Aegla quilombola, Bueno, 2017

Bueno, Sérgio Luiz De Siqueira, 2017, Taxonomic review of Aegla marginata Bond-Buckup & Buckup, 1994 (Decapoda, Anomura, Aeglidae) with description of a new species, Zootaxa 4323 (4), pp. 519-533 : 523-531

Aegla quilombola n. sp.

( Figs 3 ; 4B; 5B; 6B, D, F; 7D–F; 8D–F; 9B, D)

Aegla marginata .— Bond-Buckup & Buckup, 1994 pro parte: 218 [all specimens from São Paulo].— Rocha & Bueno (2004): 1005 [distribution].— Fernandes et al. 2011: 33 [morphology]— Maia et al. 2013: 41 [ecology and conservation].— Silva et al. 2016: 59 [reproduction]. [Not Aegla marginata Bond-Buckup & Buckup, 1994 ].

Type material. Holotype: male ( CLE 15.70 mm), Brazil, São Paulo, Ribeira de Iguape Basin, Iporanga, Intervales State Park , Colorida cave (SBE code: SP-129), 24°16’25.6”S, 048°25’11.1”W; altitude 825 m, N. Moracchioli coll. , 28 April 1991 ( MZUSP 34809 ). Paratypes: 3 males (( CLE 16.32–18.59 mm), São Paulo, Capão Bonito, Intervales State Park, Riacho Queimado track, N. Moracchioli coll. , 15 November 1991 (MZUSP 34810); 1 male (CLE 14.96 mm), Iporanga, Intervales State Park, dos Paiva cave (SBE code: SP-042), H. Santos coll., September 1996 (MZUSP 34811); 1 male ( CLE 9.46 mm), voucher of SEM, Intervales State Park, Bocaina river , C. Magalhães, E. Mossolin and F. Kiyohara coll. , 0 3 April 2001 (MZUSP 34812); 1 male ( CLE 13.00 mm), Intervales State Park, Água Comprida stream, S. Rocha and J. Domingos coll. , 19 August 2001 ( MZUSP 34813 ) and 3 males ( CLE 14.92–17.19 mm), S. Rocha coll. , 16 January 2002 (MZUSP 34814); 1 male ( CLE 15.33 mm), Intervales State Park, dos Paiva river , 0 1 July 2009 ( MZUSP 34815 ) ; 1 male ( CLE 14.35 mm), Intervales State Park, Mirante river , A.L. Castilho coll., 17 October 2013 (NEBECC not numbered) ; 3 males (CLE 14.62–16.52 mm), Intervales State Park, Roda d’água, A.L. Castilho coll., 0 4 December 2013 (NEBECC not numbered).

Other material examined. 6 males, 3 females (not measured), São Paulo, Alto Ribeira Touristic State Park ( PETAR), Casa de Pedra , E. Trajano coll., 1974 ( MZUSP 7409 ) ; 1 male (not measured), Iporanga, Colorida cave, E. Trajano coll. 30 March 1988 (MZUSP 9780) and 3 males and 1 female (not measured), P. Gnaspini Netto coll. 28 May 1988 (MZUSP 9781); 2 males and 1 female (not measured), São Paulo, Guapiara, Intervales State Park, Região do Monte Rosa , córrego Água Comprida, E. Trajano coll., 0 6 February 1989 ( MZUSP 9783 ) ; 1 male (not measured), Iporanga, Intervales State Park, dos Paiva cave, E. Trajano coll. 10 February 1989 (MZUSP 9779).

Geographical distribution. This species is presently known only from São Paulo, Ribeira de Iguape Basin (from several localities in the Intervales State Park and one locality in the Alto Ribeira Touristic State Park— PETAR).

Diagnosis. Rostrum wide at base. Extra-orbital sinus shallow. Anterolateral spines straight. Epigastric prominences pronounced. Protogastric lobes pronounced with a set of corneous scales. Anterior margin of first hepatic lobe and axis of rostrum oriented with respect to each other less than 90°. Hepatic lobes poorly defined. Transverse dorsal linea rather straight. Areola sub-rectangular. Cardiac area trapezoidal. Anterolateral angle and lateral margin of epibranchial area with small corneous scales. Anteromesial region of third thoracic sternite tapered. Major cheliped propodus with palmar crest rudimentary, low, serrated, outer surface not excavated. Anterolateral angle of second abdominal epimeron with corneous scales. Ventral angles of third and fourth abdominal epimera unarmed. Sexual tube short, wide. Uropods narrow-shaped. Telson with anterolateral and posterolateral margins well differentiated, posterolateral margin straight.

