Phycodes templus Han et Pickerill, 1994

Taxon description

Han & Pickerill, 1994a

Diagnosis: Phycodes possessing two or, more typically, several horizontally interconnected broomlike or flabellate bundles that collectively form an inverted pagoda-like structure.

Description: Specimens are preserved as convex hyporelief expressions of endorelief burrow systems on the soles of 26 to 53 mm thick, grey, argillaceous, micaceous, parallel-laminated siltstone and fine-grained sandstone. Single specimens possess a minimum of 2, typically more (up to 5), sets of broomlike or flabellate bundles of burrows, individual bundle sets each interconnecting horizontally, either straightly (e.g., Fig. 2A) or obliquely (e.g., Fig. 3A), and collectively forming inverted pagoda-shaped structures. Single broomlike or flabellate bundle sets, each 16 to 45 mm wide, consist of 3 to 7 burrows that are individually essentially straight, more rarely slightly curved, and smooth or covered with delicate wartlike structures. Vertical sectioning of selected sets indicates that individual burrows within a set are typically not vertically tiered to any great extent (Fig. 4). Instead, each set comprises variably elliptical burrows that were apparently only produced, along a single sand-mud interface, but at slightly different levels, and were clearly post-depositional in origin. The primary cross-sectional shape of the individual burrows is difficult to ascertain as a result of primary compaction and subsequent deformation. Individual burrows within a single set are 3 to 9 mm wide and 12 to 45 mm long, burrow width typically increasing distally. Single burrows within a set may or may not vary in length and width. Burrows in individual sets initiate at a single point of origin, subsequent sets initiating from the distal end of a single burrow of the previously established set. Individual sets may or, more commonly, may not overlap. In some instances individual burrows within a single set may bifurcate, although this is uncommon. Typically, interconnected sets occur on the same surface; however, in one example the individual sets, although interconnected, are clearly on a slightly different level of stratification. Burrow fill is similar in lithology to the host rock, perhaps with a slightly increased mudstone component; individual burrows are bound by an extremely thin (< 0.5 mm), dark mudstone lining (Fig. 4). No spreiten or other internal structures are present.

Synonymy list
1970     Trail of unknown affinity — Rodrigues & Gutschick, pp. 436, fig. 10C
1994     Phycodes templus isp. nov. — Han & Pickerill, pp. 39, fig. 2-4
1995     Phycodes templus Han and Pickerill, 1994 — Pickerill et al., pp. 3, fig. Fig.2