Fiddler Crabs Image Gallery

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  Figure 001. Composite Distribution Map for 23 Atlantic Fiddler Crab Species

  5-2025
  

  Composite Distribution Map for 23 Atlantic Fiddler Crab Species (Finke 2024).

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  Figure 002. Anatomical Features of the Fiddler Crab

  5-2025
  

  Anatomical features of the fiddler crab: (a) major chela, inner view; (b) major chela, outer view; (c) dorsal view of carapace; (d) view of interocular region; (e) frontal view, and (f) leg of a crab. (Modified from George and Jones 1982).

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  Figure 003. Afruca tangeri

  5-2025
  

  Alt Text: Composite photograph of the Afruca tangeri fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 3. Afruca tangeri (Eydoux, 1835). UNI 140. Collected: Aug 1974, Eastern Atlantic Ocean, Morocca, El Ribia, Oued ouner. Range: southern Portugal to Angola (33.315792, -8.337627). Scale bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Large species (width < 48 mm). Carapace length 74.8% width; frontal 17.5% carapace width (Fig. 3D). Carapace almost square with large tubercles (Fig. 3A). Eyestalks thick and moderate in length (Fig. 3D). Anterolateral junction with small point, curved inward (Fig. 3A). Dactyl and pollex much longer than manus (Fig. 3C). Pollex wider than dactyl with two central tubercles (Fig. 3C). Walking legs with dense setae (Fig. 3E). Merus width about 44% width. Only species along eastern Atlantic shore from Portugal to Angola (Fig. 3G).

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  Figure 004. Uca major

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  Alt Text: Composite photograph of the Uca major fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 4. Uca major. (Herbst, 1782). UNI 29. Collected: 19 July 2007, Bahamas, San Salvador, Pigeon Creek, Eastside Quarry (23.981211, -74.486231). Scale Bar = 10 mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).:

  Species Description: Large species (width < 35 mm). Carapace smooth, carapace length 55% width (Fig. 4A). Frontal region less than 9.4% carapace width (Fig. 4A,D). Eyestalks very long and slim (Fig. 4D). Lower orbit dentations square (Fig. 4D). Anterolateral angle forming sharp, outward-pointing spine. Dactyl and pollex almost same width (Fig. 3B), gap when large cheliped closed. Lower edge of manus with role of uniform-sized tubercles (Fig. 4B,C). Terminus of pollex with sharp spine. On walking legs, merus width is 35% of length. Very few setae in walking legs (Fig. 4E). Found in eastern Mexico, the Caribbean and northern South America (Fig. 4G).

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  Figure 005. Uca maracoani

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  Alt Text: Composite photograph of the Uca maracoani fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 5. Uca maracoani (Latreille, 1802-1803). UNI 40. Collected: 20 July 2010, southwestern Atlantic Ocean, Brazil, Maranhão, São Luis, Praia da Raposa, Rio Munin (-2.415758, -44.100823). Range: Trinidad-Tobago to Paraná, Brazil. Space bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Large species (width < 45 mm). Carapace granular, carapace length 68.7% width (Fig. 5A); female 72%, male 68%. Eyestalk very long and thin. Frontal region 9.6% carapace width (Fig. 5A,D). Suborbital margin with small, square, dentate tubercles (Fig. 5D). Anterolateral angle sharp, pointing outward. Both dactyl and pollex very broad, no large gap when closed (Fig. 5B,C). Terminus of dactyl and pollex both with sharp spines (Fig. 5C). Ventral manus with very large tubercles (Fig. 5B). Walking legs with few setae. Merus width 43.7% length. Found along the Atlantic coast of South America from Trinidad-Tobago to Florianopolis, Brazil (Fig. 5G). Not widely known in Caribbean. Very old AMNH (#2466) specimen from the Dominican Republic.

