Evidence of biotic interactions through shell repair in gastropods from the Lower Cretaceous of west-central Argentina (2023)

The Neuquén Basin, a largely triangular marine basin in west-central Argentina, is world renowned for its Lower Jurassic to Late Cretaceous marine and continental sequences that provide a nearly continuous record of rich and diverse fauna and flora (Howellet al., 2005). In particular, the Upper Jurassic and Lower Cretaceous marine sequences are superlative in terms of abundance and conservation of marine invertebrates and vertebrates described since the early 19th century. The utility of these faunas has been repeatedly demonstrated in the literature over the last 30 years, including successful applications in biostratigraphy, paleoecology, and macroevolution, among others (z.B., Aguirre-Uretaet al., 2007, 2011, 2019; Cataldo and Lazo, 2016; Tapeet al., 2005, 2008, 2009; carmona for uset al., 2018; Come, 2016). A variety of different marine communities and ecosystems have successively existed in this basin for millions of years, and many different biotic interactions must have taken place.

Biotic interactions, along with environmental parameters, are known to affect the abundance and distribution of fossil and extant species (z.B., Anderson, 2016; Gonzalez-Salazaret al., 2013). However, the amount of knowledge about past environmental parameters far exceeds that of past biotic interactions, so there is an imbalance of information between the two factors, mainly becauseliveThe interactions are difficult to identify with certainty in the fossil record. In particular, there are few documented examples of marine macrofauna in the Neuquén Basin. Notable exceptions are the well-documented mutualism between corals and serpulids and competition between bryozoans and bryozoans (z.B., Garberoglioet al., 2019; Garberoglio and Lazo, 2011; Luci and Lazo, 2015), derived symbiosis between corals and photosynthetic algae (Garberoglio, 2019) andliveEmbedding of nautilids by serpulids and bryozoans (Luci and Cichowolski, 2014). There is particularly little published evidence of durophagic predators in marine sections of the Upper Jurassic-Lower Cretaceous Neuquén Basin, despite data from several taxa capable of such behavior (Alexander and Dietl, 2003; Walker and Brett, 2002).z.B., nautiloids, ammonoids, palinurid lobsters, asteroids, picnodontiform fish, batoid rays, sharks and marine reptiles (Aguirre-Urretaet al., 2008 , 2011 ; Bocchino , 1977 ; Zion , 1999 ; Cione in Pereira, 1990; DE Fernandezet al., 2019; MEVR. Fernandezet al., 2019; Gouiric-Cavalliet al., 2018, 2019; Loveet al., 2005). To date, only three examples of shell damage attributed to durophagy are known, all in molluscs: i) In titonic ammonoids from the Vaca Muerta Formation, Vennari (2011a,b) reported fatal and sub-fatal fractures, some of which may be due to predators; ii) Complete and incomplete circular boreholes have been described in lower Valangine oysters at the boundary between the Vaca Muerta and Mulichinco formations and attributed to the action of unknown borer predators (Toscano).et al., In the press); iii) Microscopic perforations were found in lucinid shells from the Upper Hauterivian of the Agrio Formation and were also attributed to borer predators (Archuby and Gordillo, 2012).

According to Gómez-Espinosa, there is a relatively extensive literature on durophagia in Cretaceous mollusks.et al.(2015, figure 5). However, reports on the frequency of shell repairs in calcareous snails are generally lacking (see Walker and Brett 2002, Table 3). there is only one casei.e, the snail fauna of the Upper Campanian-Maastrichtian Ripley Formation of the USA (Vermeijet al., 1981; Vermeij and Dudley, 1982) in which the frequency of casing repairs was calculated. Other examples of repaired gastropod damage (due to sublethal and crushing predators) have been reported from the Late Cretaceous of Antarctica (z.B., Aguirre-Urreta en Olivero, 1992, laat Campanien; the harpistet al., 2019, Maastricht.

It is known that in the Phanerozoic, predators were a powerful driver of evolutionary trends in shallow-water marine environments. Vermeij's (1987) climbing hypothesis established for the first time the fundamental role of predator-prey interactions (as well as competition) in the development of both morphology and behaviour. These biological interactions, together with the activity of grazing animals in the epifauna, determine the rhythm of the various episodes throughout life (see Walker and Brett, 2002, Fig. 14) in which significant jumps in adaptation due to the effects of increased predation. including the Mesozoic Marine Revolution (MMR; Vermeij, 1977). Within the MMR, which presumably began in the Middle Triassic (Salamonet al., 2012; Tackett and Bottjer, 2012), the Early Cretaceous represents a crucial point in time. The structure of most communities changed before and after this period.i.e, between the Late Triassic-Early Jurassic (early MMR phase) and the Late Cretaceous (more modern ecosystems) (Vermeij, 2008, 2011). New groups of predators arose (z.B., birds), others began to diversify significantly (z.B., teleosts) and reject others (z.B., marine reptiles); Habitats and behaviors associated with the refuge (z.B., dull) extended; defensive morphological characters (z.B., thicker shells) began to be predominant in sessile and sedentary epifaunas, and some of these clades (z.B., crinoids) have even reduced or changed the environment (see Walker and Brett, 2002 for a detailed description). However, only a few predator data from this interval are available worldwide (Huntley and Kowalewski, 2007, Fig. 1; Kowalewskiet al., 1998).

Current research on MMR aims to clarify some of the many unanswered questions or to test some of its hypotheses. For example, geographic/latitude patterns in predators and adaptations, and the differential impact of MMR on communities in different environments (z.B., Buatoiset al., 2016; Harper, 2003, 2022; clog makeret al., 2019). In particular, these require data that is more geographically dispersed, comes from a broader range of settings, and has a higher temporal resolution (Harper, 2022).

In this work, we document the recovery of bivalves of a snail species from lower Barremian marginal marine deposits in the northern Neuquén Basin, west-central Argentina. This is the first documented case of shell recovery in snails from the Early Cretaceous of Argentina and, to our knowledge, the first report of shell recovery frequency from a Early Cretaceous unit anywhere in the world. Therefore, the main objectives of this article are: 1) to describe the repaired fracture; 2) discuss whether the fracture that led to the recovery of the shell can be considered of biogenic origin and caused by durophagic predators; 3) calculate repair frequencies and compare them with another case study from the Cretaceous; 4) Compare scale size distributions between populations to estimate possible geographic differences; and 5) calculate repair frequencies at clam-sized intervals to assess whether the species has reached its sanctuary.

Our hypothesis is that the intrusion is the result of attacks with predatory grenades. Possible sources of damage to the skeleton of mineralized invertebrates include, according to Zuschinet al.(2003, Fig. 2), ecological (predation, high-energy impacts, rapid excavation) causes, biostratinomic (bioerosion, abrasion, dissolution) and diagenetic (compaction, tectonic shear) processes, and sampling and/or sample handling practices . We also include modern weathering which, once released from the host matrix, allows specimens to be subjected to rolling, debris, or other fossil impacts, etc., which can also cause fractures. A number of criteria have been established to allow a reasonable assessment of whether the observed fracture of an invertebrate exoskeleton is the result of predatory activity with any degree of certainty (z.B., Alexander and Dietl, 2003; Ebbestad and Stott, 2008; the lump makeret al., 2019; Kowalewsky, 2002; Leighton, 2011; Leurder y Brett, 2002; Entregaet al., 2003).