Aegla vanini Moraes, Tavares & Bueno

Moraes, Juliana Cristina Bertacini, Terossi, Mariana, Buranelli, Raquel Corrêa, Mantelatto, Fernando L. & Bueno, Sérgio Luiz De Siqueira, 2016, Morphological and molecular data reveal the cryptic diversity among populations of Aegla paulensis (Decapoda, Anomura, Aeglidae), with descriptions of four new species and comments on dispersal routes and conservation status, Zootaxa 4193 (1), pp. 1-48 : 21-23

Aegla vanini Moraes, Tavares & Bueno n. sp.

( Figs 1 , 16–17 , 24E–F , 25C , 27C , 28C , 29C , 30 )

Aegla paulensis .— Bond-Buckup & Buckup, 1994 pro parte: 242 [not Aegla paulensis Schmitt, 1942 ].

Type material. Holotype: male [15.00 mm], Brazil, São Paulo, city of Salesópolis, Boraceia Biological Station, Venerando stream, 23°39’09.0”S –045°53’27.6”W, altitude 849 m, JCB Moraes and SLS Bueno coll., 06.vi.2014 (MZUSP 34371). Paratypes: 4 males [largest male: 16.72 mm, smallest male: 13.94 mm], ibidem, geographical coordinates not available, SA Vanin coll., 19.xi.1998 (MZUSP 34373). 8 males [largest male: 14.90 mm, smallest male: 11.38 mm], ibidem, 23°39’09.0”S–045°53’27.6”W, altitude 849 m, JCB Moraes and SLS Bueno coll., 06.vi.2014 (MZUSP 34372, genetic voucher: Genbank access KU948369 ).

Other material examined. Brazil, São Paulo, Salesópolis, Boraceia Biological Station , Venerando stream, about altitude 840 m, 02.xi.1975: 1 female [14.50 mm] ( MZUSP 7311 ) . Ibidem, Firmino R. Gomes coll., x.2010: 1 male [19.20 mm] (MZUSP 24338).

Diagnosis. Rostrum triangular, base wide, nearly deflected downward, extending beyond distal apex of compound eyes. Subrostral process on proximal half, well developed, high, broad triangular, and oriented downward. Orbital spines absent. Corneous scales at epibranchial area present on anterolateral angle only. Areola subrectangular. Anteromesial region of third thoracic sternite truncate. Chelipeds moderately large, palmar crests rectangular with margin lobulate. Uropods narrow. Posterolateral margin of telson slightly convex mesially.

Type-locality. Venerando stream, Boraceia Biological Station , city of Salesópolis, São Paulo, Brazil.

Geographical distribution. Known only from the type-locality.

Description of the male holotype. Carapace moderately convex, gastric region swollen, dorsal surface scabrous, covered with punctations and minute setae. Rostrum triangular, base wide (value = 1.03), nearly deflected downward, extending beyond distal apex of compound eyes, with sparse short setae on margin. Rostral carina low, beginning at level of protogastric lobes, extending to near apex, with small corneous scales ( Figs. 16 , 25C ). Subrostral process well developed, on proximal half of subrostral margin, tip rounded, anterior and posterior margins forming obtuse angle (99°) ( Figs. 17 A, 27C).

Eyestalk and cornea well developed. Orbital sinus U-shaped, with plumose setae subventrally. Orbital spines absent. Anterolateral spines rounded apically, straight, not reaching basal margin of cornea, with minute corneous scale and small setae ( Fig. 16 ).

Epigastric prominences pronounced with minute corneous scales. Protogastric lobes weakly pronounced with minute corneous scales ( Figs. 16 , 25C ). Gastric area prominently inflated in relation to hepatic lobes. Gastric pits small, smooth.

Demarcation between hepatic lobes weakly defined ( Figs. 16 , 25C ). Lateral margins of hepatic lobes smooth, with sparse small setae.

Transverse dorsal linea (TDL) slightly sinuous throughout its extension, sinuosity more pronounced in mesial section. Areola subrectangular (value = 1.90). Cardiac area trapezoidal (value = 1.63) ( Figs. 16 , 25C ).