Description of holotype. Carapace moderately convex, gastric region swollen, dorsal surface scabrous, covered with punctations, small corneous scales and setae. Rostrum triangular, base wide (RBW/LMR = 1.09), straight, slightly extending beyond distal apex of compound eyes, corneous scales and small setae on lateral margins and tip. Rostral carina originating at level of protogastric lobes, extending to apex distally, with corneous scales and setae. Subrostral margin low, covered by small setae ( Fig. 5B ). Subrostral process well developed, covered by small setae, occupying posterior half of subrostral margin, oriented forward, tip flattened without corneous scale, anterior and posterior margins forming distinct acute angle relative to each other ( Figs 3 , 4B , 5B , 6B ).

Eyestalk and cornea well developed. Orbital sinus deep, extra-orbital sinus shallow. Orbital sinus U-shaped, with fringe of pappose setae sub-ventrally. Orbital spines well developed, tip rounded, with two minute corneous scales. Anterolateral spines blunt with small terminal corneous scales terminally, approximately straight, and slightly extending beyond basal margin of cornea ( Figs 3 , 4B ).

Epigastric prominences distinct, with few corneous scales. Protogastric lobes pronounced, topped with set of corneous scales. Gastric area swollen relative to hepatic lobes and rostrum in lateral view. Gastric pits inconspicuous ( Figs 3 , 4B , 5B ).

Anterior margin of first hepatic lobe and axis of rostrum oriented with respect to each other less than 90° ( Fig. 4B ). Hepatic lobes poorly demarcated, not flat-topped ( Fig. 4B ). Lateral margins of hepatic lobes with scattered small corneous scales and small setae.

Transverse dorsal linea rather straight. Areola sub-rectangular (ratio = 1.79). Cardiac area trapezoidal (ratio = 1.50) ( Fig. 3 ).

Epibranchial area subtriangular with scattered small setae. Anterolateral angle blunt, with corneous scale, lateral margin with row of small corneous scales ( Figs 3 , 6D ).

Third thoracic sternite with scattered long simple setae and anteromesial region tapered with terminal corneous scales. Fourth thoracic sternite with anterolateral angles produced anteriorly, corneous scale terminally and scattered long setae ( Fig. 6F ).

Chelipeds unequal in size ( Figs 3 , 7B, D, F ). 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, flattened corneous scales followed by row of wide corneous scales up to distal end. Row of tufts of setae next to cutting margin. Propodus: outer surface more granulated than inner one, palm high (ratio = 3.46). Palmar crest rudimentary, low, serrated, outer surface not excavated, covered by corneous scales and short setae. Cutting margin of fixed finger with lobular basal tooth well developed, flattened corneous scales followed by row of wide corneous scales up to distal end. Inner and outer surfaces of fixed finger with row of tufts of long setae next to cutting margin. Carpus: subterminal lobe on dorsal margin well developed. Lobe blunt, small corneous scales and setae apically, followed by two mesial spines unequal in size with terminal corneous scale and four proximal tubercles, three most proximal, smaller, fused at base. Inner surface with group of six tubercles accompanied by corneous scales and small setae near dorsal margin. Outer surface with carpal ridge strongly pronounced, small corneous scales and setae, and with two mesial small tubercles with corneous scales apically near dorsal margin. Merus: dorsal margin with scattered corneous scales and setae, devoid of tubercles. Dorsolateral edge with two distal larger tubercles followed by row of 15 tubercles decreasing in size proximally, all with terminal corneous scale. Ventromesial edge with five tubercles ending in corneous scales, decreasing in size proximally. Ventrolateral border with five tubercles ending in corneous scale (except for the subdistal tubercle which is naked), decreasing in size proximally. Ischium: dorsolateral edge with one spine and one tubercle with terminal corneous scale and long pappose setae. Ventromesial border with one subdistal low and blunt tubercle, three mesial corneous scales, and one proximal low and blunt tubercle. Ventrolateral border smooth.

