INTRODUCTION

1 Fossil vertebrate footprints are rare in New Brunswick, with only four previously documented localities. All the specimens represent Mississippian-Pennsylvanian footprints or trackways. Only one occurrence has been adequately described, while the other identifications are inadequate or considered dubious. A single undescribed trackway in the Canadian Museum of Nature (CMN 10013) from the Mississippian (Namurian) Bonaventure Formation of Heron Island northern New Brunswick (Ells 1881; Harington et al. 2005) is identified only as ‘Amphibia?’. All other specimens are in the collection of the New Brunswick Museum (NBMG). A putative Triassic track-way identified as Isocampe lepreauense (NBMG 3044) from the Balls Lake Formation at Lepreau Falls (Sarjeant and Stringer 1978) requires reexamination as the rocks are now assigned to the Mississippian Mabou Group (Barr and White 2005). Footprints from the Pennsylvanian (Langsettian) Lancaster Formation, ‘Fern Ledges’ locality in Saint John, described by Matthew (1910) have been considered to be unrecognizable by various authors (e.g., Falcon-Lang and Miller 2007). Bipezia, represented by Bipezia bilobata (NBMG 3037-3038), was described as unrecognized "genera" by Häntzschel (1975) who considered it to be of doubtful vertebrate origin based on Matthew’s description. Glaessner (1957) thought it might be synonymous with the arthropod trace Isopodichnus (= Oniscoidichnus). Both Hylopus, represented by Hylopus(?) variabilus, (NBMG 3041-3043) and Nanopus, represented by Nanopus(?) vetustus, (NBMG 3045) were considered as unrecognized "genera" and considered as doubtful "footprints" by Häntzschel (1975). Abel (1935) believed neither represented a vertebrate track, but were unrecognizable forms. Falcon-Lang et al. (2007) described a fourth locality near Johnson Mills in the Pennsylvanian (Langsettian) Grande Anse Formation from the Maringouin Peninsula in southeastern New Brunswick. They identified most of the tracks on two slabs as Pseudobradypus (NBMG 14143, 14144).

2 The footprints described here, from the Upper Mississippian (Namurian) Enragé Formation, Upper Rockport, New Brunswick, represent a significant addition to the meagre record of Paleozoic tetrapod tracks from New Brunswick (Fig. 1). The specimen is referred to Pseudobradypus ichnosp., and represents one of the oldest tetrapod ichnofossils from New Brunswick. The oldest occurrence of Pseudobradypus is from the Lower Mississippian (Tournaisian) Horton Bluff Formation in Nova Scotia where Lucas et al. (2004) described the oldest known tetrapod trackways from the Maritime Provinces. Most Pseudobradypus are attributed to captorhinomorph reptiles (Haubold 1971). Falcon-Lang et al. (2007) argued that Pseudobradypus from the Grande Anse Formation could convincingly be attributed to a reptile trackmaker and thus provides the earliest evidence for reptiles.

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3 Tetrapod footprints are well known from Nova Scotia in the Maritimes region of eastern Canada, some of the earliest work being done by Sir William Dawson and others from the cliffs at Joggins (Sarjeant and Mossman 1978). Ironically George Frederic Matthew at the Natural History Society of New Brunswick in Saint John, who identified the dubious footprints from the ‘Fern Ledges’ site, set the pace for the study of Carboniferous tetrapod ichnology (Matthew 1903a,b, 1905; Haubold et al. 2005) by attempting to develop a classification framework for tracks. Most of his work involved Nova Scotia specimens. Haubold et al. (2005) noted that in the 100 years since Matthew’s work there has been little progress in finding a suitable classification scheme.

LOCATION AND GEOLOGY

4 The type section of the Enragé Formation is exposed along the southwest shoreline of the Maringouin Peninsula, Westmorland County, New Brunswick (NTS 21 H/10E). The specimen described here was found during the NATMAP field trip (St. Peter and Johnson 1997, STOP 11E) on a coastal exposure on the east side of the Maringouin Peninsula, along the western shore of the Cumberland Basin about half a kilometre south-southwest of Green Creek (Fig. 1). The trackway was collected from a vertical face of brick red mudrock at the top of the last fining-upward cycle of the Enragé Formation, which also represents the top of the Mabou Group in New Brunswick (Fig. 2).

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5 The Enragé Formation consists of fine-to coarse-grained, reddish orange arkosic grit, pebbly grit, arkosic sandstone, polymictic conglomerate and brick red siltstone and mudstone (St. Peter and Johnson 1997; New Brunswick Department of Natural Resources 2007). Sandstone beds, 1 to 5 metres thick, form repeated fining-upward cycles that are 4–10 metres thick. Red siltstone and mudstone form the upper 5–12 centimetres of each fining-upward cycle. The Enragé Formation of the Mabou Group occupies the stratigraphic interval immediately below the Cumberland Group in New Brunswick and is, in part, laterally equivalent to the Hopewell Cape Formation. An unconformity separates the Enragé Formation from the overlying Boss Point Formation (Fig. 2).

6 Spores from the Enragé Formation suggested an age no younger than Namurian (reported in St. Peter and Johnson 1997) from a locality near the top of the formation at Green Creek. The assemblage was considered too poor to date with confidence, and the formation age is reported as unspecific Namurian age. Calder et al. (2005) placed the Enragé Formation in the Pendleian just below the unconformity between the Mississppian and Pennsylvanian of the Maritimes.

SYSTEMATIC PALAEONTOLOGY

CONCLUSION

7 Documented vertebrate footprints and trackways are relatively rare in New Brunswick, a surprising fact given the extent of Carboniferous exposure in the eastern part of the province. Nova Scotia has produced numerous vertebrate trackways from the Joggins area (Sarjeant and Mossman 1978), Cape Breton Island (Keighley and Pickerill 1998) and Horton Bluff (Lucas et al. 2004). The New Brunswick record of skeletal remains of Carboniferous tetrapods is also poor compared to Nova Scotia (Calder 1998) with only a few unpublished or unverified records known to us. The paucity of the New Brunswick record may be, in part, due to less intensive investigation, which has proven to be the case in other taxonomic groups.

8 The footprints found near Green Creek, Upper Rockport, New Brunswick, are located in one of four known Carboniferous vertebrate footprint localities in New Brunswick; Heron Island (Ells 1881; Harington et al. 2005), Lepreau (Sarjeant and Stringer 1978), "Fern Ledges", Saint John (Matthew 1910) and the Maringouin Peninsula. The Heron Island footprints (CMN 10013) are Mississippian, earliest Namurian, and likely represent the oldest vertebrate (possibly amphibian) track-way from New Brunswick (Fig. 2). Falcon-Lang et al. (2007) described Pseudobradypus from the Pennsylvanian, basal Langsettian Grande Anse Formation on the Maringouin Peninsula. The trackways are preserved on two slabs with 114 prints that allowed a detailed analysis of the morphology. The authors considered the specimens represent the earliest evidence for the origin of reptiles. The tetrapod footprints from Upper Rockport, also identified as Pseudobradypus, and possibly of reptile origin, are of unspecified Namurian age, likely Mississippian, and older than the fossils described from the Grande Anse Formation by as much as 11 million years. Although only a few well-preserved prints are found on the Enragé Formation slab described here, they may represent even earlier evidence of amniotes, and like the Grande Anse footprints, predating the appearance of reptiles based on skeletal remains from Joggins (Calder 1998).