Latisemenia longshania , gen. et sp. nov., a new Late Devonian seed plant from China

Abstract

The earliest known ovules in the Late Devonian (Famennian) are borne terminally on fertile branches and are typically enclosed in a cupule. Among these ovules are some that have terete integumentary lobes with little or no fusion. Here, we report a new taxon, Latisemenia longshania , from the Famennian of South China, which bears cupulate ovules that are terminal as well as opposite on the fertile axis. Each ovule has four broad integumentary lobes, which are extensively fused to each other and also to the nucellus. The cupule is uniovulate, and the five flattened cupule segments of each terminal ovule are elongate cuneate and shorter than the ovule. Associated but not attached pinnules are laminate and Sphenopteris -like, with an entire or lobate margin. Latisemenia is the earliest known plant with ovules borne on the side of the fertile axis and may foreshadow the diverse ovule arrangements found among younger seed plant lineages that emerge in the Carboniferous. Following the telome theory, Latisemenia demonstrates derived features in both ovules and cupules, and the shape and fusion of integumentary lobes suggest effective pollination and protection to the nucellus. Along with other recent discoveries from China, Latisemenia extends the palaeogeographic range of the earliest seed plants.

Guazia, the earliest ovule without cupule but with unique integumentary lobes

“…Like Guazia , some medullosan ovules are borne terminally on dichotomous branches and possess four integumentary wings [ 21 ]. Among Devonian ovules, Pseudosporogonites and Latisemenia have a very short cupule only surrounding the ovule base [ 18 , 22 ]. The integumentary lobes of these two genera, especially Latisemenia , are so broad and largely fused as to effectively protect the nucellus.…”

In situ forest with lycopsid trees bearing lobed rhizomorphs from the Upper Devonian of Lincheng, China

“…The strata exposed in the field work area have been studied in previous work ( 13 ) and supported by geological maps (China National Digital Geological Map spatial database). Excavator was utilized initially to remove the overlying strata, and a big quadrat (5 m × 3 m) was subsequently established using nails, ropes, and marker pen.…”

The morphometric of lycopsid sporophylls and the evaluation of their dispersal potential: an example from the Upper Devonian of Zhejiang Province, China

“…1 ). The age of this formation at Longshan section had been discussed in detail by Wang et al [ 20 ]. The plant-bearing deposit represents the fifth bed of the subdivided strata and consists of gray mudstone.…”

“…2 Stratigraphic column at Longshan section, Changxing County (Zhejiang, China), showing the lithology and sequence of strata, and the beds of the fossil plants ( modified from Fig. S3 of Wang et al 2015 [ 20 ]) …”