Hausdorf & Hennig [ 26] proposed to use Gaussian clustering [ 25] for the determination of clusters of specimens as provisional species.
These results were corroborated by the Bayesian clustering of specimens based on chloroplast SSRs (optimal K value determined following Evanno's method, see further details in Fig. S1).
Using a likelihood framework, this new procedure detects the point of transition in the rate of lineage branching of a tree from interspecific long branches to intraspecific short burgeoning branching and identifies clusters of specimens corresponding to putative species.
Using a likelihood framework, this new procedure detects the switch in the rate of lineage branching of a tree from interspecific long branches to intraspecific short budding branching and identifies clusters of specimens corresponding to putative species.
These results were largely corroborated by the Bayesian clustering of specimens (Fig. 3B,C), where the deltaK spectrum (following Evanno's method) identified K = 3 as the most likely number of groups (see further details in Fig. S1).
In this paper, we illustrate several large clusters of specimens of Canadaspis perfecta (Walcott, 1912) [ 16] (for example, ROM 56954 and ROM 62274) collected from level -350 (approximately 350 centimeters below the base of the original Walcott Quarry, see [ 15]), as well as several megacheiran clusters (ROM 62275) and individual specimens (ROM 57711) collected at level -120.
While synchronized molting might have also occurred in other Burgess Shale species, in particular those that occur in large clusters of specimens (for example, in the bradoriid Kunmingella burgessensis), the fossil examples provided in this study are the clearest cases found so far.
The clustering of specimen locations near coasts, major ports, and large rivers evident from the map in Fig. 4 may account for the preponderance of MaxEnt models emphasizing maritime climates.