Minor cheliped similar to major cheliped except as noted ( Fig. 3 ). Dactylus: proximal lobe on dorsal margin slightly more pronounced. Cutting margin formed by narrow corneous scales, lobular basal tooth rudimentary. Propodus: palm low (ratio = 4.58), cutting margin of fixed finger with row of narrow corneous scales up to distal end, lobular basal tooth absent, palmar crest rectangular. Carpus: dorsal margin with three proximal tubercles, inner surface with five scattered tubercles unequal in size, ending in corneous scales and setae. Outer surface of carpus with three small tubercles near dorsal margin. Merus: ventrolateral border with two subdistal and two proximal low tubercles with terminal corneous scales. Ischium: ventromesial border with two mesial corneous scales.

Second, third and fourth pereiopods morphologically similar. Dactylus with several rows of setal tufts and scattered small corneous scales on general surface. Propodus and carpus with scattered setae and small corneous scales concentrated mainly along dorsal margin. Merus with scattered, small, simple setae on general surface, long pappose setae on dorsal margin, and small corneous scales on dorsal and ventral margins. Ischium with long pappose setae on dorsal margin.

Fifth pereiopods reduced, chelate. Dactylus small, flattened, forming setose minute chela with propodus. Sexual tube short, wide ( Figs 8D–E ).

Pleopods 2 to 5, showing as buds.

Anterolateral angle of second abdominal epimeron with corneous scales. Ventral angles of third and fourth abdominal epimera well defined, unarmed. Anterior margin of second abdominal epimeron concave ( Fig. 9B ).

Uropods well developed, narrow ( Fig. 9D ).

Telson with anterolateral and posterolateral margins well differentiated, posterolateral margin straight ( Fig. 9D ).

Variations. In some specimens, the epigastric prominences and protogastric lobes are less developed than in the holotype of Aegla quilombola n. sp., and the anterior margin of the first hepatic lobe and axis of rostrum can be oriented with respect to each other to form an angle of about 90°. The areola varies from sub-rectangular (male holotype and two additional males) to subquadrate (seven additional males), in which the mean ratio varies between 1.60 ± 0.11; n = 10. Also, the proximal lobe on the dorsal margin of the dactylus of the major chela may be absent (as opposed to rudimentary) and the cutting margin can present narrow corneous scales (instead of flattened corneous scales). In most specimens, the anterolateral angle of second abdominal epimeron is devoid of corneous scales.

Etymology. The specific epithet " quilombola " is derived from the African Kimbundu language "Kilombo", meaning settlement, refuge. The valley of the Ribeira de Iguape River is home to many descendants from the old "quilombos", who still preserve the culture and traditions of their ancestors. It is a noun in apposition.

Remarks. Aegla marginata Bond-Buckup & Buckup, 1994 sensu lato is herein divided into two species: Aegla marginata sensu stricto (restricted to the southern population from the Litorânea Hydrographic Basin—Paraná and Santa Catarina, Brazil) and Aegla quilombola n. sp., established herein for the populations from the Ribeira de Iguape Hydrographic Basin (São Paulo, Brazil). Aegla marginata sensu stricto and A. quilombola n. sp. resemble each other in the proximal lobe of the dorsal margin of dactylus of major chela being low and blunt, and the cutting margin of the dactylus of the major chela provided with wide corneous scales. They further share rudimentary, not excavated palmar crest on the major cheliped, whose margin is poorly indented and covered by corneous scales and short setae, and narrow corneous scales on the cutting margin of dactylus and propodus of the minor chela. However, the new species differs from Aegla marginata sensu stricto in having: (i) the proximal part of rostrum distinctly wide (versus base of rostrum much narrower in A. marginata ) ( Figs 4A, B ); (ii) markedly shallow, narrow extraorbital sinuses (versus extraorbital sinuses much deeper and wider in A. marginata ) ( Figs 4A, B ); (iii) the subrostral margin markedly low (versus subrostral margin distinctly high in A. marginata ) ( Figs 5A, B ); (iv) poorly defined hepatic lobes (versus well defined hepatic lobes in A. marginata ) ( Figs 5A, B ); (v) short subrostral process (versus subrostral process markedly longer in A. marginata ) ( Figs 6A–B ); (vi) the third thoracic sternite tapered (versus sternite abrupt in A. marginata ) ( Figs 6E–F ); (vii) the palmar crest of the minor cheliped moderately high with strongly indented margin (versus palmar crest low, margin poorly indented in A. marginata ) ( Figs 7A–B ); (viii) the major cheliped with strong carpal ridge (versus carpal ridge distinctly lower in Aegla marginata ) ( Figs 7C, D ); (ix) short and wide sexual tubes (versus sexual tubes distinctly longer and slender in Aegla marginata ( Fig. 8A–F ).

