Hyalella insulae Rangel, Limberger & Castiglioni, 2022

Rangel, Carolina, Silva, Aurea Luiza Lemes Da, Siegloch, Ana Emília, Limberger, Márcio & Castiglioni, Daniela Da Silva, 2022, First island species of Hyalella (Amphipoda, Hyalellidae) from Florianópolis, state of Santa Catarina, Southern Brazil, Zootaxa 5116 (1), pp. 40-60 : 44-52

publication ID	https://doi.org/ 10.11646/zootaxa.5116.1.2
publication LSID	lsid:zoobank.org:pub:1600EFE6-8BF6-4721-B466-60813EBFED46
DOI	https://doi.org/10.5281/zenodo.6366347
persistent identifier	https://treatment.plazi.org/id/B25B4633-330E-FFE1-FF32-FDF52A0BF9C0
treatment provided by	Plazi
scientific name	Hyalella insulae Rangel, Limberger & Castiglioni
status	sp. nov.

Treatment

Hyalella insulae Rangel, Limberger & Castiglioni View in CoL , n. sp.

( Figs. 3–8 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Type material. MNRJ 30138 — Holotype male. Body length = 5.87 mm, head length = 0.62 mm, Cachoeira Grande, Monumento Natural Municipal da Lagoa do Peri, municipality of Florianópolis, Santa Catarina Island, state of Santa Catarina , Brazil (48°32’22”W, 27°43’55.00”S), 27 August 2010, Lisboa, Lemos & Siegloch cols. GoogleMaps MNRJ 30139 — Allotype female. Body length = 4.26 mm, head length = 0.45 mm, with the same place and data as holotype. MNRJ 30140— Paratypes (3 males and 3 females), with the same place and data as holotype. Measurements from paratypes: males—mean body length 5.33 ± 0.599 mm, mean head length 0.56 ± 0.06 mm; females—mean body length 4.86 ± 0.76 mm, mean head length 0.51 ± 0 0.08 mm. UFSM 100—Site 1— Paratypes: 7 males and 13 females (being two ovigerous females wholes; 5 males and 2 females in slides), with the same place and data as holotype.

Other material: UFSM 101 — Ribeirão Grande , Sertão do Peri , Monumento Natural Municipal da Lagoa do Peri , municipality of Florianópolis, Santa Catarina Island, state of Santa Catarina , Brazil (48º32’03’W, 27º44’08”S), 28 May 2010, Coelho & Siegloch cols., 2 males and 4 females.

Type locality. Brazil, state of Santa Catarina , municipality of Florianópolis, Santa Catarina Island, locality of Monumento Natural Municipal da Lagoa do Peri, Cachoeira Grande stream (48°32’22”W, 27°43’55.00”S), 27 August 2010 ( Fig. 2 View FIGURE 2 ).

Diagnosis. Body surface smooth. Epimeral plates not acuminated. Eyes pigmented. Antenna 1 shorter than antenna 2. Mandible incisor toothed. Maxilla 1 palp short, longer than wider, reaching less than half length the distance between base of palp and tip of setae on outer plate; inner plate slender, with two papposerrate apical setae; outer plate with nine serrate setae apically. Maxilla 2 inner margin of inner plate with two papposerrate setae, being one longer. Propodus of gnathopod 1 hammer-shaped, inner face with seven serrate setae, denticles as comb scales on disto-anterior and disto-posterior margins, posterior lobe of carpus with pectinate border. Gnathopod 2 propodus ovate, elongated, irregular palm, disto-posterior margin with denticles as comb-scales, posterior lobe of carpus with pectinate border. Uropod 1 male inner ramus with curved seta. Uropod 3 peduncle with ten cuspidate setae with accessory setae, ramus with eight simple setae and one cuspidate seta. Telson apically rounded, with six cuspidate setae with accessory setae. Sternal gills on segments 2 to 7.

Description of males paratypes. ( Figure 3A View FIGURE 3 ). Mean body length: 5.87 ± 0.74 (N = 10), minimum body length = 4.70 mm, maximum body length = 6.81 mm; mean head length: 0.62 mm ± 0.09 mm (N = 10), minimum head length = 0.50 mm, maximum head length = 0.72 mm. Body surface smooth. Epimeral plates not acuminated. Head smaller than first two thoracic segments. Eyes round and pigmented.

