Hyalella carsone Reis & Bueno & Araujo 2023, sp. nov.
Creators: name: Reis, Giovanna De Oliveira
name: Bueno, Alessandra Angélica De Pádua
name: Araujo, Paula Beatriz
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Hyalellidae
Hyalella
Hyalella carsone

description: Hyalella carsone sp. nov.
(Figs. 2–8)
Type material. Holotype male, body length = 7.30 mm, head length = 0.70 mm, Ponte Alta River, municipality of Bocaina do Sul, Santa Catarina, Brazil, (27°44′4.4″S 49°59′1.0″W), MZUSP 44141. Paratypes: UFRGS 6937 - twenty five individuals and two males and one female on slide; CCUFLA 449-25 whole individuals.
Diagnosis. Antenna 1 with pappose setae. Antenna 2 with pappose and serrate setae. Upper lip and lower lip with several simple setae. Maxilla 2 with lateral simple setae. Gnathopod 1 basis, merus, ischium and carpus with serrate setae with accessory seta and comb-scales. Gnathopod 2 merus and carpus with serrate setae with accessory seta; palm 1x longer than posterior margin of propodus, slope oblique; dactylus proximal margin strongly serrated. Uropod 1 without curved seta on inner ramus. Uropod 3 with two dorsal simple setae. Microtrichs present on antenna 1 and 2, maxilliped, gnathopods 1 and 2, pereopods, uropods and telson.
Description of paratypes males. Mean body length: 6.37 ± 1.96 mm (N = 10 from 4.34 to 10.84 mm); mean head length: 0.63 mm ± 0.14 mm (N = 10, from 0.43 to 0.90 mm). Body surface smooth. Head 1.9x smaller than the first two pereonites. Eyes rounded and pigmented. Coxae 1–3 subequal in size, slightly overlapping, coxae 3 and 4 longer than 1 and 2 (Figs. 4A–D, 5A, B). Coxa 3 wider than 4 (Fig. 5A, B). Coxa 4 longer than wide, excavated posteriorly (Fig. 5B). Coxa 5 posterior lobe longer than anterior lobe (Fig. 5C). Coxa 6 wider than long (Fig. 5D). Epimeral plates accuminated.
Antenna 1 (Fig. 3A) about 2.8x smaller than body length, 1.3x smaller than antenna 2, flagellum with 10– 11 articles, 1.5x longer than peduncle; article 1 with three lateral pappose setae and two inner simple setae with accessory seta; article 2 with one lateral pappose seta; aesthetascs (Fig. 9A) occurring on flagellum from article 3 distally; microtrichs present from article 2 to 9.
Antenna 2 (Fig. 3B) 2.2x smaller than body length; peduncle slender, 2.2x longer than head; flagellum with 17–19 articles, 1x longer than peduncle; article 3 with four apical serrate setae; article 4 with three lateral pappose setae, two inner and two apical serrate setae; article 5 with one lateral pappose seta; microtrichs present from article 3 to 20, absent on articles 7 and 8.
Mandible incisor toothed; left mandible (Fig. 3C) lacinia mobilis with five teeth, setal row with four papposerrate (setules only on one side of the seta) and one serrate seta (with setules on both sides of seta, uppermost superior seta in the illustration), with setules, molar process with an accessory seta; right mandible (Fig. 3D) with four papposerrate setae and setules; molar process broad and oval, without accessory seta.
Upper lip (Fig. 3E) distal margin rounded; outer margin covered by simple setae and inner margin with setules on ventral and dorsal faces. Lower lip (Fig. 3F) outer lobes rounded and distally notched, with several simple setae and setules on dorsal and ventral faces.
Maxilla 1 (Fig. 3G) inner plate slender, 1.9x shorter than outer plate, with two apical papposerrate setae and several setules dorsally. Outer plate with nine serrate setae and several setules dorsally. Palp short, uniarticulate, 1.7x wider than long, reaching less than half the distance between the base of the palp and base of setae on the outer plate, with apical setules.
Maxilla 2 (Fig. 3H) inner plate 1.3x shorter than outer plate, with one papposerrate seta, seven serrulate setae, several lateral simple setae and dorsally setules; outer plate with several distal and lateral simple setae.
Maxilliped (Fig. 3I, J) inner plate 2.7x longer than wide, with three cuspidate distal setae and 16 papposerrate setae; outer plate 1.1x longer than inner plate, with three pappose and simple setae; palp 2.3x longer than inner and 2x longer than outer plate, with four articles; article 1 1.5x longer than wide, outer margin with simple setae; article 2 1.4x longer than wide, inner margin with several long simple setae; article 3 1.5x longer than wide, inner margin with seven serrate and several long simple setae, outer margin with long simple setae; article 4 1.9x shorter than third article, 2.8x longer than wide, with distal setae simple and 1.4x longer than nail, with comb-scales, and distal nail present.
