SciELO - Scientific Electronic Library Online

 
vol.34 número2La geodiversidad al servicio del desarrollo regional índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Revista

Articulo

Indicadores

  • No hay articulos citadosCitado por SciELO

Links relacionados

  • No hay articulos similaresSimilares en SciELO

Compartir


Serie correlación geológica

versión On-line ISSN 1666-9479

Ser. correl. geol. vol.34 no.2 San Miguel de Tucumán dic. 2018

 

ARTICULOS

Bioerosion on marine molluscs of MIS 5e in Faro Segunda Barranca, South of Buenos Aires Province, Argentina

BIOEROSIÓN EN MOLUSCOS MARINOS DE MIS 5E EN FARO SEGUNDA BARRANCA, SUR DE LA PROVINCIA DE BUENOS AIRES, ARGENTINA.

 

Melisa P. CHARÓ1, José L. CAVALLOTTO2, Guillermo ACEÑOLAZA1 y Gisela D. CHARÓ3

1 Instituto Superior de Correlación Geológica (INSUGEO /CONICET-UNT) Miguel Lillo 205, 4000 Tucumán, Argentina, e-mail: charomelisa@gmail.com, e-mail: gfacenolaza@gmail.com
2 Servicio de Hidrografía Naval, Av Montes de Oca 2124, C1270ABW Buenos Aires, Argentina, e-mail: jlcavallotto@gmail.com.
3 Laboratorio de Fluidodinámica, Departamento de Ingeniería Mecánica, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV, Ciudad Autónoma de Buenos Aires, Argentina, e-mail: charogiselad@gmail.com


Abstract: Faro Segunda Barranca is located in the south of Buenos Aires Province (40°46'S/62°16'W), where Late Pleistocene marine deposits (108 — 102 Ka correlated with MIS 5e) have been identified, as well as the modern beach. In a sample of 158 mollusc shells, nine ichnogenera and four ichnospe-cies were found in two sites. Seven ichnogenera were found in the Late Pleistocene (Site 1), while nine ichnogenera and four microbioerosion morphotypes were found in the modern beach (Site 2). Both sites yielded Iramena, Maeandropolydora, Entobia, Caulostrepsis and Pinaceocladichnus (Domichnia), Finichnia (Fixichnia) and Oichnus (Praedicnia); Trypanites and Gastrochaenolites (Domichnia) were present only in Site 2. The most abundant Late Pleistocene ichnogenera are Iramena and Pinaceocladichnus, suggesting an en-vironment of low sedimentation, with moderate water current and availability of suspension particles. Whereas in the modern beach, Maeandropolydora is dominant, suggesting a sublitoral environment and sandy bottom; the record of Trypanites and Gastrochaenolites indicates hard substrate and shallow environment. The identified ichnogenera suggest changes in the environmental features between the MIS 5e and the modern beach at Faro Segunda Barranca.

Key words: Bioerosion. Marine molluscs. Pleistocene. Argentina.

Resumen: Faro Segunda Barranca se encuentra en el sur de la Provincia de Buenos Aires (40°46'S/62°16'O), donde se identifican depósitos marinos del Pleistoceno Superior (108.000-102.000 años A. P, correlacionados con MIS 5e) y playas actuales. Se analizaron en total 158 valvas de moluscos y se identificaron nueve icnogéneros y cuatro icnoespecies en dos sitios. En los depósitos del Pleistoceno Superior (Sitio 1) se detectaron siete icnogéneros, mientras que en la playa actual (Sitio 2) se registraron nueve icnoespecies y otros cuatro morfotipos de microbioe-rosión. En ambos sitios se identificaron Iramena, Maeandropolydora, Entobia, Caulostrepsis y Pinaceocladichnus (Domichnia), Finichnia (Fixichnia) y Oichnus (Praedicnia); Trypanites y Gastrochaenolites (Domichnia) están presentes solo en el Sitio 2. En el Sitio 1 los icnogéneros más abundantes son Iramena y Pinaceocladichnus, los cuales sugieren un ambiente de baja sedimentación, corrientes de aguas moderadas y disponibilidad de partículas de suspensión. Mientras que en la playa actual domina Maeandropolydora que indica un ambiente sublitoral y sedimentos arenosos y la presencia de Trypanites y Gastrochaenolites indica sustratos duros y ambientes litorales. Los icnogéneros identificados sugieren cambios en los factores ambientales entre el Pleistoceno Superior y la playa actual en el área de estudio.

Palabras clave: Bioerosión. Moluscos marinos. Pleistoceno. Argentina. Key words: Bioerosion. Marine molluscs. Pleistocene. Argentina.


 

Introduction

Trace fossils are a key source of informa-tion about ecological interactions and animal behavior in the past (Bengtson and Rasmussen, 2009).

The subjects of paleoichnology are trace fossils (also called ichnofossils), which are fos-silized structures produced in substrates ran-ging from unlithified sediment to sedimentary rock or organic matter (including shell, bone, wood and peat) by the activity of organisms (Knaust, 2017).

Most groups of trace fossils are generally considered of little use as stratigraphic indica-tors, because they provide information on the behavior of the trace-maker rather than of its biological identity, and because most ichnota-xa are stratigraphically long-ranging (Bromley, 2004).

Trace fossils include bioturbation struc-tures (e.g., burrows, trails, footprints), and evi-dence of biodeposition (e.g., coprolites, fecal pellets), biostratification (e.g., microbial mats) and bioerosion. There is a "grey zone" of du-bious structures, however, that some workers include as trace fossils and others do not (e.g. traces: coprolites, spider webs, all kinds of nests, etc. and no traces: eggs, pearls, etc.) (Bert-ling et al, 2006).

The term ‘bioerosion’ (Neumann, 1966) itself has been reinterpreted, expanded, and/or redefined by multiple authors over the last half century (Davidson etal., 2018). Bioerosion is a mechanism of taphonomic alteration caused by mechanical and/or chemical biological activity of a large number of organisms that may bore, penetrate, gnaw, graze or etch surfaces on per-sistent firm/hard substrata including rock, she-ll, bone, dead wood, peaty or compacted mud banks and cliff faces, and human-made subs-trata (metal, concrete, plastics, etc.) (Taylor and Wilson, 2003; Davidson etal., 2018).

The bioerosion process is particularly common in the marine environment and occurs similarly on rocky bottoms, such as carbonate structures of biotic origin (eg. corals, mollusk shells, brachiopods), and skeletons of marine vertebrates (eg, whale bones). Among the organisms that produce bioerosion structures are the microborers that belong to one of the two major groups of energy generation: photoau-totrophs (bacteria, cyanobacteria and algae) and heterotrophs (foraminifera, sponges, bryo-zoans); macroborers (polychaetes, sponges, bi-valves) and browsers (echinoderms, gastropods and crustaceans) (Molinu, 2015).

Hard substrate trace fossils are classica-lly divided into macroborings versus microbo-rings, for the study of which a hand lens or a scanning electron microscope is used, respecti-vely (Bromley, 2004). Taylor et al. (1999) propo-sed an intermediate category named "mesobo-ring" for which the optical microscope is used.

Macroborings are defined as any boring that can be detected with the naked eye, about 1 mm diameter (Wilson, 2007). Marine macroborings are very common and most valuable for paleoecological analyses. Most described ma-croborings are found in marine deposits even if some of the substrate, such as wood, bones, and even coprolites (Tapanila et al, 2004) ori-ginated on dry land. They are thus important contributors to what we know about the ecological driving forces of evolution among marine organisms (Wilson, 2007). Whereas micro-bioerosion features are less than one millimeter in size with tunnel diameters commonly less than a hundred microns (Wisshak, 2012). Microborers are most common and diversified in marine environments, but are also known on fresh water and air-exposed rocks (Golubic and Schneider, 2003). Microborings are abundant in the fossil record related to calcareous substrates such as coral skeletons, mollusc and brachiopod shells, limestones and ooids (Glaub and Vogel, 2004). The well fossilized microborings of eu-endoliths are used as proxies in paleoecological and paleobathymetrical studies (Tribollet et al, 2010). This bioerosion is a useful tool in pa-leoenvironmental interpretation because of its abundance and trace morphology; as well, regarding the evolutionary rates, microboring groups are very conservative through the geolo-gic time. Diversity, distribution and abundance of microborings depend on the substrate and environmental conditions (Vogel et al., 2000).

