Leptestheria brasiliensis, Weddingen & Rabet, 2020

Weddingen, Mélanie Van & Rabet, Nicolas, 2020, Fig. 4 in Fig. 3 in Fig. 21. Sesarmops mora n in Paralbunea dayriti, Zoological Studies 59 (40), pp. 1-8 : 2-6

Suborder Spinicaudata Linder, 1945 Family Leptestheriidae Daday, 1923 Genus Leptestheria Daday, 1913

Leptestheria brasiliensis sp. nov. ( Figs. 1–4 ) urn:lsid:zoobank.org:act:5EB7FD2E-F52F-413B-AB4A-D81A4ACA761E

Type locality: Brazil, Bahia, Palmas de Monte Alto (14°9'55.98"S, 43°3'39.24"W) ( Figs. 1A , 2) in a temporary pool at 22 December 2014 by M.L. Oliveira, N. S. Silva, H. Gonçalves, J. G. Neto and S. Lacau.

Type material: Holotype, male ( MZUSP 39601 ) . Allotype, female ( MZUSP 39602 ) . Paratypes: cultured from soil 9 to 31 July 2015 MA 214 - three males and three females ( MZUSP 39603), culture from soil 9 to 23 July 2015 MA 214 - three males and three females (MNHN-IU-2019-2312).

Etymology: Epithet derived from Brazil, the country where this new species was found.

Specific Diagnosis: Both sexes: The carapace rectangular. Dorsal margin straight or slightly arched ( Figs. 3a , 4a ). Head with occipital angle convex and apically acute, interior margin concave. Rostral spine long (length/width ratio> 10) ( Figs. 3c , 4c ). Trunk with 22 segments. Thoracic segments with small mid-dorsal spines, increasing in size distally, with penultimate segments bearing the longest spines. Last segment with a short spine ( Figs. 3k , 4e ). Telson with two rows of 35–40 spines each. The spines are uniform in size next to each other but posteriorly progressively becoming longer and more aciculate. Many spines denticulate ( Figs. 3k , 4e ). Cercopods with two dorsolateral rows of spines each. Each row with about 22 spines. Spines long, acute and denticulate, covering over 80% of the cercopod proximal base. Distalmost spine longest ( Figs. 3m , 4h ).

Specific Diagnosis: Male: first thoracopod endite V distally with many short setae. The endopod (movable finger) curved, apex acute with many rounded spines. Endite IV (gripping area) with an extension and apically long blunt spines.

Specific Diagnosis: Female: ninth and tenth thoracopods with epipods bearing cylindrical extensions for supporting the eggs.

Description: Male: Wild adult carapace 7.43 mm length, 2.63 mm width, 4.16 mm height (n = 1). Cultured adult carapace 2.18–4.96 mm length (n = 7), 1–1.32 width (n = 4), 1.25–2.73 mm height (n = 7)

Head with rostrum rounded and large ( Fig. 3c ). Rostral spine long (length/width ratio of ~12–13), straight, set at 45° angle. Ocellus irregular. Head anterior margin dorsal to the eye in lateral view slightly sinuate with three small concavities. Occipital condyle directed posteriorly, dorsally flattened, and apically acute (length/width ratio of ~0.75). Posterior margin concave.

First antenna indistinctly articulated, with 12–16 lobes bearing sensory setae. Second antenna anterior (dorsal) branch with 13 to 14 flagellomeres, posterior (ventral) branch with 10 to 14 flagellomeres. Each flagellomere ventrally with two or three long setae and dorsally with three to six acute, thin and fine spines.

Carapace rectangular ( Fig. 3a ), dorsal margin straight or slightly arched. Anterior, posterior, and ventral margins rounded with marginal setae. Ventral margin setae long, becoming shorter on anteriorly and posteriorly. Carapace intervals and growth lines with short setae. Umbo short and slightly pronounced ( Fig. 3b ). Growth line numbers variable depending on age; 18 in wild specimens and averaging 12 in cultured specimens.

Trunk with 22 segments. Thoracic segments medially with small dorsal spines (starting about segment nine), increasing in size posteriorly, with penultimate segments bearing the longest spines ( Fig. 3k ). Last segment with a short spine.

Thoracopod I endite 5 ( Fig. 3d, e, f ) distally with many short setae. Endopod (movable finger) curved, apex acute with many rounded spines. Endite IV (gripping area) with an extension and apically long blunt spines.

