Multistria orthotropa Zhang, Yao & Pang, 2021

Zhang, Xiao & Chen 1, Yunzhi YaoDong Ren 2, Hong Pang 1, Huayan, 2021, New mimarachnids (Hemiptera, Fulgoromorpha, Fulgoroidea) in mid-Cretaceous Burmese amber, ZooKeys 1057, pp. 37-48 : 37

Multistria orthotropa Zhang, Yao & Pang sp. nov.

Figures 1 , 2

Etymology.

The specific name is from a Latin word " orthotropus " meaning “straight”, referring to its median carinae of mesonotum straight.

Type material.

Holotype, CNU-HOM-MA2021001, gender unknown, a complete specimen but ventral view not visible.

Locality and horizon.

Hukawng Valley, Kachin State, Myanmar; mid-Cretaceous, lowermost Cenomanian.

Diagnosis.

Pronotum with anterior margin almost straight, posterior margin slightly concave, median carinae of mesonotum straight. Tegmen without spots, common stem ScP + R shorter than basal cell, Pcu almost straight, free part of Pcu distinctly shorter than common stem of Pcu + A1. Metatibio-metatarsal formula 5: 5: 5.

Description.

A well-preserved specimen, but ventral view not visible; total length of the holotype about 15.98 mm.

Head: head with compound eyes about 2.52 mm wide, wider than half of pronotum width. Vertex triangular, without median carina, lateral margins carinate, posterior margin sinuous, trigons visible in dorsal view.

Thorax: pronotum subhexagonal, length distinctly shorter than mesonotum, about 4.3 times as wide as long in midline, posterior area of pronotum rugulose, anterior margin almost straight, posterior margin arcuate and concave, median carinae double and parallel, present throughout, lateral carinae invisible. Mesonotum poorly preserved, wider than long in midline, median carinae parallel and paired, diverging laterad on scutellum, lateral carinae invisible, scutellum indistinct. Tegula subquadrate, large and distinctly carinate.

Leg: only part of hind leg visible, covered with short setae. Hind tibia widened apically, with five apical teeth; hind tarsi with three segments, basitarsomere 1.72 mm long, distinctly longer than combined length of midtarsomere and apical tarsomere, with five apical teeth, the external teeth longer than inner group; midtarsomere 0.89 mm long, with five apical teeth, the external teeth longer than inner group; subapical setae on all pectens invisible; apical tarsomere 0.67 mm long; tarsal claws developed, arolium wide.

Wings: membranous. Tegmen 14.03 mm long, 5.55 mm wide, about 2.5 times as long as wide, with distinct venation and irregular network veinlets, and also with irregular colour bands from base to apex, costal margin weakly arched at base, anteroapical and posteroapical angles broadly rounded, posterior margin straight, tornus present. Costal area narrow and long, with transverse veinlets, narrowing toward wing apex, basal cell weak, arculus indistinct, Pc + CP extends nearly to wing apex, apical portion invisible, common stem ScP + R + M longer than common stem ScP + R, branch ScP + RA and RP subparallel to costal margin, not forked, stem MP curved at base then almost straight, forked in wing apical half, with three terminals, branch MP1+2 forked, reaching margin with two terminals, branch MP3+4 simple, CuA forked near wing basal one-third, with two terminals, CuA1 basally subparallel to CuA2, CuA2 slightly curved mediad at level of tornus, CuP present throughout wing, slightly sinuate, clavus open, Pcu and A1 fused nearly at the same level of CuA forking, free part of Pcu distinctly shorter than common stem of Pcu + A1, narrow marginal membrane absent.

Hind wing membranous, about 11.01 mm long, 6.60 mm wide, slightly shorter than tegmen, coloration of hind wing darker, two lighter irregular spots near posteroapical portion, irregular network veinlets present. Anteroapical angle round, ScP + R forked, with two terminals, ScP + RA curved in apical portion, stem MP single, CuA forked at wing midlength, reaching margin with two terminals, CuP almost straight, Pcu slightly sinuous.

Remarks.

The new genus is assigned to Mimarachnidae based on the following characters: mesonotum with double median carinae, remnants of sensory pits at the adults, wings with simplified venation, and irregular network of veinlets, basal cell weak, hind wing MP simple. This new genus is distinguished from other genera by the following characters: posterior area of pronotum rugulose (vs no such character in the other known genera); tegmen costal area exceeding 2/3 length of the wing (vs less than ½ of wing length in Chalicoridulum , Ayaimatum , and Mimaeurypterus , costal area absent in Mimaplax ); ScP + RA and RP single (vs ScP + RA and RP forked in Mimarachne and Saltissus , RP forked in Mimamontsecia ); tegmen ScP + RA and RP close to each other, subparallel (vs ScP + RA diverging from RP in Mimarachne , Saltissus , Chalicoridulum , Mimamontsecia ); MP with three terminals (vs single in Cretodorus , two terminals in Saltissus , Chalicoridulum , Mimamontsecia , Burmissus , and Ayaimatum , no fewer than four terminals in Jaculistilus and Dachibangus ); CuA forked early, near wing basal 1/3 (forked late, near wing midpoint in Mimaplax , Chalicoridulum , Saltissus , Burmissus , Ayaimatum , Cretodorus ); tegmen without narrow marginal membrane (vs with narrow marginal membrane in Mimarachne , Chalicoridulum , Mimamontsecia , Burmissus , Cretodorus , Mimaeurypterus ); hind wing CuA with two terminals (vs three terminals in Nipponoridium ).

Figures

Figure 1. Holotype of Multistria orthotropa gen. et sp. nov. A habitus in dorsal view B head and thorax in dorsal view C hind tarsus D pronotum in dorsal view. Scale bars: 2 mm (A); 1 mm (B, C); 0.25 mm (D).

Figure 2. Line drawings of Multistria orthotropa gen. et sp. nov. A head and thorax B hind tarsus C forewing D hind wing. Scale bars: 1 mm (A, B); 2 mm (C, D).