"Shells" as understood here include any mineralized invertebrate (eg. echinoderm, some bryozoans and cephalopods). External shells can be encrusted or bored while the host animal is still alive (Taylor and Wilson, 2003). Shell borings are useful for paleoecologic and tapho-nomic reconstructions (Warme, 1975).

Bored shells are very common in the Cenozoic, being the main boring agent clio-nid sponges, bivalves, polychaetes, phoronids, ctenostome cryozoans and acrothoracican bar-nades (Taylor and Wilson, 2003). Bioerosion traces have been studied in Miocene deposits worldwide (eg. Árpád, 2001, 2010; Farinati and Zavala, 2002; Verde, 2002; El-Hedeny, 2007; Santos and Mayoral, 2008; Santos et al., 2010; Domenech et al, 2014; Pineda-Salgado et al, 2015), Pliocene (eg. Mayoral, 1987, 1988ab, 1991; Gibert and Martinell, 1992; Martinell and Domenech, 1986, 1995; Gibert and Martinell, 1996; Gibert et al, 2007; Molinu et al, 2015), as well as in Pleistocene ones (eg. Bromley and D’Alessandro, 1983, Bromley, 1999; Ruggie-ro and Annunziata, 2002; Lorenzo and Verde, 2004; Wisshak and Neumann, 2018).

Bioerosion traces of the Argentine Qua-ternary have been studied mainly in Holocene ridges and modern beaches on marine molluscs (bivalves, gastropods and barnacles) and lithics (e.g. Farinati and Aliotta, 1995; Farinati and Zavala, 1995; Pastorino and Ivanov, 1996; Farinati et al, 2006; Arregui et al, 2009; Cardenas and Gordillo, 2009; Aguirre et al, 2011; Charó et al, 2012; Gordillo and Archubi, 2012; Gordillo, 2013; Spagnuolo et al, 2013; Richiano et al, 2014; 2015; Charó et al, 2015c,d, 2017a, b). However, studies of Late Pleistocene deposits are scarce (e.g. Richiano et al, 2015; Charó et al, 2015a,b).

The main goal of this paper is to describe the bioerosion traces on bivalve and gastropod shells found in Late Pleistocene deposits of Faro Segunda Barranca, south of the Buenos Aires Province, as well as to interpret the en-vironmental features and their paleoecological significance.

Geological setting

During the transgressions of the Quater-nary, large extensions of the littoral of the Province of Buenos Aires and along the Patagonian coast were affected by processes of accumulation and erosion generated by the different oscilla-tions of the sea level (Isla et al, 2000). These marine deposits have been intensely studied from a geomorphologic, stratigraphic and geochronolo-gic stand points (eg. Angulo et al, 1981; Trebino, 1987; Rutter et al, 1989, 1990; Weiler, 1988, 1993, 2000; Schnack et al, 2005; Fucks et al, 2012a, b), as well as their paleontologic content (Pastorino, 2000; Charó et al, 2013a, b, 2014; Charó, 2014).

The Pleistocene marine deposits along the Buenos Aires coastline are restricted and discontinuous, interbedded or lying over Pampean sediments, and represented by different facies (Schnack et al, 2005). The highest levels reached by these deposits are between 6—8 m, mostly distributed on the northeast and south of Buenos Aires (eg. Codignotto and Aguirre, 1993; Isla et al, 2000; Weiler, 2000; Fucks et al, 2012; Charó, 2014), and are assigned to the Puente de Pascua Formation (Fidalgo et al, 1973; Fucks et al, 2006, 2010) correlated to MIS 5e (Table 1). In some localities this transgres-sion is represented as a highly cemented coquina (Schnack et al, 2005).

Study area

Faro Segunda Barranca, is near 20 km south of Bahía San Blas (40°33'S/62°14'W) between Segunda Barranca and Punta Rasa, south of Buenos Aires Province (Figure 1).

Site 1. Late Pleistocene marine deposits are represented by littoral ridges 8-10 m high along the south of Buenos Aires Province. They are composed of clasts that correspond to a transgressive event of MIS 5e. One of these deposits was dated in 108-102 Ka at about 10 m above sea level (Rutter et a¡, 1989, 1990) (Site 1), and is divided in two layers. Only the upper layer was studied, which is composed of clast-supported gravel, with sand and sandy conglomerate level on the surface. The overall color is grey, with clearly defined parallel to low-angle cross bed-ding, showing a slight southern inclination and partial clustering in some strata (Figure 2 A and B). Site 2. Modern beaches of this area are wide and sandy with clasts and remains of marine mollusc shells (Figure 2 C).

Table 1. Ages of marine deposits of Late Pleistocene (MIS5e) in Buenos Aires Province. / Tabla 1. 'Edades de depósitos marinos del Pleistoceno Tardío (MIS 5e).

 

Isla flamenco


Figure 1. A) Study area. B) Description of Pleistocene deposits in the south of Buenos Aires Province (Charó et al, 2013). / Figura 1. A) Área de estudio. B) Descripción de los depósitos marinos pleistocenos del sur de la Provincia de Buenos Aires (Charó et al., 2013).

 

Materials and Methods

Two sites were studied. Site 1 was studied on samples 1dm3 volume. Site 2 was studied on three samples collected on a 1m x 1m quadrant on transects perpendicular to the coast line.

Once the valves were separated from the sediment with sieves, the proportion of valves with bioerosion was quantified (Charó, 2014).

The study of trace fossils was made fo-llowing the different ethologic classes of Seila-cher (1953) modified by Bromley (1981, 1994, 1996) and specific papers on ichnotaxonomy (eg. Mayoral, 1988a, b; Blissett and Pickeri-ll, 2007; Taylor et al., 2013). Bioerosion traces were observed by naked eye and images were digitalized through a scanner (HP Scanjet 300), following the technique used by Bromley and Richter (1999). Externally, microborings were studied using incident light on the surface, and the observation of microscopic marks was made through a stereoscope microscope model SMZ 800 with a program NIS - Elements (IN-SUGEO-UNT, Horco Molle, Tucumán). While the internal analysis will be studied in future in-vestigations. Images were processed with Corel — Draw 13 and Adobe Photoshop.

All graphics were created through the package PGFPlots (Feuersanger, 2010) of La-TeX program and MATLAB 16. For the analy-sis of the bioerosion marks on valves, bivalves and gastropods were divided into different sec-tions. The surface of bivalves was divided into four sections (umbonal, central, muscular and posterior areas), and gastropods were divided into two sections: whorls and last whorl, except for the genera Crepidula and Bostrypapulus.

Results

Among the collected material (158 valves) a total of 7 species of bivalves and 11 gastropods were recognized, 11 of them are bioero-ded (7 gastropods and 4 bivalves).

Bivalves and gastropods

In MIS 5e deposits, eight species were found (three gastropods and five bivalves) fos-sil remains include the gastropods Tegula patagónica, Bostrycapulus odites, Crepidula sp., and the bivalves Pitar rostratus, Mytilus edulis, Brachidontes rodriguegli, Aequipecten tehuelchus, Ostreola equestris and Ostrea puelchana. Whereas in modern bea-ches, 15 species were found (10 gastropods and five bivalves), being the most abundant the gas-tropods O. equestris, T. patagonicus, B. odites and T. argentina (Table 2).


