Hyalella sambaqui Talhaferro & Bueno, 2021

Talhaferro, Jordan Tuparai, Bueno, Alessandra Angélica De Pádua, Pires, Mateus Marques, Stenert, Cristina, Maltchik, Leonardo & Kotzian, Carla Bender, 2021, Three new species of Hyalella (Crustacea: Amphipoda: Hyalellidae) from the Southern Brazilian Coastal Plain, Zootaxa 4970 (2), pp. 257-292 : 279-288

Hyalella sambaqui Talhaferro & Bueno , n. sp.

( Figs 15–20 )

Type locality. Passo de Torres municipality, Santa Catarina state, Brazil, sampling site P4 (29º 32’ 08” S, 49º 72’ 39” W) .

Type specimens. Holotype: male, body length = 8.1 mm, head length = 0.9 mm ( MZUSP 41792 ), Passo de Torres municipality (29º 26’ 75.29” S, 49º 74’ 23.31” W), October 2015; Pires, M. M & cols . Allotype: female, body length = 5.0 mm, head length = 0.6 mm ( MZUSP 41793 ), same locality as holotype .

Paratypes: MZUSP 41794 , 10 whole specimens (5 males and 5 females); CCUFLA 442, 10 whole specimens (5 male and 5 female) and 4 males and 1 female on slides; CRU0016, 514 whole specimens (131 males, 205 females and 178 juveniles) and 2 males on slides (same collection data of the holotype) .

Additional specimens. CRU0017, 34 whole specimens (6 males and 28 females), and 5 males on slides; Balneário da Gaivota municipality, Santa Catarina state, Brazil, sampling site P5 (29º 13’ 02.58” S, 49º 62’ 02.09” W), October 2015; Pires, M. M & cols. CRU0018, 429 whole specimens (64 males, 95 females and 270 juveniles), and 5 males on slides; Balneário Arroio do Silva municipality, Santa Catarina state, Brazil, sampling site P6 (28º 98’ 22.17” S, 49º 42’ 57.15” W), October 2015; Pires, M. M. & cols. CRU0019, 7 whole specimens (6 females and 1 juvenile), and 1 male on slide; Jaguaruna municipality, Santa Catarina state, Brazil, sampling site P7 (28º 62’ 78.68” S, 48º 90’ 82.36” W), October 2015; Pires, M. M. & cols .

Diagnosis. Body surface smooth. Eyes ovoid and pigmented. Antenna 1 shorter than antenna 2. Inner plate of maxilla 1 slender with 1/3 the width of the outer plate, with two unequal papposerrate apical setae. The inner plate of maxilla 2 with one long and one shorter papposerrate setae of inner margin. Propodus of gnathopod 1 hammershaped, inner face with six serrate setae. Uropod 1 with curved setae on inner side of inner ramus. Sternal gills on pereonites 2 to 7.

Description of male: Mean of body length: 5.31 ± 0.61 mm (n=6), mean of head length: 0.68 ± 0.06 mm (n=6). Body surface smooth. Eyes ovoid and pigmented. Epimeral plate slightly acuminate ( Fig 15A ).

Antenna 1 ( Fig. 15B ) shorter than antenna 2 (1/4 times); shorter than half body length; peduncle slightly longer than head length, all segments of peduncle with group of simple and cuspidate setae; first article longer than second; third article slightly shorter than second; flagellum with 9 articles, longer than peduncle, with group of simple setae occurring on all articles. Aesthetascs were not observed.

Antenna 2 ( Fig. 15C ) reaching half the length of the body; peduncle slightly longer than head length; flagellum with 13 articles, longer than peduncle, with a group of simple setae occurring on all articles.

Basic amphipodan mandible type (in sensu of Watling 1993), with palp absent. Right mandible ( Fig. 15D ) incisor process with four denticles, and two pappose setae. Left mandible ( Fig. 15E ) incisor process with six denticles; lacinia mobilis with seven denticles (four long, three short), and three pappose setae under lacinia mobilis. In both mandibles, the molar process is large, cylindrical and triturative, with one long pappose seta on inner margin.

