, 1943:79 ( Zaire: Albert National Park: Bitshumbi), 1951:146 ( Ethiopia: Lake Anasa); Robertson, 1969:480 ( Tanzania: Urambo); R. Bohart and Menke, 1976:266 (in checklist of world Sphecidae ); Seyoum and Pulawski, 2001:325 (potential control agent of acridid pests in Ethiopia); S. Gess and F. Gess, 2003:112 ( Namibia: visiting flowers of Hermbstaedtia sp. , Amaranthaceae , and Geigeria sp. , Asteraceae ).

TAXONOMIC HISTORY. — In his 1894 paper, Kohl described T. mirus from Delagoa Bay in Mozambique (based on several females), and T. observabilis from the Island of Zanzibar (based apparently on one male). Unfortunately, he did not pay attention to the length of the galea or to the palpal formula. Both species were recognized by R. Turner (1917) and Arnold (1923a, b) in their respective revisions of the Afrotropical Tachytes , but neither of the two authors suspected that they may be the two sexes of one species. Turner (1917) thought that T. mirus was a member of his subgenus Calotachytes , thus attributing it the palpal formula of 5 + 3. Arnold (who may have seen the types of both Kohl’s species) described in 1923 as Tachytes danae the species interpreted as T. mirus by Turner, and treated T. mirus as a member of Tachytes s.s., with the palpal formula of 6 + 4. Turner also described the female of T. observabilis , and Arnold (1923) commented under T. mirus : “Except that the anterior metatarsus has six to seven spines [six in T. observabilis ] and the much shorter pygidial area, there is nothing to distinguish this form from observabilis ”.

SPECIES IDENTIFICATION. — The type material of both T. mirus and T. observabilis is deposited in the Ditsong National Museum of Natural History in Pretoria, South Africa, but I was not able to obtain them for examination in spite of many requests. Kohl (1994) description of these two species did not mention such an essential character as the length of the galea, but Arnold (1923) described it as being longer then the scape.

SPECIES RECOGNITION. — Tachytes mirus is a member of the basilicus species group which is characterized by the galea longer than the scape ( Figs. 2, 3 ), not separated from the stipes by a sulcus, the first article of the labial palpus elongate, about as long as the scape ( Fig. 3 ), the palpal formula 6 + 4, the clypeal median lobe broad, evenly arcuate, and in the male the least interocular distance short ( Fig. 4 ), smaller than the distance between the ventral ends of the hindocelli.

The basilicus species group includes the following 15 described species (all African except T. monetarius from India and T. galeatus from Madagascar): T. abercornensis Arnold, 1959 , T. basilicus (Guérin-Méneville, 1844) , T. galeatus Pulawski, 2019 , T. hamiltoni R. Turner, 1917 , T. irritabilis R. Turner, 1917 , T. labilis R. Turner, 1917 , T. mirus Kohl, 1894 (= T. observabilis Kohl, 1894 ), T. monetarius F. Smith, 1856 , T. neglectus R. Turner, 1917 , T perornatus R. Turner, 1017 , T. praestabilis R. Turner, 1917 , T. separabilis R. Turner, 1917 , T. simulatrix R. Turner, 1917 , and T. velox F. Smith, 1856 (I studied all Arnold’s, F. Smith’s, and R. Turner’s types in the Natural History Museum, London back in 1974, and took detailed notes on them). Most of them have silvery, apical fasciae on terga I-IV or I-V, and only in the following six are the gastral setae all golden, arranged in a checkered pattern ( Fig. 1 ): T. abercornensis , T. basilicus , T. mirus , T. monetarius , T. perornatus , and T. velox . They differ from T. mirus as follows:

In the male of T. abercornensis (the female is unknown), flagellomeres II-VII are slightly concave dorsally and slightly convex ventrally, and all sterna are covered with dense, erect setae, whereas in the male of T. mirus the flagellum is cylindrical and most of sterna III-V are either glabrous or covered with appressed setae (only apical depressions mesally are covered with suberect setae).

In T. basilicus the gaster is ferruginous, the scutum has appressed, silvery setae at least in the anterolateral corner, and in the female the punctures of the pygidial plate are somewhat sparser, the setae not entirely concealing the integument. In T. mirus the gaster is black (as are the flagellum and the legs), the appressed, silvery setae are absent from the scutum, and in the female the punctures of the pygidial plate are denser, the setae entirely concealing the integument.

In T. monetarius , the forewing is darkened along the anterior margin (the dark area varying in intensity, and also in length, either extending to the apex of the marginal cell, or ending at the cell’s base). In T. mirus , the wings are uniformly clear, somewhat darkened only along the apical margin.

In the male of T. perornatus (the female is unknown), sternum VIII is emarginate apically, and the midbasitarsus has short spines ventrally. In the male of T. mirus , sternum VIII is rounded apically, and the midbasitarsus has no spines on venter.

In T. velox , sternum II has large, sparse punctures, and it is largely glabrous in the male; the male midbasitarsus is slightly dilated apically, the dilated part well separated from the more basal area, and covered ventrally with short, suberect setae. In the female of T. mirus , sternum II is covered with minute, dense punctures, interspersed with somewhat larger, sparse punctures; in the male, sternum II is all covered with erect setae, the midbasitarsus has no distinct, dilated apical part and no erect setae.

JUSTIFICATION OF NEW SYNONYMY. — Many females evidently conspecific with T. mirus , and many males evidently conspecific with T. observabilis , were collected together in eight localities in Ethiopia, Kenya, Namibia, Tanzania, Zambia, and Zimbabwe (see the Records below), convincingly demonstrating that they are the opposite sexes of one species. Acting as First Reviser (Article 24.2), I hereby select Tachytes mirus as the valid name and Tachytes observabilis as its junior synonym. Tachytes pulchrivestitus , incorrectly regarded as a junior synonym of T. mirus , is actually a valid species (see below).

