Artemia, Leach, 1819

Padhye, Sameer M. & Lazo-Wasem, Eric A., 2018, An updated and detailed taxonomical account of the large Branchiopoda (Crustacea: Branchiopoda: Anostraca, Notostraca, Spinicaudata) from the Yale North India Expedition deposited in the Yale Peabody Natural History Museum, Zootaxa 4394 (2), pp. 207-218 : 208-209

Artemia sp.

Fig. 1 (A–H)

Material examined. YPM IZ 003582.CR: Five males and 3 females (for eggs); eggs from 2 females used for SEM images

Locality. Tso Kar [salt lake], Indian Tibet (per Bond, 1934). Original label date: 0 5 Sep 1932 (Ladakh, Jammu & Kashmir, India).

Comments. For general description refer to Bond (1934:32). The second antennal frontal knob is semicircular in shape ( Fig.1A–C ), nearly 0.3x the size of the antennal width (at point of attachment) ( Fig.1B & C ). Frontal knob microspinulae mostly paired, less frequently in triplets, rarely as single spines. These spinulae more densely covered the middle and lower surfaces, and were themselves stout, gently tapering to the apex ( Fig.1D ).

The gonopod bears a distinct spine like projection proximally ( Fig.1E & F ), that is nearly 0.25 x the width of the gonopod base ( Fig.1G ); the spine apex is ornamented with smaller spines. The everted gonopod was not observed ( Fig.1H ).

All cercopod setae are broken, and not properly observable.

The egg diameter ranged 176–195 µm, and bore no surface ornamentation (typical for the genus).

Absence of a gonopod basal spine is a characteristic trait of both A. salina (Linneaus, 1758) as well as A. tibetiana Abatzopoulos, Zhang & Sorgeloos, 1998 ( Mura & Brecciaroli 2004; Rogers, 2017 in press). A basal spine was clearly observed in all male specimens ( Fig.1E & F ) which indicates that the Yale specimens are not assignable to either A. tibetiana or A. salina . Artemia sinica Cai, 1989 , described from China, does have a basal spine (sensu Rogers et al., 2017 in press). The armature at the basal spine apex of the studied population also grossly resembled to that of A. sinica described by Mura & Brecciaroli (2004) as well as the microspinulae number and its frequency (as per Rogers in press). Given that A. sinica is reported from an adjacent region and considering the speculation that Tso Kar population might have been introduced by caravans carrying salt in the region [as per Bond (1934), this species could be considered as A. sinica . This species is reported to have ten or more setae on its cercopods (sensu Rogers et al., 2017 in press) which could not be observed due to damage, however, as per the illustrations depicted by Bond (1934), this number is less than eight. We have not studied the types of A. sinica . Therefore, until confirmatory investigations are carried out, we refer to this species as Artemia sp. only.

Figures

FIGURE 1. Artemia sp. A, habitus (male). B, second antenna (male). C, second antenna showing the frontal knobs. D, single frontal knob. E, penes. F & G, basal spines on the penes. H, egg. (Scale bars: A & B: 0.5 mm; C & E: 0.2mm; D: 0.05mm; F: 0.1mm; G & H: 0.02mm)