Antenna 1 less than half of body length, shorter than antenna 2, longer than peduncle of antenna 2, peduncle shorter than head; flagellum with 11–12 articles, longer than peduncle, basal article not elongated; aesthetascs on flagellum on articles 5 (2), 6 (2), 7 (2), 8 (2) and 9 (2) distally ( Fig. 4B View FIGURE 4 ).

Antenna 2 less than half of body length; peduncle with similar size of the head; flagellum with 14 to 15 articles ( Fig. 4C View FIGURE 4 )

Basic amphipodan mandible (in the sense of Watling 1993) without palp; incisor toothed; left lacinia mobilis with five teeth, setae row with three pappose setae, molar process large, cylindrical, with large accessory setae; right mandible with three pappose setae (one shorter), molar large, cylindrical, triturative with accessory seta ( Fig. 4D View FIGURE 4 ).

Upper-lip margin rounded, distal margin covered by several short setules on ventral and dorsal faces ( Fig. 4E View FIGURE 4 ).

Lower-lip lobes rounded without notches or excavations, with several small setules on dorsal and ventral faces ( Fig. 4F View FIGURE 4 ).

Maxilla 1 palp uniarticulate, longer than wider, short, reaching less than half length the distance between base of palp and tip of setae on outer plate, inner plate slender, smaller than outer plate, with two papposerrate apical setae and margin with several simple setae; outer plate with nine serrate setae ( Fig. 4G View FIGURE 4 ).

Maxilla 2 inner plate wider than outer plate and with two papposerrate setae (being one longer), 10 pappose setae, several simple setae apically, and several setules distally; outer plate apex with abundant long simple setae ( Fig. 4H View FIGURE 4 ).

Maxilliped inner plates apically rounded, with three strong cuspidate distal setae, five serrate setae and five pappose setae; outer plate larger than inner plate, apically rounded, apical, medial and facial with simple setae; palp longer than outer plate, with four articles, margin with several simple setae; dactylus unguiform, smaller than third article, with simple setae and distal nail ( Fig. 4I View FIGURE 4 ).

Gnathopod 1 subchelate; basis, ischium and merus with simple setae; carpus longer than wide, as long as propodus, with strong and wide posterior lobe, margin with polygonal pattern (border pectinate), one row of denticles as comb-scales and one row of serrate setae, ten serrate setae on ventral face; propodus length about 1.5 times maximum width (rectangular), hammer shape, inner face with seven serrate setae and five short simple setae and some triangular setae, disto-posterior border with two cuspidate setae, denticles as comb-scales and three simple setae, antero-posterior border with comb-scales and cluster of simple setae, mid-anterior margin with two simple setae; dactylus claw-like not surpassing the palm, with denticles as comb scales, one plumose seta dorsally ( Fig. 5A View FIGURE 5 ).

Gnathopod 2 subchelate; basis (long), ischium and merus with cluster of simple setae on disto-posterior border; carpus wider than long, narrow posterior lobe, margin elongated with border pectinate, one row of serrate setae and one row of denticles as comb scales; propodus ovate (length 1.2 maximum width), palm shorter than posterior margin, slope oblique, palm with irregular margin with several long and short cuspidate setae with accessory setae and some simple setae, disto-posterior margin with denticles as comb scales, two short and strong cuspidate setae with accessory setae and some simple setae, anterior margin with one simple setae, disto-anterior margin with two cluster of simple setae; dactylus claw-like, shorter than propodus, with one one plumose seta dorsally ( Fig. 5B View FIGURE 5 ).

Peraeopods 3 to 7 simple; merus, carpus and propodus posterior margins with clusters of 2–3 cuspidate setae with accessory setae, cluster of simple setae on anterior and posterior borders; peraeopods 3 to 7 dactylus less than half-length of propodus; peraeopods 3 to 6 with similar size and peraeopod 7 slightly longer; coxal plates of peraeopod 3, 5, 6 and 7 wider than longer, with small simple setae on margin; peraeopod 4 coxal plate excavated posteriorly and slightly wider than longer ( Fig. 6A–E View FIGURE 6 ).

Pleopods not modified and all similar in shape; peduncle slender; ramus longer than peduncle, with two coupling setae ( Fig. 7A View FIGURE 7 ).