Gnathopod 1 (Fig. 4A–C) subchelate; coxal plate 1.7x wider than long, with simple setae on the margin; basis with one inner serrate seta; basis, merus and ischium with disto-posterior serrate setae with accessory seta, a new type of seta that hadn’t been described for the genus (Fig. 8D) and posterior comb-scales; carpus 1.5x longer than wide, 1.3x longer than propodus, with six serrate setae with accessory seta on margin (Fig. 8D), lateral distal lobe produced with polygonal pattern, several serrate setae with accessory seta and comb-scales on posterior lobe; propodus 1.4x longer than wide, hammer-shaped, with several simple long setae, comb-scales on disto-anterior margin, inner margin with four serrate setae, with few simple, comb-scales on the disto-posterior margin; palm slope transverse, with many simple setae, margin slightly convex, posterior distal corner with two strong cuspidate setae with accessory seta; dactylus claw-like, comb-scales present on distal margin, with one plumose seta dorsally. Microtrichs present on coxal plate and propodus.
Gnathopod 2 (Fig. 4D) subchelate; coxal plate 1.8x wider than long, with several simple setae on the margin; basis with several simple setae with accessory seta, one serrate seta with accessory seta and comb-scales on disto-posterior margin; ischium with several simple setae with accessory seta and comb-scales on disto-posterior margin; merus with five serrate setae with accessory seta on disto-posterior margin and comb-scales; carpus (Fig. 4E) 1.9x wider than long, posterior lobe slim produced between merus and propodus, forming scoop-like structure, posterior margin with polygonal pattern, several serrate setae with accessory seta and comb-scales, two serrate setae with accessory seta on inner margin and two on disto-anterior, anterior margin with comb-scales; propodus (Fig. 4F) ovate, 1.2x longer than wide, with two anterior simple setae, comb-scales present, palm 1x longer than posterior margin of propodus, slope oblique, margin with one row of several cuspidate setae with accessory seta and simple setae, posterior distal corner with one long and strong cuspidate seta and with a cup for dactylus; dactylus claw-like, congruent with palm, proximal margin strongly irregular, plumose seta dorsally absent. Microtrichs present on coxal plate and dactylus.
Pereopods 3 to 7 (Fig. 5A–E) simple. Pereopods 3 and 4 basis with serrate setae and simple setae with accessory seta, respectively; merus and carpus posterior margin with several cuspidate with accessory seta and simple setae with accessory seta; propodus posterior margin with cuspidate and simple setae; dactylus 2.3x and 2x shorter than propodus, respectively, with a plumose seta dorsally and one strong cuspidate seta on proximal margin. Posterior margin of merus, carpus and propodus on pereopods 5 to 7 with several cuspidate and simple setae, some with accessory seta; dactylus approximately 2.5x shorter than propodus, with one plumose seta dorsally and one strong cuspidate seta on proximal margin. Pereopods 6 basis with serrate setae on posterior margin and on Pereopod 6 and 7 simple setae on posterior margin with accessory seta. Pereopods 3 and 4 similar in size; pereopod 5 smaller than others; pereopod 6 1.3x subequal in length to pereopod 7. Microtrichs present on coxal plates of pereopods 3 to 7; on basis of pereopods 5 to 7; on ischium of pereopods 3, 4 and 7; on merus and propodus of pereopods 4, 6 and 7; on carpus of pereopods 3 to 7; on dactylus of pereopods 6 and 7.
Pleopods (Fig. 6A) peduncle 2.5x longer than wide, 1.7x shorter than the mean size of rami, with two coupling spines; both rami with several plumose setae.
Uropod 1 (Fig. 6B) 1.7x longer than uropod 2; peduncle 1.2x longer than outer ramus and 1.2x longer than inner ramus, with six cuspidate setae some with accessory seta; inner ramus slightly longer than outer ramus, 5.9x longer than wide, with three dorsal cuspidate setae with accessory seta on margin and six cuspidate setae apically, some with accessory seta, without curved seta; outer ramus 5.9x longer than wide, with three dorsal cuspidate setae on margin, some with accessory seta and four cuspidate setae apically. Microtrichs present on peduncle, inner and outer ramus.
Uropod 2 (Fig. 6C) 1.7x smaller than uropod 1, peduncle 1.1x shorter than outer ramus and inner ramus, 2.2x wider than outer ramus and 2.1x than inner ramus, with four cuspidate setae with accessory seta; inner ramus with two dorsal cuspidate setae with accessory seta and seven apical cuspidate setae some with accessory seta; outer ramus with three dorsal cuspidate setae with accessory seta and four apical cuspidate setae, only one with accessory seta. Microtrichs present on peduncle, inner and outer ramus.
