Metastenasellus boutini Pountougnigni, Piscart & Zebaze Togouet, 2021
|
publication ID |
https://dx.doi.org/10.3897/subtbiol.40.76301 |
|
publication LSID |
lsid:zoobank.org:pub:96E9F621-B1A9-43DB-B18B-34983DD72B4B |
|
persistent identifier |
https://treatment.plazi.org/id/B56F7FB4-8AE2-4B9A-8B26-8F4FDDF0E327 |
|
taxon LSID |
lsid:zoobank.org:act:B56F7FB4-8AE2-4B9A-8B26-8F4FDDF0E327 |
|
treatment provided by |
|
|
scientific name |
Metastenasellus boutini Pountougnigni, Piscart & Zebaze Togouet |
| status |
sp. nov. |
Metastenasellus boutini Pountougnigni, Piscart & Zebaze Togouet sp. nov.
Diagnosis.
Metastenasellus boutini n.sp. is characterized by pleonites 1 and 2 around 50% as long as pereonite 7, the presence of sternal spine on each dactylus of pereopods 2-7 and endopodite of pleopod 2 in males long and large with a helicoidal spermatic duct.
Material examined.
Type-specimen: Holotype ♂ (9.8 mm), mounted on 2 slides and deposited at the Muséum national d’Histoire Naturelle de Paris ( MNHN, France) under voucher number MNHN IU-2021-1818.
Type-locality.
Cameroon, in PK21 quarter, Douala city, 04°07'16"N; 09°49'41.4"E, in a well at 60 m a.s.l. and 8 m depth, 24 April 2021. Paratypes: 5 ♂♂ in vials; same data as for holotype; MNHN IU-2021-1819 • 3 ♀♀ in vials; same data as for holotype; MNHN IU-2021-1820.
Other material examined.
22 specimens collected in seven wells around the type locality (Table 1 View Table 1 ).
Etymology.
The epithet boutini refers to the name of Dr. Claude Boutin who initiated many studies on stygofauna in northern and central Africa.
Description of male.
M. boutini sp. nov is a relatively medium-sized stenasellid, length up to 11 mm in males. Cephalon short and rounded with a concave rostral margin and convex distally. Pereonites 1 to 7 well developed, the 6th and 7th being the longest. Pleonites 1 and 2 free and as long as 50% of the length of the pereonite 7. Pleotelson subrectangular with a pointed caudal margin and partially covering the protopodite of the uropod.
Antenna 1 (Fig. 1B View Figure 1 ) slightly longer than peduncle of antenna 2, flagellum with 12-15 articles, the last 6 bearing a single distal aesthetasc (lamina olfactoria), the first two articles of the peduncle are longer than the others and bear one and two sensory plumose setae, respectively. Antenna 2 (Fig. 1C View Figure 1 ) around 30% of body length, 2.5 times as long as antenna 1, flagellum composed of a variable number of short articles (32 to 48 articles for specimens between 9 and 10 mm), peduncle articles 5 and 6 bearing one and two sensory setae, respectively; exopodite vestigial (squama) and scale-like on posterior margin of article 3 with a spine and a long simple seta on the apex. Mandibles asymmetrical, incisor processes with four teeth; left mandible (Fig. 1D View Figure 1 ) with a well-developed lacinia mobilis with four teeth, followed by a row of 18 serrate setae and 12 toothed setae; right mandible (Fig. 1E View Figure 1 ) with a shorter four-toothed lacinia mobilis followed by a row of 18 serrate setae and 12 toothed setae; palp tri-articulated, the first article with one long simple distal seta, the second with two simple setae and ten single sided serrated setae, the last article has 12 single sided serrated setae, the two terminal ones being longer. Maxilla 1 (Fig. 1F View Figure 1 ) endite clearly separated from exite with two groups of ciliated setae at the apex separated by one simple seta and four setules on external margin; exite with 12 apical serrated setae with one to six teeth and one ciliated seta. Maxilla 2 sympod (Fig. 1G View Figure 1 ) bearing on its medial margin 7 simple setae and one strong seta; endite with 14 ciliated setae at the apex, middle lobe with 7 ciliated setae and external exite with 5 ciliated setae. Maxilliped (Fig. 1H View Figure 1 ) endite bearing 4 plumose setae, 3 serrated setae, and a pair of coupling hooks on medial margin; palp 5-articulated, articles 2 and 3 distinctly longer and stronger than the other three, articles 1-5 bearing from base to apex 4, 9, 14, 14 and 2 simple setae on medial margin, article 4 with one additional simple seta on its external margin, article 5 with 10 apical simple setae.