Upper lip ( Fig. 15F ) margins rounded, distal borders covered by setules, and few smaller simple setae.

Lower lip ( Fig. 15G ) outer lobes rounded, with many setules on ventral face and inner borders.

Maxilla 1 ( Fig. 15H ) palp uniarticulate, not reaching half of the distance between the base of palp and base of setae on outer plate; inner plate slender, 1/3 shorter than the outer plate, with two apical pappose setae, with many setules along on the margins; outer plate with nine distal serrate setae.

Maxilla 2 ( Fig. 15I ) inner plate subequal in length to outer plate; inner plate with one robust and one shorter papposerrate setae proximally on inner margin, apex with many serrate and simple setae; outer plate with many serrate and simple setae on the apex.

Maxilliped ( Fig. 15J ) inner plate longer than wide, slightly shorter than outer plate, apically rounded with three cuspidate setae in cone-shaped, inner borders with five long pappose setae and apex of inner plate with many small pappose setae, surface dorsal with several setules; outer plate longer than wide, apically rounded, apex and inner border with several simple setae; palp with four articles, article 1 with 1 or 2 simple setae, inner margin with 1 to 3 simple setae; outer margin of article 2 with two simple setae and inner borders with a several long and slender simple setae; inner margin of article 3 with several long simple setae and apex with some papposerrate setae; dactyl smooth, apex with one long simple setae, and another three short simple setae subapical.

Gnathopod 1 ( Figs 16A, B ) subchelate; basis longer than wide, with two small setae on dorsal margin and a group of simple setae on disto-posterior border; ischium longer than wider with a group of simple setae on distoposterior border; merus with disto-posterior border rounded with simple setae; carpus longer than wide, posterior lobe convex, forming a shell-shaped structure with many serrate setae distributed along the margin, inner surface with three simple setae, border disto-anterior with four long serrate setae; propodus longer than wide, length about 1.2 times of maximum width, hammer-shaped, inner face with five serrate setae arranged in one row, anterior and posterior margin with one simple setae, comb-scales on disto-anterior and disto-posterior border, disto-anterior border with a group of long simple setae; outer face of propodus not observed; palm flat with length shorter than posterior margin of propodus (1.9 times) and several simple setae (some long, some short), distal margin with one cuspidate seta with accessory seta; dactyl claw-like, reaching palm angle, covered by comb-scales and with one simple setae in the outer margin.

Gnathopod 2 ( Figs 16C, D ) subchelate; basis long with three simple setae on dorsal margin, distal margin of basis and ischium with a group of simple setae; merus slightly longer than wider, posterior border rounded, with simple setae; carpus with posterior lobe elongated, forming a shell-shaped structure with many serrate setae distributed along the margin, disto-anterior margin with two simple setae; propodus ovate, length about 1.3 times of maximum width, with comb-scales on disto-posterior margin, margin disto-anterior with a cluster of short simple setae, anterior margin with one simple seta, and posterior margin with two or three simple setae; palm transverse, longer than posterior margin of propodus (1.2 times), slightly convex with several strong cuspidate medium-length and short setae, and some simple setae, distal margin of the palm with one cuspidate setae with accessory seta; dactyl claw-like and smooth, outer margin with one short simple seta and inner surface with six tiny setae, length congruent with palm.

Pereopods 3 and 4 ( Figs 17A, B ) similar in size and shape; posterior margin of carpus and propodus with cuspidate setae with accessory seta and simple seta; posterior margin of merus and basis with simple setae; dactyl less than half the length of propodus, surface smooth with simple seta. Coxal plates longer than wide, pereopod 4 excavated posteriorly; both coxal plates with small simple setae on margin, outer surface covered with microtrichs.

Pereopods 5 to 7 ( Figs 17C–E ): coxal plate of pereopod 5 wider than long with two lobes, anterior lobe slightly shorter than posterior; coxal plate of pereopod 6 wider than long with anterior lobe 1/3 of posterior lobe length; coxal plate of pereopod 7 wider than long with lobe unique; all coxal plates with small simple setae on margins and outer surface with covered by microtrichs. Pereopod 5 visibly shorter than pereopods 6 and 7, the latter two similar in length, posterior margin of basis of peraeopods 5 to 7 oval, less expanded in 6, borders finely serrate with simple setae; anterior margins of merus, carpus and propodus with groups of 2-5 cuspidate setae with one accessory seta on anterior margins; dactylus less than half the length of propodus, with simple seta.

