Cratomastax mariellaae sp. nov. by monotypy and present designation. Gender: feminine.

The genus name is derived from the Crato Formation, the type deposit of the fossil, combined with “eumastax,” referring to its systematic position within Eumastacoidea.

As for the type species by monotypy.

Cratomastax gen. nov. is attributed to Eumastacoidea based on the fusion of M and CuA in the tegmina. Despite morphological similarities to Paleochina duvergeri Schubnel, Desutter-Grandcolas, Garrouste, Hervet & Nel, 2020 and P. minuta Schubnel, Desutter-Grandcolas, Garrouste, Hervet & Nel, 2020 from the Paleocene of France (compare species remarks), we refrain from assigning Cratomastax gen. nov. to Chorotypidae Stål, 1873, the family of Paleochina, or to any other family within Eumastacoidea. The classification of fossil eumastacoids remains problematic due to the limited availability of morphological characters that define modern taxa. Extant Eumastacoidea are organized either based on molecular data (Matt et al. 2008) or on detailed examination of the external and, especially, internal genitalia (Rowell and Perez-Gelabert 2006), features that are rarely preserved in fossils. While external genitalia are occasionally visible (e.g., Husemann et al. 2025), this is not the case in C. mariellaae gen. et sp. nov. Although some modern Chorotypidae (e.g., Erucius dimidiatipes Bolívar, 1898) share a similar wing venation with Paleochina or Cratomastax gen. nov., the lack of information regarding the wing venation of the ancestors of many extant apterous or brachypterous genera across Eumastacoidea provides few opportunities for comparisons on which to base phylogenetic relationships. Because the wing venation of modern Eumastacoidea is almost unstudied, it cannot be considered a reliable character for family placement in the absence of additional corroborating morphological data. Among other fossil genera of Eumastacoidea, Taphacris Scudder, 1890, from the Eocene of Colorado, USA, and the Cretaceous–Eocene of China, and Eoerianthus Gorochov, 2012 (in Gorochov and Labandeira 2012), from the Eocene of Colorado, USA, Cratomastax gen. nov. can be differentiated by the much narrower space between CuPaβ and CuPb. It further differs from Eozaenhuepfer Zessin, 2017, from the Eocene of Denmark, which has a similarly narrow CuPaβ and CuPb space, by having one fewer branch of M, two in E. erteboellei Zessin, 2017, and one additional branch of RP, four in E. erteboellei. Cratomastax gen. nov. also differs from Archaeomastax Sharov, 1968, from the Jurassic of Kazakhstan, by having a longer ScP and ScP fused to RA, instead of reaching the costal margin as in Archaeomastax. This feature also distinguishes it from Promastax Handlirsch, 1910, from the Eocene of British Columbia, and the problematic Promastacoides Kevan & Wighton, 1981, from the Eocene of Alberta. It further differs from the two Eumastacoidea preserved in amber—Paleomastacris Perez-Gelabert, Hierro, Dominici & Otte, 1997, from Dominican amber, Miocene, and Burmeumastax Husemann, Schall, Uchida & Kotthoff, 2025, from Kachin amber, mid-Cretaceous—by its much larger and fully developed wings. The single type species of Paleomastacris is apterous, whereas the single type species of Burmeumastax is brachypterous (Perez-Gelabert et al. 1997; Husemann et al. 2025).

The species is named in honor of Prof. Dr. Mariella Herberstein, currently Head of the Center for Taxonomy and Morphology at the Leibniz Institute for the Analysis of Biodiversity Change (LIB), Hamburg, Germany, in recognition of her kind support of the first author’s dissertation work.

Type locality imprecise; from one of the several quarries in the region of Nova Olinda and Santana do Cariri municipalities, Ceará State, Brazil. Nova Olinda Member, Crato Formation, Santana Group. Early Cretaceous, Aptian.

Unsexed specimen in the collection of Museu de Paleontologia Plácido Cidade Nuvens, Universidade Regional do Cariri, Santana do Cariri, Ceará, Brazil, coll. no. MPSC 9664. Donation from the Husemann Research Collection of Prof. Dr. Martin Husemann (collection number HC_0042) as part of the guidelines discussed at the “Brazil-German Colloquium on Paleontology: Science, Cooperation, and Diplomacy for the Future.”

Forewing length 30.2 mm. Forewing length/height 7. M and CuA fused to one branch. CuA + CuPaα and M one branched. RP with five branches. ScP long, reaching origin of RP2, fused terminally with RA. ScA reaching up to 37.2% of total wing length. 1A very long, reaching anal margin almost as far distally as CuA + CuPaα. CuPb and CuPaβ parallel to 1A but each slightly shorter. Space between 1A, CuPb, and CuPaβ narrow. Head height 6.67 mm. Eye height ca. 2.09 mm, oval-shaped and not protruding above head. Metafemur ca. 19.8 mm long, ca. 3.54 mm high. Metatibia at least 19 mm long, with distinct armature consisting of 16 + spines up to 0.83 mm long (spine length measured along dorsal line of longest spine).

