Hyalella bonariensis, Santos & Araujo & Bond-Buckup, 2008

Santos, Ana Lucia Freitas Dos, Araujo, Paula Beatriz & Bond-Buckup, Georgina, 2008, New species and new reports of Hyalella (Crustacea, Amphipoda, Dogielinotidae) from Argentina, Zootaxa 1760 (1), pp. 24-36 : 25-29

publication ID	https://doi.org/ 10.11646/zootaxa.1760.1.2
persistent identifier	https://treatment.plazi.org/id/039387A2-FFFD-FFFD-FF77-FC7D8139FF1D
treatment provided by	Felipe
scientific name	Hyalella bonariensis
status	sp. nov.

Treatment

Hyalella bonariensis View in CoL n. sp. Bond-Buckup, G., Araujo, P.B. & Santos, A.L.F.

( Figs. 1 View FIGURES 1–7 to 26)

Material examined: Holotype male, Argentina, Province of Buenos Aires, near city of Salto (34º18’15.6’’S – 60º20’0.0’’W) MNRJ (20467); allotype female MNRJ (20469), September 2005, Castiglioni, D. S. & Lopes- Greco, L. colls. GoogleMaps

Paratypes: UFRGS 4007 View Materials (106 males, 119 females, 15 juveniles) , UFRGS 4008 View Materials (1 male, 1 female) , UFRGS 4009 View Materials (20 males, 12 females) , UFRGS 4010 View Materials (36 males, 10 females, 5 juveniles) , MNRJ (20468). All these samples with the same data as the holotype GoogleMaps .

Other material examined: Argentina, Province of Buenos Aires: Salto (34º16’59.4’’S – 60º27’3.4’’W), October 2003, UFRGS 3657 View Materials (18 males, 24 females) GoogleMaps ; Pergamino River (35º56’33.5’’S 60º28’13.4’’W), October 2003, UFRGS 3661 View Materials (11 males, 19 females) GoogleMaps ; “ Cañada Honda”, San Antonio de Areco (34º04’17.8’’S 59º30’26’’W), October 2003, UFRGS 3670 View Materials (22 males, 20 females) GoogleMaps ; “Arroyo Manantiales”, Guerico (33º42’14’’S 60º20’31.1’’W), October 2003, UFRGS 3673 View Materials (108 males, 92 females) GoogleMaps ; UFRGS 3776 View Materials (4 males, 5 females) GoogleMaps

Type-locality: Argentina, Province of Buenos Aires, Salto (34º18’15.6’’S – 60º20’0.0’’W), 43 m. GoogleMaps

Diagnosis: Epimeral plates not acuminate. Flagellum of antenna 1 with 11–15 articles, flagellum of antenna 2 with 9–12 articles. Inner plate of maxilla 2 with two pappose setae. Gnathopod 1 hammer-shaped, inner border of dactylus not projecting away from the external cuspidate setae with accessory seta, propodus width 2/3 of its length, palm with 3 long simple setae dorsally and 5 serrate setae ventrally. Propodus of gnathopod 2 ovate, width 4/5 of maximum length, with a lobe covered by comb scales; width of propodus of about 4/5 of its length. Inner ramus of uropod 1 with curved seta on inner side. Peduncle of uropod 3 longer than wide, width about 2/3 length. Coxal gills sac-like on segments 2 to 6. Sternal gills tubular on segments 2 to 7.

Description of male ( Figures 1 View FIGURES 1–7 to 26):

Epimeral plates not acuminate. Sessile, pigmented eyes ( Fig. 1 View FIGURES 1–7 ).

Antenna 1 ( Fig. 2 View FIGURES 1–7 ): shorter than antenna 2. Peduncle not surpassing first 2 articles of cephalothorax. Flagellum with 11 to 15 articles. Articles 3 to 10 of flagellum with aesthetascs: 0 to 1 on third article, 1 to 2 on fourth, 2 on fifth, 1 to 2 on sixth, 2 on seventh, 1 to 2 on eighth, and 1 each on ninth and tenth articles ( Fig. 3 View FIGURES 1–7 ).

Antenna 2 ( Fig. 4 View FIGURES 1–7 ): peduncle not surpassing third segment of cephalothorax, flagellum with 9 to 12 articles.

Mandible ( Fig. 5 View FIGURES 1–7 ): basic amphipodan (in the sense of Watling, 1993), but without palp; presence of penicilium, incisor toothed; lacinia mobilis with 5 teeth, setal row on left mandible with 5 main pappose setae plus accessory seta, right mandible with 5 main pappose setae plus accessory seta; molar large, cylindrical and triturative with setules around its circumference.

Upper lip margin rounded, distal border covered by short setules on dorsal and ventral faces ( Figs. 6a, 6b View FIGURES 1–7 ). Lower lip outer lobes rounded, with setules on dorsal and ventral faces ( Figs. 7a, 7b View FIGURES 1–7 ).

Maxilla 1 ( Fig. 8 View FIGURES 8–10 ): inner plate not articulated, shorter than outer plate, with long and stout pappose setae. Outer plate not articulated, with 9 serrate setae. Palp short, covered by long and fine setules.

Maxilla 2 ( Fig. 9 View FIGURES 8–10 ): inner plate with two pappose, several simple and serrate setae; outer plate with two row of simple setae.

Maxilliped ( Fig. 10 View FIGURES 8–10 ): inner plate apically with cuspidate and pappose setae in the inner border and setules on distal portion, dorsal surface with distally pappose setae. Outer plate with pappose setae; palp with simple setae in the first and second articles. Articles 3 and 4 with simple and serrate setae on the distal border. Palp ventral surface with setules in the first, second and third articles. Fourth article with comb scales.

