THREE NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS FROM THE UPPER URUGUAY RIVER HYDROGRAPHIC BASIN IN BRAZIL

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1 JOURNAL OF CRUSTACEAN BIOLOGY, 32(4), , 2012 THREE NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS FROM THE UPPER URUGUAY RIVER HYDROGRAPHIC BASIN IN BRAZIL Sandro Santos 1,, Georgina Bond-Buckup 2, Ludwig Buckup 2, Marcos Pérez-Losada 3, Maegan Finley 4, and Keith A. Crandall 4,5 1 Departamento de Biologia, Universidade Federal de Santa Maria, , Santa Maria, RS, Brazil 2 Departamento de Zoologia, Instituto Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, , Porto Alegre, RS, Brazil 3 CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, , Vairão, Portugal 4 Department of Biology, Brigham Young University, Provo, UT 8460, USA 5 Monte L. Bean Life Science Museum, Brigham Young University, Provo, UT 84602, USA ABSTRACT Surveys performed in streams from the sub-basins of the Canoas and Pelotas rivers, which jointly form the Uruguay River in southern Brazil, led to the discovering of three new species of Aeglidae: Aegla brevipalma, Aegla leachi, anda. oblata. Here we present their morphological descriptions coupled with phylogenetic analyses, to infer evolutionary relationships to other aeglids using DNA sequence data from the 16S rrna and COII gene regions of the mitochondrial genome. The presence of these new species increases the importance of the Upper Uruguay ecoregion for biodiversity richness of freshwater fauna in the Neotropical South America. KEY WORDS: Aeglidae, biodiversity, biogeography, ecoregions, molecular systematics DOI: / X INTRODUCTION The genus Aegla Leach, 1820 is represented by 69 extant species (McLaughlin et al., 2010). They have been phylogenetically clustered into five major clades reflecting, to a large extent, their geographical distribution in southern South America (Perez-Losada et al., 2004, 2009; Bond- Buckup et al., 2010; Santos et al., 2010). Clades A and B in the maximum likelihood and Bayesian consensus trees in Perez-Losada et al. (2004) encompass 17 species, some from basins draining toward the Pacific Ocean (Chile) and the others endemic to southern Argentina. Clade C includes 16 species from the Paraná and Upper Uruguay basins and from small coastal rivers flowing toward the Atlantic Ocean. Clade D clusters 13 species with a wide geographical distribution ranging from the East of the Sierra Pampeanas to the mouth of the La Plata River, between Argentina and Uruguay. Finally, clade E is represented by 14 species restricted to the state of Rio Grande do Sul, Brazil. The Upper Uruguay hydrographic basin shelters species from the transition zone between clades C {Aegla jarai Bond-Buckup and Buckup, 1994; A. odebrechtii (Müller, 1876); A. spinosa Bond-Buckup and Buckup, 1994; A. camargoi Buckup and Rossi, 1977 and A. leptodactyla Buckup and Rossi, 1977} and E (A. franciscana Buckup and Rossi, 1977 and A. serrana Buckup and Rossi, 1977). This mountainous region embraces areas of the Serra Geral, which probably influenced on its final orogeny the dispersal patterns of aeglid crabs in Santa Catarina and Rio Grande do Sul (southern Brazil) (Potter, 1997). Considering the distribution of aeglid crabs, degree of endemicity, threatened status and phylogenetic diversity, Pérez-Losada et al. (2009) established conservation priorities for 18 ecoregions in southern South American defined by Petry et al. (2006) and Abell et al. (2008). In that study, the authors concluded that the Upper Uruguay ecoregion, with 10 species (four endemic species, none of which is threatened), ranks second on aeglid biodiversity. In this taxonomic study, we describe three new species from the sub-basins of the Canoas and Pelotas Rivers, which jointly form the Uruguay River (Upper Uruguay ecoregion). Using newly generated and available mitochondrial DNA sequences (16S rrna and COII), we also discuss the phylogenetic positions of these species, as well as their distribution and conservation status. MATERIAL AND METHODS Specimens of Aegla were collected in watercourses of the upper Uruguay River basin (Fig. 1) during several sampling campaigns and were deposited in the Collection of Crustaceans of the Department of Zoology, Institute of Biosciences, Federal University of Rio Grande do Sul (UFRGS) and the Museu de Zoologia of the University of São Paulo (MZUSP). Corresponding author; ssantos@smail.ufsm.br The Crustacean Society, Published by Koninklijke Brill NV, Leiden DOI: / X635935

