Opinions and declarations Rendered by the International Commission on Zoological Nomenclature

A new species, Arctosa delaportei, is described from Laos on the basis of male specimens; it is related to A. tangguoi Wang, Li & Zhang, 2021 known from China. Arctosa depectinata (Bösenberg & Strand, 1906), A. kiangsiensis (Schenkel, 1963), and A. springiosa Yin, Wang, Xie & Peng, 1993 are reported from Laos for the first time; the records of these three species are the southernmost ones within their known ranges. All species are (re)described and illustrated.

The ant species Pheidole sexspinosa Mayr, 1870 is re-described based on colony series and individual specimens collected from various mangroves in Singapore; the worker, queen, and male, including male genitalia, are described. The recognition of P. sexspinosa in Singapore constitutes the species’ first discovery in the Oriental region. Pheidole sexspinosa was previously thought to be restricted to Oceania, but our findings suggest a much broader geographic distribution including continental Asia. COI partial sequences from the Singapore specimens are almost identical (100% cover, 99% identity) to those from Palau (Micronesia) specimens, which were identified as P. sexspinosa and registered in GenBank. The Singapore populations of P. sexspinosa were found nesting in a decayed stem of a Rhizophora L. (Rhizophoraceae) tree, and in cable roots of Excoecaria agallocha L. (Euphorbiaceae). The apparent wide distribution of P. sexspinosa may be attributed to long distance dispersal of rotten logs and branches, and viviparous seeds of mangrove trees carrying queens or queen-right colonies by seasonal circulatory currents, or human-mediated dispersal.

The ant species Pheidole sexspinosa Mayr, 1870 is re-described based on colony series and individual specimens collected from various mangroves in Singapore; the worker, queen, and male, including male genitalia, are described. The recognition of P. sexspinosa in Singapore constitutes the species’ first discovery in the Oriental region. Pheidole sexspinosa was previously thought to be restricted to Oceania, but our findings suggest a much broader geographic distribution including continental Asia. COI partial sequences from the Singapore specimens are almost identical (100% cover, 99% identity) to those from Palau (Micronesia) specimens, which were identified as P. sexspinosa and registered in GenBank. The Singapore populations of P. sexspinosa were found nesting in a decayed stem of a Rhizophora L. (Rhizophoraceae) tree, and in cable roots of Excoecaria agallocha L. (Euphorbiaceae). The apparent wide distribution of P. sexspinosa may be attributed to long distance dispersal of rotten logs and branches, and viviparous seeds of mangrove trees carrying queens or queen-right colonies by seasonal circulatory currents, or human-mediated dispersal.