Panopeus lacustris Desbonne, 1867

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

3.4. Panopeus lacustris Desbonne in Desbonne & Schramm, 1867

( Fig. 1D , 7 A-H)

Panopeus lacustris Desbonne and Schramm, 1867: 28 ; Williams, 1983: 868, Fig. 4 ; Abele and Kim, 1986: 51; Melo, 1996: 373; Schubart et al., 2000: 13; Barros and Pimentel, 2001: 30; Almeida et al., 2006: 14; Coelho et al., 2008: 34 ; Ng et al., 2008: 191; Felder et al., 2009: 1082; Thoma et al., 2014: 96; Sousa et al., 2015: 341; Mantelatto et al., 2020: 75 .

Panopeus herbstii Gibbes, 1850: 176 (part); Smith, 1869a: 276 (part); Smith 1869b: 34 (part); von Martens, 1872: 89; Verrill, 1908: 547 (part); A. Milne-Edwards, 1880: 13; Kingsley, 1880: 393 (part); Rathbun, 1898: 772 (part); Benedict and Rathbun, 1891:358 (part); Young, 1900: 132; Gundlach et al., 1917: 564, Fig. 16; Rathbun, 1900: 14; Rathbun, 1930: 336, pl. 157, Fig. 3 ; Rathbun, 1933: 61, Fig. 53; Holthuis, 1959: 207; Coelho, 1966: 163; Fausto Filho, 1966: 33; Chace and Hobbs, 1969: 154,

Fig. 46c e 47; Coelho, 1971: 283; Coelho and Ramos, 1972: 190; Markham and McDermott, 1981: 1273; Williams, 1984: 412 (part).

Panopeus herbstii var. obesus Smith, 1869a, 278 (part).

Panopeus herbstii granulosus A. Milne-Edwards, 1881: 309 ; Benedict and Rathbun, 1891: 383; Young, 1900: 134.

Panopeus crassus A. Milne-Edwards, 1880: 313 , pl. 57, Fig. 1 and 1a ; Benedict and Rathbun, 1891: 383.

Eurypanopeus herbstii Rathbun, 1898: 18 .

Eupanopeus herbstii Rathbun, 1898: 273 ; Rathbun, 1900: 140; Rathbun, 1901: 28.

Panopeus herbstii obesus Young, 1900: 134 .

E. herbstii , var. or subspecies, minax Verrill, 1908: 348, Fig. 15, pl. 5,

Fig. 2.

3.4.1. Type material Not available. Type-locality: Guadeloupe: Caribbean Sea .

3.4.2. Material examined

Panama: Bocas del Toro: 1 female (CW 15.3 mm), CCDB 3554 , Bocas del Toro, 09 ◦ 21.06’N, 82 ◦ 15.43’W, 01.viii.2011 .

3.4.3. Diagnosis

Front slightly quadrilobed with outer lobes little prominent and shallow median sinus. Carapace smooth on its dorsal surface, with transverse granulate striations not outstanding; carapace regions not raised. Anterolateral teeth of carapace not prominent; first and second separated by a shallow sinus; third similar to the homologous in P. austrobesus , but more triangular and less sub-quadrate than in other species; fourth and fifth notably triangular. Carpus of the chelipeds smooth and without remarkable groove. Pigmented spot on the inner surface of third maxilipeds. Trilobed gonopod apex present. Vulva less than half the length of the sternite 6; vulva with circular shape.

3.4.4. Distribution

Western Atlantic – Bermuda, United States (from Georgia to Florida), Antilles, Costa Rica, Panama and Brazil (Par´a, Maranh˜ao, Piauí, Rio Grande do Norte, Pernambuco, Alagoas, Bahia, Rio de Janeiro, S˜ao Paulo) (Santos Filho et al., 2017; Mantelatto et al., 2020).

3.4.5. Variation

Some specimens present a flattening near the distal margin of the carpus of chelipeds similar to that which occurs in P. austrobesus .

3.4.6. Remarks

Despite the investigation of a large number of individuals sampled from the Brazilian coast, no specimens were identified as P. lacustris . After our integrative analysis, even some individuals which were previously labelled as P. lacustris had their identifications rectified to P. austrobesus . These observations point to a doubt on the occurrence of this species along the Brazilian coast. The corroboration of this hypothesis requires expanding the sample size of material evaluated from other collections.

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. 7. Panopeus lacustris Desbonne in Desbonne & Schramm, 1867. A-H =female (CCDB 3554; CW =15.3 mm), Bocas del Toro, Panama. (A) Carapace, dorsal view. (B) Third maxilliped, view of the inner surface. (C) Front, dorsal view. (D) Anterolateral margin of the carapace, dorsal view. (E) Cheliped, outer view. (F) Right vulva. (G) Carapace, frontal view. (H) Fourth pereopod, lateral view. White arrow indicates the pigmented spot on the third maxilliped. Scale bars (mm): A =7.5; B, H = 2; C = 1.5; D = 4; E = 5.5, F = 0.25; G = 3.

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.

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