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  Figure 006. Leptuca cumulanta

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  Alt Text: Composite photograph of the Leptuca cumulanta fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 6. Leptuca cumulanta (Crane, 1943). UNI 732. Collected: 30 July 2018, North Atlantic Ocean, Guyana, East Demerara, Pigeon Island (LBI), mud on canal and mangroves (6.81521, -58.06480). Space bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Small species (width < 16 mm). Carapace shiny, smooth and strongly convex but not cylindrical (Fig. 6A). Carapace length 64% width. Frontal region 26% carapace width (Fig. A,D). Eyestalks short and thick. Anterior lateral margins straight and parallel (Fig. 6A). Dactyl and pollex of cheliped about same length as manus (Fig. 6 B, C). Tubercles line gap, pollex lined fully with tubercles, serrate elevation near distal end. Fused tubercles forming larger tooth near mid-line of pollex. Proximal edge of dactyl with large tubercles. Tip of dactyl pointed down and over hanging pollex, gap large (Fig. 6B,C). Oblique ridge on inner cheliped for tubercle carina following front edge of carpal cavity (Fig. 6C). Walking legs without many setae (Fig. 6E). Merus width averages 43% length: female 49%, male 40%. Found in southern Caribbean and coast on South American south to the states of Rio de Janeiro and Sao Paulo (Fig. 6G). This may be an invasive species moving southward.

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  Figure 007. Leptuca leptodactyla

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  Alt Text: Composite photograph of the Leptuca leptodoctyla fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 7. Leptuca leptodactyla (Rathbun, 1898). UNI 20. Collected: 11 May 2003, USA, Puerto Rico, Catano, Canal Rio Bayamon, mouth (18.4467997, -66.1597323). Scale Bar= 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Very small species, (width < 12 mm). Carapace smooth, cylindrical; widest at antero-lateral junction (Fig. 7A). Carapace length 60% width; frontal region about 29% carapace width (Fig. 7A,D). H-depression shallow. Eyestalks short. Dactyl and pollex of large cheliped very long compared to manus, large gap (Fig. 7B,C). Two tubercles in middle of dactyl, large proximal to articulation. Pollex with numerous small tubercles. Oblique ridge on inner surface of manus with large tubercles (Fig. 7C). Third to sixth abdominal segments (pleons) of male fused. Walking legs with few setae (Fig. 7E). Merus width of walking legs 32% length. Pan-tropical in the Caribbean and along the coast of South America. No records between southern Trinidad-Tobago to Sao Luis, Maranhão, Brazil (Fig. 7G).

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  Figure 008. Leptuca Panacea

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  Alt Text: Composite photograph of the Leptuca panacea fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 8. Leptuca panacea (Novak and Salmon, 1974) UNI 882. Collected: Gulf of Mexico, United States, Florida, Wakulla Co., Panacea, Mashes Island (30.016905; -84368426). Range: West Florida to Campeche, MX. Scale bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024

  Species Description: Moderate-sized (width < 25 mm). Carapace globular, length 71 % width. Frontal region about 37% carapace with. Eyestalk short. When carapace dried, it appears dull or matt. Antero-lateral angle sharp and pointed forward. Anterior lateral margins straight but strongly curved in posterior. Dactyl and pollex equal to or longer than manus. Gap very large, few large tubercles on dactyl, 4-6 larger tubercles on pollex. Both dactyl and pollex thin. End of pollex sharp hook. Dactyl overlaps end of pollex when closed. Distinct row of evenly spaced tubercles on pollex at proximal end of gap. No oblique tubercle ridge across inner surface of lower manus. Inner palmar surface with large evenly space tubercles. Walking legs thin with few long setae. Merus width 33% length: female 34%, male 30%. Found along western Gulf of Mexico from Panacea, Wakula Co., FL, USA to Sabancuy, Campeche, Mexico (Fig. 8G).