Figure 2. A and B) Late Pleistocene marine deposit (MIS 5e) a) sandy conglomerate level and b) clast-supported gravel with sand. C) Modern beach at FSB. / Figura 2. Ay B) Depósito marino del Pleistoceno Tardío (MIS 5e), a) nivel de conglomerado arenoso y b) grava clasto-sostén con arena. C) Playa actual en FSB.

Paleoecology

The benthic community of molluscs found in MIS 5e deposits is characterized by the dominance of euryhaline, epifaunal, roc-ky substrate species, mostly filtering and her-bivores. Whereas the living communities are mostly euryhaline, with lesser proportion of polyhaline-euhaline and increasing species of rocky substrate, being mostly carnivores with a low proportion of filtering species (Table 3, Figure 3).

Marine bioerosion

Bioerosion traces are represented by nine ichnogenera (Iramena, Maeandropolydora, Entobia, Caulostrepsis, Pinaceocladichnus, Trypanites and Gas-trochaenolites (Domichnia), Finichnia (Fixichnia) and Oichnus (Praedicnia) (Figure 4), and four ichnospecies (O. simplex, M. sulcans, P. onubensis and C. taeniola) (Figure 5), as well as four micro-bioerosion morphotypes (Figure 6).

Macrobioerosion

Finichnia (Taylor et al., 2013) are groups of elliptic or pear-shaped pits wider than deep, ranging from the Cretaceous to Recent (Man-gano and Buatois, 2016). This ichnogenus is dominant in Site 2. It covers the umbonal and central areas of bivalves, and the whorls area of gastropods. It was found on T. patagonica and B. odites of both sites (Figure 5A, B).

Caulostrepsis Clarke, 1908 is a boring of a single entrance, U-shaped, on the surface of the valve. The branches may be connected through a lamella, or merging the margins producing an oval or flat "pocket" (Verde, 2002). It has been attributed to the activity of spionid polychaetes and is known since the Devonian (Taylor and Wilson, 2003). This ichnogenus was found in the umbonal area of P. rostratus in Site 1 and O. puelchana in Site 2. The ichnospecies Caulostrepsis taeniola Clarke, 1908 is a subdivided U-shaped gallery, with the internal margins connected by a sheath; it was identified on the umbonal area of O. puelchana of Site 2 (Figure 5C, E).

Maeandropolydora Voigt, 1965 is abundant in Site 2 and covers the umbonal, muscular and central areas of bivalves. This ichnogenus is dominant in Crepidula sp. and O. equestris of Site 1 and B. odites, O. equestris and O. puelchana of Site 2. The ichnoespecies Maeandropolydora sulcans (Bromley and D’Alessandro, 1983) was identified in Site 2. It is represented by cylindri-cal borings, uniform in diameter, with irregular sinuous, plano-spiral and/or helicoidal shape (Taylor and Wilson, 2003). It is known since the Cretaceous (Taylor and Wilson, 2003), occu-rring in both shallow- and deep-marine settings (Mangano and Buatois, 2016) (Figure 5D).

Table 2. Bivalvia and gastropods found in Faro Segunda Barranca, south of Buenos Aires Province/ Tabla 2. Bivalvos y gasterópodos encontrados en Faro Segunda Barranca, sur de Buenos Aires.

Acronym

Bivalvia

Site 1

Site 2

Br

Brachidontes (B.) rodriguezi (d'Orbigny, 1846)

X

Me

Mytilus edulis platensis d'Orbigny, 1846

X

Oe

Ostreola equestris (Say, 1834)

X

X

Op

Ostrea puelchana d'Orbigny 1841

X

cg

Crassostrea gigas (Thunberg, 1793)

X

At

Aequipecten tehuelchus (d'Orbigny, 1842)

X

X

Pr

Pitar (P.) rostratus (Philippi, 1844)

X

X

Gastropods

Dp

Diodora (D.) patagonica (d1 Orbigny, 1841)

X

Tep

Tegula (A.) patagonica (d'Orbigny, 1835)

X

X

Bo

Bostrycapulus odites (Coltin, 2005)

X

X

Ca

Crepidula argentina Simone, Pastorino &

Penchaszadeh, 2000

X

Ha

Heleobia australis (d'Orbigny, 1835)

X

Tp

Trophon patagonicus (d’Orbigny, 1839)

X

Zd

Zidona dufresnei (Donovan, 1823)

X

Bm

Buccinanops monilifer (Kiener, 1834)

X

Table 3. Paleoecology and distribution of bivalvia and gastropods. Ep= epífaunal; I=infaunal; Ce= cemented; Ec=ectoparasite; R=hard;S=soft; M=mixed; C=carnivorous; He=herbivore; F= suspension feeder; O=Oligohaline (3-8%o); M=mesohaline (8-18%o); P=polyhaline (18-30%o); E=euhaline (30-35 %ó)./ Tabla 3. Paleoecología y distribución de bivalvosy gasterópodos. E= epifaunal; I=infaunal; Ce=cementado; Ec=ectoparásito; R=rocoso; S=arenosos; C=carnívoro; He=her-bívoro; F=filtradores suspensívoros; O=oligohalino; M=mesohalino; P=polihalino; E=euhalino.

Bivalvia

Salinity

Life habit

Depth

Substrate

Trophic

type

Distribution a rea

Brachidontes (B.) rodriguezi ( d'Orbigny,

1846)

P-E

Ep

0-25

R

F

34°S - 42°S

Mytilus edulis platensis d'Orbigny, 1846

P-E

Ep

0-50

R

F

68°N - 55.5°S

Ostreola equestris (Say, 1834)

P-E

Ce

0-80

R

C

37°N - 42°S

Ostrea puelchana d'Orbigny 1841

P-E

Ce

0-70

R

C

22°S - 42°S

Crassostrea gigas (Thunberg, 1793)

E

Ce

0-40

R

F

Cosmopolitan

Aequipecten tehuelchus (d'Orbigny, 1842)

E

Ep

10- 120

M

F

21°S - 53°S

Pitar (P.) rostratus (Philippi, 1844)

E

I

10 -100

S

F

22°S - 38.7°S

Gastropods

Diodora (D.) patagonica (d' Orbigny, 1841)

E

Ep

0-15

R

He

11°N - 45°S

Tegula (A.) patagonica (d'Orbigny, 1835)

E

Ep

0-57

R

He

23°S - 54°S

Bostrycapulus odites (Collin, 2005)

E

Ep

0-46

R

F

25°S - 45.8°S

Crepidula argentina Simone, Pastorino & Penchaszadeh, 2000

E

Ep

30-50

R

F

38°S-41.03°S

Heleobia australis (d'Orbigny, 1835)

O, P, M

Ep

0-60

M

He

24°S - 41 °S

Trophon patagonicus (d’Orbigny, 1839)

E

Ep

0-50

R

C

32°S-40°S

Zidona dufresnei (Donovan, 1823)

E

Ep

10-90

S

C

23°S - 42°S

Buccinanops monilifer (Kiener, 1834)

E

Ep

0-50

S

C

35°N - 42°S

Buccinanops globulosus (Kiener, 1834)

E

Ep

0-6

S

C

35°S - 46°S

Olivancillaria carcettesi Kiappenbach, 1965

E

Ep

0-22

S

C

23°S - 42.5°S

Parvanachis isabellei (d'Orbigny, 1839)

E

Ec

10-65

S

C

30°S - 54°S

 

Iramena Boekschoten, 1970 is a boring system consisting in long primary tunnels litt-le bifurcated, in irregular pattern with primary apertures, rounded to kidney-shaped, opening into a main cavity (Mayoral, 1988a). This ichnogenus covers the entire external surface of the valve of bivalves and the whorls and last whorl areas of gastropods. It is abundant in B. odites, Crepidula sp., P. rostratus, B. rodriguezii and T. patagonica of Site 1, and in B. odites, D. moni-liferum, B. globulosus and Crepidula sp. of Site 2 (Figure 5F).

