Leptestheria timmsi, Padhye & Rabet, 2023

Padhye, Sameer M. & Rabet, Nicolas, 2023, Assigning the Australian clam shrimp Eoleptestheria (Branchiopoda: Spinicaudata: Leptestheriidae) to a new species status, Zootaxa 5318 (4), pp. 563-570 : 564-566

Leptestheria timmsi sp. nov.

( Figs.2A–B ; Figs.3A–E )

Eoleptestheria ticinensis Timms (2009)

Etymology. The new species is named after Dr. Brian Timms, an expert on large branchiopods who has contributed extensively to the taxonomy and systematics of Australian animals

Type locality. Australia, Queensland, Bindegolly National Park, Lake Toomaroo ; - 27° 58’ 47.604” N, 144° 12’ 3.708” E. Type material. Holotype. 1 hermaphrodite (collected by M. Handley on 01.02.2006) deposited at the Australian museum, Sydney (Registration number: P92974 ).

Paratypes. 8 hermaphrodites deposited at the Australian museum, Sydney (Registration number: P80191).

Other material examined. Slovakia (Trebišov District/Novosad; MNHN-IU-2007-1122 (= MNHN-Bp83)). Mali (Mopti region/Sanga (Sangha); MNHN-IU-2007-747 (= MNHN-Bp463).

Description (Diagnosis) of putative hermaphrodite. Population from the type locality of this species has been thoroughly described by Timms (2009) and hence we focus only the diagnostic traits and the traits that were not elaborated earlier.

Head ( Fig. 2A ) with a distinct ocular tubercle. Eyes moderate sized about 0.6–0.7 times the width of ocular tubercle. The ratio of RL/TL ranging from 0.7–0.8. Occipital condyle rounded with a straight dorso-posterior margin. The rostral spine long, arched and nearly 6–8 times as long as the width at its base.

Carapace oval with maximum width to maximum length ratio ranging from 0.55–0.6.

Trunk. Last 12–14 body segments, each bear group of stout setae, directed posteriorly with acute apices, longest setae ~ 6–8 times as long as wide at the base ( Fig.3B ), numbers and size of longest setae increasing initially and then both decreasing gradually.

Telson marginal spines ~ 40–45 in number, gradually increasing in length posteriorly ( Fig. 2B ). Telson marginal spines broadly of two types based on their length and shape. Posterior 1/3 rd spines 1.5–2 times longer than the anterior 2/3 rd. Anterior spines as long as their width at the base while posterior 1/3 rd 2–3 times the width at their base ( Figs. 2B , 3A, 3C ). Distance between the spines is subequal, lesser in the bigger spines and increases anteriorly ( Figs. 2B , 3A, 3C ). Telson filaments located between the 1–3 rd marginal spines ( Fig. 2B ).

Cercopod long, gently arched, slightly extending beyond the telson spiniform projection and nearly equal to the length of the telson dorsal margin ( Fig. 2B ). Cercopod marginal spines closely spaced, increasing in size posteriorly with the most posterior spines 3-4 times in length than the most anterior spines ( Figs. 2B , 3E ). Smallest spines 2 times in length as compared with their base while the longest spines nearly 4–5 times in length as compared to their base ( Fig.2B ). Most of the anterior spines aligned medially and therefore not directly visible ( Fig. 3D ).

Distribution. Northern Australia. In addition to the Lake Toomaroo population, two other populations are known (but not studied in this work), namely the Kuranda population in Queensland and the Benmore Well clay pan population (Pilbara) in Western Australia (see Timms, 2009).

Figures

FIGURE 2. Leptestheria timmsi sp. nov. female. A, head. B, telson with cercopod (complete). Scale bars 0.5 mm.

FIGURE 3. Leptestheria timmsi sp. nov. female. A, posterior region of telson showing the dorsal marginal spines. B, dorsal armature. C, middle region of telson showing the dorsal marginal spines. D, anterior region of cercopod. E, posterior region of cercopod. Scale bars 0.1 mm.