Allarete patriciae, Szx, 2021

Szx, André Nel, 2021, New Cecidomyiidae from the Lowermost Eocene French amber (Diptera), Palaeoentomology 4 (6), pp. 620-628 : 620-623

Allarete patriciae sp. nov.

( Figs 1 , 2 ) urn:lsid:zoobank.org:act:8C1B9548-F53E-4377-844C-799462867464

Material. Holotype MNHN.F.A71372 (PA 128 1/2, male, together with a male Chironomidae , collection Langlois- Meurinne/ De Ploëg, mounted in Canada balsam), deposited in the Département Histoire de la Terre, Muséum national d’Histoire naturelle, Paris, France.

Etymology. After my wife, Dr Patricia Nel.

Diagnosis. Male characters only. Flagellomeres with nodes and necks of equal length, eyes meeting above by five ommatidia; fourth palpal segment is twice as long as third palpal segment; vein apicR1 short but 5–6 times longer than basal part of Rs; gonostylus simple, not divided into a large inner lobe and an apical lobe.

Description. Male ( Fig. 1 ). Head 0.19 mm long, 0.27 mm high; eyes very broad; eye bridge complete with eyes meeting in about five ommatidia; two nearly contiguous ocelli well developed just above compound eyes; antenna about 1.1 mm long, scape 0.02 mm long, 0.04 mm wide, pedicel 0.02 mm long, 0.04 mm wide, 14 long flagellomeres, of nearly the same sizes, all longer than wide (1 st flagellomere 0.09 mm long, 0.04 mm wide), and with a distinct neck, node of flagellomeres as long as neck ( Fig. 2A ), last flagellomere 0.04 mm long; flagellomeres with two rows of setae, one complete and one incomplete, both crenulate; digitate sensoria absent on flagellomeres; gena short; palpus very long, with four visible long segments, with palpal segment 1 short and stout, distal three palpal segments elongate, 2nd palpal segment 0.04 mm long, 3 rd palpal segment 0.06 mm long, 4 th palpal segment 0.12 mm long. Thorax 0.4 mm long, 0.4 mm high.

Wing ( Fig. 2B ) 1.17 mm long, 0.43 mm wide, hyaline, with microtrichia and macrotrichia, especially in posterior part of wing and along posterior margin; veins of posterior part of wing weaker than those of anterior part; antC ending at apex of R4+5, costal break situated at this point; humeral vein present, 0.13 mm from wing base; subcostal vein incomplete, 0.19 mm long, not reaching wing margin; vein apicR1 short but 5–6 times longer than basal part of Rs, reaching anterior wing margin 0.37 mm basal of apex of R4+5; Rs emerging from R close to apex of R1 (0.06 mm); crossvein r-m present but very short, 0.02 mm long; M1+2 not fused to Rs; M1+2 basal to fork into M1 and M2 0.28 mm long, distinctly shorter than branches of fork; M1 complete and curved basally; M2 complete; M1 slightly broader and darker than M2; both M1 and M2 with closely set setae; vein bm-m absent; M4 distinct, simple and nearly straight; CuA simple, curved; CuP curved and long, complete basally and ending close to posterior wing margin; Both dorsal and ventral macrotrichia present on Rs, M, and A.

Haltere with large knob, 0.06 mm wide and 0.12 mm long, and stem 0.1 mm long.

Legs without scales; all legs with five tarsomeres, with tarsomere 1 longer than 2; fore femur 0.36 mm long, tibia 0.39 mm long, 1 st tarsomere 0.23 mm long, 2 nd tarsomere 0.11 mm long; mid femur 0.46 mm long, tibia 0.46 mm long, tarsus 0.51 mm long; hind femur 0.49 mm long, tibia 0.58 mm long, tarsi about 0.63 mm long; femora and tibiae not swollen; tibial spurs absent.

Abdomen with eight segments before genitalia, 0.67 mm long, 0.25 mm wide, bearing few long setae; segment 8 unmodified; parameres not visible, hidden by wings; gonostylus simple, short and broad, curved, 0.06 mm long, 0.02 mm wide ( Fig. 2C ). Female unknown.

Type locality and horizon. Earliest Eocene, in amber, ca. -53 Ma, Sparnacian, level MP7 of the mammal fauna of Dormaal ( Nel et al., 1999), farm Le Quesnoy, Chevrière, region of Creil, Oise department (northern France) .

