Thursday, February 15, 2024

[Crustacea • 2024] Macrobrachium panhai & M. rostrolevatus • Molecular Phylogeny and Taxonomic Position of Macrobrachium lanchesteri (De Man, 1911) (Decapoda: Caridea: Palaemonidae), with Descriptions of Two New Species from Thailand

  

 C, D Macrobrachium rostrolevatus Chaowvieng & Siriwut, sp. nov. 
from Bueng Khong Long, Bueng Kan, Thailand

M. panhai Chaowvieng & Siriwut, sp. nov. 
from Sri Nakarin Dam, Tha Kradan, Si Sawat, Kanchanaburi, Thailand.

in Chaowvieng, Sutcharit, Chanabun, Srisonchai, Jeratthitikul et Siriwut, 2024. 
Scale bars: 1 cm.

Abstract
Macrobrachium lanchesteri (De Man, 1911), a translucent freshwater prawn has a wide distribution range throughout mainland Southeast Asia. A high morphological variation and genetic divergence between different geographical M. lanchesteri populations in Thailand have peculiarly extended the uncertainty of species boundaries and blended confusingly with several Macrobrachium species. To clarify these circumstances, broad sample examinations of the morphological variation, including topotype specimens, and phylogenetic reconstruction based on the concatenated mitochondrial dataset (16s rRNA and COI genes) were performed. Broad morphological examination of M. lanchesteri has shown congruency with phylogenetic analyses by revealing prominent lineages of M. lanchesteri sensu stricto and two new sibling lineages with interspecific variation between 6.48–8.76% for COI and 3.06–4.23% for 16S. Descriptions of two new species, named herein as M. panhai Chaowvieng & Siriwut, sp. nov. and M. rostrolevatus Chaowvieng & Siriwut, sp. nov. are provided. Morphological investigation of rostral form suggested plasticity in M. rostrolevatus populations showing the morphological trait associated with their habitat preferences. Furthermore, phylogenetic positions of the three taxa affirmed the hidden diversity of Thai freshwater Macrobrachium fauna correlated with the river network in the Mekong and Chao Phraya basins, Thailand. The genetic data and distribution records obtained in this study may also assist future river conservation plans as well as the sustainable management of freshwater prawn diversity.

Key words: Edible prawns, Lower Mekong Basin, morphological plasticity, new species

Living habit of specimens of three Macrobrachium species
A, B M. lanchesteri from Bang Khiat, Singhanakhon, Songkhla, Thailand
C, D M. rostrolevatus sp. nov. from Bueng Khong Long, Bueng Kan, Thailand
M. panhai sp. nov. from Sri Nakarin Dam, Tha Kradan, Si Sawat, Kanchanaburi, Thailand.
Scale bars: 1 cm.


 Apisara Chaowvieng, Chirasak Sutcharit, Ratmanee Chanabun, Ruttapon Srisonchai, Ekgachai Jeratthitikul and Warut Siriwut. 2024. Molecular Phylogeny and Taxonomic Position of Macrobrachium lanchesteri (De Man, 1911), with Descriptions of Two  New Species from Thailand (Decapoda, Caridea, Palaemonidae). ZooKeys. 1190: 163-193. DOI: 10.3897/zookeys.1190.113898