[11][12] Conjunctio was named from a specimen originally referred to Aspidosaurus novomexicanus by Case et al. (1913)[13] that was also placed in Broiliellus by American paleontologist Wann Langston in 1953[14] before being divided again by Carroll.
[16] DeMar also provided the first synthesis of the morphological diversity and possible function of dissorophid osteoderms in 1966[17] and named two new species of Broiliellus in 1967, B. arroyoensis and B. olsoni,[18] and completed a detailed revision of D. multicinctus in 1968.
[19] In 1971, American paleontologist Peter Vaughn described one of the few dissorophids outside of New Mexico, Texas, and Oklahoma, Astreptorhachis ohioensis from the late Carboniferous of Ohio, represented by a series of fused neural spines and osteoderms.
[28] In 1999, Chinese paleontologists Li Jinling and Cheng Zhengwu described the first and only dissorophid from eastern Asia, the middle Permian Anakamacops petrolicus from China.
[36] A team led by German paleontologist Florian Witzmann published a comparative histology study that sampled a number of dissorophids in 2010.
[39] In 2013, three new dissorophids were named in a festschrift dedicated to Reisz in Comptes Rendus Palévol: Broiliellus reiszi from the early Permian of New Mexico in a study led by Canadian paleontologist Robert Holmes;[40] Scapanops neglecta from the early Permian of Texas in a study by German paleontologists Schoch and Hans-Dieter Sues, re-evaluating a specimen historically referred to as the Admiral Taxon;[41] and Reiszerpeton renascentis from the early Permian of Texas in a review of material referred to the amphibamiform Tersomius texensis by a team led by Canadian paleontologist Hillary C.
[42] In 2018, Chinese paleontologist Liu Jun provided an updated osteology of Anakamacops based on substantially more complete material and erected the tribe Kamacopini to group the middle Permian dissorophids from Eurasia.
[43] Two separate studies led by Gee were also published that year, one reappraising the early Permian Alegeinosaurus aphthitos from Texas, which he suggested to be a junior synonym of Aspidosaurus,[44] and another reappraising the middle Permian Fayella chickashaensis from Oklahoma, in which the authors determined that the holotype was a nomen dubium but that the referred specimen was sufficiently distinct to warrant erecting a new taxon, Nooxobeia gracilis.
Schoch & Milner (2014) list several features that diagnose dissorophids, but most of these are only useful for differentiating the clade from the closely related trematopids, and some are outdated in light of newer research: (1) maxillary tooth row terminating at or anterior to the posterior orbital margin; (2) basipterygoid region firmly sutured; (3) no prefrontal-postfrontal contact; (4) absence of denticles on the basal plate of the parasphenoid; (5) no pterygoid-vomer contact; (6) short postorbital; (7) long and parallel-sided choana; and (8) absence of a supinator process.
[1] Aspidosaurines and platyhystricines are represented largely by postcranial material, and thus features such as osteoderms are some of the only differentiators for these taxa, but dissorophines and eucacopiens also have many cranial differences, such as the relative proportions of the skull.
Most dissorophids are medium-sized, being intermediate between the small amphibamiforms and the larger trematopids, but Dissorophidae includes the largest known dissorophoids, all from the middle Permian of Eurasia, with skull lengths exceeding 30 cm.
Eucacopine (sensu Schoch & Sues, 2013) was traditionally referred to as Cacopinae and includes Cacops and the middle Permian Eurasian taxa (Anakamacops, Iratusaurus, Kamacops, Zygosaurus).
These are the two most widely utilized distinctions within Dissorophidae, although Aspidosaurinae[8] (which includes only Aspidosaurus and indeterminate Aspidosaurus-like material) was recently revived along with the erection of the new Platyhystricinae (Platyhystrix and Astreptorhachis).