Gnathopod 1 ( Fig. 11 View FIGURES 11–13 ): subchelate, dactylus claw-like with comb scales, simple and plumose setae. Propodus width 2/3 of maximum length, hammer-shaped, with comb scales; distally with several short simple setae. Palm slope transverse, sinuose margin; posterior distal corner with comb scales and two cuspidate setae with accessory seta; 3 long simple setae dorsally ( Fig.12 View FIGURES 11–13 ) and 5 serrate setae ventrally ( Fig.13 View FIGURES 11–13 ). Carpus longer than wide, with strong, concave, wide posterior lobe with pectinate border and a row of several serrate setae. Merus, ischium and basis also with comb scales dorsally forming a poligonal pattern of setae. Coxal plate longer than wide, with simple setae.

Gnathopod 2 ( Fig. 14 View FIGURES 14–15 ): subchelate, dactylus claw-like without comb scales, with 1 plumose seta. Propodus ovate, width 4/5 of maximum length, with a lobe covered by comb scales. Carpus wider than long, with strong, concave, wide posterior lobe with pectinate border and a row of several serrate setae ( Fig. 15 View FIGURES 14–15 ). Merus, ischium, basis and coxal plate like G1.

Pereiopods ( Figs. 16 View FIGURES 16–20 to 20): dactylus, propodus, carpus, ischium and basis with simple and cuspidate setae with accessory seta. Coxal plates: pereiopod 3: longer than wide, width about half its length; pereiopod 4: wider than long; pereiopod 5: wider than long, with 2 lobes, inner lobe shorter than outer lobe; pereiopod 6: ovate; pereiopod 7: wider than long. All coxal plates with simple setae on the border.

Pleopods ( Fig. 21 View FIGURES 21–26 ): peduncle smaller than flagellum rami, which have plumose setae.

Uropod 1 ( Fig. 22 View FIGURES 21–26 ): peduncle longer than rami; inner ramus with 8 cuspidate setae with accessory seta, 1 curved seta plus 2 other, cuspidate setae ( Fig. 23 View FIGURES 21–26 ). Outer ramus with 5 cuspidate setae with accessory seta and 2 cuspidade setae.

Uropod 2 ( Fig. 24 View FIGURES 21–26 ): shorter than uropod 1. Rami length about ¾ of peduncle. Peduncle with 6 cuspidate setae with accessory seta. Inner ramus with 6 cuspidate setae with accessory seta and 2 cuspidate setae.

Uropod 3 ( Fig. 25 View FIGURES 21–26 ): shorter than other uropods, peduncle longer than wide, width about 2/3 length, with 6 cuspidate setae with accessory seta and 1 simple seta. Ramus with 4 long simple setae plus 4 shorter setae.

Telson ( Fig. 26 View FIGURES 21–26 ): quadrangular, with 2–3 cuspidate setae appically. Sometimes with plumose setae.

Coxal gills sac-like on segments 2 to 6. Sternal gills tubular on segments 2 to 7.

Measurements: Male (n = 10): 8.77 ± 1.06 mm total length (head: 0.85 ± 0.12 mm length).

Female ( Figs. 27 View FIGURES 27–33 to 33)

Antenna 1 ( Fig. 28 View FIGURES 27–33 ): flagellum with 8 articles. Aesthetascs: 1 on second article, 2 on third, 2 on fourth, 2 on fifth, 1 on sixth and one on seventh.

Antenna 2 ( Fig. 29 View FIGURES 27–33 ): longer than antenna 1, flagellum with 10 articles. Other characters similar to male.

Gnathopod 1 ( Figs. 30, 31 View FIGURES 27–33 ): size similar to gnathopod 2. Propodus wider than long. Similar to male gnathopod, except for 7 serrate setae on dorsal face of palm. Coxal plate width less than 3/4 of the length.

Gnathopod 2 ( Figs. 32, 33 View FIGURES 27–33 ): Propodus subrectangular, longer than wide, with 3 serrate setae ventrally and 2 simple setae dorsally on palm, plus 6 simple setae laterally. Carpus with 2 simple setae on posterior lobe. Coxal plate basis width about 3/5 of total length of plate. Other characteristics similar to male.

Measurements (n = 10): 6.69 ± 1.15 mm total length (head: 0.62 ± 0.083 mm length).

The other characters are similar to the male, except for the absence of curved seta on uropod 1, and the presence of a notch on the second epimeral plate.

Habitat: freshwater, epigean, collected most frequently on Ceratophyllum demersum L. ( Ceratophyllaceae ).

Etymology: the specific name, bonariensis , refers to natives or residents of Buenos Aires Province.

Remarks. In the Province of Buenos Aires, besides H. bonariensis , H. pampeana Cavalieri, 1968 also occurs. These species have some similarities, especially the presence of curved seta on the inner ramus of uropod 1. They differ in total length: H. pampeana is 5 mm long, and H. bonariensis 8.3 mm. The width of the propodus of gnathopod 1 in H. pampeana is about ¾ of its length, whereas in H. bonariensis the width is about 2/3 of its length. The most apparent difference between these two species is the presence of a space between the dactylus and the margin of the propodus of gnathopod 2 in H. pampeana ; this space is absent in H. bonariensis ( Table 2). The seven other species differ mainly in the number of articles of the flagellum of the antenna, the number of coxal and sternal gills, the width of the propodus of gnathopod 1 and 2, and the presence or absence of curved seta on the inner ramus of uropod 1 ( Table 2).