Aegla rosanae Campos Jr., 1998 n

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 : 15-19

Aegla rosanae Campos Jr., 1998 n . stat.

( Figs 1 , 12–13 , 24C–D , 25b , 26B , 27B , 28B , 29B , 30 )

Aegla rosanae Campos Jr., 1998: 138 –139, figs 1–4 [female holotype].

Aegla paulensis .— Bond-Buckup & Buckup, 2000 pro parte: 386 [not Aegla paulensis Schmitt, 1942 ].

Type material. Holotype: female [8.80 mm], Brazil, São Paulo, city of Piquete, Benfica stream headwater, geographical coordinates and altitude not available, RS Lima, O Takeshi and O Campos Jr. coll., 26.vi.1992 ( MZUSP 11162 ).

Other material examined. 1 male topotype [12.61 mm], Brazil, São Paulo, city of Piquete, Benfica stream headwater, 22°35’43.8”S –045°13’35.1”W, altitude 630 m, JCB Moraes and SLS Bueno coll., 28.ix.2012 (MZUSP 34370). 11 males topotypes [largest male: 15.52 mm, smallest male: 9.47 mm], ibidem, JCB Moraes and SLS Bueno coll., 07.xii.2012 (MZUSP 34369, genetic voucher: Genbank access KU948373 ).

Type-locality. Benfica stream headwater, city of Piquete, São Paulo, Brazil.

Geographical distribution. Known only from the type-locality.

Diagnosis. Rostrum triangular, base narrow, curved upward distally, extending beyond distal apex of compound eyes. Subrostral process on proximal half, well developed, low, broad, triangular, and tip oriented anteriorly. Orbital spines well developed. Epibranchial area with corneous scales on anterolateral angle and on lateral margin. Areola rectangular. Anteromesial region of third thoracic sternite abrupt. Chelipeds moderately large, palmar crests rectangular with margin lobulate. Uropods narrow. Posterolateral margin of telson straight mesially.

Description of male topotype. Carapace moderately convex, gastric region flattened, dorsal surface scabrous, covered with small setae. Rostrum triangular, slightly linguilate, base narrow (value = 0.94), curved upward distally, extending beyond distal apex of compound eyes, with small corneous scales and setae on lateral margins and tip ( Figs. 12 , 26B ). Rostral carina beginning at level of protogastric lobes, extending to near apex, with small simple setae. Subrostral process well developed, on proximal half of subrostral margin, tip rounded and directed anteriorly, anterior and posterior margins forming obtuse angle (116°) ( Figs. 13 A, 27B).

Eyestalk and cornea well developed. Orbital sinus U-shaped, with plumose setae subventrally. Orbital spines well developed, rounded apically, tipped by small simple setae and minute corneous scale. Anterolateral spines rounded apically, with terminal corneous scale and scattered simple setae, straight, and extending beyond basal margin of cornea ( Fig. 12 ).

Epigastric prominences and protogastric lobes pronounced, without corneous scales. Gastric area slightly inflated in relation to hepatic lobes and rostrum in lateral view ( Figs. 12 , 26B ). Gastric pits small and smooth.

Demarcation between hepatic lobes well defined. Lateral margins of hepatic lobes with small corneous scales and small setae ( Figs. 12 , 25B ).

Transverse dorsal linea (TDL) sinuous throughout its extension. Areola rectangular (value = 2.59). Cardiac area trapezoidal (value = 1.48) ( Figs. 12 , 25B ).

Epibranchial area slightly elongated, triangular shaped, anterolateral angle blunt with a small corneous scale, lateral margin with row of small corneous scales and scattered small simple setae ( Figs. 13 B, 28B).

Anteromesial region of third thoracic sternite abrupt, with scattered setae. Fourth thoracic sternite with anterolateral angles strongly produced, with scattered setae ( Figs. 14 c, 29b).

Chelipeds unequal in size ( Fig. 12 ). Major cheliped. Dactylus: dorsal margin and outer surface granulate; inner surface smooth; proximal lobe on dorsal margin blunt; cutting margin with lobular basal tooth well developed proximally, with flattened corneous scales, followed by row of narrow corneous scales up to distal end; row of tufts of long simple setae next to cutting margin. Propodus: outer surface granulate; palm high (value = 3.25); 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 narrow 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 2 naked tubercles proximally, 2 median spines with terminal corneous scale, 1 tubercle sub-distally with terminal corneous scale, and sub-terminal lobe well defined, blunt, with small corneous scales and setae apically; inner surface with one spine with terminal corneous scale, near dorsal margin and long setae; outer surface with carpal ridge high and formed by tubercles. Merus: dorsal margin with one tubercle; dorsolateral edge with one tubercle with terminal corneous scale distally, three low tubercles with terminal corneous scale, followed by row of tubercles decreasing in size proximally; ventromesial edge with one spine with terminal corneous scale distally, followed by five low naked tubercles; ventrolateral border with two tubercles with terminal corneous scale distally, followed by several small tubercles proximally. Ischium: dorsolateral edge with one naked tubercle distally; ventromesial border with four tubercles (two median ones naked); ventrolateral border smooth.

Minor cheliped similar to major cheliped except as noted hereafter. Dactylus: cutting margin with lobular basal tooth weakly developed proximally. Propodus: cutting margin of fixed finger with lobular basal tooth rudimentary. Carpus: one tubercle with terminal corneous scale on dorsal margin. Merus: dorsolateral edge with one tubercle with terminal corneous scale distally, two low naked tubercles, followed by row of tubercles decreasing in size proximally; ventromesial edge with two merged spines distally with terminal corneous scale on each tip, followed by three medianproximal tubercles with terminal corneous scale. Ischium: ventromesial edge with four tubercles (two distalmost ones with terminal corneous scale).