Figures

FIGURE 3. Aegla quilombola n. sp., male holotype, CLE 15.70 mm (MZUSP 34809). Scale bar: 3.0 mm.

FIGURE 4. A, B. Dorsal view of the anterior region of the cephalothorax. (A) Aegla marginata sensu stricto, male holotype, CLE 18.80 mm (MHNCI 759). (B) Aegla quilombola n. sp., male holotype, CLE 15.70 mm (MZUSP 34809). Note: A (thick arrows) well defined hepatic lobes (lobes poorly defined in Aegla quilombola n. sp.); deep, wide extraorbital sinus (thin arrow) (sinus much shallower and narrower in Aegla quilombola n. sp.). Scale bars: 1.0 mm.

FIGURE 5. A, B. Lateral view of anterior region of the cephalothorax. (A) Aegla marginata sensu stricto, male holotype, CLE 18.80 mm (MHNCI 759). (B) Aegla quilombola n. sp., male holotype CLE 15.70 mm (MZUSP 34809). Note: A: (i) epigastric prominences low and flattened (thick arrow) (prominences distinctly higher and swollen in A. quilombola n. sp.); (ii) protogastric lobes more produced in A. marginata (thin arrow) (lobes lower in A. quilombola n. sp.); (iii) large height of ventral surface of rostrum (vertical bar showing upper and lower limits) (height markedly lower in A. quilombola n. sp.). Scale bars = 1.0 mm.

FIGURE 6. A, C, E. Aegla marginata sensu stricto, A, male topotype CLE 17.86 mm (MZUSP 34808). C, E, male holotype, CLE 18.80 mm (MHNCI 759). B, D, F. Aegla quilombola n. sp., male holotype CLE 15.70 mm (MZUSP 34809). (A) (B) Rostral region of the cephalothorax in lateral view. (C) (D) Epibranchial area. (E) (F) Third and fourth thoracic sternites. Note: A, long subrostral process (arrow) (markedly shorter in Aegla quilombola n. sp.). Scale bars: A, B, D, F = 0.5 mm; C = 0.2 mm; E = 1.0 mm.

FIGURE 7. A, C, E. Aegla marginata sensu stricto, male holotype, CLE 18.80 mm (MHNCI 759). B, D, F. Aegla quilombola n. sp., CLE 15.70 mm (MZUSP 34809). (A) (B) Palmar crest of major cheliped. (C) (D) Carpus of the major cheliped. (E) (F) Ischium of major cheliped. Note: C and D, low carpal ridges of major cheliped in A. marginata compared to more pronounced condition in Aegla quilombola n. sp.; E and F, different density of tubercles on cheliped ischia (higher in A. marginata than in A. quilombola n. sp.). Scale bars = 1.0 mm.

FIGURE 8. A – F. Sexual tube. A – C. Aegla marginata sensu stricto, male topotype, CLE 16.35 mm (MZUSP 34808). D – F. Aegla quilombola n. sp. male paratype, CLE 9.46 mm (MZUSP 34812). (A) (D) Dorsal view. (B) (E) Lateral view. (C) (F) Ventral view. Scale bars: A – C = 200 µm; D – F = 100 µm.

FIGURE 9. A, C. Aegla marginata sensu stricto, male holotype, CLE 18.80 mm (MHNCI 759). B, D. Aegla quilombola n. sp., male holotype, CLE 15.70 mm (MZUSP 34809). (A) (B) Posterior and anterior regions of carapace and abdomen in dorsal view. (C) (D) Fifth and sixth abdominal segments, uropods and telson. Note: B, curvature (arrows) on anterior margin of the second abdominal segment more pronounced in A. quilombola n. sp. Scale bars: A, C, D = 2.0 mm; B = 1.0 mm.