Remarks. Following the key to dipteran families of McAlpine (1981), Allarete patriciae sp. nov. falls in the Cecidomyiidae : Lestremiinae because of the following characters: vein A2 absent, R with only two branches, C continuing around wing, first tarsomere longer than second, each tarsus five-segmented, two ocelli present (although some Lestremiinae have no ocelli, see Gagné, 1995). After Wood & Borkent (1986, 1989), Allarete patriciae sp. nov. falls in the Cecidomyiidae rather than in Sciaridae , because of the following synapomorphies: presence of an eye bridge (character also present in Sciaridae and Scatopsidae ), tibial spurs absent ( Gagné, 1994) (but character also present in some Scatopsidae ); setae of flagellomeres arranged in encircling whorls.

Allarete patriciae sp. nov. has all the diagnostic characters of the Lestremiinae sensu Jaschhof (1998) ; and, following the key to the African Cecidomyiidae of Dorchin et al. (2017), it falls in the Lestremiinae because of the ocelli present; first tarsomeres longer than second; vein M+2 furcate. Following the keys to Nearctic and European genera proposed in Gagné (1981, 1994) and Skuhravá (1997), Allarete patriciae sp. nov. falls in the Lestremiini because of the following characters: only two ocelli present, five tarsomeres, first tarsomere distinctly longer than second tarsomere, M1+2 present, with its fork longer than its stem, legs without scales, macropterous, CuA simple, M4 distinct, R4+5 more than two-thirds length of wing, 14 (more than six) flagellomeres, each longer than wide, tibiae without disto-ventral spines, Rs shorter than r-m. Jaschhof (1998: fig. 236, characters 7, 8) characterised the Lestremiini after the relative sizes of the scape, pedicel, and flagellomeres. Allarete patriciae sp. nov. has a broad and large scape and pedicel, distinctly broader than its flagellomeres. In the key to the Lestremiinae of New Zealand, Jaschhof & Jaschhof (2003) characterised the Lestremiini after the presence of a forked vein M1+2, excluding affinities of our fossil with the tribe Pteridomyiini Jaschhof in Jaschhof & Jaschhof (2003) , among others. Allarete patriciae sp. nov. also falls in the Lestremiini after the key to the Lestremiinae of Fennoscandia of Jaschhof & Jaschhof (2009) because of the following characters:M1+2 branched; CuA not furcate; M-stem shorter than fork; costal break situated in apical half of wing, and in the genera Allarete or Gongromastix Enderlein, 1936 because of the following characters: costal break situated before apex of M2; antenna in males with pedicel of normal size, 13–14 flagellomeres; eye bridge more than two ommatidia long laterally; and apicRl comparatively long, i.e., clearly longer than Rs. In Lestremia Macquart, 1826 and the other European genera of Lestremiini , the apicR1 is short, only slightly longer than Rs, unlike in Allarete patriciae sp. nov. Plakidas (2017) separated Lestremia from Allarete by the M1 and M2 veins having a few setae vs. with closely set setae, as in Allarete patriciae sp. nov. Jaschhof & Jaschhof (2009) separated Allarete from Gongromastix by the presence of dorsal and ventral setae on M, as in Allarete patriciae sp. nov.

Both Allarete and Gongromastix have a long CuP, also present in Allarete patriciae sp. nov., as in Eomastix Jaschhof & Jaschhof, 2009 . The latter has a long antC reaching wing apex, unlike Allarete patriciae sp. nov.

In Gongromastix , the apicR1 is many times longer than Rs, while it is only 5–6 times longer in Allarete and Allarete patriciae sp. nov. Gongromastix has two-lobed gonostyli unlike Allarete patriciae sp. nov. and at least the type species of Allarete , Allarete africana ( Enderlein, 1911) and Allarete vernalis ( Felt, 1908) , ( Pritchard, 1951; Jaschhof & Jaschhof, 2009 , 2011).

Affinities with Mangogrostix Mamaev,1985(possibly related to Gongromastix after Jaschhof & Jaschhof, 2009 ), and Buschingomyia Jaschhof & Jaschhof, 2011 are excluded because they lack ocelli ( Jaschhof & Jaschhof, 2011 ).

