Tuff-bearing upper Cambrian–lowermost Ordovician strata on Ko Tarutao (Tarutao Island) in Satun province, southernmost peninsular Thailand, contain a rich trilobite fauna relevant to global biostratigraphy, peri-Gondwanan palaeogeography, and shifting evolutionary mode. This area of Sibumasu, a lower Palaeozoic marginal Gondwanan terrane, is shown to be closely associated with Australia, North China (Sino-Korea), and other continental fragments from the supercontinent’s northern equatorial sector including South China. Shared fauna with Kazakhstan are also notable and shared similiarities with Laurentia are of similar magnitude to those of some other parts of equatorial Gondwana. Extensive collections from eight different sections have yielded a number of newly-discovered taxa. With the new taxa and revision of taxa known previously, we refine the age of the upper formations of the Tarutao Group as the middle of Cambrian Stage 10 and lower Tremadocian. Newly described taxa include Tsinania sirindhornae, Pseudokoldinioidia maneekuti, Pagodia? uhleini, Asaphellus charoenmiti, Apatokephalus arcuatus, Yosimuraspis acufrons, Tarutaoia techawani, Jiia talowaois, Caznaia imsamuti, Caznaia? undulata, Lophosaukia nuchanongi, and Corbinia perforata. Taxa previouly unknown on Tarutao but described from other terranes include Mansuyia orientalis? Sun, Parakoldinioidia callosa Qian, Pseudagnostus Jaekel, Homagnostus obesus Belt, Haniwa mucronata Shergold, H. sosanensis Kobayashi, Lichengia simplex Shergold, Pacootasaukia Sohn and Choi, Wuhuia? Kobayashi, Plethopeltella Kobayashi, Akoldinioida lata Park and Kihm, and Koldinioidia choii Park and Kihm. 

The data contained herein includes morphometric landmark coordinates for specimens of Quadraticephalus and Haniwa, which are 2 different datasets. The landmark schemes for each genus are provided in the associated paper. Data was collected using ImageJ on Z-stacked images acquired with a Leica M-series stereoscope. Some, but not all, of these images can be found in the associated paper. A scale was used to record landmark placement, so the datasets are already adjusted for size comparisons and ontogeny. Data is formatted for use with the Integrated Morphometrics Package (Webster and Sheets, 2010). The code 999 indicates a missing landmark. 

This dataset (created with Excel) is formatted to be used with the Integrated Morphometrics Package (Webster and Sheets, 2010). The code 999 indicates a missing landmark - these can still be used by reflecting and averaging the data which is bilaterally symmetrical. The files labeled "formatted" are ready to import to IMP. The other sheets contain additional information, including specimen numbers. DGSC indicates the Thai Department of Mineral Resources Geoscience Reference Collection.