Aegla japi 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 : 24-27

Aegla japi Moraes, Tavares & Bueno n. sp.

( Figs 1 , 18–19 , 24G–H , 25D , 27D , 28D , 29D , 30 )

Type material. Holotype: male [15.80 mm], Brazil, São Paulo, city of Jundiaí , Serra do Japi Biological Reserve, Clube Monte Horebe stream, 23°13’57.2”S –046°55’29.8”W, altitude 881 m, JCB Moraes and SLS Bueno coll., 11.vi.2014 (MZUSP 34374). Paratypes: 10 males paratypes [largest male: 15.62 mm, smallest male: 13.69 mm], ibidem, JCB Moraes and SLS Bueno coll., 11.vi.2014 (MZUSP 34375, genetic voucher: Genbank access KU948370 ).

Type-locality. Clube Monte Horebe stream, Serra do Japi Biological Reserve, city of Jundiaí , São Paulo, Brazil.

Geographical distribution. Known only from the type-locality.

Diagnosis. Rostrum triangular, base wide, nearly deflected downward, not reaching distal apex of compound eyes. Subrostral process on proximal half, poorly developed, low, lobular, and oriented downward. Orbital spines rudimentary. Epibranchial area with corneous scales on anterolateral angle only. Areola subrectangular. Anteromesial region of third thoracic sternite tapered. Chelipeds large, palmar crests rectangular with margin entire. Uropods narrow. Posterolateral margin of telson slightly convex mesially.

Description of the male holotype. Carapace moderately convex, gastric region swollen, dorsal surface covered with punctations. Rostrum triangular, base wide (value = 1.15), slightly deflected downward, not reaching distal apex of compound eyes, with small simple setae and rounded corneous scales on lateral margins and tip ( Figs. 18 , 25D ). Rostral carina beginning at level of protogastric lobes, extending to near apex, with minute corneous scales ( Figs. 18 , 25D ). Subrostral process poorly developed, on proximal half of subrostral margin, tip rounded, anterior and posterior margins forming obtuse angle (139°) ( Fig. 19 A).

Eyestalk and cornea well developed. Orbital sinus U-shaped in dorsal view, with plumose setae sub-ventrally and rounded corneous scales at margin. Orbital spines rudimentary, rounded, with terminal small corneous scale. Anterolateral spines rounded apically with terminal small corneous scale, straight, short, not reaching basal margin of cornea ( Figs. 18 , 25D ).

Epigastric prominences and protogastric lobes pronounced, with minute corneous scales. Gastric area prominently inflated in relation to hepatic lobes ( Figs. 18 , 25D ). Gastric pits inconspicuous.

Demarcation between hepatic lobes well defined. Lateral margins of hepatic lobes with minute corneous scales and sparse small simple setae ( Figs. 18 , 25D ).

Transverse dorsal linea (TDL) slightly sinuous throughout its extension. Areola subrectangular (value = 2.30). Cardiac area trapezoidal (value = 1.45) ( Figs. 18 , 25D ).

Epibranchial area strongly elongated, anterolateral angle blunt with a small corneous scale, margins and surface with scattered small simple setae ( Figs. 19 B, 28D).

Anteromesial region of third thoracic sternite truncate, with corneous scale at tip and scattered setae on the surface. Fourth thoracic sternite with anterolateral angles slightly produced ( Figs. 19 C, 29D).

Chelipeds unequal in size ( Fig. 18 ). Major cheliped. Dactylus: dorsal margin and outer surface granulate; inner surface smooth; proximal lobe on dorsal margin rudimentary; 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 = 3.08); palmar crest rectangular, margin entire, outer surface not 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 poorly defined, blunt, with small corneous scales apically; inner surface with two tubercles (the largest one with terminal corneous scale) and long setae; outer surface with carpal ridge high and formed by tubercles. Merus: dorsal margin with one tubercle; dorsolateral edge with three larger naked tubercles distally, followed by row of naked tubercles decreasing in size proximally; ventromesial edge with one naked spine distally and four tubercles with terminal corneous scale; ventrolateral border with two small naked tubercles distally. Ischium: dorsolateral edge with one naked tubercle distally; ventromesial border with four small naked tubercles median-distally and one naked tubercle proximally; ventrolateral border smooth.

Minor chelipeds similar to major chelipeds except as noted hereafter. Dactylus and fixed finger (propodus): lobular basal tooth followed by row of narrow corneous scales on cutting margin. Carpus: inner surface with one naked spine and two small naked tubercles. Merus: dorsolateral edge with six naked tubercles distally (the distalmost larger), followed by row of small naked tubercles; ventromesial edge with one tubercle distally with terminal corneous scale; ventrolateral border with two small naked tubercles distally. Ischium: ventromesial border with two small naked median tubercles and one naked tubercle proximally.

