Lysmata vittata (Stimpson, 1860)

Guéron, Rodrigo, Almeida, Alexandre Oliveira, Aguilar, Robert, Ogburn, Matthew B., Prakash, Sanjeevi & Baeza, J. Antonio, 2022, Delimiting species within the Lysmata vittata (Stimpson, 1860) (Decapoda: Lysmatidae) species complex in a world full of invaders, Zootaxa 5150 (2), pp. 189-216 : 201

Untangling the Lysmata vittata species complex

Due to the great morphological variability within the L. vittata complex, absence of type material, and history of doubtful records of this species, we applied an integrative analysis to delimit the putative species within the complex and resolve the taxonomic status of L. rauli and L. durbanensis . Our integrated morphological and molecular data strongly support the hypothesis that L. vittata sensu lato is comprised of six taxonomic entities (including three undescribed species) with important morphological and distributional differences among constituent members.

We noted clear and consistent morphological and color pattern differences among various members of the L. vittata complex that were further supported by molecular analyses. Most strikingly was the absence of both an accessory branch (in L. vittata [clade LV1] and L. durbanensis ) and pleonal red transverse bands in L. vittata , compared with a one-segmented accessory branch observed in L. rauli (clade LV4) and L. sp. AUS2 (clade LV3) and the presence of pleonal transverse bands in L. rauli . We also observed important differences in the number of carpal and meral segments of the second pereopod, particularly between L. vittata and L. rauli .

Further , our phylogeny recovered five strongly supported and divergent clades, (fig. 4), which were also delineated as putative species by ASAP and included LV1 (the eastern USA, Hong Kong [type locality], New Zealand, and Taiwan ), LV2 (a single individual from northern Australia), LV3 (northern Australia), LV4 (Panama, Brazil [type locality], Thailand, and Hong Kong), and LV5 (a single individual identified as “ L. vittata ” from Xiamen , China). Genetic differences were extremely wide, with minimum inter-clade genetic distances (p -distances) ranging from 0.048 (LV3 vs. LV4) to 0.430 (LV2 vs. LV5). These findings are bolstered by Aguilar et al. (2022), which also recovered four similar strongly supported clades and were all delimited as putative species using Automatic Barcode Gap Discovery analysis ( ABGD) .

The fixing of a neotype by Aguilar et al. (2022), provided the necessary criteria to define L. vittata , with major morphological characters including: 1) uniramous dorsal antennule; 2) rostrum reaching distal end of second antennular article; 3) scaphocerite overreaching the end of the antennular peduncle; 4) stylocerite reaching the mid-length of the first antennular article; 5) presence of a pterygostomial spine; 6) 8–13 meral segments of the second pereopod; 7) 18–23 carpal segments of the second pereopod; and 8) coloration pattern consisting of numerous longitudinal red stripes without dark transverse bands on the pleon. These important morphological criteria provided a framework to delimit the putative species within the L. vittata species complex using integrative taxonomic methods, helping to settle over a century of taxonomic uncertainty.