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  Figure 009. Leptuca pugilator

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  Alt Text: Composite photograph of the Leptuca pugilator fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 9. Leptuca pugilator (Bosc, 1802). UNI 397. Collected: 14-Aug-2005, USA, Florida, St. Joseph Peninsula State Park, near boat ramp on bay (29.764246, -85.402083) Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate-sized (< 26 mm). Carapace length 71% width; frontal region about 37% carapace width (Fig. 9A, D). Eyestalks short. Dry carapace appears glossy; strongly convex (Fig. 9A). Antero-lateral angle weak and curved inward. Lateral lines curved (Fig. 9A). Dactyl and pollex longer than manus (Fig. 9B,C), both are broad, blade-like. Dactyl with more or less evenly distributed tubercles. Pollex with four large tubercles distributed distally (Fig. 9C). On inner surface long row of tubercles extend from near tip to articulation of dactyl (Fig. 9C). Distal tip of pollex serrated and angled. Distal dactyl overlaps end of pollex (Fig. 9c). No oblique tubercle ridge across inner surface of lower manus (Fig. 9C). Walking legs thin with a few long setae (Fig. 9E). Merus width 33% length: female 35%, male 31%. Distribution (Fig. 9G) entirely within USA from Cape Cod Bay, Massachusetts to Pensacola, Florida.

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  Figure 010. Leptuca speciosa

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  Alt Text: Composite photograph of the Leptuca speciosa fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 10. Leptuca speciosa (Ives, 1891). UNI-93. Collected: 4 September 1976, Mexico, Yucatan, Harbor, West of Progresso (21.277956, -89.703382). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Small species (< 16 mm). Carapace length 69% width; frontal region about 37% of carapace width (Fig. 10A,D). Eyestalks short. Carapace widest at antero-lateral angle (Fig. 10A). Anterolateral angles pointed forward. Anterior lateral margins straight and parallel. Carapace surface often smooth but may have W-shape arrangement of pubescence on posterior carapace (Fig. 10A). Dactyl and pollex much longer than manus (Fig. 10 B,C). Gape wide. Dactyl overlaps distal pollex with few tubercles lining dactyl and pollex. Distal pollex pointed (Fig. 10C). On inner manus, tuberculated, oblique ridge prominent (Fig. 10C). Walking legs with some setae (Fig. 10E). For walking legs, thick pile on dorsal surface of dactyl and propodus. Merus width 34% length; female 30%, male 36%. Inhabiting coast of Mississippi, Florida, Bahamas Cuba and the Yucatan peninsula in Mexico (Fig. 10G).

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  Figure 011. Leptuca spinicarpa

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  Alt Text: Composite photograph of the Leptuca spinicarpa fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 11. Leptuca spinicarpa (Rathbun, 1900). UNI 590. Collected: 22-Jun-2011, USA, Alabama, Mobile Co., East Dauphin Island, Causeway (30.31233, -88.13845). Scale Bar =10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Spine (s) on the carpus of male. (G) Color Photo. (H) Distribution Map (Finke 2024).

  Species Description: Description. Moderate-sized species (width < 22 mm). Carapace length 68% width; frontal region about 34% carapace width (Fig. 11A,D). Eyestalks short. Carapace surface smooth but textured (Fig. 11A). H- depression prominent, very little pubescence on carapace. Carapace widest at antero-lateral angle. Lateral margins straight and parallel (Fig. 11A). Dactyl and pollex longer than manus (Fig. 11B,C). Gap large, small tubercles line dactyl and pollex. Most of large cheliped outer surface smooth. Pollex very straight. Obliques ridge of tubercles on inner surface of manus raised forming right angle in carpal cavity (Fig. 11C). Line of tubercles following gap margin on inner pollex. Carpus after large cheliped in male with prominent spine (Fig. 11Cs,Fs). Walking legs moderately setose, very little pubescence on dactyl and propodus (Fig. 11E). Merus width 41% length. Distributed along west coast of Gulf of Mexico from west Florida to the state of Tabasco, Mexico (Fig. 11H).