Oichnus Bromley, 1981 are circular, subcircular or oval borings perpendicular to the substrate that can or cannot perforate the surface. It is mostly generated during predation by gastropods and octopods (Wisshak et al, 2015). This ichnogenus is known from the Ediacaran to Recent (Taylor and Wilson, 2003) occurring in both shallow- and deep-marine settings (Mangano and Buatois, 2016) (Figure 5G).


Figure 3. Paleoecological requirements of bivalves and gastropods in Late Pleistocene A) Salinity; C) Life habit; E) Substrates; G) Trophic type and modern beaches B) Salinity; D) Life habit; F) Substrates and H) Trophic type. / Figura 3. Requerimientospaleoecológicos de bivalvos y gasterópodos en el Pleistoceno Tardío A) Salinidad; C) Modo de vida; E) Sustratos; G) Tipos tróficos, y playas actuales: B) Salinidad D) Modo de vida F) Sustratos y H) Tipos tróficos.

 

The ichnospecies Oichnus simplexBromley, 1981 is characterized by a cylindrical or sub-cylindrical aperture, perpendicular to the surface of the substrate. It was identified in both sites, on bivalves mostly on the umbonal, central and muscular areas, and on gastropods, on the last whorl area. It was found on C. argentina of Site 1 and on B. globulosus, T. patagonica, O. carcelle-si, O. equestris and O. puelchana of Site 2.


Figure 4. Morphological classification of bioerosional trace fossils (Knaust and Bromley, 2012). / Figura 4. Clasificación morfológica de trabas fósiles de bioerosión (Knaust and Bromley, 2012).

 

Trypanites Magdefrau, 1932 and Gastrochae-noRtes Kelly and Bromley, 1984 were found only in Site 2. Trypanites are simple borings, elongated or cylindrical, generally circular in cross-section. This ichnogenus covers the umbonal and central areas of the internal valve of O. equestris of Site 2 (Figure 5H). GastrochaenoRtes is a club-sha-ped boring with the apertural region narrower than the main chamber that may be circular, oval or dumb-bell. In this case, the apertural region is circular with the widest part near the base and perpendicular to the substrate surfa-ce. This ichnogenus was found in the umbonal, muscular and central areas of the external valve of O. equestris of Site 2 (Figure 5J).

Pinaceocladichnus Mayoral, 1988b is a boring pattern formed by a regular network of fine tunnels, slightly curved and laterally oppo-site. The ichnospecies Pinaceocladichnus onubensis (Mayoral, 1988b) is a pattern of straight to slightly arched main tunnels with verticillate and also random bifurcations. It has elongate cavi-ties with apertures near the bifurcation of the tunnels. This bioerosion mark was identified in both sites covering the umbonal, central and posterior areas of bivalves. It was found on B. odites and P. rostratus of Site 1 and on O. equestris of Site 2 (Figure 5I).

Entobia Bronn, 1838 are cylindrical ga-lleries parallel to the surface, composed by in-terconnected chambers, with network-shaped borings on the surface of the valve (Árpád, 2010). This ichnogenus covers mainly the umbonal area of bivalves and the whorls area of gastropods. It was recorded on O. equestris and P. rostratus of Site 1 and T. patagonica of Site 2 (Figure 5K).

Microbioerosion

Microborings made by tallophytas were found in low frequency in Site 2. Four morpho-types were identified. Morphotype 1 is a series of cylindrical conducts very uniform in diameter with a bifurcated pattern in almost orthogonal angles that can bifurcate again in the same way or more frequently as Y-shape. It was found in the inner valve of O. equestris (Figure 6A). It is re-cognized by Mayoral (1988a) as morphotype C.


Figure 5. Ichnogenera of FSB sites. A) Fimchmts on B. odites (PIL, Site 2, modem); B) details of A; C) Caulostrepsis tamida on O. equestris (PIL:, Site 2, modern); D) Maeandnpodydora sudcans on O. equestris (PIL:, Site 2, modern); E) Caulostrepsis taenmb on O. puedchana (PIL:, Site 2, modem); F) Iramena on B. odites (PIL , Site 2, modern); G) Oricbnus on O. camlksi (PIL:, Site 2, modern); H) Trypanites on Ostreap. (PIL:, Site 2, modern); I) Pinaceodcdkhnus on P. rostrauts (PIL:, Site 2, modern); J) Gastmchaenolites on O. equestris (PIL:, Site 2, modern) and K) Entibia on P. rostratus (PIL, Site 1, Pleistocene). / Figura 5. Ichnogéneros en dos slos de FSB. A) Finichnus en B. odites (PIL, Sido 2,aOud); B) detades de A; C) Caulostiepsis taeniola en O. equestris (PIE; Sitio 2, ctíud); D) Maeandropolydora sulcans en O. equestris (PIE; Sitio 2, ctíud); E) Caulostrepsis taeniola en O. puelchana (PIL; Siio 2, actud); F) Iramena en B odites (PIL, Sido 2, actud); G) Oichnus en O. carcellesi (PIE; Sido 2, actud); H) Trypanites en Ostrea sp. (PIE, Sitio 2, actud); I) Pinaceodadichnus en P rostratus (PIE, Sitio 2, actud); J) Gastrochaenolites en O. equestris (PIE, Sido 2, actud) yy K) Entibia en P rostratus (PIL, Sido 1, Pdeistoceno).

Morphotype 2 consists of a series of su-bircular subcavities which are part of the main filament; they bifurcate in secondary filaments in almost orthogonal angles that in turn bifurca-te in shorter filaments at lower angles (Mayoral, 1988a) (Figura 6B). It was found in the inner valve of O. equestris. It is recognized by Mayoral (1988a) as morphotype B1. This is the first record in Argentine modern beaches.

Morphotype 3 is composed by four curved furrows similar in length and opposite; each furrow is almost 1500- 2000 |am long (Figura 6C). This microbioerosion is abundant on epifaunal elements, and was found on O. equestris in Site 2. It is recognized by Mayoral (1988a) as morphotype B4. This is the first record in Argentine modern beaches.


Figure 6. Microbioerosion in intemal valves of Site 2 of FSB. A) Morphotype 1 on O. equestris (PIL: 15.210); B) Morphotype 2 on O. equestris (PIL: 15.770); C) Morphotype 3 on O. equestris (PIL: 15.771) and D) Morphotype 4 on B. odites (PIL: 15.772). / Figura 6. Microbioerosion en valvas internas dd Sitio 2 de FSB. A) Morfotipo 1 en O. equestris (PIL: 15.210); B) Morfotipo 2 en O. equestris (PIL: 15.770); C) Morfotipo 3 en O. equestris (PIL 15.771) andD) Morfotipo 4 en B. odites (PIL: 15.772).

 

Mophotype 4 is an arborescent model of reduced extension that originates from a subcircular opening located on the surface of the shells. It consists of a series of more or less radial furrows and a rounded central cavity not quite defined, dichotomically bifurcated and Y-shaped (Figura 6D). It is recognized as morphotype B in Mayoral (1988a); the most eroded ones are similar to morphotypes B3 or B2.

Ichnogenera vs. Abundance

The dominant ichnogenera of Site 1 are Iramena, Pinaceocladicbnus and Entobia with a low proportion of Oicbnus and Caulostrepsis, whereas the most abundant of Site 2 are Maeandropolydora, Iramena and Oicbnus with less representation of Fi-nícbnía, Trypanites and Pinaceocladicbnus (Figura7A).

Traces are located according to the behavior of the organism. Dwelling traces (Domichnia): for

Maeandmpoiydora and Caulostrepsis there is not a particular area, they are produced by locomotion. Entobia is more frequent on the last whorl of gastropods and the central and umbonal area of bivalves. Pinaceocladicbnus and Iramena found the umbonal area, being Iramena dominant on all the shell. Predation traces (Praeácbnrn): Oicbnus affects mainly the muscular area of bivalves and the last whorl of gastropods (Figura 7B).