Pleopods ( Fig. 18A ) all pleopods similar, peduncle shorter than ramus, biramous, ramus multi-annulated and both ramus with many long plumose setae.

Uropod 1 ( Fig. 18B ) peduncle slightly longer than ramus, peduncle with six cuspidate setae on dorsal surface with accessory setae; ramus subequal in length; inner ramus with two dorsal cuspidate setae with accessory seta, one long curved setae on inner side, four distal cuspidate setae with accessory setae (one long), and two cuspidate setae o the apex; outer ramus with three dorsal cuspidate setae with accessory setae, two subapical cuspidate setae with accessory seta, and two robust cuspidate setae on the apex.

Uropod 2 ( Fig. 18C ) shorter than uropod 1, peduncle slightly longer than wide with four cuspidate setae on dorsal with accessory setae; inner ramus with two dorsal cuspidate setae with accessory seta, three subapical cuspidate setae with accessory seta and two cuspidate setae o the apex; outer ramus with two dorsal cuspidate setae with accessory seta, two subapical cuspidate setae with accessory seta and two cuspidate setae on the apex.

Uropod 3 ( Fig. 18D ) shorter than peduncle of uropod 1, subequal in length in relation to peduncle of uropod 2; peduncle longer than wide and wider than ramus, with three simple setae on basis and three cuspidate setae with accessory seta on the apex; outer ramus inarticulate, slightly longer than peduncle, with three simple setae and one strong and smaller cuspidate setae apically.

Telson ( Fig. 18E ) wider than long, apically rounded, bearing three cuspidate setae with accessory setae unsymmetrically distributed on the distal margin and two small plumose setae on both margin sides.

Coxal gills sac-like, present on pereonites 2 to 6.

Sternal gills tubular, present on pereonites 2 to 7.

Description of the female. CCUFLA 442, body length: 4.30 mm; head length: 4.3 mm. Antenna 1 ( Fig. 19A ) shorter than antenna 2 (1/4 times), flagellum with eight articles. Antenna 2 ( Fig. 19B ) reaching half the length of the body, flagellum with nine articles.

Gnathopod 1 ( Figs 19C, D ) subchelate; basis longer than wider; ischium and merus with comb-scales in posterior margin; posterior lobe of carpus convex, forming a shell-shaped structure with many serrate setae distributed along the margin, inner face with three long simple setae, disto-anterior margin with a group of simple setae; propodus slightly longer than wide, length about 1.2 times of maximum width hammer-shaped, comb-scales in distoposterior and disto-anterior margin, inner face with five serrate setae arranged in one row; outer face of propodus not observed palm margin slightly shorter than posterior margin length of propodus (1.3 times) with two long and slender simple setae with several simple and cuspidate setae smaller, distal margin with one robust cuspidate setae with accessory setae; dactyl claw-like with comb-scales, one plumose seta on dorsal margin, length reaching distal border of palm of propodus.

Gnathopod 2 ( Figs 19E, F ) subchelate; basis, ischium, merus and carpus similar to gnathopod 1; propodus longer than wider, rectangular shape, length about 1.7 times of maximum width, differing from male gnathopod 2 in shape and size, inner face with four serrate setae arranged in one row, disto-anterior and disto-posterior border with several comb-scales, disto-posterior border with two simple setae; palm slightly flat, smaller than 1/2 the maximum posterior margin length of propodus with two long and slender simple setae and some smaller cuspidate setae with accessory seta, distal margin with only one small and robust cuspidate seta with accessory setae; dactyl claw-like, reaching the length of palm with comb-scales and one plumose seta on dorsal margin.

