Plesioblattogryllus magnificus, Huang & Nel & Petrulevičius, 2008

Huang, Di-Ying, Nel, André & Petrulevičius, Julian F., 2008, New evolutionary evidence of Grylloblattida from the Middle Jurassic of Inner Mongolia, north-east China (Insecta, Polyneoptera), Zoological Journal of the Linnean Society 152 (1), pp. 17-24 : 21-22

GRYLLOBLATTIDA

After the available phylogenetic analysis of the fossil taxa currently attributed to the Grylloblattida , P. magnificus gen. nov., sp. nov., would fall in the Blattogryllidae Rasnitsyn, 1976 because of the following characters, after Storozhenko (1998, 2002): (1) forewing with sigmoidal cross-veins in area between CuP and M + CuA/CuA. Storozhenko (2002) interpreted them as branches of CuA terminating on CuP; (2) costal area of fore and hindwings narrow; (3) cross-veins of forewing area between Sc and C simple, not H- or Y-shaped. Storozhenko (2002: 284) indicated that the Blattogryllidae have ‘Sc veinlets H- or Y-shaped’, which is absolutely not the case in all the taxa currently included in the family; (4) forewing veins CuA and M basally fused (no veinlet ‘M5’ between them); (5) forewing cubital area with a series of branches of CuA directed to posterior wing margin; (6) forewing CuA with a strong anterior flexure at base. In fact, its forewing venation is closely similar to that of B. karatavicus Rasnitsyn 1976 .

However, Storozhenko (1988a, b, 2002: 284) indicated that both B. karatavicus and Blattogryllulus mongolicus have tarsi with a large arolia and lacking claws. Plesioblattogryllus has strong claws and no arolia. These two characters are sufficient to separate Plesioblattogryllus from the Blattogryllidae , as the type species of this last family is B. karatavicus .

Another possible difference is the thorax as broad as pronotum in the Blattogryllidae , unlike the thorax with broad lateral expansions of Plesioblattogryllus . But it is necessary to be prudent with this character because of the taphonomic deformations of the body structures in these insects with large thoraces and heads. Interestingly, the thorax of Parakhosara nasuta Storozhenko, 1993 ( Megakhosaridae Sharov, 1961 ; sister group of Blattogryllidae + Mesoblattinidae , after Storozhenko, 2002) is similar to that of Plesioblattogryllus .

We also have to compare Plesioblattogryllus with the taxa currently attributed to the Blattogryllidae because some of these taxa are based on isolated wings:

(i) Baharellus Storozhenko, 1988a (two species: Baharellus lineatus Storozhenko, 1988a , Middle Jurassic, and Baharellus madygensis Storozhenko, 1992 ; Triassic). Both have the forewing Rs with only two main branches and with a corresponding area relatively reduced ( Storozhenko, 1988a, 1992, 1998). (ii) Blattogryllulus Storozhenko, 1988a (two species: B. mongolicus Storozhenko, 1988a , and Blattogryllulus lucidus Storozhenko, 1988a , both Upper Jurassic). Both have a forewing MA and CuA simple, and an Rs not pectinate, with a double fork ( Storozhenko, 1988a).

(iii) Parablattogryllus Storozhenko, 1988a (one species: Parablattogryllus obscurus Storozhenko, 1988a , Lower Cretaceous). This taxon is based on a hindwing, even if it was labelled as a forewing in Storozhenko (1988a: fig. 1.i). Thus, it is difficult to compare with our specimen but its Rs is not pectinate.

(iv) Dorniella Bode, 1953 (two species: Dorniella pulchra Bode, 1953 ; Lower Jurassic, Dorniella primitiva Storozhenko, 1992 , Middle or Upper Triassic). Both have Rs with only two branches ( Storozhenko, 1988a, 1992). D. primitiva is based on a hindwing, which is very difficult to compare with the known forewings of D. pulchra . Thus the generic identity of these two species is questionable.

(v) Costatoviblatta Storozhenko, 1992 (one species: Costatoviblatta aenigmatosa Storozhenko, 1992 ; Middle or Upper Triassic).

(vi) Mesoblattogryllus Storozhenko, 1990 (three species: Mesoblattogryllus intermedius Storozhenko, 1990 ; Mesoblattogryllus conjuctus Storozhenko, 1992 ; both from Middle or Upper Triassic, Mesoblattogryllus longipennis Storozhenko, 1992 ; Lower or Middle Jurassic). These two genera have a short Sc and its first branch of Rs is pectinate, instead of being simple ( Storozhenko, 1992, 1998).

(vii) Baharellinus Storozhenko, 1992 (two species: Baharellinus dimidiatus Storozhenko, 1992 ; Baharellinus pectinatus Storozhenko, 1992 ; both from Middle or Upper Triassic). They have very different wing shapes, rounded in B. dimidiatus and very elongate in B. pectinatus . Nevertheless, their Sc is short and Rs has three branches ( Storozhenko, 1992, 1998).

(viii) Protoblattogryllus Storozhenko, 1990 (three species: Protoblattogryllus zajsanicus Storozhenko, 1990 ; Protoblattogryllus asiaticus Storozhenko, 1990 ; Protoblattogryllus abruptus Storozhenko, 1990 ; Middle or Upper Triassic). They have a short Sc and an Rs with two branches ( Storozhenko, 1990).

(ix) Microblattogryllus Storozhenko (1990) (one species: Microblattogryllus variabilis Storozhenko, 1990 ; Middle or Upper Triassic). It has a short Sc and a simple Rs.

(x) Anoblattogryllus Storozhenko, 1990 (one species: Anoblattogryllus fundatus Storozhenko, 1990 ; Middle or Upper Triassic). Its Sc is short.

(xi) Gryphopteron Handlirsch, 1939 (one species: Gryphopteron molle Handlirsch, 1939; Lower Jurassic). Its MA is fused with Rs, and its Rs has two distal branches ( Ansorge, 1996).

(xii) Megablattogryllus Storozhenko, 1990 (two species: Megablattogryllus magister Storozhenko, 1990 ; Megablattogryllus austerus Storozhenko, 1990 ; Megablattogryllus pinguis Storozhenko, 1990 ; Middle or Upper Triassic). Their CuA emerges first from M + CuA, then MP, and lastly MA, unlike our fossil. (xii) Blattogryllus Rasnitsyn, 1976 (two species: B. karatavicus Rasnitsyn, 1976 ; Upper Jurassic, Blattogryllus rasnitsyni Storozhenko, 1990 ; Lower Jurassic). The only difference of Plesioblattogryllus with Blattogryllus in the wing venation is its MP being apparently simple. All other characters are identical ( Rasnitsyn, 1976; Storozhenko, 1990).

Remark: All the species currently attributed to the Blattogryllidae based on isolated wings now fall into uncertain position between the Blattogryllidae and the Plesioblattogryllidae because these two families can be separated only on the basis of the body characters.