Seven bioeroded species were identified in Site 1: the gastropods Tegulapatagonica, Bostrycapu-lus odites, Crepidula argentina and Olivancillaria carce-llesi and the bivalves Bracbidontes rodriguegii, Ostreola equestris and Pitar rostratus. Of a total of 52 valves, 30.76 % showed bioerosion marks of Iramena, Pi-naceocladicbnus, Entobia, Finicbnus, Maeandropolydora, Caulostrepsis and Oicbnus (Figura 7C).

Eight bioeroded species were recorded in Site 2: the gastropods Tegula patagonica, Bostrycapu-lus odites, Zidona dufresnei, Tropbon patagonicus, Dors-anum moniliferum, Olivancillaria carcellesi, Buccinanops ghbuhsus and the bivalve Ostreola equestris. Of a total of 106 valves, 44.33 % showed bioerosion marks of Maeandropolydora, Iramena, Oichnus, Entobia, Caulostrepsis, Gastrochaenolites, Finichnus, Trypanites and Pinaceocladichnus (Figura 7D).


Figure 7. A) Abundance of ichnogenera in Late Pleistocene and modern beaches; B) Bioerosion traces found in the different areas of bivalves and gastropods. Total: total area; ua: umbonal area; ca: central area; ma: muscular area; pa: posterior area; wa: whorls area; lwa: last whorl area; C) Proportion of ichnogenera present in the Late Pleistocene and D) Proportion of ichnogenera present in the Modern beach. I: Iramena, M: Maeandropolydora, E: Entobia, C: Caulostrepsis, F: Finichnus, O: Oichnus, T: Trypanites, P: Pinaceocladichnus and G: Gastrochaenolites. / Figura 7. A) Abundancia de icnogéneros en elPleistoceno Tardío y playas actuales; B) Tragas de bioerosión encontradas en las diferentes áreas de valvas de bivalvos y gasterópodos. Total: área total; ua: área umbonal; ca: área central, ma: área muscular; pa: área posterior; wa: área de espira; lwa: área de la última vuelta; C) Proporción de icnogéneros presentes en el Pleistoceno Tardíoy D) Proporción de icnogéneros presentes en las playas actuales. I: Iramena, M: Maeandropolydora, E: Entobia, C: Caulostrepsis, F: Finichnus, O: Oichnus, T: Trypanites, P: Pinaceocladichnus and G: Gastrochaenolites.

 

Discussion

Ichnogenera were more abundant in Site 2 than in Site 1 of Faro Segunda Barranca. In Site 1 Iramena and Pinaceocladichnus were dominant, suggesting quiet waters of low sedimentation, moderate water currents and sandy bottom. Both ichnogenera indicate a benthic communi-ty composed of ctenostomata briozoans. Their increasing record in the Pleistocene deposit su-ggests larger availability of phyto and zooplank-ton in the environment and high oxygenation of water. The dominance of both ichnogenera indicates intermediate stability in the marine en-vironment. In Site 2, instead, the abundance of Maeandropolydora suggests the existence of poly-chaete annelids, mostly Spionidae and indicates sandy bottom at the sediment-water interface. The occurrence of Oichnus does not indicate any particular environment but suggests the existence of muricaceans, such as T. patagonicus which is abundant in this site. The presence of Gastrochaenolites produced by bivalves of the Family Mytiladae and Trypanites made by sipunculid annelids (Neumann et al., 2008), indicates hard substrate and a shallow coastal marine environ-ment. The presence of G. torpedo in modern beaches suggests a shallow marine environment than that of the Late Pleistocene.

Macrobioerosion on marine molluscs in the Late Pleistocene of South America

Richiano et al. (2014) studied bioerosion markers in bivalves and gastropods in Quater-nary deposits along the Atlantic Argentine coast from Río de la Plata to Patagonia, southern Santa Cruz Province. These authors recognized five ichnogenera (Maeandropolydom, Finichnus, Entobia, Caulostrepsis and Oichnus) for the Late Pleistocene of Patagonia. While in this paper, seven ichnogenera and two ichnospecies (O. simplex and P. onubensis) were recognized sug-gesting that the south of Buenos Aires is richer in bioerosion on mollusc shells than Patagonia. From the ethological point of view, the domi-nant ichnofacies was Domichnia, the same as in both sites of Faro Segunda Barranca.

Charó et al. (2015b) studied two littoral ridges of the north Patagonian coast, San Antonio Oeste (SAO) (40°42’S/ 64°57’W) and La Rinconada (LR) (40°48’S/ 65°4’W) sites. Both deposits are Late Pleistocene in age (120 Ka, MIS 5e). In SAO the authors reported 33 % of bioerosion markers with three ichnogenera: Entobia, Maeandropolydora and low proportion of Oichnus. While for LR, they reported 10.3 % of bioerosion markers (Entobia, Iramena, Pinaceocla-dichnus and low proportion of Meandropolydorá) in all the valves. All these ichnogenera were pre-sent in Site 1 of Faro Segunda Barranca. The abundance of Entobia in both sites (SAO and LR) of north Patagonia indicates stable subs-trate; on the contrary, Entobia was found in low proportion in both sites of Faro Segunda Barranca. Although with different abundance of gastropod and bivalve species because of the geographic location of the sites, the record of Iramena and Pinaceocladichnus in LR is similar to that of Site 1 of Faro Segunda Barranca.

Richiano et al. (2015) studied the bioe-rosion on marine mollusc in the Middle Pleis-tocene (MIS 11) of Bahia Camarones, Chubut Province (44°50'S/65°40'W). They studied 536 valves of molluscs and found 8 ichnogenera: Entobia, Maeandropolydora, Iramena, Caulostrepsis, Pinaceocladichnus, Finichnus, Podichnus and Oichnus. All of them are represented in the study area except for Podichnus. The most abundant was Iramena, similar to Site 1 of Faro Segunda Barranca (Table 4).

Microbioerosion in the south of Buenos Aires Province.

Microbioerosion is an important issue in the study of marine communities but it has not been studied as comprehensively as macrobioe-rosion in the marine Quaternary of Argentina.

In the microbioerosion analysis four mor-photypes were found on mollusc shells of the modern beaches. Morphotype 1, recognized as Orthogonum lineare Glaub, 1994 is produced by an unknown heterotroph. It has been recorded from the Ordovician to the Recent (Wisshak, 2012). This ichnospecies is found in Lower Pliocene and Pleistocene sediments of the NW Mediterranean (Molinu et all, 2015) and Arenas de Huelva Forma-tion (Inferior Pliocene) (Mayoral, 1988a) in Spain. Its paleobathymetric significance is under debate (Heindel et aZ, 2009); whereas other authors sta-ted that this morphotype is used to recognize the aphotic zone (Glaub, 2004; Wissack, 2012)

Morphotypes 2-4, display an arborescent model which is typically produced by algae, but no taxonomic assignment is concluded. Morphotype 2 is observed as macroborings with an arborescent model in surface. Its very common on Ostreidae in the Pliocene Arena de Huel-va Formation, Bajo Guadalquivir Basin, Spain (Mayoral, 1988a). This microbioerosion morphotype was found in the inner valve of Amian-tispurpurata from the Holocene of Jabalí Island (40°34’S/ 62°13’W) (Charó et all., 2017).

 

Table 4. Ichnogenera presents in Pleistocene marine deposits in South of America. / Tabla 4. Icnogénerospresentes en los depósitos marinos Pleistoceno en el Sur de América.