SIMILAR UNDESCRIBED FORMS. — Seven males from Zimbabwe and two from Namibia in the California Academy of Sciences closely resemble T. mirus in having an elongate galea, golden gastral setae and an equally narrow postocellar area. They differ from T. mirus in having the ventral side of flagellomeres I-VI to I-VIII clearly yellowish brown, and at least flagellomeres II-VI with the dorsal surface slightly concave and the ventral surface convex. Also, the hindfemoral venter has no erect setae in the specimens from Zimbabwe. Most likely they represent an undescribed species. Unfortunately, no associated female is available.

The three specimens in NHMW determined as T. observabilis (examined 19 January 2019) are as follows: 1. a male from “N.W. Tanganika, Grauer, 1910”, is like the males of T. mirus above, with flagellomeres black and cylindrical, determined “ observabilis , det. Kohl”; 2. a female labeled ” Senegal 1896, Brauer don.”, is like T. mirus described above but with the flagellum brown ferruginous ventrally, determined “ velox Sm. , det. Kohl” and “ Tachytes observabilis Kohl , det. P.P. Babiy 1941”; 3. a male labeled “Africa”, with flagellomeres II-IX yellowish brown, and flagellomeres II-IV with the dorsal surface minimally concave and the ventral surface minimally convex (practically cylindrical), is determined “ velox , det. Kohl” and “ Tachytes observabilis Kohl , det. P.P. Babiy 1941”. Specimens no. 2 and 3 may be species similar to T. mirus , but unrecognized so far.

GEOGRAPHIC DISTRIBUTION ( Fig. 5 ).— Ethiopia to South Africa and Namibia.

RECORDS (all the specimens recorded are from the California Academy of Sciences collection).

ETHIOPIA: Gamo Gofa Province: 40 road km NNE Arba Minch (1 ♀, 1 ♂) . Harerge Province: 44 km ENE Jijiga (1 ♂) .

KENYA: Coast Province: Mount Kasigau at 3º50ʹS 38º40ʹE (1 ♂) , Taita Hill Discovery Centre at 3º42.3ʹS 38º46.6ʹE (3 ♂) , Tiwi Beaches ca 17 km S Mombasa at 4º14.4ʹS 39º36.2ʹE (1 ♀, 3 ♂) . Eastern Province: Mwingi at 0º56.4ʹS 38º02.8ʹE (1 ♂) . Rift Valley Province: Lodwar road 4 km N road to Sigor at 1º33.7ʹN 35º27.7ʹE (2 ♂) , Marich Pass Field Studies Centre at 1º32.2ʹN 35º27.4ʹE (3 ♀, 11 ♂) .

MOZAMBIQUE: Maputo Bay ( Kohl, 1894, as Delagoa Bay).

NAMIBIA: Oshikoto Region: 10 km SE Tsumeb (1 ♀, 1 ♂) . Otjozondjupa Region: 18 km NE Kalkfield at 20º45ʹS 16º16ʹE (1 ♂) , 28 km NW Otjiwarongo at 20º21ʹS 16º27ʹE (1 ♂) .

SOUTH AFRICA: North West Province: Hartiebeespoort (2 ♀) .

TANZANIA: Coast Region: 17 km E Chalinze at 6º39.2ʹS 38º30.2ʹE (3 ♀, 4 ♂) . Iringa Region: 18 km W Iringa at 7º53.8ʹS 35º35.7ʹE (1 ♀, 1 ♂) . Kilimanjaro Region: 20 km SE Same at 4º05.1ʹS 37º53.54ʹE (1 ♂) . Morogoro Region: 3 km S Mikumi at 7º25.6ʹS 36º59.1ʹE (1 ♀), 48 km W Morogoro at 6º56.9ʹE 37º20.2ʹE (1 ♂) . Zanzibar: no specific locality ( Kohl, 1894).

ZAMBIA: Central Province: 65 km WNW Lusaka at 15º10ʹS 27º25ʹE (1 ♂) , 2 km E Mumbwa at 15º01ʹS 27º04ʹE (1 ♂) , 6 km W Mumbwa at 15º02ʹS 27º00ʹE (1 ♂) . Eastern Province: 6-18 km SW Mfuwe (1 ♀, 9 ♂) , 31 km E Petauke at 14º18ʹS 31º36ʹE (5 ♂) , 32 km E Petauke at 14º17ʹS 31º37ʹE (1 ♂) . Lusaka Province: 25 km E Lusaka at 15º21ʹS 28º30ʹE (2 ♂) . Northern Province: 60 km N Kasama at 9º42ʹS 31º10ʹE (3 ♂) .

ZIMBABWE: Bulawayo airport at 20º00ʹS 28º38ʹE (1 ♀) , 30 km S Harare (1 ♂) , Leighwoods 52 km SW Bulawayo at 20º26ʹS 28º15ʹE (1 ♂) , Lion and Cheetah Park 24 km W Harare at 17º50ʹS 30º49ʹE (4 ♂) , Redbank at Kami River at 20º00ʹS 28º22ʹE (3 ♂) , Victoria Falls at 17º56ʹS 25º50ʹE (1 ♀, 3 ♂) .

Figures

FIGURES 1–4. Tachytes mirus: 1: female gaster dorsally; 2: female head in lateral view showing elongate galea; 3: female galea in lateral view; 4: male vertex in dorsal view.

FIGURE 5. Collecting localities of Tachytes mirus.