Anarete Haliday, 1833 and Conarete Pritchard, 1951 can be excluded because of the presence of 14 longnecked flagellomeres, instead of six to eight with short or indistinct stems (Li & Bu, 2002; Plakidas, 2017). The absence of digitate and/or of non-hairlike sensillae on the flagellomeres [also excluding affinities with Allaretella Meyer & Spungis, 1994 (junior syn. Cratotocha Plakidas, 2017 ) and Insulestremia Jaschhof, 2004 ], together with M4 with proximal end close to M, well before the level of r-m, exclude the genus Anaretella (Edwards, 1938; Meyer & Spungis, 1994; Skuhravá, 1997; Jaschhof, 1998 ; Do Carmo-Neto et al, 2021). The genus Allaretella also differs from Allarete patriciae sp. nov. in having only nine flagellomeres instead of 14, and the R4+5 vein reaching the C before the M4—C juncture ( Plakidas, 2017).

After Mani (1935, 1945), the Indian genus Neolestremia Mani, 1935 has a three-segmented palpus, instead of a four-segmented palpus in Allarete patriciae sp. nov. The new fossil does not present the main character of Insulestremia sinclairi Jaschhof, 2004 (Galapagos Islands), i.e., presence of flattened sensillae on the antennal flagellum ( Jaschhof, 2004 : fig. 2).

Jaschhof (1997: 528) indicated that ‘Probably Allarete is not a natural group of species, but, in the present sense includes species with these plesiomorphic wing characters: the long R, and A; macrotrichia on both sides of R5, M1+2 including fork and A; and 2 (not 1) sensory pores on R5 proximally’. Allarete patriciae sp. nov. has all these characters except the presence vs. absence of sensory pores on Rs.

Allarete patriciae sp. nov. differs from Lestremia eocenica Nel & Prokop, 2006 in the nodes of flagellomeres as long as the necks, instead of being distinctly longer. It differs from Lestremia deploegi Nel & Prokop, 2006 in the eye-bridge five facets broad instead of having the eyes meeting dorsally at only one point ( Nel & Prokop, 2006). Lestremia pinites Meunier, 1904 from the late Eocene Baltic amber differs from Allarete patriciae sp. nov. in the relative length of its palpal segments (fourth segment about twice as long as third in Allarete patriciae sp. nov. instead of being only 1.3 as long as third) ( Meunier, 1904: 31, pl. 3, figs 3, 5). Nothing is known on the male genitalia of L. pinites .

Deshpande et al. (2002) proposed a key to the Indian species of Anaretella , some of which were later transferred into Allarete , viz. Allarete bhokarensis ( Deshpande, Shaikh & Sharma 2002) , Allarete deepica ( Deshpande, Shaikh & Sharma 2002) , Allarete hindica Jaschhof & Jaschhof, 2011 [new name for Anaretella indica Deshpande, Shaikh & Sharma, 2002 ], and Allarete spinosa Deshpande, Shaikh & Sharma, 2002 . They discriminated them on the basis of the shape of the subdorsal plate, unknown in the new fossil. Jaschhof (1997) characterized his new species Allarete bicornuta on the basis of genital structures too. Pritchard (1951) discriminated Allarete vernalis ( Felt, 1908) in having medial fork twice length of stem (as in Allarete patriciae sp. nov.), vs. three times in A. barberi ( Felt, 1908) . Allarete indica ( Grover, 1964) has also the branches of M longer than the stem. It differs from Allarete patriciae sp. nov. in having only 11 antennomeres instead of 16. Allarete africana ( Enderlein, 1911) has the medial fork more than twice length of stem ( Enderlein, 1911: pl. 2, fig. 31). Allarete nigra Mamaev, 1994 has a different shape of gonostylus ( Mamaev, 1994: fig. 1). The two species Allarete bharatica Grover & Bakhshi, 1978 and Allarete spatuliformis Grover, 1979 have not been not revised.

Figures

FIGURE 1. Allarete patriciae sp. nov., holotype PA 128 1/2, male, habitus. A, Microphotograph. B, Drawing. Scale bar = 0.5 mm.

FIGURE 2. Allarete patriciae sp. nov., holotype PA 128 1/2, male.A, Drawing of detail of antennal flagellomere.B, Drawing of the wing. C, Drawing of male terminalia. Scale bars: A = 0.1 mm, B = 0.3 mm, C = 0.25 mm.