Adeliella debroyeri Souza-Filho, Guedes-Silva & Andrade, 2024

Souza-Filho, Jesser F., Guedes-Silva, Elkênita & Andrade, Luiz F., 2024, Four new species and two new records of deep-sea Amphipoda (Crustacea: Peracarida) from Potiguar Basin, north-eastern Brazil, Journal of Natural History 58 (41 - 44), pp. 1615-1655 : 1618-1623

publication ID	https://doi.org/ 10.1080/00222933.2024.2374404
DOI	https://doi.org/10.5281/zenodo.13784980
persistent identifier	https://treatment.plazi.org/id/2A3B87F7-FFAA-FFD2-FEFC-759AFDFAFB1F
treatment provided by	Plazi
scientific name	Adeliella debroyeri Souza-Filho, Guedes-Silva & Andrade
status	sp. nov.

Treatment

Adeliella debroyeri Souza-Filho, Guedes-Silva & Andrade sp. n.

( Figures 1–5 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 )

Material examined

Holotype female, 28 mm, Potiguar Basin , - 4.6113°S, 36.5248°W, Rio Grande do Norte state, Brazil, 2000 m depth, 4 May 2011, R / V Seward Johnson col. ( MOUFPE 20192 View Materials ). GoogleMaps

Type locality

Slope of Rio Grande do Norte state, north-eastern Brazil, 4.6113°S, 36.5248°W GoogleMaps .

Diagnosis

Mandible lacinia mobilis present in both left and right; molar asymmetric, right large. Lower lip inner plate absent. Maxilla 2 inner plate subequal to outer plate. Maxilla 2 outer plate with 7 apical robust setae, gnathopod 1 carpus less than half of the propodus length; carpus subrectangular, palm almost transverse. Gnathopod 2 carpus lacking posterodistal lobe; propodus palm defined by 1 robust seta. Uropod 1 peduncle inflated proximally, almost 2.5× longer than outer ramus. Uropod 3 inner ramus half the length of outer ramus; outer ramus article 2 about 0.2× shorter than article 1. Telson ovate.

Description

Based on female holotype, 28 mm, MOUFPE 20192. Body as in Figure 1 View Figure 1 . Head ( Figure 2a View Figure 2 ) short, lateral cephalic lobe broad and rounded, eyes absent. Antenna 1 ( Figure 2b View Figure 2 ) stout and reduced; flagellum 11-articulate, article 1 with a dense row of callynophores; accessory flagellum 3-articulate. Antenna 2 ( Figure 2c View Figure 2 ) weakly setose, articles 4–5 bearing dorsal setae; flagellum stout and short, 12-articulate. Upper lip ( Figure 2d View Figure 2 ) rounded, naked. Lower lip ( Figure 2e View Figure 2 ) naked. Mandibles ( Figure 2f–g View Figure 2 ) right incisor with 3 blunt teeth; left incisor smooth with 2 short teeth; molar triturative; right lacinia mobilis distally broadened with 3 apical teeth; left lacinia mobilis as a single tapering peg; accessory setal row with 2 robust setae; palp 3-articulate, article 2 with distal facial setae, article 3 about 0.6× the length of article 2. Maxilla 1 ( Figure 2h View Figure 2 ) inner plate with 1 short seta; outer plate with 8 robust setae; palp 2-articulate, article 2 broad, with 7 robust setae. Maxilla 2 ( Figure 2i View Figure 2 ) plates thin and elongated; inner plate subequal to outer, with 4 apical setae; outer plate with 6 apical setae. Maxilliped ( Figure 2j View Figure 2 ) inner plate apex with 6 setae; outer plate broad, tapering distally, with 14 short robust setae; palp article 4 about 0.3× the length of article 3, bearing an apical nail.

Coxa 1 ( Figure 3a View Figure 3 ) slightly broadening distally. Coxa 4 ( Figure 4b View Figure 4 ) posterodorsally excavated. Coxae 6–7 ( Figure 4c–d View Figure 4 ) with strong posteroventral lobe. Gnathopod 1 ( Figure 3a View Figure 3 ) basis anterior and posterior margin with short setae; propodus 1.4× longer than wide; palm almost transverse, defined by a robust seta inserted in an acute projection, margin with 7 humps varying from acute- to blunt-tipped; dactylus curved, almost reaching the palmar corner. Gnathopod 2 ( Figure 3b View Figure 3 ) ischium elongated; carpus 1.8× longer than propodus; propodus 3.7× longer than wide anterior and posterior margins covered with setules; palm bearing a long robust seta near palmar corner, margin with a shallow concavity; dactylus short and curved, longer than palm. Pereopods 3–4 ( Figure 4a–c View Figure 4 similar in shape, weakly setose; merus longer than carpus; dactylus short. Pereopod 5 ( Figure 4c View Figure 4 ) basis broad, slightly longer than wide, posterodistal corner produced as a lobe; merus posterodistal corner produced into a subacute lobe. Pereopods 6–7 ( Figure 4d–e View Figure 4 ) basis about 1.5× longer than wide; basis–carpus anterior margin with sparse short robust setae.

Urosomite 1 ( Figure 1 View Figure 1 ) with a rounded carina. Epimera 1–3 ( Figure 5a–c View Figure 5 ) naked, margins rounded. Uropod 1 ( Figure 5d View Figure 5 ) peduncle elongated, 2.9× longer than wide, dorsal margin with a row of robust setae; rami lanceolate, with sparse robust setae bearing short apical nail; outer ramus slightly longer than inner. Uropod 2 ( Figure 5e View Figure 5 ) peduncle 2.1× longer than wide; rami lanceolate, subequal, with marginal robust setae, bearing short apical nail. Uropod 3 ( Figure 5f View Figure 5 ) peduncle 1.4× longer than wide; rami lanceolate; outer ramus 2-articulate, 1.8× longer than inner, article 2 about 0.2× the length of article 1; inner ramus with an apical short seta. Telson ( Figure 5g View Figure 5 ) about 45% cleft, each lobe rounded with 1 short seta.

Etymology

The specific epithet is dedicated to Dr Claude De Broyer, for his great contribution to the taxonomy of amphipods and to the genus Adeliella .

Distribution and bathymetry

Known only from the type locality (slope of Rio Grande do Norte state, north-eastern Brazil, - 4,6113°S, - 36,5248°W), at 2000 m deep ( Figure 23 View Figure 23 ) GoogleMaps .

Remarks

The new species described here can be distinguished from the other three species of the genus by the following: maxilla 1 inner plate bearing 7 robust setae; maxilla 2 inner plate subequal to outer plate; gnathopod 1 carpus 0.4× of propodus length, while the other species present maxilla 1 inner plate bearing 5 or 6 robust setae; maxilla 2 inner plate about half length of outer plate and gnathopod 1 carpus subequal to propodus.

Additionally, it closely resembles Ad. takoradia (J.L. Barnard 1961) in the gnathopod 2 carpus without a well-developed posterodistal and telson more than 40% cleft. However, Ad. debroyeri sp. n. differs from Ad. takoradia (characters in parenthesis) by having accessory flagellum shorter than article 1 of peduncle (longer than article 1); gnathopod 1 basis slender (moderately inflated), palm with blunt processes (subacute processes); and coxa 5 posterior lobe deeper than anterior (lobes subequal).

This is the first report of Adeliellidae and Adeliella from the South Atlantic Ocean and, consequently, from Brazilian waters.