Intraspecific variation. There was variation in the number of setae in the uropod 3, with a difference even between individuals. In some individuals, the peduncle presents six cuspidate setae, and a long simple seta on the inner margin of the peduncle. However, in the other peduncle the simple seta on the inner margin was absent, and the ramus shows a robust cuspidate seta, but the number of cuspidate setae is upper of three ( Fig. 20A ). The telson presented a different shape for some individuals, with a rectangular shape and the presence of four cuspidate setae on the apex and three small plumose setae on both margin sides ( Fig. 20B ).

Measurements. For males, the mean body length was 5.57 ± 0.91 mm, while the mean head length was 0.62 ± 0.14 mm (n=229). The smallest male specimen had 3.2 mm of body length, and 0.3 mm of head length, while the largest male reached 8.3 mm of body length, with head length reaching 1.0 mm. For females, the mean body length was 4.7 ± 0.9 mm, and the mean head length was 0.56 ± 0.13 mm (n=346). The body size of the smallest female reached 2.4 mm and the head length, 0.3 mm, while the body size of the largest female measured 8.0 mm and its head length, 0.9 mm.

Etymology. The specific name, sambaqui, is a word of Tupi etymology (tamba = shellfish, and ki = pilling-up). The term describes the main characteristics of the coastal region of Santa Catarina during the first arrivals from Europe, regions with enormous amounts of shellmounds. The term also is attributed to the first inhabitants of the region of the municipality of Passo de Torres, called “men of sambaqui”.

Habitat. Freshwater, epigean. Hyalella sambaqui n. sp. was found in intermittent and temporary ponds, with a size-area smaller than one-hectare, depth with 50 cm (± 20 cm), and feature emergent and floating vegetation in the margins of the ponds.

Distribution. Hyalella sambaqui n. sp. was recorded in four wetlands across the extension of the Coastal Plain of Santa Catarina ( Fig. 1 ). The sites P4 and P5 feature permanent hydroperiod, while sites P6 and P7 has a temporary hydroperiod. Of the four collection sites, only site P5 is isolate, without hydrological connection with any other water bodies. In all sampling sites, there is the presence of herbaceous vegetation in margin of the ponds, with total size-area ranging from 2,306 m ² to 5,340 m ² and depth not exceeding 50 cm, ranging around 20 cm in the sites P4 and P6.

Taxonomic remarks. In general, the new species shares some morphological characteristics of taxonomic importance with most epigean species of Hyalella from Southern of the Brazil. As well as most species Hyalella sambaqui n. sp. shows one long curved seta on the inner ramus of uropod 1 (except in H. pseudoazteca González & Watling, 2003 , in which the curved seta is absent). Hyalella sambaqui n. sp. also shares with most other species of the genus the body surface smooth (except with H. kaingang , that has flanges on pleonites 1 and 2; H. pleoacuta , with flanges on pereion 7 and pleonites 1, 2 and 3; and H. pseudoazteca , with flanges on pereion 7 and pleonites 1 and 2).

Hyalella sambaqui n. sp. shares some similarities with Hyalella palmeirensis , such as the number of serrate setae on the inner face of the propodus of gnathopod 1, the number of cuspidate setae on the inner side of the inner ramus of uropod 1, and the number of cuspidate setae on the peduncle of the inner and outer rami of uropod 2. However, both species differ in the number of setae in the peduncle of uropod 1 ( H. palmeirensis shows four setae), number of apical and plumose setae on telson ( H. palmeirensis has two long simple and three plumose setae), papposerrate setae in the inner plate of the maxilla 2 ( H. palmeirensis shows one robust papposerrate setae), ornament on the distal inner margin of gnathopod 2 (absent in H. palmeirensis ), setae on telson ( H. palmeirensis with two long simple and three plumose accessory setae), and sternal gills in the pereonites ( H. palmeirensis has gills in pereonites 3 to 7).

