Taungurungia garrattii McSweeney, Shimeta and Buckeridge, 2022

McSweeney, Fearghus R., Shimeta, Jeff & Buckeridge, John St J. S., 2022, Taungurungia gen. nov., from the Lower Devonian of Yea, central Victoria, Australia, Memoirs of Museum Victoria 81, pp. 43-53 : 45

Taungurungia garrattii McSweeney, Shimeta and Buckeridge , sp. nov.

Figures 3–10

Species diagnosis: As for genus. Plant at least 185 mm high with axes at least 7.8 mm wide. Emergences up to 1.5 mm wide and 3.4 mm long. Mature axes terminate in a single ovate sporangium at least 7.5 mm wide and at least 15.5 mm long. Small fusiform to elliptical bodies (buds/sterile sporangia) 0.5 mm wide and 1 mm long, some with short stalks occurring on all axes.

Etymology: Named for Michael Garratt in recognition of his work in Palaeozoic palaeontology, especially on brachiopods.

Holotype: NMV P257028.1 (part; F103-1p) and NMV P257028.2 (counterpart; F103-1cp), part and counterpart respectively.

Locality: The exposure occurs on the Goulburn Valley Highway (B340) 5 km west of Yea and was designated F103 by Garratt (1980). 37° 12' 30" S; 145° 21' 56" E.

Stratigraphy and age: Norton Gully Sandstone Formation, late Pragian–Emsian, Lower Devonian.

Figures

Figure 3. Taungurungia garrattii gen. et sp. nov., holotype: a, part specimen (NMV P257028.1) with lower arrow at K-branching. Terminal ovate sporangia at S1 and S2. At Ax is an axis that goes into the matrix. K- or H-branching at lower arrow; b, counterpart (NMV P257028.2). At upper arrow S3 is poorly preserved sporangium. Lower arrow points the axis curving upwards which is visible in fig. 7c, d close-up after dégagment. The counterpart image is reversed to be in the same orientation as the part; c, line-drawing without small bud/sterile sporangial bodies included. Images a and b were taken by Rodney Start © Museums Victoria.

Figure 4. Taungurungia garrattii gen. et sp. nov., holotype, part specimen NMV P257028.1: a, ovate sporangium pre-dégagement. Left arrow is at apex of poorly preserved sporangium. Right arrows are at two lateral axes close to the base of the sporangium. Close-up of lower axis in fig. 7e; b, post-dégagement, reveals sporangium preserved in relief; c, faint impressions at arrows of fusiform bodies (buds/sterile sporangia) on counterpart. Lower arrow shows a fusiform body attached directly to the axis at the junction with the sporangium; d, dégagement above the sporanium revealed numerous small fusiform bodies (buds/sterile sporangia) at arrows similar to c. Tip of sporangium disintegrated during dégagement, positioning highlighted with dotted line. Image a taken by Rodney Start © Museums Victoria.

Figure 5. Taungurungia garrattii gen. et sp. nov., holotype, part specimen NMV P257028.1. Large sporangium low down on the specimen. The apex is slightly curved (upper arrow) and more elongate then the sporangium in fig. 4. Branching visible (lower arrow). Note: the sporangium appears partly embedded in its subtending axis. Image taken by Rodney Start © Museums Victoria.

Figure 6.Taungurungia garrattii gen. et sp. nov. holotype, part specimen NMV P257028.1: a–d, ontogenetic changes in morphology and orientation of emergences. In image b, arrow at possible vascular trace extending out to tip. Images were taken by Rodney Start © Museums Victoria.

Figure 7. Taungurungia garrattii gen. et sp. nov. holotype, fusiform bodies (buds/sterile sporangia). Some of these are highlighted with enlarged dotted outlines near them: a, anisotomous branching with terminal partial fusiform body (upper arrow). Emergence or branching (lower arrow); b, post-dégagement, several fusiform bodies with short subtending axes are visible along the edge of the axis. Distally the axis narrows and terminates in an elongate rounded body (Arrow on right); c, curved axis displaying negative geotropism. Close-up (rectangular region) is in (d); d, distal part of curved axis possesses minute fusiform bodies (at arrows). An insert highlights the morphology. Evidence of determinate growth can be seen as the axis is terminated by one of these fusiform bodies; e, fine axis emanating about 4 mm on the same axis subtending the large central terminal sporangium, with arrow at small terminal body. All images are from the counterpart (NMV P257028.2). Image a was taken by Rodney Start © Museums Victoria. Images b–e were taken with a unidirectional light source.

Figure 8. Taungurungia garrattii gen. et sp. nov. holotype, fusiform to elongate rounded (buds/sterile sporangia) bodies with some highlighted with enlarged dotted outlines beside them: a, b, on the side of axes in carbonised matter; c, faint axis (Ax) with?fusiform bodies; d, close-up of fusiform bodies (arrows) on one of the large parent axes. No clear dehiscence lines are present. A short narrow stalk is subtending the sporangium on the left. Images a, b and d are from the counterpart (NMV P257028.2).

Figure 9. Taungurungia garrattii gen. et sp. nov. holotype, part specimen, NMV P257028.1 close-up of fusiform to elongate rounded (buds/sterile sporangia) body: a, immediate area above and right of the main terminal sporangium with some poorly preserved casts of fusiform bodies evident at the arrows. An ovate body (arrow c) pre-dégagement; b, the same ovate body post-dégagement. Its shape may represent partial compression because it is slightly dipping down into the matrix from its subtending axis. At arrow evidence of possible dehiscence line.

Figure 10.Taungurungia garrattii gen. et sp. nov.holotype, counterpart, P257028.2. Micrograph of an axis (part specimen) with longitudinal structures, possibly indicative of cell orientation. Taken using an FEI Quanta 200 scanning electron microscope in low vacuum mode.