Epibranchial area shortened, rounded, anterolateral angle blunt with a small corneous scale, margins with small simple setae ( Figs. 17 B, 28C).

Anteromesial region of third thoracic sternite truncate, with long simple setae on surface and with two small corneous scales on anterior flattened margin. Fourth thoracic sternite with anterolateral angles moderately produced, with simple setae ( Figs. 17 C, 29C).

Chelipeds unequal in size ( Fig. 16 ). Major cheliped. Dactylus: dorsal margin and outer surface granulate; inner surface smooth; proximal lobe of moderate size on dorsal margin; cutting margin with lobular basal tooth well developed proximally with flattened corneous scales, followed by row of wide corneous scales up to distal end; row of tufts of long simple setae next to cutting margin. Propodus: outer surface granulate; palm high (value = 3.37); palmar crest rectangular, margin lobulate, outer surface excavated; cutting margin of fixed finger with lobular basal tooth well developed proximally, with flattened corneous scales, followed by row of wide corneous scales up to distal end; scattered tufts of long simple setae over inner surface and alongside inner and outer surfaces next to cutting margin. Carpus: dorsal margin with one naked tubercle proximally, two median spines with terminal corneous scale, and sub-terminal lobe well defined, blunt, with two small corneous scales apically; inner surface with two naked tubercles, near dorsal margin and long setae; outer surface with carpal ridge of moderate height and formed by tubercles. Merus: dorsal margin with one tubercle; dorsolateral edge with three larger tubercles on distal half, followed by row of tubercles proximally; ventromesial edge with one large tubercle distally with terminal corneous scale and four small naked tubercles proximally; ventrolateral border with two large naked tubercles distally, followed by row of several small naked tubercles proximally. Ischium: dorsolateral edge with one spine with terminal small corneous scale distally; ventromesial border with four naked tubercles; ventrolateral border smooth.

Minor chelipeds similar to major chelipeds except as noted hereafter: Dactylus: proximal lobe rudimentary on dorsal margin; cutting margin with lobular basal tooth rudimentary, followed by row of narrow corneous scales up to distal end. Propodus: cutting margin with lobular basal tooth rudimentary, followed by row of narrow corneous scales up to distal end. Carpus: inner surface with one spine with two terminal corneous scales. Merus: dorsolateral edge with one spine with terminal corneous scale distally, followed by row of small naked tubercles proximally; ventrolateral border with four small naked tubercles median-distally. Ischium: dorsolateral edge with one naked spine; ventromesial border with three naked tubercles (the mesial one is the smallest); ventrolateral border smooth.

Second third and fourth pereiopods similar in form, except where noted. Dactyli with several rows of setal tufts on all surfaces. Propodi with scattered setae, concentrated mainly along dorsal and ventral margins. Carpi with scattered setae, concentrated mainly along dorsal margin second and third pereiopods with small corneous scale on distal portion of dorsal margin. Meri and ischii with scattered setae, concentrated mainly along dorsal margin ( Fig. 16 ).

Fifth pereiopods reduced and chelate. Dactylus small, flattened, forming setose minute chela with propodus. Sexual tube long, narrow, opening on coxa ( Figs. 24E–F ).

Pleopod 2 absent, pleopods 3 to 5 showing as buds.

Anterolateral angle of second abdominal epimeron well defined, with minute corneous scale apically. Ventral angles of third and fourth abdominal epimera well defined, unarmed.

Uropods well developed, narrow ( Fig. 17 D).

Telson with anterolateral and posterolateral margins poorly differentiated; posterolateral margin slightly convex mesially ( Fig. 17 D).

Variations. The rostrum is generally wide base triangular-shaped, but in some specimens is the narrow base one (type-series RBW/LMR mean ratio = 1.01 ± 0.07; n = 13). In 7:13 individuals the angle formed between the subrostral process with anterior and posterior margins is somewhat smaller, 45–90° instead of 99°. The hepatic lobes are usually weakly defined, but some specimens may have well defined hepatic lobes. The anterolateral angles of the fourth thoracic sternite are more distinctly produced in the male paratypes than in the male holotype. The anterolateral angle of second abdominal epimeron may be naked in some specimens instead of having minute corneous scales apically, and the ventral angle of third abdominal epimeron may present corneous scales apically instead of being naked as in the holotype.

