Panopeus meridionalis Williams, 1983

Oliveira-Rogeri, Lucas, França, Nielson Felix Caetano, Peres, Pedro Augusto & Mantelatto, Fernando L., 2023, Cleaning the mud: Integrative approach clarifies the taxonomy of mud crabs of the genus Panopeus H. Milne Edwards, 1834 (Decapoda: Brachyura: Panopeidae) along the Southwestern Atlantic, Zoologischer Anzeiger 307, pp. 96-124 : 104-105

3.5. Panopeus meridionalis Williams, 1983

( Fig. 1E , 8 A-L)

Panopeus meridionalis Williams, 1983: 872 , Fig. 5 ; Luppi et al., 2003: 923, Figs. 1-5 ; Spivak and Luppi, 2005: Fig. 1.

3.5.1. Type material

Holotype. Uruguay: 1 male, USNM 99846 (Smithsonian National Museum of Natural History), Montevideo and Punta Carretas , 1955 (not accessed).

3.5.2. Material examined

Uruguay: Maldonado: 8 male (CW 10.4 mm, 17.3 mm, 17.5 mm, 17.9 mm, 18.9 mm, 21.6 mm, 28.5 mm, 34.2 mm) and 1 female (CW 11.7 mm), CCDB 6678 , Jose´Ignacio, 34 ◦ 50’45.48"S, 54 ◦ 37’57.77"W, 03.x.2013 .

3.5.3. Diagnosis

Front projected and slightly quadrilobed with a shallow median sinus. Carapace smooth with transverse granulate striations not prominent; carapace regions not raised. First anterolateral tooth separated by a shallow sinus from the second. Tip of the anterolateral teeth rounded in the second, but acute and curved forward in the three posteriors. Upper surface of carpus and propodus of chelipeds finely granulate. Carpal groove absent. Propodus of chelipeds swollen laterally. Dark color of immovable finger invading the palm. Ischium of the third maxilliped with a pigmented spot on the inner surface. Sternites 3 and 4 ornamented with small punctuations; suture between these sternites covered by a continuous fringe of setae. Width of pleonite 6 shorter at the distal end than at the proximal end; length:width ratio of pleonite 6 greater than 0.70; socket of pleonal locking mechanism not reaching the half of pleonite 6. Gonopod apex with trilobed structure, lateral tooth bifid. Vulva less than half the length of the sternite 6; vulva with oval shape.

3.5.4. Distribution

Western Atlantic – Uruguay and Argentina ( Williams, 1983; Spivak and Luppi, 2005).

3.5.5. Variation

The upper surface of the carpus and the propodus of the chelipeds can vary from a very fine granulate pattern, providing a smooth general appearance, to a coarser granulation, giving the surfaces of these articles a rough pattern.

Figures

Fig. 1. Genus Panopeus H. Milne Edwards, 1834. (A) Panopeus americanus Saussure, 1857 (CCDB 2227; CW = 17.8 mm), Rio de Janeiro, Brazil. (B) Panopeus austrobesus Williams, 1983 (CCDB 2240; CW = 13.4 mm), Espírito Santo, Brazil. (C) Panopeus harttii Smith, 1869 (CCDB 2347; CW = 16.1 mm), Cear´a, Brazil. (D) Panopeus lacustris Desbonne in Desbonne & Schramm, 1867 (CCDB 3554; CW =15.3 mm), Bocas del Toro, Panama. (E) Panopeus meridionalis Williams, 1983 (CCDB 6678; CW = 28.5 mm), Maldonado, Uruguay. (F) Panopeus occidentalis Saussure, 1857 (CCDB 2337; CW = 17.8 mm), Cear´a, Brazil. (G) Panopeus rugosus A. Milne-Edwards, 1880 (CCDB 6411; CW = 49.3 mm), S˜ao Paulo, Brazil. Scale bars (mm): A = 8.9; B = 6.7; C = 8; D = 7.6; E = 14.2; F = 4.5; G = 24.6.