Telson spine rows of 36–40 denticulate spines each ( Fig. 3k, l ). Spine length relatively regular with some slightly smaller spines interposed irregularly. Spines increasing in size posteriorly, becoming aciculate (length/width ratio approximately 1.7 to 5.5; ratio larger/smaller length 2.6 to 2.7).

Cercopod with two dorsolateral spine rows ( Fig 3m only right cercopod medial row represented). Each row about 22 spines long, acute and denticulate (length/width ratio of 2.9–3.7) covering over 80% of the proximal base of the cercopods. Distalmost spine longest (length/width ratio of 3.9; 1.5 to 2.2 longer than the proximal spines).

Description: Female: Wild specimen carapace 6.1 mm length, 1.9 mm width, 3.6 mm height (n = 1). Cultured specimen carapace 3.3–4.8 mm length (n = 6), 1.0–1.9 width (n = 4), 1.9–2.8 mm height (n = 6).

Carapace similar to male with various number of growth lines; ~ 17 in wild specimens and ~ 11 in cultured specimens.

Head with a rounded and small, angular rostrum ( Fig. 4c ). Rostral spine long and arcuate (length/width ratio of ~10–11). Ocellus irregular. Anterior margin in lateral view dorsal to eye with a small concavity. Occipital condyle anteriorly rounded, convex, apically acute (length/width ratio of ~0.95), posterior margin concave.

First antenna indistinctly articulated, with 12–16 lobes bearing sensory setae. Second antenna anterior (dorsal) branch with 13 to 16 flagellomeres, posterior (ventral) branch with 10 to 14 flagellomeres. Each flagellomere ventrally with one to three long setae and dorsally with two to seven acute, thin spines

Trunk with 22 segments.

Thorax dorsomedially with small spines, increasing in size posteriorly, with distal most spines very long ( Fig. 4e ). Distalmost thoracic segments with spines very long and denticulate. Last segment with a short spine. These spines smaller than in the male.

Thoracopods IX and X ( Fig. 4d ) with epipods bearing cylindrical extensions (egg mass supporting appendages).

Telson ( Fig. 4e, f, g ) and cercopods ( Fig. 4h ) as in male.

Ecology and habitat

The habitat of L. brasiliensis is temporary pools in the southern part of Bahia State in the municipality of Palmas de Monte Alto in the Caatinga climatic zone. The species was observed in two other loamy pools some kilometres near the locus typicus. The species was also observed in turbid water rock pools bordering small inselbergs (e.g., 14°9'20.64"S, 43°3'28.14"W) (fig. 1B; and Rabet et al. 2018, fig. 7–E).

Two culture series from the locus typicus sediment provided specimens and information on species growth. First mating was observed 10 days after culture inundation, and individual longevity was at least two months. In the field, L. brasiliensis was most often observed co-occurring with Dendrocephalus orientalis Rabet & Thiéry, 1996 in various pool types, but in the pools with heavy loam it also co-occurred with Spiralifrons mira ( Gurney 1931) , Eulimnadia colombiensis Roessler, 1989 and Eulimnadia sp. In rock pools L. brasiliensis was associated with Metalimnadia sp. However, only Metalimnadia sp. alone occurred in clear water at the top of the inselbergs.

Figures

Fig. 1. Representative Leptestheria brasiliensis sp. nov. habitats. A: clay pond 22 December 2014 – locus typicus, B: 23 December 2014 rock pool.

Fig. 3. Leptestheria brasiliensis sp. nov. male. a: carapace, b: carapace detail, c: head, d: first thoracopod, e, f: thoracopod detail, g: second thoracopod, h, i: second thoracopod detail, j: third thoracopod, k: telson, l: telson margin detail; m: right cercopod detail (only medial spine row represented). Scale bars: a = 1 mm; b = 0.2 mm; e, f, h, i, l, m = 0.1 mm; c, d, g, j, k = 0.5 mm.

Fig. 4. Leptestheria brasiliensis sp. nov. female. a: carapace, b: carapace detail, c: head, d: ovigerous thoracopod, e: telson, f, g: telson margin detail.; h: right cercopod detail (only medial spine row represented). Scale bars: a = 1 mm; b = 0.2 mm; h = 0.1 mm; f, g = 0.05 mm; c, d, e = 0.5 mm.