2 530 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 32, NO. 4, 2012 Fig. 1. Upper Uruguay system, showing the sub-basins of the Canoas, Caveiras and Lava-Tudo Rivers and sampling localities (Aegla brevipalma, circle; Aegla leachi, triangle; Aegla oblata, square). The descriptions of the new species were based on examination of the characters of the type-series. For the measurements of the specimens, the methods of Bond- Buckup and Buckup (1994) was adopted, with the following abbreviations: Letter m = males, f = females, f ov = ovate females, j = juveniles, CL = total cephalothorax length (between the tip of rostrum and the midpoint of the posterior margin of the carapace), PCW = pre-cervical width (between the left and right epibranchial margins), FW = frontal width (between the tips of the spines of the anterolateral angles of the carapace), AL = areola length, and AW = areola width. Museum code: MZUSP Museu de Zoologia da Universidade de São Paulo; UFRGS Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. Morphometric Analysis For the description of the new species, the following body dimensions were recorded for all animals of the type series and also the non-paratype animals: CL, PCW, FW, AL, and AW. The morphometric ratios PCW/FW and AL/AW were calculated for the set of animals from each locality. Molecular Analysis Total genomic DNA from five specimens (four A. leachi and one A. oblata) from the following localities was extracted using methods described by Crandall and Fitzpatrick (1996): Matador River, Passo Fundo stream (Rio Caveiras subbasin) and Engenho Velho stream (Rio Caveiras sub-basin). A. Brevipalma was sequenced (Aegla n. sp. 3) in Pérez- Losada et al. (2004). Sections of the mitochondrial (16S rrna and COII) genes (1036 bp total) were amplified via polymerase chain reaction (PCR), using primers, sequencing conditions and protocols described in Pérez-Losada et al. (2004). Sequences were deposited in GenBank under accession numbers JQ JQ New sequences of Aegla were aligned together with those in Pérez-Losada et al. (2009) using MAFFT v5.7 (Katoh et al., 2005). No questionable regions were observed in any of the alignments. Maximum likelihood phylogenies were inferred in RaxML (Stamakis, 2006) using 100 random additions and mixed models. DNA model selection followed the procedure outlined by Posada and Buckley (2004) as implemented in ModelTest v3.6 (Posada and Crandall, 1998). The GTR + Gamma + I model (Tavaré, 1986) was selected for all gene regions as the best-fit model to the data. Clade support was assessed using the nonparametric bootstrap procedure (Felsenstein, 1985) with 1000 bootstrap replicates and one random addition per replicate. SYSTEMATICS Aegla brevipalma n. sp. Bond-Buckup and Santos (Fig. 2) Type-material. Holotype: male, Brazil, state of Santa Catarina, Matador River, BR 282 at bridge, km 136, Bom Retiro, Canoas River sub-basin, Uruguay River basin, S, W; 875 m (Fig. 1: circle), 25.x.2000, col.: Bueno, A.; Bond-Buckup, G.; Jara, C. and Pérez-Losada, M. (MZUSP 23465). Paratypes: 1 m, 1 f ov, 1 exuvia, same data as holotype (UFRGS 2679P); 1 m, same data as holotype, (UFRGS 3005); 9 m, also same data as holotype (UFRGS 3010). Diagnosis. Anterolateral spine of carapace short, not reaching base of cornea; protogastric and epigastric lobes absent; extra-orbital sinus absent, rostrum triangular, deflected, carinate, outer proximal margin of movable finger of cheliped with lobe; palmar crest of cheliped subdisciform; anterior angle of ventral margin of epimeron 2 with modest

3 SANTOS ET AL.: NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS 531 Fig. 2. Aegla brevipalma n. sp. Bond-Buckup Santos (male holotype, MZUSP 23465, scale: 5 mm: A, dorsal view; B, anterior portion of carapace (lateral view); C, basis-ischium of cheliped (ventral view); D, third and fourth thoracic sternites (ventral view); E, epimeron 2 (lateral view).