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  Figure 012. Leptuca subcylindrica

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  Alt Text: Composite photograph of the Leptuca subcylindrica fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 12. Leptuca subcylindrica (Stimpson, 1859). UNI 98. Collected: July 1995, USA, Texas, Kleberg Co., Kingsville, under US 77 bridge over Santa Gertrudis Creek (27.47677, -97.855088). Space Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate sized (width < 25 mm). Carapace length 66% width (Fig. 12A). Frontal regions about 37% carapace width (Fig. 12A, D). Short eyestalks. Branchial region of carapace appears swollen. Carapace widest just posterior to antero-lateral angle. Antero-lateral margins strongly curved (Fig. 12A). Large cheliped with dactyl and propodus about same length as manus, gap large (Fig. 12B,C). Dactyl overhangs terminus of pollex. Pollex with prominent suture below dactyl articulation (Fig. 12B). Tubercles on dactyl and pollex large. Inner manus with no oblique ridge of tubercles (Fig. 12C). Line of tubercles extends from tip of pollex along gap up to the articulation junction. Walking legs with extremely numerous long setae(Fig. 12E). Merus width 40% length. Species restricted to sub-arid coastal areas of the Laguna Madre system between Refugio Co., Texas in USA and Altamira, Lomas del Real, Tamaulipas, Mexico (Fig. 12G).

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  Figure 013. Leptuca thayeri

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  Alt Text: Composite photograph of the Leptuca thayeri fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 13. Leptuca thayeri (Rathbun, 1900). UNI 151. Collected: June- 2003, USA, Florida, Monroe Co., Chokoloskee Bay, West Everglades (25.818773, -81.359583). Scale Bar = 10 mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Large species (width < 30 mm). Carapace shape near trapezoidal (Fig. 13A). Carapace length 66% width; frontal region 22% carapace width (Fig. 13A, D). Eyestalks moderate length. Lateral sides strongly angled inward Fig. 13A). Tufts of pubescence scattered along dorsal lateral margins. Dactyl and pollex 50% to 80% longer than manus (Fig. 13B,C). Pollex usually straight or bent downward, slightly (Fig. 13B). On inner surface of large cheliped, line of oval tubercles follow gap at edge of pollex (Fig. 13C). Gap moderately wide. Oblique ridge progresses to carpal cavity. It turns and follows carpal cavity a short distance. Merus segments of walking leg unusually wide; width (Fig. 13E). Merus width about 50% length; 56% in females, 47% in males. Pantropical species, found from south Florida and Yucatan peninsulas to Florianopolis, Brazil (Fig. 13G).

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  Figure 014. Leptuca uruguayensis

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  Alt Text: Composite photograph of the Leptuca uruguayensis fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 14. Leptuca uruguayensis (Nobili, 1901). UNI 63. Collected: Jan-2011, Argentina, Provincia Buenos Aires, Mar Chiquita, Arroyo sur (-37.746733, -57.433427). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Small species (width < 17 mm). Carapace wider than long, very convex (Fig. 14A). Carapace length 63% width. Front 25% carapace width. Eyestalks short. Antero-lateral angle sharp and pointing outward. Anterio-lateral margins short and parallel (Fig. 14A). Lateral margin converging in posterior. Dactyl and pollex of large cheliped longer than manus (Fig. 14B,C). Dactyl with 4-5 evenly spaced large tubercles. Gap wide. Inner manus with clear oblique ridge of large tubercles that terminate at the edge of the carpal cavity. Few setae on walking legs (Fig. 14e). Merus width 37 % length. Found from Cabo Frio, Rio de Janeiro to northern Argentina (Fig. 14G).

