TY - JOUR
T1 - An integrative approach to characterize cryptic species in the Thoracostoma trachygaster Hope, 1967 complex (Nematoda: Leptosomatidae)
AU - De Oliveira, Daniel Apolonio Silva
AU - Decraemer, Wilfrida
AU - Holovachov, Oleksander
AU - Burr, Jay
AU - De Ley, Irma Tandingan
AU - De Ley, Paul
AU - Moens, Tom
AU - Derycke, Sofie
PY - 2012/1/1
Y1 - 2012/1/1
N2 - Nematode diversity may seriously be underestimated when taking into account cryptic speciation. Thoracostoma trachygaster is commonly found in kelp holdfasts along the California coastline and was recently shown to consist of at least two distinct molecular clades (I and II). Here, we provide detailed morphological analysis of both clades, based on measurements taken from video vouchers of respectively eight and 16 individuals from the previous study, as well as 80 newly collected specimens from four Californian beaches. The latter were vouchered, measured, and then subjected to molecular analyses of the mitochondrial cytochrome oxidase c subunit I (COI) gene, and the ribosomal D2D3 and internal transcribed spacer (ITS) regions. This integrative approach shows that the three molecular clades are phylogenetically and morphologically distinct species, but a combination of morphological characters is needed to distinguish them. Two new species, Thoracostoma fatimae sp. nov. and Thoracostoma igniferum sp. nov., are identified and described. The spicule length of T. fatimae sp. nov. is significantly shorter than that of T. trachygaster. Thoracostoma igniferum sp. nov. can be distinguished by the irregular posterior edge of the cephalic capsule and the two internal subdorsal tropis-like projections in the wall of the cephalic capsule, which are lacking in T. fatimae sp. nov. and T. trachygaster.
AB - Nematode diversity may seriously be underestimated when taking into account cryptic speciation. Thoracostoma trachygaster is commonly found in kelp holdfasts along the California coastline and was recently shown to consist of at least two distinct molecular clades (I and II). Here, we provide detailed morphological analysis of both clades, based on measurements taken from video vouchers of respectively eight and 16 individuals from the previous study, as well as 80 newly collected specimens from four Californian beaches. The latter were vouchered, measured, and then subjected to molecular analyses of the mitochondrial cytochrome oxidase c subunit I (COI) gene, and the ribosomal D2D3 and internal transcribed spacer (ITS) regions. This integrative approach shows that the three molecular clades are phylogenetically and morphologically distinct species, but a combination of morphological characters is needed to distinguish them. Two new species, Thoracostoma fatimae sp. nov. and Thoracostoma igniferum sp. nov., are identified and described. The spicule length of T. fatimae sp. nov. is significantly shorter than that of T. trachygaster. Thoracostoma igniferum sp. nov. can be distinguished by the irregular posterior edge of the cephalic capsule and the two internal subdorsal tropis-like projections in the wall of the cephalic capsule, which are lacking in T. fatimae sp. nov. and T. trachygaster.
KW - California
KW - COI
KW - D2D3
KW - integrative taxonomy
KW - ITS
KW - marine
KW - morphology
U2 - 10.1111/j.1096-3642.2011.00758.x
DO - 10.1111/j.1096-3642.2011.00758.x
M3 - Article
SN - 0024-4082
VL - 164
SP - 18
EP - 35
JO - ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY
JF - ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY
IS - 1
ER -