Wings, head, and metathoracic leg preserved up to distal metatibia. Pro-, mesothoracic leg and body fragmentary.

Forewing. Length/height-ratio 7. ScP long and narrow, 93.1% of total wing length (twl). ScA reaching costal wing margin after 37.2% of twl. ScP distally with slight upwards path, fused to RA. Space between ScP and RA 7.4% of total wing height (measured at meeting point of CuA + CuPaα reaching anal margin). Origin of RP at 52.2% of twl, slightly posterior to bifurcation of M + CuA. Space between RA and RP 12% of wing height (measured at same point as before). RP with five branches. M and CuA + CuPaα simple; bifurcation of M + CuA at 48.2% of twl. M reaching anal wing margin at 88.5% of twl. CuA + CuPaα reaching anal wing margin at 80.2% of twl. CuPaβ simple, fused to CuPb at 61.7% of twl. CuPb fused to 1A at 65.4% of twl. 1A reaching anal wing margin after 78.3% of twl. Space between 1A and CuPb and CuPaβ and CuPb narrow. All three veins run parallel. Cross vein pattern simple, except for between RP branches, especially distally where it becomes a more complex net pattern.

Head. 6.67 mm high and 3.96 mm wide at widest point (at mid-eye level). Fastigium not prolonged. Antennae not preserved. Eye height ca. 2.09 mm, oval shape, not protruding above head height.

Metathoracic leg. 19.8 mm long, 3.54 mm wide (widest point). Metatibia at least 19 mm long (broken off distally), 0.81 mm wide (widest point). A single row of spines is visible on the dorsal margin of the metatibia, consisting of 16 preserved spines. Spines vary in (preserved) length between 0.18 (first preserved spine) and 0.83 mm (spine at middle). Tarsus not preserved, except for possible fragment at distal end of preserved tibia.

Among known fossil species of Eumastacoidea, Cratomastax mariellaae sp. nov. most closely resembles Paleochina duvergeri and P. minuta from the Early Cenozoic of France, although it is closer in size to P. duvergeri. Cratomastax mariellaae differs from P. duvergeri by its larger forewing length (30.2 mm vs. 23.3 mm in P. duvergeri), a different forewing length-to-height ratio (7.0 to 8.6), and a narrower spacing between CuPaβ and CuPb. The presence of a eumastacoid in the Crato Formation is not unexpected, although this is the first species to be formally described. Martins-Neto (1991) had already suggested the presence of such forms based on preliminary observations of undetermined specimens. Today, several subfamilies of Eumastacidae Burr, 1899, are represented in the modern faunas of Brazil and surrounding countries. In contrast, Chorotypidae are absent from the extant South American fauna and are currently restricted to Africa and Southeast Asia (Cigliano et al. 2025).

Aestuacrida stereofemoris Schall, Lima, Heads, Pinheiro, Kotthoff & Husemann, 2025

Two branches of M and four branches of CuA + CuPaα (after Schall et al. 2025). CuA + CuPaα do not terminate at fusion to CuPaβ (which, if present, looks like a cross vein), but near wing base.

The species name is a combination of the Ancient Greek mikron (small) and aulion (farm), dedicated to Dr. Ulrich Kotthoff (Leibniz-Institute for the Analysis of Biodiversity Change, Hamburg), who has co-authored several studies on fossil Orthoptera with the first author.

Type locality imprecise; from one of the several quarries in the region of Nova Olinda and Santana do Cariri municipalities, Ceará State, Brazil. Nova Olinda Member, Crato Formation, Santana Group. Early Cretaceous, Aptian.

Male specimen in the collection of Museu de Paleontologia Plácido Cidade Nuvens, Universidade Regional do Cariri, Santana do Cariri, Ceará, Brazil, coll. no. MPSC 9665. Donation from the Private Collection of Prof. Dr. Martin Husemann (collection number MH_Fossil_0075) as part of the guidelines discussed at the “Brazil-German Colloquium on Paleontology: Science, Cooperation, and Diplomacy for the Future.”

Generic characters (see above). Forewing: RP with five branches. Anterior two branches of CuA + CuPaα reaching anal wing margin, posterior two fused to CuPaβ. ScP long and fused to RA. Forewing length 27.9 mm, maximum height 4.8 mm. Body length 19.1 mm, height (measured at wing base) 6.28 mm. Head height 4.8 mm.

