Aegla oblata, Santos & Bond-Buckup & Buckup & Pérez-Losada & Finley & Crandall, 2012
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publication ID |
https://doi.org/ 10.1163/193724012X635935 |
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https://treatment.plazi.org/id/03E15A15-AD4A-FFE7-22BA-F9B8FB032491 |
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Carolina |
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scientific name |
Aegla oblata |
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sp. nov. |
Aegla oblata View in CoL n. sp. Bond-Buckup and Santos
( Fig. 4 View Fig )
Type-material.— Holotype: male, Brazil, state of Santa Catarina, Painel, Engenho Velho stream, Caveiras River subbasin, Uruguay River hydrographic basin ( Fig 1 View Fig .: square); 27 ◦ 54 ' 12. 8 '' S, 50 ◦ 04 ' 19. 6 '' 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 View in CoL , Urupema, Caronas River , Lava-Tudo sub-basin , 27 ◦ 59 ' 42. 9 '' S, 49 ◦ 51 ' 19. 6 '' 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 , 28 ◦ 15 ' 3. 9 '' S, 49 ◦ 58 ' 16 '' 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, 28 ◦ 11 ' 58. 5 '' S, 49 ◦ 45 ' 54. 9 '' W, 1265 m, ditto ( UFRGS 3928 ) ; 19 m, 18 f, Urubici, Lava-Tudo River headwater , Pelotas River sub-basin, 28 ◦ 05 ' 17. 9 '' S, 49 ◦ 38 ' 23. 7 '' W, 1461 m, ditto ( UFRGS 3935 ) ; 12 m, 5 f, São Joaquim, Lava-Tudo River , Pelotas River sub-basin, 28 ◦ 09 ' 05. 3 '' S, 49 ◦ 43 ' 04. 8 '' 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 Vshaped depression. Front wide; PCW/FW ratio of holotype male 1.94. 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 1.93.
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 thoracic 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 19.22 mm CL; male paratypes (n = 28) with mean CL 17.46 mm; paratype females (n = 21) with mean CL 14.92 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 1.89.
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 1.84.
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 20000 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.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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