Uropod 3 (Fig. 6D) 1.6x shorter than peduncle of uropod 1 and 1.2x than peduncle of uropod 2; peduncle 1.6x longer than wide, with five distal cuspidate setae some with accessory seta, two dorsal simple setae; inner ramus absent; outer ramus uniarticulate, 1x longer than peduncle, 3.7x longer than wide, with six simple and one cuspidate seta apically. Microtrichs present on peduncle.
Telson (Fig. 6E, F) entire, subequal in length and wide, apically rounded, with two apical cuspidate setae, with two simple setae laterally, microtrichs present (Fig. 6E). Variations: telson about 1.2x larger than wide with three apical cuspidate setae with accessory seta, and three lateral serrate setae.
Coxal gills sac-like present on pereonites 2 to 6. Sternal gills tubular present on pereonites 2 to 7.
Female (Fig. 2B). Mean body length: 5.88 ± 1.08 mm (N = 10, from 4.20 to 7.80 mm); mean head length: 0.59 ± 0.09 mm (N = 10, from 0.44 to 0.74 mm).
Gnathopod 1 (Fig. 7A) similar to male Gnathopod 1; basis with inner serrate setae; basis, ischium and merus with distal serrate setae with accessory seta; ischium and merus with simple setae with accessory seta, comb-scales present in both articles; carpus 1.5x longer than wide, posterior lobe produced and forming scoop-like structure, pectinate margin with comb-scales, several serrate setae with accessory seta and polygonal pattern, inner margin with six serrate setae with accessory seta; propodus 1.5x longer than wide, hammer-shaped, with comb-scales on anterior and posterior margins, anterior margin with one serrate and two simple setae; palm 2x shorter than posterior margin of propodus, without comb-scales, inner margin with 7 serrate setae with accessory seta, palm slope transverse; dactylus claw-like, with comb-scales, plumose setae dorsally. Microtrichs present on coxal plate.
Gnathopod 2 (Fig. 7B) similar in size and shape to Gnathopod 1; basis, ischium, merus and carpus with few serrate setae with accessory seta, comb-scales present on ischium; carpus with serrate setae with accessory seta on disto-anterior margin, four serrate setae on inner margin, posterior lobe produced and forming scoop-like structure, pectinate margin with comb-scales, serrate setae with accessory seta and polygonal pattern; propodus 1.9x longer than wide, with reduced quantity of comb-scales on posterior margin, inner margin with three serrate setae, palm transverse with several long simple setae; dactylus with comb-scales and plumose seta on distal margin. Microtrichs present on coxal plate.
Telson (Fig. 7C, D) subequal in length and wide, similar in shape to male, with three apical simple setae and two lateral simple setae on both sides (Fig. 7C). Variations: four apical cuspidate setae, with or without accessory seta, two and three lateral serrate setae, microtrichs present.
Taxonomical remarks. Comparisons of characteristics of the new species and other species registered from state of Santa Catarina, Brazil can be seen on Tables 1 and 2. Hyalella carsone sp. nov. shares the absence of curved seta on the inner ramus of uropod 1 with epigean species: H. bala Penoni & Bueno, 2021, H. dielaii Pereira, 2004, H. gracilicornis (Faxon, 1876), H. longipropodus Limberger, Graichen & Castiglioni, 2021, H. longistila (Faxon, 1876), H. meinerti Stebbing, 1899, H. montana Rodrigues, Senna, Quadra & Bueno, 2017, H. minensis Bastos-Pereira & Bueno, 2013, H. pseudoazteca González & Watling, 2003, H. virgineae Lares, Penoni & Bueno, 2021 and H. warmingi Stebbing, 1899. In this group, the new species differs from all of them by the presence of serrate setae with accessory seta on gnathopods (basis, merus, ischium and carpus), a new type of seta not mentioned before for the genus, by the presence of pappose setae on antenna 1 and serrate and pappose setae on antenna 2 on peduncles, the simple setae present on upper and lower lip, the dactylus with proximal margin strongly serrated, the microtrichs present on antennae 1 and 2, maxilliped, gnathopods 1 and 2, pereopods, uropods and telson.
Habitat. Epigean.
Etymology. The species epithet “ carsone ” is in reference to Rachel Carson, a biologist, environmentalist and acclaimed author, by all of her books is the famous ‘Silent Spring’.
description: Published as part of Reis, Giovanna De Oliveira, Bueno, Alessandra Angélica De Pádua & Araujo, Paula Beatriz, 2023, Two new species of Hyalella Smith, 1874 (Malacostraca: Amphipoda: Hyalellidae) from the state of Santa Catarina, Brazil, pp. 351-372 in Zootaxa 5319 (3) on pages 353-360, DOI: 10.11646/zootaxa.5319.3.3, http://zenodo.org/record/8202950