Uropod 1 longer than uropod 2; peduncle longer than ramus, seven cuspidate setae with accessory setae on dorsal surface; inner ramus slightly longer than outer ramus with three cuspidate setae with accessory setae and one curved seta on lateral margin, apex with five cuspidate setae with accessory setae and two strong cuspidate setae; outer ramus with four dorsal cuspidate setae with accessory setae and four distal cuspidate setae (two with accessory setae) ( Fig. 7B View FIGURE 7 ).

Uropod 2 peduncle longer than wide, similar size of ramus with five cuspidate setae with accessory setae; inner ramus with three dorsal cuspidate setae with accessory seta and six distal cuspidate setae (four with accessory setae); outer ramus with four dorsal and four distal setae (two with accessory setae) ( Fig. 7C View FIGURE 7 ).

Uropod 3 peduncle rectangular and slightly longer than ramus, with ten strong cuspidate setae with accessory setae, outer margin with one simple seta and three simple setae on basis; inner ramus absent; outer ramus uniarticulate with eight simple setae (some longer than others) and one small cuspidate seta ( Fig. 7D View FIGURE 7 ).

Telson wider than long, apically rounded, with six cuspidate setae with accessory setae and two small plumose setae laterally close to each distal seta ( Fig. 7E View FIGURE 7 ).

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

Description of paratypes females ( Figure 3B View FIGURE 3 ): Mean body length: 4.60 ± 0.36 (N = 10), minimum body length = 4.23 mm, maximum body length = 5.17 mm; mean head length: 0.49 mm ± 0.04 mm (N = 10), minimum head length = 0.45 mm, maximum head length = 0.55 mm. Antenna 1 shorter than Antenna 2. Antenna 1 flagellum with nine to ten articles. Antenna 2 similar in shape to male, flagellum with eleven to twelve articles.

Gnathopod 1 slightly wider than gnathopod 2; similar to male gnathopod 1 in size and shape; basis, ischium and merus without comb-scales; carpus with pectinate lobe with comb-scales and several serrate setae, four serrate setae on ventral face; propodus inner face with seven serrate setae, simple setae on the inner margin, disto-anterior border with comb-scales, disto-posterior border without comb-scales but with a cluster of simple setae; dactylus claw-like with one plumose setae and with comb-scales ( Fig. 8A View FIGURE 8 ).

Gnathopod 2 different from male gnathopod 2 in shape and size; gnathopod 2 slightly slender than gnathopod 1; basis, ischium and merus without comb-scales; carpus with pectinate lobe with comb-scales and two serrate setae on ventral face; propodus length about 1.5 times maximum width, four serrate setae on ventral (inner) face, anterodistal margin with comb-scales and two simple setae, disto-posterior margin without comb-scales and with cluster of simple setae, mid-posterior margin with one simple seta; dactylus claw-like with comb-scales and one plumose setae ( Fig. 8B View FIGURE 8 ).

Habitat. Freshwater, epigean. The Cachoeira Grande watershed, from the source to the outfall, is inserted in the Monumento Natural Municipal da Lagoa do Peri. The Cachoeira Grande watershed is composed of first, second, and third-order streams that trains an area of 1.66 km 2. In this portion, the Atlantic Rainforest is at an advanced stage of regeneration ( Caruso 1983), with a thick canopy cover of 73–88%. The stretch of the stream where the H. insulae n. sp. was found is characterized as a second order stream located in the Cachoeira Grande watershed (48°32’22”W – 27°43’55.00”S). In this stretch, there is primary riparian vegetation with about 90% of vegetation cover, abundant diversity of habitats with stony substrate, and accumulation of allochthonous organic matter in stretches of rapids and backwaters. The stretch has an average width of 2.95 m and 0.22 m deep, with good oxygenation (8.62 mg /l), low electrical conductivity (60.26 μS/cm) and hydrogen potential close to neutrality (7.45). The holotype was collected in organic material deposited in backwater.

The Ribeirão Grande watershed is composed of first, second, and third-order streams. The vegetation is in an intermediate stage of conservation because of anthropogenic impact, e.g., deforestation watershed. The streams have riparian vegetation composed of secondary forest and introduced species; thus, the tree cover shows a sparse canopy, and the streams receive greater solar insolation. The surrounding area is characterized by traditional families who explore the preserved area by developing subsistence agriculture ( Schmitt et al. 2019). Some individuals of H. insulae n. sp. were sampled in a stretch of a third-order stream (48º32’03’W–27º44’08’S) located in the Ribeirão Grande watershed. This stretch of the stream presents at least 30 m of riparian vegetation width along the sampled section. This stream is characterized by pools and riffles stretches with the benthic substrate composed mainly of sand and coarse organic matter. The stretch presents average values of 2.61 in width and 0.24 m in depth with running water (0,16 m/s), good oxygenation (8.41 mg /l), low electrical conductivity (53.8 μS/cm) and hydrogen potential close to neutrality (7.21).

