The decapod family Penaeidae comprises most of the economically important marine shrimp species. Its members are widespread throughout the world, with its highest species diversity centred in the Indo‐West Pacific region. Despite this importance, their taxonomy, classification and phylogeny are not yet settled due in part to incongruence among hypotheses proposed from molecular versus morphological studies. In this study, using a thorough taxonomic sampling of especially the South‐East Asian species, we aim to (a) utilize a reconstructed phylogeny to test the monophyly of the Penaeidae and its currently recognized genera and (b) explore its species diversity in South‐East Asian waters. To infer the phylogeny, a combined gene data set (including 109 ingroup and six outgroup taxa) of mitochondrial genes, COI and 16S rRNA, and two nuclear genes, NaK and PEPCK, was utilized. To explore its diversity, another data set that included 371 COI gene sequences (231 newly generated and 140 retrieved from public sources) was compiled and subsequently analysed with two different tools (ABGD and bPTP) for species delimitation. Other than supporting the non‐monophyly of the Penaeidae with the Sicyoniidae nested within the penaeid tribe Trachypenaeini, the genera Penaeus, Mierspenaeopsis and Parapenaeopsis were also revealed to be polyphyletic. Our species delimitation analysis inferred that 94 putative species actually existed within the 71 morphospecies reviewed, indicating an underestimated biodiversity in this family and the potential presence of new species within the following morphospecies: Kishinouyepenaeopsis cornuta, K. incisa, Mierspenaeopsis sculptilis, M hardwicki, Parapenaeopsis coromandelica and Penaeus monodon.

Background: Fejevarya limnocharis (Dicroglossidae) is found widespread in Peninsular Malaysia. We analyzed the mitochondrial DNA control region sequence data to evaluate the genetic variability and population structure of this species, based on 106 individuals from 14 populations in the west coast (northwest and central west) and two populations from the east coast of Peninsular Malaysia. Results: Of 519, 13 variable sites (six parsimony informative sites) were observed, defining 14 unique haplotypes. We found very low levels of genetic variability, with three of the 16 populations exhibiting total absence of genetic variation. Both phylogenetic analyses based on NJ and MP methods failed to detect any geographic structuring between the east and west coast (northwest and central west combined) populations.Conclusions: Consequently, it can be inferred that genetic structuring F. limnocharis populations in the Peninsular Malaysia was largely shaped by natural barriers. However, when this breaks down as between the central west and east peninsular regions, genetic differentiation is reduced. Further studies, with more efficient markers and larger populations, especially from the southern regions, are required to corroborate the findings.

A pseudocryptic form of the commercially important prawn Penaeus monodon  Fabricius, 1798 from Aceh Province, Indonesia was recently named Penaeus acehensis  Sektiana, Tahang, Andriyono, Alam & Kim, 2018 based solely on coloration, number of rostral teeth, and unspecified mitochondrial genome sequence differences from P. monodon and other species of Penaeus sensu lato. Penaeus acehensis, however, is unavailable on account of not fulfilling the numerous provisions of Articles 8 and 16 of the International Code of Zoological Nomenclature. Comparisons between the Aceh form and an extensive series of P. monodon from various Indo-West Pacific localities revealed that the former is morphologically distinct in having a relatively longer rostrum, shorter adrostral carina, and longer hepatic carina. Barcoding genetic analysis also supports the specific status of the Aceh form. By examining the types or topotypic material of all the synonyms in P. monodon, and selecting a lectotype for Penaeus caeruleus  Stebbing, 1905 and neotypes for P. Manilensis de Procé, 1822 and P. durbani  Stebbing, 1917, no available name is applicable to the Aceh species, which is named. The Aceh species is hereby named Penaeus simplex  sp. nov. for its body lacking a banded color pattern, which is very characteristic compared to the closely related species, P. monodon.