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  Figure 015. Minuca burgersi

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  Alt Text: Composite photograph of the Minuca burgersi crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map

  Composite Image Description: Figure 15. Minuca burgersi (Holthuis, 1967)*. UNI 207. Collected: 25-Nov-2008, USA, Puerto Rico, Toa Baja, Rio La Plata, mouth (18.4660138, -66.1999654). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate-sized species (< 20 mm). Carapace length about 65% width, frontal region 34% width (Fig. 15A). Carapace convex with shape almost trapezoidal or hexagonal. Surface smooth but uneven. Post-orbital depression deep. Antero-lateral angle pointed forward. Antero-lateral margins curving inward. Postero-lateral margins curving to midline. Manus finely granular. Dactyl and pollex blade-line, about same length as manus (Fig. 15B,C). Gap wide. Pollex nearly straight in larger specimens, single large tubercle at mid-length. Dactyl with moderate sized tubercles, four proximal and one distal. On inner manus, oblique ridge high terminating in carpal cavity, no carina lining (Fig. 15C). Carina following dorsal edge of cavity, distal end flexed toward dactyl articulation. Two pre-dactyl ridges present, lower ridge diverging outward then bend back toward articulation. On walking legs, merus width 37% length (Fig. 15E). Pubescence on dorsal surface of carpus and propodus, very few setae. Species is primarily distributed in eastern Mexico, central America, northern South America and Caribbean including south Florida (Fig. 15G). *This species is morphologically identical to Minuca panema (Coelho, 1972). Species best distinguished based on collecting location and DNA sequencing (Thurman et al. 2023).

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  Figure 016. Minuca longisignalis

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  Alt Text: Composite photograph of the Minuca longisignails fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map

  Composite Image Description: Figure 16. Minuca longisignalis (Salmon and Atsaides, 1968). UNI 247. Collected: 20-Jun-2002, USA, Alabama, Baldwin Co., Mobile Bay, Tenesaw River at I-10 bridge (30.67395, -87.95417). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Comparison of legs between M. minax and M. longisignalis. (G) Color Photo. (H) Distribution Map (Finke 2024).

  Species Description: Large species < 25.6 mm. Carapace length about 67% width. Frontal region about 38% carapace width. Surface finely granular. H-depression shallow; cardiac-mesogastric region slightly swollen. Dactyl and pollex, wide; slight longer than manus. Gape wide; dactyl with four larger proximal tubercles; pollex with two large tubercle, on at mid-length the other near terminus. Outer manus with fine tubercles. No red pigment in articulations. On inner manus, oblique ridge highly developed near carpal cavity. Line of tubercles on inner pollex from distal tip to articulation. Line bifurcates at base of articulation. On walking legs, merus wide; width 43% of length. Ventral margin with a few long setae, marginal pile and pubescence. Species found only along the northern coast of the Gulf of Mexico between the Rio Grande in Texas and Cedar Key, Levi Co., Florida (Fig. 16H). This species is often confused with Minuca minax. A walking leg from M. longisignalis and are compared in Fig. 16F.

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  Figure 017. Minuca marguerita

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  Alt Text: Composite photograph of the Minuca marguerita fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 17. Minuca marguerita (Thurman, 1981). UNI 33. Collected: December 1972, Mexico, Tamaulipas, Tampico, Rio, Panuco, riverbank near ferry (22.245792, -97.82552). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate-sized crab (< 25mm). Carapace length 66% of width; surface finely granular and pitted (Fig. 17A). Frontal region 31% carapace width. Antero-lateral angle pointed forward. H-depression prominent. Posterior lateral margins curving to midline. Dactyl and pollex about same length as manus (Fig. 17B). Gap wide. Pollex with two large tubercles; one central second near terminus (Fig. 17C). Manus covered with fine tubercles. On inner manus, obliques ridge developed near carpal cavity but weak distally (Fig. 17C). Ridge comes to peak at carpal cavity then a line of tubercles follows outer edge of cavity up to dorsal edge. Another prominent row of tubercles extends forward toward base of dactyl. On walking legs, merus width 40 % of length (Fig. 17E). Dorsal margin of walking legs slightly convex with short setae. Some pubescence on manus segment. Species endemic to eastern Mexico between Laguna Largo, Tamaulipas and Rio Champotón, Campeche (Fig.17G).