4 532 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 32, NO. 4, 2012 scales; inner margin of ventral surface of ischium of cheliped with distal scaliform tubercle. Description. Carapace very compressed, dorsal surface scabrous, covered with punctations and scales. Front wide; PCW/FW ratio of holotype male Rostrum triangular, low, tapered, deflected, carinate, distal portion of rostrum slightly recurved distally. Sub-rostral process very developed; in profile, rostrum with ventral portion larger than dorsal. Rostral carina begins at height of first hepatic lobe, with a row of scales reaching the apex; scales decrease in size and become more spaced as they reach the distal portion of rostrum; carina slightly elevated in median portion and very low in distal third. Lateral margins of rostrum scaly. Orbits wide, deep. Orbital margin with scales. Orbital spine absent, extraorbital sinus lacking. Antero-lateral angle of carapace projecting anteriorly in a spine, which does not reach base of cornea. Outer and inner margins of antero-lateral lobe with scales. First hepatic lobe delimited anteriorly by modest fissure; lateral margin with scales; second and third hepatic lobes not indicated; lateral margins with scales. Epigastric prominences absent, scabrous surface. Protogastric lobes absent, without indication. Transverse dorsal line slightly sinuous. Areola quadrate. AL/AW ratio of holotype male Epibranchial area triangular, with scales. Lateral margins of anterior branchial area with subequal scales and posterior branchial area with sparse scales. Anterior angle of ventral margin of epimeron 2 unarmed, indicated by small scale; ventrolateral margin nearly straight; posterior angle of ventral margin obtuse, unarmed. Epimera of third to sixth segments projecting; on third and fourth segments, lateral projection ornamented with small apical scale. Telson divided by longitudinal suture. Anterior extremity of third sternite truncate, projected between coxae of exopods of third maxillipeds. Fourth thoracic sternite plain, tufts of long setae present anteromesially, antero-lateral angles projected by tubercle. Chelipeds subequal, hand subquadrate. Chelae globose, covered by scales and sparse scaliform tubercles. Larger cheliped slightly more robust; outer proximal margin more inflated. Palmar crest of the minor cheliped subdisciform, especially at its proximal margin which forms an acute angle; palmar crest of major cheliped subrectangular, margin ornamented with elevations with scales, indicating lobes. Predactylar lobe forming a small step with anterior margin of propodus, with scales. Fingers thickened, covered by scales and sparse setae, and distally by scaliform tubercles. Proximal outer margin of movable finger with lobe tipped with scales. Prehensile margins of fingers with scaliform denticles along their entire length and with fitted opposed lobular teeth associated with the major cheliped. Dorsal surface of carpus scabrous, with punctuations and scales; inner margin with four spines, with the penultimate distalmost spine being most developed; last spine is reduced and situated close to basis of penultimate spine; these spines with some scales and setae on the lateral margins; inner antero-lateral angle obtuse, ornamented with scales; anterodorsal margin with scales. Distal part of dorsal surface with modest depression parallel to distal margin. Carpal crest modest, more elevated in proximal region; medial and distal parts with setae and scales clustered in clumps of three to five units on elevations of crest; outer ventral angle of carpus obtuse, with tubercle; ventral surface with conical tubercle and long setae. Dorsal margin of merus of cheliped with elevation tipped with scales decreasing in size in proximal direction, followed by long setae; antero-dorsal margin with sparse scales. Lateral surfaces with punctuations and scales. Inner ventral margin of merus with one distal spine; outer ventral margin with pronounced distal spine followed by tubercle. Dorsal margin of ischium with one tubercle, scales and long setae; inner margin of ventral surface with small distal conical tubercle and elevation bearing proximal scale. Dorsal margin of dactylus, propodus, and carpus of second through fourth pereiopods with rows of setae and scales arranged in longitudinal series; dactyli of same pereiopods covered with scales and short setae; dorsal margins of meri covered with long setae, lending the surface a pubescent appearance. Variations. In some paratype specimens, the protogastric lobes are delimited anteriorly by sparse scales, although these are lacking in other specimens. Proximal outer margin of movable finger, in some specimens, bears scales suggesting a lobe. Some paratypes do not possess fitted opposed lobular teeth on the prehensile margin of the fingers, but only scaliform denticles along their entire length. Measurements: Male holotype, CL mm. Paratypes (n = 10) with mean CL 13.54, i.e., a small-sized species. The ovate female measured CL mm. PCW/FW ratio of paratypes (n = 7) ranging from 1.72 to 1.94, with mean of 1.82, i.e., a wide front in small-sized animals and narrow front in larger animals. Paratypes (n = 