Preservation of wings and body without legs (or the legs are pressed to the body and hardly visible). Measurements of the body and head are given under diagnosis of species.

Forewing. Length/height-ratio 5.8. ScP long and narrow, 92.15% of total wing length (twl). ScP distally with slight upwards path, fused to RA. Space between ScP and RA 7.9% of total wing height (measured at origin of RP3). Origin of RP at 53.9% of twl, posterior to bifurcation of M. Space between RA and RP 7.9% of wing height (measured at same point as before). RP with five branches. M with two branches; bifurcation of M at 49.1% of twl. MA2 reaching anal wing margin at 91.5% of twl. Anterior-most branch of CuA + CuPaα reaching anal wing margin at 82.9% of twl. MP reaching anal wing margin in the middle of MA2 and anterior branch of CuA + CuPaα (precise reaching point damaged). Branches of RP up to first two anterior branches of CuA + CuPaα more or less parallel. Posterior two branches of CuA + CuPaα fused to CuPaβ at 55.3% and 49.8% of twl, respectively. CuPaβ and CuPb long, parallel, and with narrow space in between. 1A relatively short, reaching anal wing margin after 35.8% of twl. Cross vein pattern simple between cubital branches and more complex net pattern between branches of M and RP.

Aestuacrida mikronaulion sp. nov. differs from its congeneric species A. stereofemoris mainly by being significantly larger (forewing length 27.9 mm vs. 16 mm; body length 19.1 mm vs. 12.9 mm). This size difference is unlikely to result from sexual dimorphism, as both known specimens of Aestuacrida are probably males. In the new species, the pathing of CuA + CuPaα can be observed, which was obscured in the holotype of A. stereofemoris. The absence of fusion between CuA + CuPaα and CuPaβ and the continuation of CuA + CuPaα toward the wing base support the placement of Aestuacrida within Pseudoacridinae. However, the genus differs from Pseudoacrida Lin, 1982, in having one fewer branch of M and three additional branches of CuA + CuPaα. It can also be distinguished from Auroralocusta Schall, Lima, Kotthoff, Pinheiro, Heads & Husemann, submitted, by having three more branches of CuA + CuPaα. The addition of Aestuacrida to Pseudoacridinae reinforces the exceptional taxonomic diversity of Locustopsidae in the Crato Formation. Notably, two of the three currently recognized genera within the subfamily—Aestuacrida and Auroralocusta—are endemic to this deposit.

Locustrix audax Martins-Neto, 2003; Locustrix gallegoi Martins-Neto, 2003 (type species).

Following Martins-Neto (2003), the genus is diagnosed by a short ScP, MA (= M, consisting of MP and MA) two-branched, MP + CuA (= CuA + CuPaα) two-branched and fore- and hindwings with RP three-branched. This diagnosis is herein confirmed. It is possible that the new specimen of Locustrix gallegoi described below has RP of the forewing with four branches instead of three, but preservation of venation features in the most distal part of the specimen’s wings is not ideal.

The new specimen is attributed to Locustrix based on the short ScP, as well as the presence of two branches in both M and CuA + CuPaα, all observed in the forewing. Although Martins-Neto (2003) illustrated the CuA + CuPaα vein in both original Locustrix specimens as single-branched, the generic diagnosis explicitly states the presence of two branches. Locustrix can be separated from Cratolocustopsis Martins-Neto, 2003—another genus exhibiting two branches of M and CuA + CuPaα—by the markedly shorter ScP in the forewing. In Cratolocustopsis, the ScP is of typical locustopsid length, reaching close to the wing apex. Locustrix can be assigned to the subfamily Locustopsinae based on forewing venation features—namely, the presence of more than one branch of M and CuA + CuPaα not extending beyond its connection with CuPaβ. Gorochov et al. (2006) tentatively suggested that Locustrix may belong to an undescribed subfamily of Locustopsidae characterized by a shortened ScP. However, based on the evidence currently available, we consider that the abbreviated ScP is better interpreted as a genus-level diagnostic feature. Given the limited number of specimens (n = 3), no additional characters currently support the recognition of Locustrix as representing a distinct subfamily. This interpretation may be revised should further material become available in the future.

Male specimen (not of the type series) in the collection of the State Museum for Natural History Karlsruhe, collection number SMNK-PAL 76082.

Locustrix was established by Martins-Neto (2003) based on two specimens, with the description of two species: L. gallegoi, the type species, and L. audax. Locustrix audax differs from L. gallegoi by having a longer ScP reaching the costal margin posterior to the origin of RP, anterior in L. gallegoi, and by the bifurcation point of M posterior to the RP origin, anterior in L. gallegoi. At the species level, the new specimen can be assigned to L. gallegoi based on the shared position of the ScP termination and the anterior location of the M bifurcation point relative to RP.