Ichnogenera

Southern Brazil

Chui Creek Formation (230

ky)

(Lopes et al., 2013)

Uruguay

Villa

Soriano

Formation

(Pl-Hol)

(Lorenzo and Verde, 2004)

South of

Buenos Aires Province (this paper)

North of Rio Negro Province

(Charóet al. 2015) MIS5e

SAO    LR

North

patagonia

(Richiano et al., 2015)

South of Patagonia

(Richiano et al., 2015)

PELntabia

X

X

X

X

X

Maeandroppoíydora

X

X

X

X

Oichnus

X

X

X

X

X

Caulostrepsis

X

X

X

X

Finichnus

X

X

X

Iramena

X

X

Pinaceocladich nus

X

X

Pemnitic/im/s

X

X

Garertchasntl^esr

X

X

Tr^panites

X

 

Morphotype 3 is an irregular arbores-cent microboring. It was found in Arenas de Huelva Formation (lower Pliocene) in Spain (Mayoral, 1988a). This morphotype is similar to Cüonolithes but quite smaller. Morphotype 4 is found on the inner valve of Bostrycapu-lus odites in the Holocene of Villalonga Canal (40°01'S/ 62°19'W), south of Buenos Aires Morphotypess 3 and 4 are dominant, sugges-ting low energy waters, and are found on shells of infaunal organisms.

Charó et al. (2017a) studied for the first time microbioerosion on bivalves and gastro-pods shells in Holocene marine deposits of the Buenos Aires Province. In this study, the au-thors described the microbioerosion morpho-types observed through optical microscope on internal valves of Crpidula and Plicatula gibbosa from the Holocene deposit of Villa 7 de Marzo (40°48'S/62°59'W) and the inner valve of B. odites in the Holocene of Villalonga Canal (40°01'S/62°19'W). Among the microbioerosion morphotypes preliminary described only two were found in the study area (Morphotype 1 and Morphotype 4).

Conclusions

The dominant ichnofacies in both sites of FSB is Domichnia with the presence of Fixich-nia and Praedichnia. The following ichnogenera were identified in both sites: Iramena, Maeandro-polydora, Entobia, Caulostrepsis, Pinaceocladichnus, Finichnia, Oichnus, Trypanites and Gastrochaenoli-tes, as well as four ichnospecies: O. simplex, M. sulcans, P. onubensis and C. taeniola. Iramena and Pinaceocladichnus were the most abundant ichnogenera in Site 1, whereas Meandropolydora, Irame-na and Oichnus were the most abundant in Site 2. Among microbioerosion traces, four mor-photypes were found, produced by endolithic microorganisms (eg. heterotrophs and algae) in modern shells. The study of this kind of trace will enlarge the knowledge of past environmen-tal factors and will also be useful in paleobathy-metric and paleotemperature issues.

All the ichnogenera suggested a marine benthic community composed of ctenostoma-te bryozoans, polychaete annelids, carnivorous gastropods, bivalves, clionaid sponges, sipun-culids annelids and algae. The Late Pleistocene was characterized by low sedimentation, high oxygenation of water, and moderate stability in the marine environment, sublittoral and sandy bottom. The modern beach instead, is characterized by sandy bottom at the sediment-water interface suggested by the dominance of Meandro-potadora and hard bottom and low sedimentation rate suggested by Gastrochaenolites and Trypanites, and the dominance of morphotipe 3 and 4 sug-gesting low energy waters.

Acknowledgements

The authors thank Dr. Cecilia Deschamps for her help in editing the English version, Sr. Erik Gómez Hasselrot (UTN-Tucumán, Argentina) for the elaboration of the graphics and Dra. Doménech Rosa for the critical comments on the manuscript. CONICET and PICT 468 (ANPCYT) provided financial support.

Referencias

Abdel-Fattah, Z. A. and Assal, E. M. 2016. Bioerosion in the Miocene Reefs of the northwest Red Sea, Egypt. Lethaia, 49: 398-41.         [ Links ]

Aguirre, M. L. and Whatley, R. C.1995. Late Quaternary marginal marine deposits and palaeoenviron-ments from northeastern Buenos Aires Provin-ce, Argentina: A review, Quaternary Science Reviews, 14(3): 223-254.         [ Links ]

Aguirre, M.L., Richiano, S., Farinati, E. and Fucks, E., 2011. Taphonomic comparison between two bi-valves (Mactra and Brachidontes) from Late Qua-ternary deposits in northern Argentina: Which intrinsic and extrinsic factors prevail under diffe-rent palaeoenvironmental conditions?. Quaternary International, 233: 113-129.         [ Links ]

Arpád, D. 2001. Macrobioerosion in the Shells of Ear-ly-Miocene Oyster of two Localities- a Com-parision (Hegyesko road cut, Szarvasko and abandoned limestone quarry, Nagyvisnyó; Bükk Mountains, Hungary). Malakologiai Tájékoytató 19: 5-12.         [ Links ]

Arpád, D. 2010. Macrobioerosion on Early-Miocene (Karpatian) Pebbles; Dédestapolcsány, Hungary. Acta GGM Debrecina Geology, Geomorphology, Physical Geography Series. DEBRECEN, 4-5: 53-56.         [ Links ]

Arregui, M., Aguirre, M., Charó, M., Richiano, S., Farinati, E, Boretto, G. and Fucks, E. 2009. Signos tafonómicos (Bioerosión e Incrustación) en Gas-tropoda y Bivalvia del Cuaternario marino del área de Bahía Bustamante (Provincia de Chubut, Patagonia). Reunión Anual de comunicaciones de la asociación paleontológica argentina. Ciudad Autónoma de Buenos Aires, Argentina. pp.15.         [ Links ]

Cárdenas, J., and Gordillo, S. 2009. Paleoenvironmental interpretation of late Quaternary molluscan as-semblages from southern South America: A taphonomic comparison between the Strait of Ma-gellan and the Beagle Channel. Andean Geology, 36 (1): 81-93.         [ Links ]

Bengtson, S. and Rasmussen, B. 2009. New and Ancient Trace Makers. Science, 323: 346-347.         [ Links ]

Bertling, M., Braddy, S. J., Bromley, R. G., Demathieu, R. G., Genise, J., Mikulás, R., Nielsen, K. J., Niel-sen, A., Rindsberg, K., Schlirf, M. and Uchman, A. 2016. Names for trace fossils: a uniform approach. Lethaia, 39: 265-286.         [ Links ]

Blissett, D.J., and Pickerill, R.K. 2007. Systematic ichno-logy of microborings from the Cenozoic White Limestone Group, Jamaica, West Indies. Scripta Geologica, 134: 77-108.         [ Links ]

Bromley, R. G. 1999. Anomiid (bivalve) bioerosion on Pleistocene pectinid (bivalve) shells, Rhodes, Greece Geologie en Mijnbouw 78: 175-177.         [ Links ]

Bromley, R.G. 2004. A stratigraphy of marine bioerosion. In Macllroy, D. (Ed.). The Application of Ichno-logy to Palaeoenvironmental and Stratigraphic Analysis. Geological Society London, Spec. Publ., V (228), pp. 445-479.         [ Links ]

Bromley, R.G., D’Alessandro A. 1983. Bioerosion in the Pleistocene of Southern Italy: ichnogenera Cau-lostrepsis and Maeandropolydora. Revista Italiana di Paleontología e Stratigrafia, 89(2), 283-309.         [ Links ]

Bromley, R. G. and Richter, B. 1999. Direkte skanning ny teknik til illustrering af geologisk materiale. Geolo-gisk Tidskrift, 4: 1-10.         [ Links ]

Charó, M.P. 2014. Caracterización paleoambiental y pa-leodiversidad malacológica en los depósitos marinos cuaternarios del norte patagónico (Sur de Buenos Aires y Norte de Río Negro). Tesis doctoral, Facultad de Ciencias Naturales y Museo, La Plata, Argentina.         [ Links ]

Charó, M. P., Pisano, F., Gordillo, S. and Fucks, E. 2012. Bioerosión en bivalvos y gasterópodos del Cuaternario marino de los Pocitos e Isla Jabalí (Sur Bonaerense). V Congreso Argentino Cuaternario y Geomofológico. Río Cuarto, Córdoba, Argentina. pp. 45-46.         [ Links ]

Charó, M. P, Gordillo, S. and Fucks, E. E. 2013. Paleoe-cology significance of Late Quaternary mollus-can faunas of the Bahía San Blas area, Argentina. Quaternary International, 301: 135-149. http:dx.doi. org/10.1016/j.quaint.2012.12.019.         [ Links ]

Charó, M. P., Cavallotto, J. L. and Aceñolaza, G. 2015a. Icnodiversidad en valvas de moluscos marinos del MIS 5e y de playa actual en Faro Segunda Barranca (sur de Provincia de Buenos Aires, Argentina). III Congreso Latinoamericano de Icnología, Colonia de Sacramento, Uruguay. pp. 32.