Remarks. Aegla vanini n. sp. is herein described upon 13 adult males from the high lands of Boraceia Biological Station. The new species has been previously confused with A. paulensis Schmitt, 1942 s . str. by Bond- Buckup & Buckup (1994), who at that time had only two young specimens from Boraceia at their disposal. Nevertheless, A. vanini n. sp. can be differentiated from all the congeners of this species complex in the absence of orbital spines ( Figs. 16 , 25C ). It can be further differentiated from A. paulensis s. str. in having: (i) the rostrum nearly deflected downward (distinctly curved downward in A. paulensis s. str.); (ii) rostrum wide base triangularshaped (narrow base triangular-shaped in A. paulensis s. str.); (iii) the anteromesial margin of the third thoracic sternite truncate (anteromesial margin tapered in A. paulensis s. str.) ( Fig. 29C ); (iii) the uropods narrow (uropods wide in A. paulensis s. str.) ( Fig. 17 D); (iv) the telson with posterolateral margins convex mesially (posterolateral margins concave mesially in A. paulensis s. str.) ( Fig. 17 D).

Aegla vanini n. sp. and A. rosanae further differs from each other in the (i) rostrum nearly deflected downward (rostrum curved upward distally in A. rosanae ) ( Figs. 13 A, 17A); (ii) the areola subrectangular in shape (areola rectangular in A. rosanae ) ( Figs. 12 , 16 ); (iii) the posterolateral margin of telson slightly convex mesially (posterolateral margin of telson straight mesially in A. rosanae ) ( Figs. 13 D, 17D); (iv) the anteromesial margin of the third thoracic sternite truncate (margin of the third thoracic sternite abrupt in A. rosanae ) ( Figs. 29B, C ).

Aegla vanini n. sp. additionally differs from A. lancinhas in (i) the absence of corneous scales in the lateral margin of the epibranchial area (corneous scales present in both regions in A. lancinhas ) ( Figs. 15 C, 28C) and (ii) the anteromesial margin of the third thoracic sternite truncate (margin of the third thoracic sternite abrupt in A. lancinhas ) ( Figs. 15 D, 29C).

The material MZUSP 7311 and MZUSP 7315 from the Boraceia Biological Station assigned to A. paulensis by Bond-Buckup and Buckup (1994) is here reassigned to A. vanini n. sp.

Biology. Unknown.

Etymology. Homage to Dr. Sergio Antonio Vanin, professor from the Department of Zoology of the University of São Paulo and eminent entomologist known for his most relevant contributions on the systematic, evolution and biogeography of Coleoptera. He was the first to collect samples of Aegla from the Venerando stream back in 1998 and kindly made his collection available to us for study.

Figures

FIGURE 1. Distribution of the species of Aegla in four main hydrographic basins of southern Brazil: Rio Grande, Rio Tietê (Upper Paraná system), Rio Paraíba do Sul and Ribeira de Iguape. Indications L 1 through L 7 refer to the locations mentioned under “ sampling area ” in the Material & Methods section.

FIGURE 12. Dorsal view of Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). Bar = 3.0 mm.

FIGURE 13. Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). A, lateral view of the anterior region of the cephalothorax. B, dorsal view of epibranchial area. C, third and fourth thoracic sternites. D, telson, uropods and sixth abdominal segment. Note in A, the subrostral process (arrow). Bars: A, D = 2.0 mm. B = 0.5 mm. C = 1.0 mm.