4) mean ratio AL/AW 1.61, ranging from 1.47 to Distribution. BRAZIL: State of Santa Catarina, Uruguay River basin, Canoas River sub-basin. Etymology. From Latin, brevis = short and palma = inside of the hand. Conservation status. Critically Endangered (CR) B2ab(iii): Area of occupancy estimated to be less than 10 km 2 ; known to exist at only a single location; continuing decline, inferred from quality of habitat (IUCN, 2001). Biology. Unknown. Remarks. The hallmark of this species, the short palm length, is shared with A. plana, a species that also occurs in hydrographic basins in southern Brazil, and with several species from Argentina including A. neuquensis, A. riolimayana, A. ringueleti and A. humauaca. It differs from A. plana, among other characters, especially by the shape of the palmar crest, which is subdisciform in the new species and subrectangular in A. plana. Similarly to A. leachi n. sp., it belongs to the small-sized group within aeglids, showing a small CL. The new species occurs in sympatry with Aegla jarai Bond-Buckup and Buckup, 1994 as aforementioned for the sub-basins of the Upper Uruguay River (Bond-Buckup and Buckup, 1994; Bond-Buckup et al., 2009). The type-locality is heavily impacted, with cattle and hogs being raised next to the watercourse, resulting in continuous degradation of the

5 SANTOS ET AL.: NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS 533 water quality. In a recent survey at the stream (2010), the authors did not find new specimens of the species. Aegla leachi n. sp. Bond-Buckup and Buckup (Fig. 3) Type-material. Holotype: male, Brazil, state of Santa Catarina, Painel, Passo Fundo stream, Painel River tributary, Caveiras River sub-basin, Uruguay River hydrographic basin, S, W (Fig. 1: triangle); 1051 m, 30.ix.2004, col.: Bond-Buckup, G.; Sokolowicz, C., Bavaresco, F. (MZUSP 23466). Paratypes: Uruguay River basin, state of Santa Catarina: 33 males, 17 females, same data as holotype (UFRGS 3910P); 3 males, 2 females, Urupema, Galafre River, Caveiras River sub-basin, S, W; 1050 m, 30.ix.2004, col.: Bond-Buckup, G.; Sokolowicz, C., Bavaresco, F. (UFRGS 3933); 8 males, 7 females, Marombas River affluent stream, highway BR 470 between São Cristóvão do Sul and Curitibanos, Canoas River sub-basin, S, W, 935 m, 18.xii.2004, col.: Bond- Buckup; G.; Sokolowicz, C.; Quadros, A.; Bavaresco, F. (UFRGS 3944); 3 males, 2 females, São Cristóvão do Sul, Marombas River affluent stream, BR 470 between São Cristóvão do Sul and Pouso Redondo, Canoas River subbasin, S, W; 1010 m, 18.xii.2004, col.: Bond-Buckup; G.; Sokolowicz, C.; Quadros, A.; Bavaresco, F. (UFRGS 3950). Diagnosis. Antero-lateral spines of carapace short, reaching base of cornea; protogastric and epigastric lobes absent; extra-orbital sinus absent, rostrum triangular, deflected, carinate, outer proximal margin of movable finger of cheliped with lobe; palmar crest of the major cheliped absent and hand inflated; anterior angle of ventral margin of epimeron 2 unarmed; inner margin of ventral surface of ischium of cheliped without ornamentation. Description. Carapace convex, dorsal surface scabrous, covered with punctations and scales. Front narrow in the male holotype; PCW/FW ratio Rostrum triangular, short, deflected, carinate along its entire length. Sub-rostral process very developed; in profile, rostrum with ventral portion larger than dorsal. Rostral carina begins at height of first hepatic lobe, with two rows of scales combining in only one row in distal third; carina low along its entire extension; slightly excavated. Lateral margins of rostrum with sparse scales. Orbits moderately wide, deep. Orbital margin without orbital spine, with sparse scales. Extraorbital sinus lacking. Antero-lateral angles of carapace short, projecting anteriorly in a tubercle, which reaches base of cornea; inner margin with a distinct depression, parallel to orbit. Outer and inner margins of antero-lateral lobe scabrous. First hepatic lobe delimited anteriorly by modest fissure; lateral margin scabrous; second and third hepatic lobes not indicated; lateral margins with scales. Epigastric prominences absent, surface scabrous. Protogastric lobes absent, without indication. Transverse dorsal line slightly sinuous. Areola quadrate. AL/AW ratio of holotype male Epibranchial area triangular, with scales. Lateral margins of anterior and posterior branchial areas with sparse scales. Anterior angle of ventral margin of epimeron 2 unarmed, indicated by small scale; ventro-lateral margin nearly straight; posterior angle of ventral margin obtuse, unarmed. Epimera of third through sixth segments projecting, obtuse; third and sixth segments with tufts of subapical setae. Telson divided by longitudinal suture. Anterior extremity of third sternite tapered, projected between coxae of exopods of third maxillipeds. Fourth thoracic sternite plain, median anterior region with tufts of long setae; antero-lateral angles projected by elevations. Chelipeds subequal, hand sub-quadrate. Major chelae with more robust appearance, globose, covered by scales and sparse scaliform tubercles; outer proximal margin more inflated. Cheliped palmar crest absent; smaller chelae with palm inner