Resolving the Lourinia armata (Claus, 1866) complex with remarks on the monophyletic status of Louriniidae, Monard 1927 (Copepoda: Harpacticoida)

Abstract

An attempt was made to test if Lourinia armata (Claus, 1866)—as it is currently diagnosed—represents a species complex. Detailed examination and comparisons of several specimens collected from different localities suggest that L. armata indeed represents a complex of four closely related morphospecies that can be differentiated from one another by only detailed observations. One of the four species is identified as Lourinia aff. armata and the other three species are described as new to science and named as Lourinia wellsi sp. nov., L. gocmeni sp. nov., and L. aldabraensis sp. nov. Detailed review of previous species records indicates that the genus Lourinia Wilson, 1924 is distributed worldwide. Ceyloniella nicobarica Sewell, 1940, originally described from Nicobar Island and previously considered a junior subjective synonym of L. armata is reinstated as Lourinia nicobarica (Sewell, 1940) comb. nov. on the basis of the unique paddle-shaped caudal ramus seta V. It is postulated that almost all of these records are unreliable in terms of representing true Lourinia aff. armata described herein. On the other hand, the comparative evaluation of the illustrations and descriptions in the published literature indicates the presence of several new species waiting to be discovered in the genus Lourinia.
 It has been determined that, according to updated modern keys, the recent inclusion of the monotypic genus Archeolourinia Corgosinho & Schizas, 2013 in the Louriniidae is not justified since Archeolourinia shermani Corgosinho & Schizas, 2013 does not belong to this family but should be assigned to the Canthocamptidae. On the other hand, it has been argued that the exact phylogenetic position of the Louriniidae still remains problematic since none of the diagnostic characters supports the monophyly of the family within the Oligoarthra. It has also been argued that the close relationship between Louriniidae and Canthocamptidae is supported since both families share the homologous sexual dimorphism (apophysis) on P3 endopod. The most important characteristic that can possibly be used to define Louriniidae is the reduction of maxilliped.

Two new species of Bryocamptus (Copepoda, Harpacticoida, Canthocamptidae) from the Russian Arctic and comparison with Bryocamptus minutus (Claus, 1863)

“…The structure of the P3 endopod, on closer examination, can be one of the most important taxonomic characters distinguishing closely related species. In particular, for the genus Lourinia Wilson, 1924, closely related to Canthocamptidae, a very strong interspecific variability in the P3 apophysis was described recently; it can vary in length and curvature, as well as in the shape of the tip (Karaytuğ et al 2021). The three studied species also have significant differences in the structure of the endopod.…”

Taxonomic review of the genus Stenocaris Sars (Copepoda, Harpacticoida, Cylindropsyllidae), with (re)descriptions of two Stenocaris species from the Far East

“…minor . Because harpacticoid species complexes can be divided into several cryptic species ( e.g ., Fiers & Kotwicki, 2013 ; Huys & Mu, 2021 ; Karaytuğ et al, 2021 ), some of these records might be part of a Stenocaris minor complex. Monard (1935) and Kunz (1938) reported the characteristics of males of this species from European waters near the type locality.…”

A new species of Bryocamptus Chappuis, 1929 (Copepoda: Harpacticoida: Canthocamptidae) from the hydrothermal seep of Lake Baikal

“…Such an interesting structure could be attributed to the peculiarity of the species, given that the structure of the P3 male endopod can often be species-specific both in Bryocamptus [Novikov et al, 2023] and in other genera of Canthocamptidae and genera from families, close related to Canthocamptidae, for example, Lourinia C.B. Wilson, 1924[Karaytuğ et al, 2021, Mesochra Boeck, 1865 [Soyer, 1977] or Cletocamptus Schmankevitsch, 1875 [Gómez et al, 2017]. However, an almost identical structure is found in both the Baikalian endemic species [Borutzky, Okuneva, 1972], B. zschokkei from Korea [Lee, Chang, 2006] and B. spinulosus [Borutzky, 1934].…”