Regarding the number of the articles of the flagellum in antennae 1 and 2, H. bonariensis present between 9–12 and 12–15 articles, respectively, being similar to Hyalella sambaqui n. sp., besides that share the presence of sternal gills in the pereonites from 2 to 7; the number of papposerrate setae on the inner plate of the maxilla 1; the number of serrate setae ventrally of the propodus of gnathopod 1. They differ in the setae of the inner plate of the maxilla 2 ( H. bonariensis with two rows of simple setae; Hyalella sambaqui n. sp. with several serrulate and simple setae); peduncle of uropod 3 ( H. bonariensis with six cuspidate and one simple setae; Hyalella sambaqui n. sp. with three cuspidate setae).

As in H. sambaqui n. sp., H. gauchensis and H. georginae present plumose setae on the apex of the telson, however, differs in number of cuspidate setae on the inner and outer rami of uropod 1; the number of serrate setae on the inner face of the propodus of gnathopod 1 ( H. sambaqui n. sp. with five serrate setae; H. gauchensis and H. georginae with 9 or 10 and 9 serrate setae, respectively), and in the outer plate of the maxilla 2 ( H. gauchensis and H. georginae with several simple setae apically; and H. sambaqui n. sp. with many serrate and simple setae).

Hyalella sambaqui n. sp. differs from H. castroi in the number and type of setae on the inner face of the propodus of gnathopod 1 ( H. castroi with more than ten papposerrate setae), and the number and type of setae on the inner plate of the maxilla 2 ( H. castroi with one strong pappose seta, and H. sambaqui n. sp. with two papposerrate setae on inner margin).

Hyalella sambaqui n. sp. differs from H. curvispina in the number of setae on the inner face of the propodus of gnathopod 1 ( H. curvispina with five to seven setae arranged to 3 rows), just like in the number of setae on the peduncle of uropod 1 ( H. curvispina with seven setae), and the number of setae on the inner and outer rami of uropod 2 ( H. curvispina with two or three distal setae and eight setae apically on the inner ramus, and the outer ramus with three distal setae and four setae apically). However, H. curvispina is similar to H. sambaqui n. sp. in the number of setae on the apex of the peduncle of uropod 3 (with three setae), but differs on the number of setae on the apex of the both rami of uropod 3 ( H. curvispina with eight slender and one robust setae).

Hyalella sambaqui n. sp. also resembles H. brasiliensis Bousfield, 1996 described from Rio dos Patos, Paraná state. The description of H. brasiliensis is old and shows few morphological information. However, it is possible to observe that both species show some similarities, such as the presence of sternal gills in the pereonites 2 to 7; the form and number of plumose setae on the inner margin of the inner plate of the maxilla 2, and also in the size of the peduncle in relation to the size of the ramus of uropod 1. Hyalella sambaqui n. sp. differs from H. brasiliensis in the number of articles in the flagellum of antennae 1 and 2 ( H. brasiliensis with 14 and 19 articles, respectively), the number of the setae on the outer ramus of uropod 1 ( H. brasiliensis with four marginal setae on outer ramus), and in length of the ramus of uropod 2 ( H. brasiliensis shows ramus slightly shorter than peduncle while in Hyalella sambaqui n. sp. ramus is slightly longer than peduncle).

Hyalella sambaqui n. sp. also shows some differences in relation to the two species recently described from the Santa Catarina state. Hyalella catarinensis differs from Hyalella sambaqui n. sp. by the absence of serrate apical setae on the outer plate of the maxilla 2, absence of serrate setae on the inner surface of gnathopod 1, and absence of pappose setae on the inner plate of the maxilliped. Hyalella catarinensis also differs by the number of cuspidate setae on the peduncles of uropods 1 and 2 ( H. catarinensis with five cuspidate setae with accessory setae on the peduncle of uropod 1, and with three cuspidate setae on the peduncle of uropod 2).

Hyalella rioantensis differs from Hyalella sambaqui n. sp. due to the presence of papposerrate setae and the absence of simple setae on the inner plate of the maxilla 2, the absence of serrate setae on the inner margin of gnathopod 1, and the number of cuspidate setae on the peduncles of uropods 1 and 2 ( H. rioantensis with four to six cuspidate setae with accessory setae on the peduncle of uropod 1, and with three or four cuspidate setae with accessory setae on the peduncle of uropod 2).