margin having elevations tipped by scales, suggesting a modest crest. Pre-dactylar lobe forming a small step with anterior margin of propodus, with sparse scales. Fingers thickened, covered by scales and sparse setae, and distally by scaliform tubercles. Proximal outer margin of movable finger with modest lobe with scales. Prehensile margins of fingers with scaliform denticles along their entire length. Dorsal surface of carpus scabrous, with punctuations and scales; inner margin differentiated with only two spines, the distalmost spine being most developed; elevations with scales in proximal position; these spines bear some proximal scales and setae; inner anterolateral angle obtuse, ornamented with scales; anterodorsal margin with scales. Distal part of dorsal surface with modest median depression parallel to distal margin. Carpal crest practically absent, in its proximal portion showing modest elevations with scales agglutinated, suggesting a crest, which disappears distally; outer ventral angle of carpus obtuse, unarmed; ventral surface with tuft of long setae. Dorsal margin of merus of blate ds with elevation tipped with scales, followed by scales; antero-dorsal margin with sparse scales. Lateral surfaces with punctations and scales. Inner ventral margin of merus with elevation with distal scales; outer ventral margin with protrusion with distal scales, followed by smaller elevations. Dorsal margin of ischium with one scaliform tubercle and long setae; inner margin of ventral surface of ischium without ornament, except sparse setae. Dorsal margin of dactylus, propodus, and carpus of second through fourth pereiopods with rows of setae and scales arranged in longitudinal series; dactylus of same pereiopods covered with scales and short setae; dorsal margin of meri of same pereiopods covered with long setae in proximal portion, lending the surface a pubescent appearance. Variations. The specimens from the Canoas River subbasin show variations in some characters, although these are insufficient to identify a distinct species. These characters are, in particular, the slightly elevated protogastric lobes, and epigastric lobes indicated by scales; the extra-orbital sinus is subtly indicated in these specimens and a characteristic orbital spine is lacking. The rostral carina is slightly more elevated and the rostrum slightly excavated. The inner margin of the minor cheliped palm has some variable

6 534 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 32, NO. 4, 2012 Fig. 3. Aegla leachi n. sp. Bond-Buckup Buckup (male holotype, MZUSP 23466, scale: 5 mm: A, dorsal view; B, anterior portion of carapace (lateral view); C, basis-ischium of cheliped (ventral view); D, third and fourth thoracic sternites (ventral view); E, epimeron 2 (lateral view).

7 SANTOS ET AL.: NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS 535 elevations tipped by scales, suggesting a palmar crest in some animals. Measurements. Male holotype with mm CL; male paratypes (n = 15), mean CL mm; paratype females (n = 10), mean mm CL. PCW/FW mean ratio of male paratypes (n = 15) 1.55, ranging from 1.73 to 2.09; female paratypes (n = 10) PCW/FW mean ratio 1.99, ranging from 1.80 to 2.29, indicating that small-sized animals have a wide front and as they grow the front tends to narrow. AL/AW ratio of male paratypes (n = 15) 1.55, ranging from 1.38 to 1.89; AL/AW ratio of female paratypes (n = 10) 1.41, ranging from 1.24 to The mean total cephalothorax length of paratypes of both sexes reached mm, indicating a small-sized species. In four females carrying juveniles in the pleopods, the CL ranged from to mm. The smallest female found was mm in CL and the largest female measured mm CL. Distribution. BRAZIL: State of Santa Catarina, Uruguay River basin, Canoas River and Caveiras River sub-basins. The tributaries of the Canoas River have high aeglid diversity in the same watercourse, as in lots UFRGS 3047 and 3950, where Aegla jarai, A. odebrechtii, A. oblata, and A. leachi n. sp. occurred sympatrically. Etymology. The specific epithet leachi is given in honor of the eminent British zoologist Dr. W. E. Leach, who named the genus Aegla. Conservation status. Vulnerable (VU) B1ab(iii): Area of occupancy estimated to be less than km 2 ; known to exist in fewer than ten locations; continuing decline, inferred from the quality of the habitat (IUCN, 2001). The construction of a hydroelectric dam in this area is another threat for this species. Biology. Unknown. Remarks. A. leachi belongs to the group of the smallest species of aeglids, reaching a mean total LC that exceeds only those of A. muelleri, A. ligulata, A. violacea, A. obstipa, A. prado, A. leptodactyla and A. inermis. The new species is distinguished from the other known species by the characteristic inner margin of the carpus of the chelipeds with modest spines, in number as in size and projection. A. leachi shares with A. inermis the lack of a palmar crest, but A. leachi differs by its more robust and globose cheliped, in addition to the different shape of the rostrum and the presence of a rostral carina. Aegla oblata n. sp. Bond-Buckup and Santos (Fig. 4) Type-material. Holotype: male, Brazil, state of