Aegla leachi, 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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persistent identifier |
https://treatment.plazi.org/id/03E15A15-AD48-FFE9-22BF-FF28FDFE213A |
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treatment provided by |
Carolina |
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scientific name |
Aegla leachi |
| status |
sp. nov. |
Aegla leachi View in CoL n. sp. Bond-Buckup and Buckup
( Fig. 3 View Fig )
Type-material.— Holotype: male, Brazil, state of Santa Catarina, Painel, Passo Fundo stream, Painel River tributary, Caveiras River sub-basin, Uruguay River hydrographic basin , 27 ◦ 54 ' 34. 4 '' S, 50 ◦ 05 ' 14. 6 '' W ( Fig. 1 View Fig : 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 , 27 ◦ 52 ' 58 '' S, 50 ◦ 02 ' 10. 6 '' 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, 27 ◦ 15 ' 55 '' S, 50 ◦ 28 ' 14. 1 '' 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, 27 ◦ 18 ' 6. 8 '' S, 50 ◦ 18 ' 5. 5 '' 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 2.07. 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 1.43.
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 elevations tipped by scales, suggesting a palmar crest in some animals.
Measurements.—Male holotype with 12.14 mm CL; male paratypes (n = 15), mean CL 12.14 mm; paratype females (n = 10), mean 11.62 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 1.55.
The mean total cephalothorax length of paratypes of both sexes reached 11.93 mm, indicating a small-sized species. In four females carrying juveniles in the pleopods, the CL ranged from 10.16 to 12.20 mm. The smallest female found was 10.05 mm in CL and the largest female measured 14.58 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 20000 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.
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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