Hyalella sambaqui n. sp. differs from Hyalella minuana n. sp. and Hyalella lagoana n. sp. in the number of serrate setae on the inner surface of gnathopod 1 (nine serrate setae on Hyalella minuana n. sp.; four serrate setae on Hyalella lagoana n. sp.); the number of cuspidate setae on the inner ramus of uropod 2 (two cuspidate setae on Hyalella sambaqui n. sp.; three cuspidate setae on Hyalella minuana n. sp. and Hyalella lagoana n. sp.); and in the format of telson, besides the presence of plumose setae in margins of the telson only Hyalella sambaqui n. sp..

Distribution. The distribution of Hyalella species in wetlands along the southern Brazilian Coastal Plain (states of Santa Catarina and the Rio Grande do Sul) is structured according to the freshwater ecoregions and biomes present in the region ( Fig. 1 ). Hyalella minuana n. sp. occurred exclusively in the Pampa biome and Laguna dos Patos hydrographic ecoregion, while Hyalella sambaqui n. sp. occurred exclusively in the Atlantic Forest biome and in two freshwater ecoregions (Southeastern Mata Atlântica and Tramandaí-Mampituba). Hyalella lagoana n. sp. occurred along the transition between Atlantic Forest and Pampa biomes and the in two ecoregions (Laguna dos Patos and Southeastern Mata Atlântica). Finally, no Hyalella species recorded in the study occurred in sympatry with any of the other ones.

Figures

FIGURE 1. Map showing the geographical location of the study area and the sampling sites.

FIGURE 15. Hyalella sambaqui n. sp., municipality of Passo de Torres, Santa Catarina State, Brazil (29º 32’ 08” S, 49º 72’ 39” W). Paratype male, 5.0 mm. Habitus (A); Antenna 1 (B); Antenna 2 (C); Left mandible (D); Right mandible (E); Upper lip (F); Lower lip (G); Maxilla 1 (H); Maxilla 2 (I); Maxilliped (J). Scale bars: 2.0 mm (A); 0.5 mm (B–C); 0.2 mm (D–I); 0.5 mm (J).

FIGURE 16. Hyalella sambaqui n. sp., municipality of Passo de Torres, Santa Catarina State, Brazil (29º 32’ 08” S, 49º 72’ 39” W). Paratype male, 5.0 mm. Gnathopod 1 (A); Detail of the carpus, propodus and dactylus (B); Gnathopod 2 (C); Detail of the carpus, propodus and dactylus (D). Scale bars: 0.5 mm.

FIGURE 17. Hyalella sambaqui n. sp., municipality of Passo de Torres, Santa Catarina State, Brazil (29º 32’ 08” S, 49º 72’ 39” W). Paratype male, 5.0 mm. Peraeopod 3 (A); Peraeopod 4 (B); Peraeopod 5 (C); Peraeopod 6 (D); Peraeopod 7 (E). Scale bars: 0.5 mm.

FIGURE 18. Hyalella sambaqui n. sp., municipality of Passo de Torres, Santa Catarina State, Brazil (29º 32’ 08” S, 49º 72’ 39” W). Paratype male, 5.0 mm. Pleopods (A); Uropod 1 (B); Uropod 2 (C); Uropod 3 (D); Telson (E). Scale bars: 0.5 mm (A); 0.3 mm (B–C); 0.2 mm (D); 0.1 mm (E).

FIGURE 19. Hyalella sambaqui n. sp., municipality of Passo de Torres Santa Catarina State, Brazil (29º 32’ 08” S, 49º 72’ 39” W). Paratype female, 4.3 mm.Antenna 1 (A); Antenna 2 (B); Gnathopod 1 (C); Detail of the carpus, propodus and dactylus (D); Gnathopod 2 (E); Detail of the carpus, propodus and dactylus (F). Scale bars: 0.5 mm.

FIGURE 20. Hyalella sambaqui n. sp., municipality of Passo de Torres, Santa Catarina State, Brazil (29º 32’ 08” S, 49º 72’ 39” W). Paratype male. Uropod 3 (A); Telson (B). Scale bars: 0.5 mm.