Santa Catarina, Painel, Engenho Velho stream, Caveiras River subbasin, Uruguay River hydrographic basin (Fig 1.: square); S, W; 1134 m, 30.ix.2004, col.: Bond-Buckup, G.; Sokolowicz, C.; Bavaresco, F. (MZUSP 23467). Paratypes: Uruguay River hydrographic basin, state of Santa Catarina: 41 m, 21 f, same data as holotype (UFRGS 3916P); 39 m, 16 f, same data as holotype (UFRGS 3913); 42 m, 22 f, 34 j, together with Aegla odebrechtii, Urupema, Caronas River, Lava-Tudo sub-basin, S, W, 1281 m, 01.x.2004, coll.: Bond-Buckup, G.; Sokolowicz, C.; Bavaresco, F. (UFRGS 3920); 3 m, 2 f, São Joaquim, Antoninha River, Lava-Tudo River sub-basin, S, W, 1171 m, 02.x.2004, coll.: Bond- Buckup, G.; Sokolowicz, C.; Bavaresco, F (UFRGS 3923); 190 m, 138 f, São Joaquim, Périco Redondo River, Pelotas River sub-basin, S, W, 1265 m, ditto (UFRGS 3928); 19 m, 18 f, Urubici, Lava-Tudo River headwater, Pelotas River sub-basin, S, W, 1461 m, ditto (UFRGS 3935); 12 m, 5 f, São Joaquim, Lava-Tudo River, Pelotas River sub-basin, S, W, 1219 m, ditto (UFRGS 3939). Diagnosis. Antero-lateral spine not reaching to base of cornea; protogastric lobes absent; extra-orbital sinus absent, rostrum subtriangular, short, carinate, outer proximal margin of movable finger of cheliped with lobe; palmar crest of cheliped subdisciform, with lobes; anterior angle of ventral margin of epimeron 2 unarmed; inner margin of ventral surface of ischium of cheliped with elevation ornamented with scaliform distal tubercle. Description. Carapace flat, area of gastric region nearly plain, dorsal surface scabrous, covered with punctuations; anterior dorsal region delimiting base of rostrum by V- shaped depression. Front wide; PCW/FW ratio of holotype male Rostrum subtriangular, short, carinate along its entire length, straight. Subrostral process developed; proximal region with ventral portion of rostrum slightly larger than dorsal. Rostral carina begins at height of the anterior margin of the first hepatic lobe, very low, slightly excavated and indistinct in distal third portion; carina with two parallel rows of scales which in the distal third combine in only one row reaching the apex. Lateral margins of rostrum with juxtaposed scales. Orbits wide, slightly deep, without orbital spine. Orbital margin with sparse scales. Extra-orbital sinus absent. Antero-lateral angle of carapace slightly projecting anteriorly in a scale, which does not reach base of cornea. Outer and inner margins of antero-lateral lobe with scales. First hepatic lobe delimited anteriorly by distinct fissure; lateral margin with scales; second and third hepatic lobes not delimited, with only modest indication; lateral margins with sparse scales. Epigastric prominences absent, irregular surface with sparse scales. Protogastric lobes absent, anterior margin indicated by some scales. Transverse dorsal line slightly sinuous. Areola subrectangular. AL/AW ratio of holotype male Epibranchial area subrectangular, with scaliform apical tubercle followed by scales. Lateral margins of anterior branchial area with prominent scales, and posterior margins with subequal scales. Anterior angle of ventral margin of epimeron 2 unarmed, with only small scales and setae; ventro-lateral margin nearly straight; posterior angle of ventral margin obtuse, unarmed. Epimera of third through sixth segments obtuse, ornamented with long setae. Telson divided by longitudinal suture. Anterior extremity of third sternite triangular, projected between coxae of exopods of third maxillipeds. Fourth tho-

8 536 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 32, NO. 4, 2012 Fig. 4. Aegla oblata n. sp. Bond-Buckup Santos (male holotype, MZUSP 23467, scale: 5 mm: A, dorsal view; B, anterior portion of carapace (lateral view); C, basis-ischium of cheliped (ventral view); D, third and fourth thoracic sternites (ventral view); E, epimeron 2 (lateral view).

9 SANTOS ET AL.: NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS 537 racic sternite elevated in median region, without ornament, with tufts of setae, antero-lateral margins slightly recurved. Chelipeds subequal in shape, hand subrectangular. Minor chelae with delicate appearance, elongated, covered by scales. Major propod with more globose appearance, palm slightly more inflated in posterolateral region, covered with scales. Palmar crest subdisciform, margin with lobes ornamented with apical scaliform tubercle, scales and long setae recurved in proximal portion. Pre-dactylar lobe forming a small step with anterior margin of propodus, ornamented with apical scaliform tubercle, scales and long setae. Fingers slender, covered by scales and scaliform tubercles on distal extremities. Proximal outer margin of movable finger with distinct lobe with scaliform apical tubercle, scales and long setae. Prehensile margins of fingers with scaliform denticles along their entire length and with distinct fitted opposed lobular teeth on the major cheliped. Dorsal surface of carpus scabrous, with scales; inner margin with three to four spines of which distalmost spine is most developed; these spines bear scales and long setae on lateral margins; on the base of the distal spine there is a small spine in a more