Fig. 8. Panopeus meridionalis Williams, 1983. A, D, E, G-I =male (CCDB 6678; CW =28.5 mm), Maldonado, Uruguay; B, C, G, J-L =male (CCDB 6678; CW = 21.6 mm), Maldonado, Uruguay; F = female (CCDB 6678; CW = 11.7 mm), Maldonado, Uruguay. (A) Carapace, dorsal view. (B) Sixth pleonite, view of the external surface. (C) Sixth pleonite, view of the inner surface. (D) G1 apex, mesial lateral view (generated on a stereomicroscope). (E) Third maxilliped, view of the inner surface. (F) Right vulva. (G) Carapace, frontal view. (H) Cheliped, outer view. (I) Front, dorsal view. (J) Anterolateral margin of the carapace, dorsal view. (K) Fourth pereopod, lateral view. (L) Sternites 3 and 4, ventral view. White arrow indicates the pigmented spot on the third maxilliped. Scale bars (mm): A =14; B, C, K =4; D = 0.25; E = 3; F = 0.25; G, H = 7; I = 2; J, L = 5.5.

Fig. 5. Panopeus austrobesus Williams, 1983. A, F, I =holotype male (USNM 59462), Paran´a, Brazil; D, G, J =female (CCDB 2240; CW =13.4 mm), Espírito Santo, Brazil; B, C, E, K, M O = male (CCDB 2599; CW =23.6 mm), Bahia, Brazil; H = male (CCDB 5858; CW =26.9 mm), Pernambuco, Brazil; L =female (CCDB 2599; CW = 26.3 mm); Bahia, Brazil. (A) General dorsal view of Panopeus austrobesus holotype. (B, I) Carapace, frontal view. (C) Anterolateral margin of the carapace, dorsal view. (D) Carapace, dorsal view. (E, F) G1 apex, mesial lateral view (coloured images were generated on a stereomicroscope; grayscale image was produced on a CT-scan equipment). (G) Cheliped, outer view. (H) Third maxilliped, view of the inner surface. (J) Front, dorsal view. (K) Fourth pereopod, lateral view. (L) Right vulva. (M) Sternites 3 and 4, ventral view. (N) Sixth pleonite, view of the inner surface. (O) Sixth pleonite, view of the external surface. White arrows indicate the pigmented spot on the third maxilliped. Scale bars (mm): B = 8; C, M = 6; D = 5; E = 0.25; G, J, K = 3.5; H, N, O = 3; L = 1.

Fig. 2. Map showing the Southwestern Atlantic coast and the approximate localities of the evaluated specimens.

Fig. 3. Illustrated morphological guide for Panopeus diagnostic characters. (A) Carapace in dorsal view with anterolateral teeth and transverse granulate striations. (B) Lateral view of the carpus, propodus and dactyl of right cheliped. (C) Inner surface of third maxilliped. (D) Mesial lateral view of right gonopod with the trilobed apex. Abbreviations: alt, anterolateral tooth; ap, accessory process; cc, carpus of cheliped; cg, carpal groove; dc, dactyl of cheliped; fr, front; itm, ischium of third maxilliped; lt, lateral tooth; mp, median process; msf, median sinus of the front; mtm, merus of third maxilliped; pc, propodus of cheliped; pg, propodal groove; ps, pigmented spot. Scale bars (mm): A =4.5; B = 2; C = 0.25; D = 4.

Fig. 4. Panopeus americanus Saussure, 1857. A, D, E = syntype male (MHNG 16422), Guadeloupe; B, C, F–H, L-N = male (CCDB 2227; CW = 17.8 mm), Rio de Janeiro, Brazil; I =male (CCDB 4445; CW =21.3 mm), Par´a, Brazil; J =male (CCDB 6602; CW =22.6 mm), Maranh˜ao, Brazil; K =female (CCDB 2227; CW =18.2 mm), Rio de Janeiro, Brazil. (A) General dorsal view of Panopeus americanus syntype. (B, D) Front, dorsal view. (C, E) Anterolateral margin of the carapace, dorsal view. (F) Cheliped, outer view. (G) Third maxilliped, view of the inner surface. (H) Fourth pereopod, lateral view. (I) G1 apex, mesial lateral view (coloured image was generated on a stereomicroscope; grayscale image was produced on a CT-scan equipment). (J) Carapace, dorsal view. (K) Right vulva. (L) Carapace, frontal view. Blue arrow indicates the carpal groove. (M) Thoracic sternum and pleon, carapace ventral view. (N) Sixth pleonite, view of the inner surface. Scale bars (mm): B, L = 2; C, F = 5.5; G, N = 2; H = 2.5; I = 0.25; J = 11; K = 0.5; L, M = 4.