Charó, M. P, Aceñolaza, G. and Cavallotto, J. L. 2015b. Bioerosión en valvas de moluscos en depósitos marinos del MIS 5e (norte de la Provincia de Río Negro, Argentina). III Congreso Latinoamericano de Icnologta, Colonia de Sacramento, Uruguay. pp. 30.

Charó, M. P, Pisano, M. F. y Luengo, M. S., 2015c. Bioe-rosión en moluscos holocenos a lo largo de la costa bonaerense: resultados preliminares. Reunión de comunicaciones de la Asociación Paleontologica Argentina, Mar del Plata, Argentina. pp. 58.

Charó, M. P Cavallotto, J. L. y Aceñolaza, G., 2015d. Macrobioerosión y microbioerosión en valvas de moluscos en el Sitio Villa 7 de marzo (Límite prov de Bs As y Río Negro, Argentina. Reunión de comunicaciones de la Asociación Paleontologtca Argentina, Mar del Plata, Argentina. pp. 59.

Charó, M. P, Cavallotto, J. L. and Aceñolaza, G. 2017a. Macrobioerosion and microbioerosion in marine molluscan shells from holocene and modern bea-ches (39°-40° S, south of Buenos Aires Provin-ce, Argentina). Acta Geologica Sinica-English edition. 91(4): 801-840.

Charó, M. P, Aceñolaza, G. and Cavallotto, J. L. 2017b. Macrobioerosion of Quaternary on marine mo-lluscs in Isla Jabalí (south of Buenos Aires Pro-vince, Argentina). Workshop Bioerosion 2017, Roma, Italy, pp. 93-95.

Davidson, T. M., Altieri, A. H., Ruiz, G. M., and Torchin, M. E. 2018. Bioerosion in a changing world: a conceptual framework. Ecology Letters 21: 422-438

Domenech, R., Farinati, E and Martinell, J. 2014. Cras-sostrea patagonica (d’Orbigny, 1842) shell con-centrations from the late Miocene Rio Negro pro-vince, NE Patagonia, Argentina. Spanish Journal of Palaeontology, 29 (2): 165-182.

El-Hedeny, M. 2007. Encrustation and bioerosion on Middle Miocene bivalve shells and echinoid skele-tons: paleoenviromental implications. Revue de Paleobiologie, 26 (2): 381-389.

Farinati, E. A. and Aliotta, S. 1995. Análisis tafonómicos de conchillas en cordones holocenos, Bahía Blanca, Argentina. Cuartas Jornadas Geológicasy Geofísicas Bonaerenses, Junín, Buenos Aires, Argentina. pp. 89-97.

Farinati, E. A. and Zavala, C. 1995. Análisis tafonómi-co de moluscos y análisis de facies en la Serie Holocena del Río Quequen Salado, Provincia de Buenos Aires, Argentina. VI Congreso Argentino de Paleontología y Bioestratigrafía, Trelew, Chubut, Argentina. pp. 117-122.

Feuersanger, C. 2010. Manual for Package pgfplots. Ver-sion 1.3. http://sourceforge.net/projects/pgfplots.

Fucks, E., Aguirre, M. L. and Deschampsc, C. M. 2005. Late Quaternary continental and marine sedi-ments of northeastern Buenos Aires province (Argentina): Fossil content and paleoenvironmen-tal interpretation. Journal of South American Earth Sciences, 20: 45-56.

Fucks, E. E., Schnack. E. J. y Aguirre, M. L. 2010. Nuevo ordenamiento estratigráfico de las secuencias marinas del sector continental de la Bahía Sam-borombón, provincia de Buenos Aires. Revista de Asociación Geológica Argentina, 67 (1): 27-39.

Gibert, J. M. de and Martinell, J. 1996. Trace fossil assem-blages and their palaeoenvironmental significance in the Pliocene marginal marine deposits of the Baix Ebre (Catalonia, NE Spain): Géologie Médite-rranénne, v 23, p. 211-225.

Gibert, J. M. de, Domenech, R. and Martinell, J. 2007. Bioerosion in shell beds from the Pliocene Rous-sillon Basin, France. Implications for the (macro) bioerosion ichnofacies model. Acta Palaeontologica Polonica, 52 (4): 783-798.

González, M. A. y Weiler, N. E. 1983. Ciclicidad de niveles marinos holocénicos en Bahía Blanca y en el delta del río Colorado. Simposio "Oscilaciones del nivel del mar durante el Ultimo Hemiciclo Deglacial en la Argentina". Revista de la asociación Geológica Argentina, Mar del Plata. Actas: 69-90.

Glaub, I. 2004. Recent and sub-recent microborings from the upwelling area off Mauritania (West Africa) and their implications for palaeoecology. In McIlroy, D. (ed.). The Application of Ichnology to Palaeoenvironmental and Stratigraphic Analysis, Geological Society of London, Special Publication 228: 63-77.

Glaub, I. and Vogel, K. 2004. The stratigraphic record of microborings. Fossils Strata 51:126-135.

Golubic, S. and Schneider, J. 2003. Microbial endoliths as internal biofilms. In: Krumbein, WE., Dornieden, T. & Volkmann, M. (eds): Fossil and Recent Biofilms, pp. 249-263, Dordtrecht (Kluwer Academic Publishers).

Gordillo, S. and Archuby, F 2012. Predation by drilling gastropods and asteroids upon mussels in rocky shallow shores of southernmost South America: Paleontological implications. Acta Palaeontologica Polomca, 57 (3): 633-646.

Isla, F., Rutter, N., Schnack, E., y Zárate, M. 2000. La trasgresión Belgranense en Buenos Aires. Una revisión a cien años de su definición. Cuaternario y Ciencias Ambientales, 1: 3-14.

Knaust, D. 2017. Atlas of Trace Fossils in Well Core. Ich-nological Basics, Principles and Concepts . Chap-ter 2. Springer.

Lopes, R.P 2011. Ichnology of fossil oysters (Bivalvia, Ostreidae) from the southern Brazilian coast. Gaea, 7:94-103. doi:10.4013/ gaea.2011.72.02

Lopes, R. P, Simone, L. R. L., Dillenburg, S. R., Schultz, C. L. and Pereira, J. C. 2013. A middle Pleistocene marine molluscan assemblage from the southern coastal plain of Rio Grande do Sul State, Brazil. Revista Brasileira de Paleontología, 16(3): 343-360.

Lorenzo, N. and Verde, M. 2004. Estructuras de bioero-sión en moluscos marinos de la Formación Villa Soriano (Pleistoceno Tardío — Holoceno) de Uruguay. Revista Brasileira de Paleontología, 7(3):319-328.

Mángano, G. M. and Buatois, L. A. 2016. The trace-fossil record of Major Evolutionary Events. Volumen 2: Mesozoic and Cenozoic. Topics in Geology V (40), pp. 497.

Mayoral, E. 1987. Acción bioerosiva de Mollusca (Gas-tropoda, Bivalvia) en el Plioceno inferior de la Cuenca del Bajo Gaudalquivir. Revista Española de Paleontología, 2: 49-58.

Mayoral, E. 1988a. Microperforaciones (Tallophyta) sobre bivalvia del Plioceno del Bajo Guadalquivir. Importancia paleoecológica. Estudios geológicos, 44: 301-316.