inner position; inner anterolateral angle sub-obtuse, with apical scaliform tubercle and scales; anterodorsal margin with scales. Distal part of dorsal surface with depression parallel to distal margin. Carpal crest more elevated in proximal region, with scales agglutinated into groups of three to five units on elevations of crest; outer ventral angle of carpus with one or two elevations ornamented with scaliform tubercle and tufts of setae. Dorsal margin of merus of cheliped with a more distinct scaliform tubercle, followed by smaller scaliform tubercles and tufts of long setae; anterodorsal margin with scales. Lateral surfaces with few punctuations. Inner ventral margin of merus with a distal spine followed by tubercles, elevations with scales and tufts of setae; on outer ventral margin a distal spine protrudes, followed by tubercles and scales. Dorsal margin of ischium with one tubercle and tufts of setae; inner margin of ventral surface with elevation ornamented with distal scaliform tubercle and other, smaller elevations with scales. Dorsal margin of dactylus, propodus, and carpus of second through fourth pereiopods with rows of setae and scales arranged in longitudinal series; dorsal margin of meri of same pereiopods with long setae, lending the surface a pubescent appearance, extending to midlength of segment. Variations. The specimens of lot 3920 have a slightly longer rostrum, with the rostral carina more elevated and slightly more excavated. Measurements. Male holotype with mm CL; male paratypes (n = 28) with mean CL mm; paratype females (n = 21) with mean CL mm. PCW/FW mean ratio of male paratypes (n = 28) 1.78, ranging from 1.65 to 1.95; female paratypes (n = 21) PCW/FW mean ratio 1.77, ranging from 1.59 to AL/AW ratio of male paratypes (n = 20) 1.74, ranging from 1.43 to 2.00; AL/AW ratio of female paratypes (n = 21) 1.61, ranging from 1.48 to Distribution. BRAZIL: State of Santa Catarina, Uruguay River basin, Caveiras (Canoas) River and Lava-Tudo (Pelotas) River sub-basins. A. oblata occurs in sympatry with Aegla jarai in the Canoas River sub-basin, and in sympatry with Aegla spinosa, Aegla jarai, A. odebrechtii and A. camargoi in the Pelotas River sub-basin. Etymology. From Latin, oblatus = depressed, for the very flat, plain carapace of the species. Conservation status. Vulnerable (VU) B1ab(iii): Area of occupancy estimated to be less than km 2 ; known to exist at fewer than ten locations; continuing decline, inferred from quality of habitat (IUCN, 2001). The aggression to the headwater, by deforesting, agriculture pesticides and the construction of hydroelectric dam, are the main threat to the upper Uruguay environment. Biology. Unknown. Remarks. The new species A. oblata has a very short rostrum compared with the other known species of the genus. It shares some characteristics with A. camargoi, such as the subdisciform shape with lobes of the palmar crest. However, A. camargoi has the palmar crest more developed, with more lobes and a long rostrum. In A. oblata the propodus of the cheliped is globose and the inner spines of the carpus margin are less projected than in A. camargoi.the new species resembles the shape of the palmar crest with lobes of A. franciscana. Notwithstanding, the former differs by the subdisciform crest and by the slight difference in the distal portion of the rostral carina. DISCUSSION Phylogeny Using the molecular data collected from regions of the 16S and COII genes from the mitochondrial genome, we estimated phylogenetic relationships among the new species and selected described species (Fig. 5). The resulting phylogeny clearly shows that each of the newly described species is a distinct phylogenetic lineage. Two of the new species (A. oblata and A. brevipalma) fall in the Clade D and are sister to A. camargoi and A. spinosa, respectively. The third species, A. leachi falls in the Clade E and is sister to A. inermis. Ecology Aegla brevipalma occurs sympatrically with A. jarai in the Canoas River sub-basin (Table 1), although evolutionarily is sister to A. spinosa (Fig. 5, clade D). Morphologically, A. brevipalma differs from A. spinosa. In A. brevipalma the anterolateral spine does not reach the basis of the cornea, but in A. spinosa it extends beyond the half of the cornea. A. brevipalma has a triangular rostrum, which is elongated in A. spinosa. A. leachi is phylogenetically closely related to A. inermis (Fig. 5, clade E). A. inermis is found only in the Jacuí/Guaíba drainage system, in which the rivers rise on the slopes of the Serra Geral, in central, northeastern and eastern Rio Grande do Sul and discharge in the Laguna dos Patos, parallel to the Atlantic Ocean. On the other hand, A. leachi is recorded only from the Upper Uruguay basin, in which the rivers rise along the boundary between Rio Grande do Sul and Santa Catarina, with the main course flowing westward (Fig. 1). Concerning the morphology, although the two species have

10 538 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 32, NO. 4, 2012 Fig. 5. Maximum likelihood tree. Bootstrap proportions (if >50%) are indicated for each clade. Branch lengths are shown proportional to the amount of change along the branches.