Second, third and fourth pereiopods morphologically similar, except where noted. Dactyli with several rows of setal tufts on all surfaces and with small scattered corneous scales on dorsal margin. Propodi with scattered long setae, concentrated mainly along dorsal and ventral margins, and scattered small corneous scales on dorsal margin. Carpi with small corneous scale on distal portion of dorsal margin and with scattered setae concentrated mainly along dorsal margin. Meri and ischii with scattered long setae concentrated mainly along dorsal margin ( Fig. 18 ).

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

Pleopods 2 to 5 showing as buds.

Anterolateral angle of second abdominal epimeron well defined, with minute corneous scale apically. Ventral angle of third abdominal epimeron well defined, without corneous scale. Fourth abdominal epimeron well defined, with small corneous scales apically.

Uropods well developed, narrow ( Fig. 19 D).

Telson with anterolateral and posterolateral margins well-differentiated; posterolateral margin straight, slightly convex mesially ( Fig. 19 D).

Variations. The length of the rostral carina varies considerably among specimens as it can either begin anteriorly to the protogastric lobes or at level of the protogastric lobes. In some specimens the angle formed between the anterior margin of the first hepatic lobe and the axis of the rostrum is much smaller, 90° instead of 139°. The areola can be subrectangular or rectangular in shape (mean value = 2.35 ± 0.21; n = 11). In a few individuals the cutting margin of fixed finger the lobular basal tooth is rudimentary instead of well developed. The palmar crest of the minor chela can be either lobulate. The corneous scales on the anterolateral angle of the second abdominal epimeron may vary from minute to small, while the ventral angle of the third abdominal epimeron may present small corneous scale apically instead of being naked.

Remarks. Aegla japi n. sp. is unique in the species complex in that its subrostral process is poorly developed, low and lobular in shape ( Fig. 27D ). The new species is similar to A. vanini n. sp. in having: (i) the rostrum nearly deflected downward ( Figs. 17 A, 19A); (ii) the rostrum wide base triangular shaped ( Figs. 16 , 18 ); (iii) the uropods narrow ( Figs. 17 D, 19D) and (iv) the posterolateral margin of the telson slightly convex mesially ( Figs. 17 D, 19D). These characters also allow the distinction between A. japi n. sp. and A. paulensis s. str. (see under A. vanini n. sp. for details). Additionally, A. japi n. sp. can be distinguished from A. paulensis s. str. in that (i) its orbital spines are rudimentary (the orbital spines are well developed in A. paulensis s. str.) ( Figs. 10 , 18 ) and (ii) the palmar crests of both chelipeds are entire (the palmar crests are lobulate in A. paulensis s. str.) ( Figs. 10 , 18 ).

Aegla japi n. sp. differs from A. vanini n. sp. in that (i) its rostrum does not reach the distal apex of the compound eyes (the rostrum extends beyond distal apex of compound eyes in A. vanini n. sp.) ( Figs. 16 , 18 ), and (ii) the subrostral process is poorly developed and low (the subrostral process is well developed and high in A. vanini n. sp.) ( Figs. 17 A, 19A, 27C, D).

Aegla japi n. sp. and A. rosanae can be separated from each other in that (i) the rostrum is wide base triangular shaped (the rostrum is narrow base triangular shaped in A. rosanae ) ( Figs. 12 , 18 ), (ii) the rostrum is nearly deflected downward (the rostrum is curved upward distally in A. rosanae ), (iii) the orbital spine is rudimentary (orbital spine is well developed in A. rosanae ) ( Figs. 25B, D ), (iv) the areola is subrectangular (the areola is rectangular in A. rosanae ) ( Figs. 12 , 18 ), (vi) the posterolateral margin of the telson is slightly convex medially (the posterolateral margin of the telson is straight medially in A. rosanae ) ( Figs. 13 D, 19D), and (v) the anteromesial margin of the third thoracic sternite is truncate (anteromesial margin of the third thoracic sternite is abrupt in A. rosanae ) ( Figs. 13 C, 19C, 29B, D).

Aegla japi n. sp. and A. lancinhas differ from each other in that (i) the rostrum does not reach distal apex of compound eyes (rostrum extending beyond distal apex of compound eyes in A. lancinhas ), (ii) the orbital spine is rudimentary (orbital spine well developed in A. lancinhas ), and (iii) the corneous scales are inconspicuous in both, the epigastric prominences and protogastric lobes and absent in the lateral margin of the epibranchial area (corneous scales present in both regions in A. lancinhas ).

Biology. Unknown.

Etymology. The specific epithet “ japi ”, from the indigenous Tupi-Guarani language “ yapi ” (“ ya ” = to open, to crack + “ pi ” = deep), meaning “deep opening”, refers to the type-locality “Serra do Japi ”. It is a noun in apposition.

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 10. Dorsal view of Aegla paulensis Schmitt, 1942 s. str., male holotype (USNM 80023). Bar = 3.0 mm.

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 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 18. Dorsal view of Aegla japi n. sp., male holotype (MZUSP 34374). Bar = 3.0 mm.

FIGURE 19. Aegla japi n. sp., male holotype (MZUSP 34374). 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, C = 1.0 mm; B = 0.25 mm; D = 2.0 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.