Mayoral, E. 1988b. Pennatichnus nov. icnogen.; Pin-aceocladichnus nov. icnogen. e Iramena. Huellas de bioerosión debidas a Bryozoa perforantes (Ctenostomata, Plioceno inferior) en la Cuenca del Bajo Guadalquivir. Revista Española de Paleontología, 3:13-22.

Mayoral, E. 1991. Actividad bioerosiva de briozoos ctenos-tomados en el Ordovícico Superior de la zona Cantábrica del Macizo Hespérico (Cabo Vidrias, Oviedo). Revista Española de Paleontología, 6 (1): 27-36.

Mayoral, E., Gutierrez Marco, J. C. and Martinell, J. 1991. Primeras evidencias de briozoos perforantes (Ctenosto-mata) en braquiópodos ordovícicos de los Montes de Toledo (Zona Centroiberica Meridional, España). Revista Española de Paleontología, 9 (2): 185-194.

Molinu, A. R. 2015. Microbioerosion en substratos esqueléticos del Neógeno y el cuaternario marino del Mediterraneo Occidental. Facultat de Geología. Universitat de Barcelona pp. 250.

Molinu, A. R., Domenech, R. and Martinell, J. 2015. Mi-croendoliths in Lower Pliocene Oysters from the Alt Empordá Basin, NW Mediterranean: Paleoen-vironmental Inferences: Paleoenvironmental In-ferences, Ichnos: An International Journal for Plant and Animal Traces, 22:2, 77-86.

Neumann, A. C. 1966. Observations on coastal erosion in Bermuda and measurements of boring rate of sponge Cliona lampa. Limnology and Oceanography, 11:92-108.

Pastorino, G. and Ivanov, V 1996. Marcas de prelación en bivalvos del Cuaternario marino de la costa de la provincia de Buenos Aires, Argentina. Iberus, 14:93-101.

Pineda-Salgadoa, G., .Quiroz-Barroso, S. A., Sour-To-varb, F., 2015. Analysis of bioerosion in clasts from a Miocene rocky-shore, Concepción Forma-tion, Veracruz, México. Palaeogeography, Palaeoclima-tology, Palaeoecology, 439 50-62.

Richiano, S., Aguirre, M. and Farinati, E. 2014. Bioerosion structures in Quaternary marine mollusks from Argentina. Ichnology of Latin America, 159-177.

Richiano, S., Aguirre, M. L., Davies, K., Castellanos, I and Farinati, E. 2015. Estructuras de bioerosion en moluscos marinos cuaternarios del área costera de bahía Camarones, Provincia de Chubut, Pata-gonia, Argentina. III Congreso Latinoamericano de Ic-nología, Colonia de Sacramento, Uruguay. Acta: 66.

Ruggiero, E. and Annunziata, G. 2002. Bioerosion on a Terebratulla scillae population from the Lower Pleistocene of Lecce area (Southern Italy). Acta Geologica Hispanica, 37: 43-51.

Rutter, N., Schnack, E., Del Río, J., Fasano J., Isla, F and Radtke U. 1989. Correlation and dating of Qua-ternary littoral zones along the patagonian coast, Argentina. Quaternary Science Revienes, 8:213-234.

Rutter, N., Radtke, U. and Schnack, E. 1990. Comparison of ESR and amino acid data in correlating and dating quaternary shorelines along the Patagonian coast, Argentina. Journal of Coastal Research, 6 (2): 391-411.

Santos, A. and Mayoral, E. 2008. Bioerosion versus colo-nisation on Bivalvia: a case study from the Upper Miocene of Cacela (southeast Portugal). Geobios, 41: 43-59.

Santos, A., Mayoral, E., Marques da Silva, C., Cachao, Mário and Kullberg, J. C. 2010. Trypanites ich-nofacies: Palaeoenvironmental and tectonic im-plications. A case study from the Miocene dis-conformity at Foz da Fonte (Lower Tagus Basin, Portugal). Palaeogeography palaeoclimatology palaeoecology, 292 (1-2): 35-42.

Santos, A., Mayoral, E., da Silva, C. M., Cachao, M., Domenech, R. and Martinell, J. 2008. Trace fossil assemblages on Miocene rocky shores of southern Iberia. Wisshak M, Tapanila L (eds), 2008, Current De-velopments in Bioerosion. Springer, Berlin Hei-delberg New York, pp 431-450.

Spagnuolo, J. O., Farinati, E. A. and Aliotta, S. 2013. Rodados bioerosionados en depósitos marinos holoce-nos del estuario de Bahía Blanca, Argentina: consideraciones paleoambientales y procedencia. Latin american journalof aquatic research, 41(3): 412-422.

Tapanila, L., Roberts, E. M., B, M.L., Bouaré, M. L., Sis-soko, F and O'Leary, M. A. 2004. Bivalve boring in phosphatic coprolites and bone, Cretaceous-Paleogene, northeastern Mali. Palaios, 19: 565-573.

Taylor, P. D. and Wilson, M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews, 62:1-103.

Taylor, P. D., Wilson, M. A. and Bromley, R. G. 1999. A new ichnogenus for etchings made by substrate. Talaeontology, 42, 595-64.

Trebino, L.G. 1987. Geomorfología y evolución de la costa en los alrededores del pueblo de san Blas, provincia de Buenos Aires. Revista de la Asociación Geológica Argentina 42(1-2):9-22.

Tribollet, A., Radtke, G. and Golubic, S., 2011. Ency-clopedia in Geobiology. Edition: Encyclopedia of Earth Sciences. Bioerosion. pp. 117-133. Sprin-ger-Verlag. Editors: Reitner, J. & Thiel. DOI 10.1007/978-1-4020-9212-1.

Verde, M. 2002. Icnología de la Formación Camacho (Mioceno Tardío) del Uruguay. Universidad de la República, Uruguay. Tesis de maestría.

Vogel,K., Gektidis, M., Golubic, S., Kiene, WE. and Radtke, G. 2000. Experimental studies on microbial bioerosion at Lee Stocking Island, Bahamas and One Tree Island, Great Barrier Reef, Australia: implications for paleoecological reconstructions. Lethaia 33:190—204.

Warme J.E. 1975. Borings as Trace Fossils, and the Processes of Marine Bioerosion. In: Frey R.W. (eds) The Study of Trace Fossils. Springer, Berlin, Heidelberg.

Weiler, N. E. 1993. Niveles marinos del Pleistoceno tardío y Holoceno en Bahía Anegada, Provincia de Buenos Aires. Geocronología y correlaciones. Revista de la Asociación Geológica Argentina, 48 (3-4): 207-216.

Weiler, N. E. 2000. Evolución de los depósitos litorales en Bahía Anegada, Provincia de Buenos Aires, durante el Cuaternario tardío. Tesis Doctoral, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 184 p.

Wilson, M. A. 2007. "Macroborings and the evolution of bioe-rosiori’. In Miller III, W Trace fossils: concepts, problems, prospects. Amsterdam: Elsevier. pp. 356-367. ISBN 0-444-52949-7.

Wisshak, M. 2012. Microbioerosion. In Knaust D., Bromley R. G. (eds). Trace fossils as indicators of sedimentary environments: Develop in Sedim 64: 213-243.

Wisshak, M., Kroh, A., Bertling, M. Knaust, D., Nielsen, J. K., Jagt, J. WM., Neumann, C. and Nielsen, K. S. S. 2015. In defense of an iconic ichnogenus — Oi-chnus Bromley, 1981. Annales Societatis Geologontm Poloniae, 85: 445-451.

Wisshak, M. and Neumann, C. 2018. Large dendrinids meet giant clam: the bioerosion trace fossil Neo-dendrina carnelia igen. et isp. n. in a Tridacna shell from Pleistocene—Holocene coral reef deposits, Red Sea, Egypt. Fossil Record, 21: 1-9.

Recibido: 21 de Noviembre del 2017
Aceptado: 18 de Diciembre del 2018

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons