This specialization towards small prey ecologically separated Knoetschkesuchus from most of the other diverse crocodilians that it lived with in the island ecosystem of Jurassic Europe.

Other distinguishing traits include the relatively wide skull, and the presence of the antorbital and mandibular fenestrae in all life stages.

Stereomicroscopy was used to examine the specimens, which were described in a 2017 paper published by Daniela Schwarz, Maik Raddatz, and Oliver Wings.

There are two primary vertebrate-bearing lignite strata within the so-called Guimarota-strata, which are separated by marly limestone and respectively known as the "Fundschichten" and "Ruafolge" subunits; K. guimarotae is known from both of these layers.

[5][6][7] The remains of K. guimarotae are stored at the Institute of Geological Sciences of the Free University of Berlin (hereafter IPFUB).

[8] The backs of both of the known species are covered with two rows of bony rectangular osteoderms, centred at the midline, that are wider than they are long.

The oval-shaped antorbital fenestra is small, being only 9% the length of the eye socket; its presence is unique to both species of the genus among atoposaurids.

The back of the bone bears a small notch in K. langenbergensis and a general concavity in K. guimarotae that slightly exposes the underlying supraoccipital.

At the front of the pterygoid is a small projection that extends backwards to form a ridge, on either side of which is a furrow-like depression (the choanal groove) containing the choanae.

[5] Like the maxilla, distinct sockets for dentary teeth are replaced by a groove from the eleventh tooth backwards in K.

[3] When the known specimens of K. langenbergensis were first described in a preliminary fashion by a 2006 paper from Hans-Volker Karl et al., they were referred to the genus Theriosuchus.

This was on the basis of the short skull, divided nostrils, large eye sockets compared to the supratemporal fenestrae, and the bevelled side of the squamosal.

However, they noted that the nasals essentially completely divide the nostrils to the exclusion of other bones, which is not seen in the genus of Theriosuchus.

Many recent taxonomic studies have not provided an explicit set of characteristics that unite species of Theriosuchus and separate them from other atoposaurids;[13][14][15] the only such diagnoses that have been produced were given by Steve Salisbury and Darren Naish in 2011,[16] and Jeremy Martin et al. in 2010.

[17] In 2016 Mark Young et al. criticized these diagnoses, noting that many characters were either more widely distributed among the Atoposauridae, difficult to assess, or—in the case of the latter diagnosis—not present at all.

These include the presence of only two unique tooth morphotypes; the choanae being placed in shallow grooves rather than a bowl-like depression; the relatively wide top of the skull; the presence of antorbital and mandibular fenestrae in all life stages; and the relatively limited contact between the lacrimal and nasal.

Additionally, K. langenbergensis differs from other species in lacking teeth with low crowns; having a longer maxillary symphysis; having a crest on the side of the downward-projecting process of the postorbital; having overlap between the postorbital and the front of the squamosal; and a rectangular parietal that does not form part of the supratemporal fenestra.

[3] In the 2017 description of K. langenbergensis, Schwarz et al. used the 2015 phylogenetic dataset of Alan Turner,[18] which was revised to remove irrelevant characteristics, add K. langenbergensis and T. grandinaris, and correct flaws in the coded traits of K. guimarotae (due to low-resolution images, inaccuracies in the original reconstruction, and the acquirement of new data).

The phylogenetic trees recovered by this analysis consistently found that Atoposauridae, represented by Knoetschkesuchus, Theriosuchus, and Alligatorium, forms a monophyletic clade.

[3] Pachycheilosuchus trinquel Isisfordia duncani Acynodon adriaticus Acynodon iberoccitanus Susisuchus anatoceps Iharkutosuchus makadii Hylaeochampsa vectiana Allodaposuchus subjuniperus Allodaposuchus precedens Theriosuchus symphiestodon Theriosuchus pusillus Alligatorium spp.

[5] During the Kimmeridgian, Europe was covered by the shallow inland Tethys Ocean, with exposed landmasses being a series of scattered archipelagos.

[24] Besides K. langenbergensis, other crocodilians from the Langenberg Quarry include the marine Machimosaurus hugii and Steneosaurus aff.

brevirostris,[11] which would have lived offshore and fed on turtles and fish; and the amphibious generalist Goniopholis simus,[11] which subsisted on a diet of both shelly and soft prey like modern alligators.

[25] Isolated teeth show that there were at least four different types of theropods present at the locality, including the megalosaurid Torvosaurus sp.

as well as an additional megalosaurid and indeterminate members of the Allosauridae and Ceratosauria;[26] theropod tracks from two different species (not identifiable to the family level) are also known.

[1] Remains attributable to diplodocids (possibly also dwarfed) and stegosaurs have also been found,[24] alongside an indeterminate dsungaripterid pterosaur.

These include a paramacellodid lizard;[28] the turtles Thalassemys sp.,[29] Plesiochelys etalloni,[30] and a juvenile eucryptodiran;[31] plagiaulacid multituberculate,[32] dryolestid, and docodont mammals known from teeth;[24] the mammaliaform Storchodon;[33] a diverse actinopterygian fish fauna dominated by Lepidotes sp.

[3] The vertebrate-bearing Guimarota-strata was deposited in a brackish lagoon that periodically received both freshwater and saltwater influxes.

[36][37] Plants known from megafossils include the horsetails Equisetum and Schizoneura; the seed fern Caytonia; the cycad Otozamites; the araucaria Brachyphyllum; Ginkgo; and the charophyte algae Porochara.

[40] Additionally, Bernissartia sp., Lisboasaurus estesi, and Lusitanisuchus mitracostatus have also been found;[41] the latter two were small, being less than 50 centimetres (20 in) in length, and likely also fed on insects like K.