Abstract
Metacyclops sakaeratensis sp. nov. and M. brancelji sp. nov. are described as being present in the mountainous areas of Northeastern and Southern Thailand, respectively. Two new species resemble M. woni in both sexes, but they are easily distinguished from their Cambodian relative by having: 1) transverse suture on the dorsal surface of the genital double-somite, 2) serrated hyaline frill on the posterior margin of third pedigerous somite, 3) different length / width ratio of caudal ramus, and 4) a row of spinule on caudal surface of intercoxal sclerite of the third swimming legs. The significant differences between M. sakaeratensis sp. nov. and M. brancelji sp. nov. are present in both sexes, including the body size, integumental ornamentation of the body surface, length / width ratio of caudal ramus, armature of the fifth swimming leg, and the male sixth swimming leg. In addition, an up-to-date key to the female of all fifteen species of Metacyclops recorded in Asia is provided.
Highlights
Metacyclops Kiefer, 1927 is the third largest genus of the subfamily Cyclopinae Kiefer, 1927, represented by 62 species and subspecies (Dussart & Defaye 2006)
According to Defaye & Por (2010), Karanovic et al (2011), and Lee & Chang (2015), M. sakaeratensis sp. nov. and M. brancelji sp. nov. should be classified within the genus Metacyclops based on the combination of the following characteristics: (1) P1–P4 with two-segmented exp and enp (2) setal and spine formulae of exp-2 of P1–P4 5.5.5.5 and 3.4.4.3, respectively (3) P4 enp-2 with armature formula 1, I, 3 (4) P5 one-segmented, with spine and seta inserted close to each other
Based on the original description of the three Asian species of Metacyclops (i.e., M. amicitiae, M. ryukyuensis, and M. woni) and two species in which P4 enp-2 bears one single apical spine, including M. deserticus, and M. hannensis, as well as the two new species, the outer seta on P4 enp-2 is shorter than twice the length of apical spine of P4 enp-2, and the seta representing exp reaches the tip of enp-3 of antenna
Summary
Metacyclops Kiefer, 1927 is the third largest genus of the subfamily Cyclopinae Kiefer, 1927, represented by 62 species and subspecies (Dussart & Defaye 2006). Based on either fine-detailed re-examination or morphology-based cladistic analysis of the Australian and New Zealand species of Metacyclops, three new genera have been established, including Meridiecyclops Fiers, 2001, Fierscyclops Karanovic, 2004, and Pescecyclops Karanovic, Eberhard & Murdoch, 2011 (Fiers 2001; Karanovic 2004a; Karanovic et al 2011). During 2010–2018, Karanovic et al (2011) transferred six species of the “trispinosus” group to the genus Pescecyclops and Fiers (2012) removed Allocyclops (Allocyclops) arenicolous (Fryer, 1965) back to the genus Metacyclops
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
