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

Abstract

Two new species of Bryocamptus Chappuis, 1929 from the Russian Arctic from the Bryocamptus minutus species group are described: Bryocamptus putoranussp. nov. and Bryocamptus abramovaesp. nov. A complete morphological comparison of the new species with the type species Bryocamptus minutus (Claus, 1863) was carried out. Significant interspecific differences were shown at the level of microcharacters, such as integumental sensillae and pores, ornamentation of segments of mouthparts and swimming legs, and pores on swimming legs. A significant correlation has also been shown in the shape of the caudal rami of the females and the antennules of the males, which is likely caused by an evolutionary sexual arms race. Bryocamptus putoranussp. nov. and B. minutus have a similar structure of caudal rami, but completely different male antennules, which may indicate a convergent origin of modifications and highlights the importance of depicting male antennules in the species descriptions.

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

“…So, it can be described as both 3-segmented and 2-segmented. Such an incomplete fusion of segments can also be seen in other species of Bryocamptus, such as B. putoranus Novikov, Sharafutdinova et Chertoprud, 2023[Novikov et al, 2023, or in species of other genera, for example in Attheyella nordenskioldii (Lilljeborg, 1902) [Novikov et al, unpublished].…”

“…In the new species, the outer seta is massive, evenly thickened, and has two rows of spinules in the distal part. 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].…”

“…On segment 8, the laminar setae are considerably enlarged, one of them is elongated and its apical end extends beyond the base of segment 9. Previously, Novikov et al [2023] suggested that the coevolution of male antennules and female caudal rami is associated with a sexual arms race. Since it is more difficult for males to grasp a female with modified caudal rami, males with the most successful form of antennules leave more offspring.…”

A New Species of Diacyclops (Copepoda, Cyclopoida) from the D. crassicaudis (Sars, 1863) Species Group with Critical Taxonomy Remarks

“…In recent years, five new for-science species of the order Harpacticoida (Copepoda) have been described from the north of Middle Siberia [3]. At the same time, little attention has been paid to the faunas of the other free-living copepod orders.…”