11 SANTOS ET AL.: NEW SPECIES OF AEGLA (ANOMURA) FRESHWATER CRABS 539 Table 1. Species of Aeglidae recorded for the region of the Upper Uruguay River. Hydrographic sub-basins Species Caveiras River Aegla jarai Bond-Buckup and Buckup, 1994 Aegla odebrechtii (Müller, 1876) Aegla spinosa Bond-Buckup and Buckup, 1994 Aegla leachi n. sp. Bond-Buckup and Buckup Aegla oblata n. sp. Bond-Buckup and Santos Canoas River Aegla jarai Bond-Buckup and Buckup, 1994 Aegla odebrechtii (Müller, 1876) Aegla spinosa Bond-Buckup and Buckup, 1994 Aegla leachi sp. n. Bond-Buckup and Buckup Aegla brevipalma n. sp. Bond-Buckup and Santos Pelotas River Aegla camargoi Buckup and Rossi, 1977 Aegla franciscana Buckup and Rossi, 1977 Aegla jarai Bond-Buckup and Buckup, 1994 Aegla leptodactyla Buckup and Rossi, 1977 Aegla odebrechtii (Müller, 1876) Aegla serrana Buckup and Rossi, 1977 Aegla spinosa Bond-Buckup and Buckup, 1994 Aegla oblata n. sp. Bond-Buckup and Santos some similar characteristics, such as the absence of a palmar crest and the antero-lateral spine reaching to the base of the cornea, they differ with respect to the presence of protogastric and epigastric lobes; by the presence of conical tubercles on ventral surface of the ischium of cheliped in A. inermis; and by the presence of a lobe on the movable finger of the cheliped only in A. leachi. A. oblata occurs sympatrically with A. jarai in the Canoas River sub-basin, and with A. spinosa, A. jarai and A. camargoi in the Pelotas River sub-basin (Table 1). Phylogenetically, A. oblata is a sister-species to A. camargoi (Fig. 5, clade D). These two latter species have a subdisciform palmar crest, a lobe on the movable finger of the cheliped and tubercles on the ventral margin of the ischium of the cheliped. However, in A. camargoi, the anterolateral spines extend beyond the basis of the cornea, the protogastric and epigastric lobes are present, the extra-orbital sinus is also visible, the rostrum is long, and the epimeron 2 has a spine; characteristics not found in A. oblata. The distribution areas of A. camargoi and A. franscicana, for which new records of occurrence were cited by Bond-Buckup et al. (2009), are extended, occurring in tributaries of the right bank of the Pelotas River (Table 1). The region along the border between Santa Catarina and Rio Grande do Sul has an uneven relief, characteristic of an active orogenic process which originated the mountain range Serra do Mar and greatly contributed to the formation of the drainage system in southern Brazil (Ribeiro, 2006). Access to this area is relatively difficult, making it hard to survey the aquatic fauna. In spite of this, the recent expansion of some agricultural activities, such as silviculture of exotic species and large-scale cultivation of apples and potatoes with extensive use of pesticides, has impaired the quality of the aquatic environment. These activities are completely acceptable and important from economic and social points of view. Notwithstanding, it is increasingly essential that agricultural practices respect the principle of sustainability. Inappropriate practices, especially the damage to the aquatic environment, require an effort of the scientific community to search for solutions for biodiversity conservation in the region. According to the Brazilian Ministry of the Environment, the region of upper Uruguay is part of the Atlantic Forest biome, identified as the Araucaria Plateau (Planalto das Araucárias MMA, 2002). More recent studies (MMA, 2009) consider this area to be of extreme biological importance, recommending it as a priority area for conservation. According to Pérez-Losada et al. (2009), the regions of the Upper Uruguay and Jacuí/Guaíba System (Patos Lagoon) harbor the greatest richness of species of the family Aeglidae Dana, The Jacuí/Guaíba system also contains the largest number of endemic species of this family, 11 species, including the recently described Aegla renana Bond-Buckup and Santos, 2010 (Pérez-Losada et al., 2009; Santos et al., 2010). The description of these three new species makes the Upper Uruguay basin also an important center of endemism for the South-American aeglids, now totaling six species. In view of the high diversity of endemic crustaceans in the watercourses of the Araucaria Plateau, we hope that the importance of this fauna for the food webs of limnetic environments may alert public officials to the need for adequate management of the hydrographic basins and the preservation of this region. ACKNOWLEDGEMENTS We are grateful to our colleagues Dr. Carlos Jara, Dr. Alessandra Bueno, Dr. Carolina Sokolowicz, Dr. Aline Quadros and Felipe Bavaresco for helping in the crustacean sampling in the Campos de Cima da Serra. To CNPq for the productivity grants to GBB (306490/2007-2) and SS (308723/2008-2). REFERENCES Abell, R., M. L. Thieme, M. H. Sabah Perez, and P. Petry Freshwater ecoregions of the world: a new map of biogeographic units for freshwater biodiversity conservation. BioScience 58: Bond-Buckup, G., and L. Buckup A família Aeglidae (Crustacea, Decapoda, Anomura). Arquivos de Zoologia 32:

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