Gnathopod (pereopod 1) (Fig. 2A View Figure 2 ) short, powerful, and haptorial with a dense chaetotaxis and strongly armed on the ventral margin of the last four articles; basis with 8 short setae on the ventral margin; ischium subtrapezoidal and bearing two setae on each margin; merus and carpus subtriangular, bearing on the ventral margin 5 and 6 long setae, 2 and 7 pen-like setae, respectively, merus bearing 2 additional long and strong setae on its outer tip; propodus enlarged with simple setae alternating with 9 toothed setae and 4 strong proximal denticulated setae; dactylus armed with 7 toothed setae and few simple setae on its ventral margin and 8-10 simple setae on the dorsal margin.
Pereopods 2 to 7 (Fig. 2B-D View Figure 2 ; Fig. 3 View Figure 3 ) typically ambulatory, slender, and rather long, with a more or less developed chaetotaxis and a similar morphology with sensorial setae on dorsal margin of the basis, a strong armature of all articles with spines of various sizes and few setae, one strong sternal spine on each dactylus; pereopod 2 (Fig. 2B View Figure 2 ) and 6 (Fig. 3B View Figure 3 ) also bearing a sensorial seta on the distal part of dorsal margin of the propodus and carpus, respectively.
Pleopod 1 (Fig. 4A View Figure 4 ) uniramous; propodus subrectangular and convex on its external margin, glabrous and without retinacula; exopodite oval, 2.5 times as long as wide with 17 distal setae, the 5 medial ones being the longest. Pleopod 2 (Fig. 4B View Figure 4 ) biramous, rami clearly separated; protopodite subpentagonal with an oblique distal part and a developed process on the external margin, slightly overreaching the first segment of the exopodite; endopodite biarticulated, proximal article not clearly delimited and ankylosed to the second one, second article highly developed, fusiform and twisted, containing a helicoidal spermatic channel with a large proximal-internal afferent opening and a smaller distal efferent orifice, surrounded by chitinous teeth; exopodite, narrower than endopodite, biarticulate with a rounded second article, larger than the first article with one subterminal seta and 2 or 3 marginal external setae. Pleopod 3 (Fig. 4D View Figure 4 ) with a very short protopodite; endopodite smaller than the first article of the exopodite and biarticulated, with the second article, larger, distally oval; exopodite also biarticulated, first article long and subrectangular, bearing on its external margin 12 setae of varying size; second article subtriangular, shorter than the first one and bearing 4 simple proximal setae on its external margin and 4 apical setae. Pleopod 4 (Fig. 4E View Figure 4 ) with a short protopodite; endopodite biarticulated with the second article more than 3 times longer than the first one; exopodite large, glabrous, with very oblique interarticular suture, first article much larger and longer than the second one. Pleopod 5 (Fig. 4F View Figure 4 ) with a subrectangular protopodite; endopodite biarticulated with the second article more than 4 times as long as the first one; exopodite biarticulated, slightly longer than endopodite; first article short, second article much larger and longer than the first one. Uropod (Fig. 4G View Figure 4 ) biramous as long as the pleotelson; protopodite subrectangular with dorsal and marginal setae; endopodite slightly longer than exopodite, both with numerous setae and spines and with several long apical setae; sensorial setae present only on the endopodite.
Female. Females are very similar to males with a reduced chaetotaxis on uropods. They are slightly longer than males, size up to 12 mm. Pleopod 2 (Fig. 4C View Figure 4 ) typical of female Metastenasellus formed by two single sub-triangular plates, with external and distal angles rounded. The lateral and apical margins of plates varied from concave to convex and bear few setae (0 to 3) each. Left and right pleopodal plates joined over 10% of their proximal part and are well separated on their distal part. Each plate bearing several (5-10) small ventral setae.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.