A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyclops groups

Abstract

Two obligate cave-dwelling species of cyclopoid copepods (Copepoda, Cyclopoida) were discovered inside caves in central Thailand. Siamcyclops cavernicolus gen. et sp. nov. was recognised as a member of a new genus. It resembles Bryocyclops jankowskajae Monchenko, 1972 from Uzbekistan (part of the former USSR). It differs from it by (1) lack of pointed triangular prominences on the intercoxal sclerite of the fourth swimming leg, (2) mandibular palp with three setae, (3) spine and setal formulae of swimming legs 3.3.3.2 and 5.5.5.5, respectively, and (4) specific shape of spermatophore. Metacyclops thailandicus sp. nov. resembles M. cushae Reid, 1991 from Louisiana (USA). It differs from it by (1) distal segment of the endopod of the fourth swimming leg with one apical spine, (2) the fifth swimming legs with one broad segment, (3) the spine formula of the distal segment of the exopod of the swimming legs 3.4.3.3, and (4) well developed anal operculum reaching articulation with caudal rami. Detailed descriptions of the habitats of the new species and up-to-date keys to the genera and subgenera of the Bryocyclops and Microcyclops groups are provided, along with an updated list of obligate groundwater species of Copepoda in Southeast Asia.

A new representative of the genus Bryocyclops Kiefer, 1927 from a karst cave in north-eastern Thailand (Copepoda, Cyclopoida, Cyclopidae) and comments on the generic affinities

“…asetus, B. muscicola, B. muscicoloides and B. trangensis. This transformed spine on the male P3 Enp-2 has also been reported in the Thalamocyclops, Palaeocyclops and Siamcyclops genera (Monchenko 1972;Fiers and Van Damme 2017;Boonyanusith et al 2018). This characteristic has traditionally been used to recognise Bryocyclops and to reasonably conclude that the genera Thalamocyclops, Palaeocyclops and Siamcyclops are more closely related to Bryocyclops s. str.…”

“…The shape of the spermatophore has, therefore, been used as a generic characteristic to differentiate Siamcyclops from Bryocyclops s. str. Siamcyclops have L-shaped spermatophore structures versus the kidney or bean-shaped spermatophore structures found in most Bryocyclops species (Boonyanusith et al 2018). However, this characteristic does not fit B. trangensis and B. asetus, which present two other shapes (see Watiroyram 2018a, fig.…”

Onychocamptus Daday, 1903 from Thailand, with descriptions of two new species and two new records (Crustacea, Copepoda, Harpacticoida, Laophontidae)

“…With the description of the two new species and new records of the two species from Thailand, the number of Onychocamptus species recorded in Thailand has now increased from one to five. Sampling of cave-dwelling copepods in this country has revealed a large number of new species of the genera Elaphoidella, Bryocyclops, Fierscyclops , and Thermocyclops (Boonyanusith et al 2013, Brancelj et al 2010, Karanovic et al 2017, Watiroyram 2018, Watiroyram and Brancelj 2016, Watiroyram et al 2012, 2015a, b), and a new genus, Siamcyclops , from west Thailand (Boonyanusith et al 2018). Most of the samples were collected from a single cave.…”

Parapseudoleptomesochra phayaoensis, a new species of copepod (Copepoda: Harpacticoida: Ameiridae) from a cave in northern Thailand

“…In Southeast Asia, approximately 42 species of groundwater copepods belong to the genera Asiacaris Cottarelli, Bruno et Berera, 2010, Attheyella Brady, 1880, Boholina Fosshagen et Iliffe, 1989, Bryocyclops Kiefer, 1927, Elaphoidella Chappuis, 1929, Epactophanes Mrázek, 1893, Fierscyclops Karanovic, 2004, Hadodiaptomus Brancelj, 2005, Kinnecaris Jakobi, 1972, Nitokra Boeck, 1865, Onychocamptus Daday, 1903, Parastenocaris Kessler, 1913, and Phyllognathopus Mrázek, 1893. Most of the species are recorded from Thailand, and have been collected from epikarstic habitats (Brancelj et al, 2010(Brancelj et al, , 2013Watiroyram et al, 2012;Watiroyram et al, 2015aWatiroyram et al, , b, 2017Watiroyram, Brancelj, 2016;Karanovic et al, 2017, Как Boonyanusith et al, 2018;Watiroyram, 2018a, b). However, no representative of the genus Parapseudoleptomesochra has been reported from Thailand.…”