FIGURE 15. Aegla lancinhas Bond-Buckup & Buckup in Santos et al., 2015, male topotype (MZUSP 34403). A, lateral view of the anterior region of the cephalothorax. B, lateral view of subrostral process (arrow). C, epibranchial area with small corneous scale on the anterolateral angle and lateral margin (arrows). D, anteromesial region of third thoracic sternite abruptshaped. E, chelipeds subequal and poorly inflated. F, telson, uropods and sixth abdominal segment Bars: A = 1.0 mm; B, D = 0.5 mm; C = 0.2 mm; E, F = 2.0 mm.

FIGURE 16. Dorsal view of Aegla vanini n. sp., male holotype (MZUSP 34371). Bar = 3.0 mm.

FIGURE 17. Aegla vanini n. sp., male holotype (MZUSP 34371). A, lateral view of the anterior region of the cephalothorax. B, dorsal view of the right epibranchial area. C, third and fourth thoracic sternites. D, telson, uropods and sixth abdominal segment. Note in A, the subrostral process (arrow). Bars: A, D = 2.0 mm; B = 0.25 mm; C = 1.0 mm.

FIGURE 30. Bayesian tree (TPM 2 uf + G) for Aegla species based on partial fragment of 16 S. Node numbers represent posterior probabilities (values <50 % are not shown), and divergence time in millions of years (my); * indicates the calibration points to molecular clock. The clade C proposed by Pérez-Losada et al. (2004) is highlighted in grey. The basin and sub-basin origin of the discussed species in this study are shown after the specific names.

FIGURE 24. A – L, proximal portion of fifth pereiopod showing coxa and sexual tube of long and narrow type. A – B, Aegla paulensis Schmitt, 1942 s. str., male topotype (MZUSP 34368). C – D, Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). E – F, Aegla vanini n. sp., male paratype (MZUSP 34372). G – H, Aegla japi n. sp., male paratype (MZUSP 34375). I – J, Aegla jaragua n. sp. male paratype (MZUSP 34378). K-L, Aegla jundiai n. sp., male paratype (MZUSP 13490). Bars: A – D, F – H, J = 200 µm; K, L = 100 µm; E, I = 500 µm.

FIGURE 25. A – F, dorsal view of cephalothorax and anterior portion of abdomen. A, Aegla paulensis Schmitt, 1942 s. str., male topotype (MZUSP 34367). B, Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). C, Aegla vanini n. sp., male holotype (MZUSP 34371). D, Aegla japi n. sp., male paratype (MZUSP 34375). E, Aegla jaragua n. sp., male paratype (MZUSP 34377). F, Aegla jundiai n. sp., female holotype (MZUSP 13493).

FIGURE 27. A – F, lateral view of subrostral process. A, Aegla paulensis Schmitt, 1942 s. str., male topotype (MZUSP 34367). B, Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). C, Aegla vanini n. sp., male holotype (MZUSP 34371). D, Aegla japi n. sp., male paratype (MZUSP 34375). Aegla jaragua n. sp., male paratype (MZUSP 34377). F, Aegla jundiai n. sp., female holotype (MZUSP 13493). Bars: A, D = 1.0 mm; B, C, E, F = 0.5 mm.

FIGURE 28. A – F, dorsal view of epibranchial area. A, Aegla paulensis Schmitt, 1942 s. str., male topotype (MZUSP 34367). B, Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). C, Aegla vanini n. sp., male holotype (MZUSP 34371). D, Aegla japi n. sp., male paratype (MZUSP 34375). E, Aegla jaragua n. sp., male paratype (MZUSP 34377). F, Aegla jundiai n. sp., female holotype (MZUSP 13493). Bars: 0.2 mm.

FIGURE 29. A – F, Ventral view of third (St 3) and fourth thoracic sternites. A, Aegla paulensis Schmitt, 1942 s. str., male topotype (MZUSP 34367). B, Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). C, Aegla vanini n. sp., male holotype (MZUSP 34371). D, Aegla japi n. sp., male paratype (MZUSP 34375). E, Aegla jaragua n. sp., male paratype (MZUSP 34377). F, Aegla jundiai n. sp., female holotype (MZUSP 13493). Note in A, St 3 tapered distally; St 3 abrupt in B; and St 3 truncate in C – F. Bars = 0.5 mm.