The main environmental impacts that can interfere with the local biodiversity of the Cachoeira Grande watershed are related to the urban occupation around the MNLP. On the other hand, around the main rivers and streams of the Ribeirão Grande watershed, there is a development of subsistence agriculture by traditional families (that already occupied the area before the implementation of the UC) with small plantations of banana, beans, cassava, corn, and others, plus small livestock ( Schmitt et al. 2019). However, it is noteworthy that the streams sampled have riparian vegetation along its entire extension.

Etymology. The species epithet “ insulae ” is in reference of the first species of the genus in a Brazil island.

Remarks. In general, H. insulae n. sp. has similarities with most species from state of Santa Catarina , and the neighboring states, Parana and Rio Grande do Sul, in some features of taxonomic importance, such as the presence of a curved seta on the inner ramus of uropod 1 (absent only in H. pseudoazteca González & Watling, 2003 , and H. longipropodus Limberger, Graichen & Castiglioni, 2021 ). The new species differs in relation to the body surface smooth only from H. kaingang Araujo & Cardoso, 2013 (flanges on pleonites 1 and 2), H. pleoacuta González, Bond-Buckup & Araujo, 2006 (flanges on pereonite 7 and pleonites 1, 2 and 3) and H. pseudoazteca (flanges on pereonite 7 and pleonites 1 and 2) ( Table 1 View TABLE 1 ). Other similarity is the location of the sternal gills from the 2nd to the 7th thoracic segment (except H. curvispina Shoemaker, 1942 , H. imbya Rodrigues & Bueno, 2012 , H. montenegrinae Bond-Buckup & Araujo, 1998 , H. palmeirensis Streck-Marx & Castiglioni, 2020 , and H. pseudoazteca , which present from the 3rd to the 7th).

However, it is noticed that H. insulae n. sp. differs from the other species from state of Santa Catarina in some remarkable features. The species H. insulae n. sp. has morphological differences in the maxilla 2 (two papposerrate setae, one smaller) when comparing with H. catarinensis (only one papposerrate setae) and H. rioantensis (several papposerrate setae), but shares similarity with H. sambaqui and H. lagoana , which also present two papposerrate setae, one smaller than the other ( Table 1 View TABLE 1 ). The four species with occurrence in the state of Santa Catarina , differ from H. insulae n. sp. in the number of serrate setae in the inner face of male gnathopod 1, number of setae of uropods 1, 2 and 3, and number and shape of setae on telson ( Table 1 View TABLE 1 ). The species H. insulae n. sp. has a greater number of setae in the peduncle of uropod 3 (9–10 cuspidate setae), when comparing to H. catarinensis , H. rioantensis (both with six cuspidate setae), H. sambaqui (three cuspidate setae) and H. lagoana (five cuspidate setae) ( Table 1 View TABLE 1 ). It was observed that only H. lagoana share similarity with H. insulae n. sp. in the number of setae on telson, which also present six cuspidate setae, but the new species present telson wider than long and H. lagoana , just like the other species from state of Santa Catarina , present telson longer than wide.

When comparing with the species of the neighboring states, Rio Grande do Sul and Paraná, H. insulae n. sp. also differ in relation to the number and shape of setae of the gnathopods, uropods and telson ( Table 1 View TABLE 1 ). Hyalella gauchensis Streck & Castiglioni, 2017 , H. kaigang , H. longipropodus and H. minuana Talhaferro & Bueno, 2021 are similar to H. insulae n. sp. in relation to the presence of two papposerrate setae (one longer than the other) on the inner margin of maxilla 2. When comparing the number of serrate setae in the inner face of propodus of gnathopod 1, it was noticed that only H. imbya and H. longipropodus resembles H. insulae n. sp. (with seven serrate setae) ( Table 1 View TABLE 1 ). The only species that resembles Hyalella n. sp. when comparing the type and number of setae of telson is H. gauchensis Streck & Castiglioni, 2017 (with six cuspidate setae) ( Table 1 View TABLE 1 ).