Sanfordiacaulis

Sanfordiacaulis is an enigmatic genus of early Carboniferous plant from New Brunswick, Canada, described in 2024, distinguished by its unusual crown morphology and known from five specimens.^[1][2][3] It was discovered in 2017 near Norton, now part of Valley Waters.^[4] This genus contains one species, Sanfordiacaulis densifolia.

Sanfordiacaulis Temporal range: Tournaisian PreꞒ Ꞓ O S D C P T J K Pg N
A reconstruction of Sanfordiacaulis
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Order:	incertae sedis
Genus:	†Sanfordiacaulis Gastaldo et al., 2024
Species:	†S. densifolia
Binomial name
†Sanfordiacaulis densifolia Gastaldo et al., 2024

Description

Sanfordiacaulis is an indeterminate vascular plant, roughly 2 m (6 ft 7 in) in height, with a non-woody stem 16 cm (6.3 in) wide and a crown width of 5 to 6 m (16 to 20 ft). Its leaves are arranged in a tightly packed, non-Fibonacci spiral, with the portion of the trunk bearing leaves estimated to have had over 200 laterals based on petiole distribution.^[1] The trunk is covered in elliptical leaf bases (not visible on the upper portion due to the leaves obscuring them), with no evidence of a downward-facing leaf skirt like in palm trees. The bases of the petioles are decurrent (extend down the stem) and extend upwards for around 7 cm (2.8 in) before changing their direction further outwards, with the angle becoming sharper towards the tip down to around 20°. On the adaxial (towards the growth axis) surface a large groove is present, decreasing in size towards the tip which changes the cross-section from cordate (heart-shaped) to triangular/oval. These petioles decrease from around 3 cm (1.2 in) across at the trunk to 1.5 cm (0.59 in) at the tip, with the petioles at roughly a 90° angle from the trunk. Secondary laterals start around 50 cm (20 in) from the petiole base, each around 3-4 mm wide and at least 3 to 4 cm (1.2 to 1.6 in) long. The lack of preserved reproductive structures unfortunately means no classification finer than a vascular plant can be determined.^[1]

Etymology

Sanfordiacaulis's genus name is derived from the quarry containing the specimens and its owner, Laurie Sanford, whereas its specific name, densifolia is derived from the dense arrangement of leaves.^[1]