Racovitzaibathynella beninensis Camacho and Lagnika, 2024

Camacho, A. I., Mas-Peinado, P., Lagnika, M., Martin, P., Dorda, B. A. & Rey, I., 2024, First record of Bathynellacea (Crustacea: Malacostraca) in Benin (West Africa): two new species and their phylogenetic position within the Parabathynellidae family, Journal of Natural History 58 (17 - 20), pp. 570-602 : 578-579

Racovitzaibathynella beninensis Camacho and Lagnika sp. n.

( Figures 2–4 )

urn:lsid:zoobank.org:pub:

Material examined

Type locality. Modern wells ( BEN147 ), Vanhoui, Djougou, Donga, Benin (9.56519°N, 1.82198°E, 388 m alt.; WGS84), 28/08/2017 (one female) and 27/05/2018 (one male); collected by M . Lagnika, J . Hotepko and P . Martin.

Type material. Holotype male ( MNCN 20.04 /20,703), allotype female ( MNCN 20.04 / 20,704), type series comprised of the two specimens, each on an individual slide, and two DNA samples as the DNA types ( MNCN / ADN 54919 male and MNCN / ADN 54873 female).

Description

Body. Total length of holotype 1.1 mm and allotype 0.91 mm. Body elongated ( Figure 2 ), segments widening towards posterior end; approximately 9 times as long as wide. Head one-third longer than wide. All drawings are of the (male) holotype except for ThVIII, antenna, labrum and Md of the allotype (female).

Antennule. ( Figure 3 (a)). Six-segmented; length of first three articles 1.4 times longer than other three articles combined; sixth article as long as the third article but half as wide; inner flagellum rectangular, large, and half the height of the fourth article; setation as in Figure 3 (a); article three with three smooth setae; article five with three terminal aesthetascs, similar in size; sixth article with three aesthetascs, one slightly shorter than the other two. AI longer than AII.

Antenna. ( Figure 3 (b)). Five-segmented; as long as the first four articles of AI; first two articles are similar in length; the third is the shortest, the fourth is 2.5 times longer than the first two, and the fifth is slightly shorter than the fourth one; last article with three setae: one smooth, one plumose and one outer seta transformed into a long strong fang that is curved inwards (sexual dimorphism); setal formula: 0/0/1 + 0/1 + 0/3(1).

Antenna of the allotype. ( Figure 3 (c)). Similar to that of the holotype but with four setae on the last article, with the outer seta smooth and not transformed; setal formula: 0/0/ 1 + 0/1 + 0/4(1).

Labrum. ( Figure 3 (d)). Distal edge concave, with 12 teeth, the lateral ones somewhat smaller than the central ones.

Labrum of the allotype. ( Figure 3 (e)). Similar to the male’s but with fewer teeth, only 11; the central teeth are triangular and slightly larger than the lateral ones.

Mandible. ( Figure 3 (f)). Pars incisiva with three teeth on the distal part, and a well-developed tooth on the ventral edge; pars molaris with four claws, the two most proximal joined and with many fine hairs; mandibular palp, one-segmented, with a distal seta that extends beyond the pars incisiva.

Figures

Figure 2. Habitus of Racovitzaibathynella beninensis sp. n.

Figure 3. Racovitzaibathynella beninensis sp. n. (a, b, d, f, h, j–n) Male holotype. (c, e, g, i) Female allotype. (a) Antennule (dorsal view); (b) antenna (dorsal view); (c) antenna, female (dorsal view); (d) labrum; (e) labrum, female; (f) mandible; (g) mandible, female; (h) maxillule; (i) maxillule, female; (j) maxilla (dorsal view); (k) thoracopod VIII (latero-external view); (l) thoracopod VIII (latero-internal view); (m) thoracopod VIII (latero-external view); (n) thoracopod VIII (latero-internal view); (o) thoracopod VIII of female allotype (ventral view). Scale bars in mm. Abbreviations: Bsp = basipod; D. lb = dentate lobe; Exp = exopod; Endp = endopod; O. lb = outer lobe; P. lb = penial lobe.

Figure 4. Racovitzaibathynella beninensis sp. n. Male holotype. (a) Thoracopod I; (b) thoracopod II; (c) thoracopod III; (d) thoracopod IV; (e) thoracopod V; (f) thoracopod VI; (g) thoracopod VII; (h) uropod (latero-external view); (i) furcal rami (dorsal view). Scale bars in mm.