Second, third and fourth pereiopods morphologically similar, except where noted. Dactyli with several rows of setal tufts on general surface. Propodi with small corneous scales on dorsal and ventral margins, and 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. 12 ).

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

Pleopods 2 through 5 showing as buds.

Anterolateral angle of second abdominal epimeron well defined with small corneous scale apically. Ventral angle of third abdominal epimeron well defined with small corneous scale apically. Ventral angle of fourth abdominal epimeron well defined, unarmed apically.

Uropods well developed, narrow (13D).

Telson with anterolateral and posterolateral margins well differentiated; posterolateral margin straight mesially ( Fig. 13 D).

Variations. The base of the triangular rostrum is usually narrower than the length of the sides, but in a few specimens the width of the base is larger than the length of the sides (RBW/LMR mean ratio = 0.97 ± 0.04; n = 12). In some individuals (7:12) the anterolateral spines are shorter than usual, only reaching the basal margin of cornea; the areola can be rectangular or subrectangular in shape (mean value = 2.42 ± 0.18; n = 12), and the carpal ridge varies in height. In some individuals the anterolateral and posterolateral margins of the telson are unusually poorly differentiated and the posterolateral margin slightly convex mesially, instead of straight.

Remarks. Campos Jr. (1998) and Bond-Buckup & Buckup (2000) referred to the holotype (MZUSP 11162) as being a male specimen, whereas it is actually a female specimen. Furthermore, Campos Jr. (1998) mentions that the length of the holotype is 22 mm without specifying whether the measurement refers to carapace length or total body length. The CLE of female holotype is actually 8.80 mm.

Two recent expeditions to the type-locality allowed for the collection of 12 male topotypes whose morphological traits agree well with the female holotype of A. rosanae . They are as follow: (i) rostrum curved upward distally; (ii) subrostral process directed anteriorly; (iii) pronounced protogastric lobes; (iv) epibranchial area with anterolateral angle and lateral margin with small corneous scales; (v) anteromesial region of third thoracic sternite abrupt ( Figs. 14 A–D).

Aegla rosanae was based on a single female from Piquete, Paraíba do Sul Basin, São Paulo, Brazil ( Campos Jr., 1998). According to Campos Jr. (1998), though A. rosanae is similar to A. paulensis Schmitt, 1942 , it can be differentiated from the latter species in having the anterolateral spines of the carapace reaching the basal margin of cornea, gastric [epigastric] prominences weakly pronounced, rostrum reaching base of the antenna and the ischium of the cheliped with two spines. Later on, Bond-Buckup (2000) considered that the arguments put forward by Campos Jr. to differentiate between the two species are inaccurate and placed A. rosanae Campos Jr., 1998 into the synonymy of A. paulensis Schmitt, 1942 (sensu Bond-Buckup & Buckup, 1994). The synonymy between the two species is not confirmed here. Actually, the aeglid population from Piquete (Paraíba do Sul River Basin) does exhibit a constant combination of morphological traits which can be used to easily separate them from Aegla paulensis s. str. from Upper Tietê River Basin, from Alto da Serra de Paranapiacaba. In Aegla rosanae the distal portion of the rostrum is curved upward, while in A. paulensis s. str. the whole extension of the rostrum is characteristically oriented downward ( Fig. 26 ). Furthermore, in A. rosanae the elevation of the gastric area is moderate, producing a fairly seamless continuous transition with the second hepatic lobe, while in A. paulensis s. str. the gastric area is highly elevated whose transition with the second hepatic lobe is markedly inflected ( Fig. 26 ). Aegla rosanae can be further separated from A. paulensis s. str. by the absence of corneous scales on the epigastric prominences and protogastric lobes (such corneous scales are present in A. paulensis s. str.), by the anteromesial region of the third thoracic sternite abrupt shaped (it is tapered in A. paulensis s. str) ( Figs. 29A–B ), by the presence of corneous scales on lateral margin of epibranchial area (such corneous scales are absent in A. paulensis ) ( Figs. 28 A–B ), and by the narrow shape of the uropods (the uropods are wide in A. paulensis s. str.) ( Figs. 11 D, 13D). Therefore, A. rosanae Campos Jr., 1998 , is here removed from the synonymy of A. paulensis Schmitt, 1942 s . str.

Biology. Unknown.

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 11. Aegla paulensis Schmitt, 1942 s. str., male holotype (USNM 80023). 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 = 2.0 mm. B = 0.50 mm. C = 1.0 mm. D = 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 14. Aegla rosanae Campos Jr., 1998, female holotype (MZUSP 11162). A, ventral view of the posterior region of the cephalothorax and anterior region of the abdomen. B, lateral view of the anterior region of the cephalothorax. C, epibranchial area with small corneous scales on the anterolateral angle and lateral margin (arrows). D, anteromesial region of third thoracic sternite abrupt-shaped. Note in A, female gonopores and pleopods (arrows). Note in B, protogastric lobes (wide arrow), subrostral process (thin arrow) and rostrum nearly curved upward distally. Bars: A = 1.0 mm; B, D = 0.5 mm; C = 0.2 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 26. A – B, lateral view of the anterior region of the cephalothorax showing the orientation of the rostrum and the elevation of gastric area. A, Aegla paulensis Schmitt, 1942 s. str., male topotype (MZUSP 34367). B, Aegla rosanae Campos Jr., 1998, male topotype (MZUSP 34369). Note in A, gastric area strongly swollen and subrostral process. Bars = 1.0 mm.

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.