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  Figure 018. Minuca minax

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  Alt Text: Composite photograph of the Minuca minax fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 18. Minuca minax (LeConte, 1855). UNI 562. Collected: Gulf of Mexico, United States, Louisiana, Iberia Parish, Louisa, intracoastal canal bridge on HWY 319 (29.771180, -91.784839). Range: East coast of United States (Cape Cod, MA to northeast Florida) and Gulf coast (west Florida to east Texas). Scale bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Comparison of legs between M. minax and M. longisignalis. (G) Color Photo. (H) Distribution Map (Finke 2024).

  Species Description: Large species < 39 mm; carapace length 69% width. Frontal region about 40% carapace width (Fig. 18A). Eyestalks very short. Antero-later angle not sharp and turned inward. Lateral margins strongly curve to mid-line of carapace. Dactyl and pollex very thick, heavy appearing (Fig. 18B, C). Articulation joints usually with red pigment (Fig. 18G). Gap large. Dactyl with numerous tubercles along length. Pollex with large central tubercle. Tubercles at distal end forming trifurcation. Upper manus with very large tubercles. Inner manus with definite oblique ridge with tubercles to carpal cavity (Fig. 18C). Ambulatory legs with slim merus; width 39% length. Dorsal surface with thick pile or pubescence. Ventral surface without pile or bristles but numerous long setae (Fig. 18E,F). Species distribution within USA along both Atlantic and Gulf of Mexico coasts (Fig. 18H). In the northern Gulf of Mexico, this species is often confused with M. longisignalis. M. longisignalis has wider merus and pubescence and pile on underside merus (Fig. 18F). Oblique ridge is more distinct in M. minax (Fig. 18C).

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  Figure 019. Minuca mordax

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  Alt Text: Composite photograph of the Minuca mordax fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 19. Minuca mordax (Smith, 1870). UNI 726. Collected: 12 March 2018, Atlantic Ocean, Trinidad and Tobago, Cocos Bay, Narvia Co., Bush-Bush Wildlife Sanctuary, Mouth Navet River (10.39862, -61,02523). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Species moderate-sized (< 26mm). Carapace smooth without pubescence or pile (Fig. 19A). Length 70% width; frontal region about 40% carapace width. Eyestalks very short. Antero-lateral margins converging to midline. Posterior lateral line strongly converging giving carapace a trapezoid shape. Dactyl and pollex longer than manus (Fig. 19B,C). Gap about same width as base of pollex. Distal dactyl overlaps pollex. Dactyl with low tubercles; one large tubercle at mid-length. Pollex with single large tubercle near mid-length, terminus trifurcated. On inner manus, oblique ridge distinct but tubercles not arranged in a single row. Where ridge meets carpal cavity there are several prominent tubercles. No carina along carpal cavity. Merus of walking legs with pubescence and long setae (Fig. 19A,E). Merus width 33% length. First walking leg with pubescence completely surrounding carpus and propodus (Fig. 19E). Pantropical species collected between the Sittee River, Freetown Area, Belize and Mampituba River, Torres, Rio Grande do Sul, Brazil. Not found on Caribbean islands (Fig. 19G).

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  Figure 20. Minuca panema

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  Alt Text: Composite photograph of the Minuca panema fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 20. Minuca panema (Coelho, 1972). UNI 721. Collected: March 13, 2018, Caribbean Sea, Trinidad and Tobago, St. Ann’s Co., Maracas Bay, Burro River (10.75943, -61.44206). (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate-sized species (width < 19mm). Carapace length 68% width; frontal region 37% carapace width. Eyestalks short. Carapace widest posterior to frontal margin (Fig. 20A). Antero-lateral angle about 90°. Carapace smooth, convex and trapezoidal, < 20 mm. Lateral margins curve strongly to midline. Dactyl and pollex about same length as manus. Gap wide. Dactyl with two larger tubercles: one proximal the other distal (Fig. 20B,C). Pollex with larger tubercles distally. Inner surface of major cheliped with carina of tubercles lining dorsal edge of carpal cavity (Fig. 20C: ). Carina often ending in a patch of tubercles with upper row pointed to dactyl. A smooth triangular area above the carina terminus. Lower edge of carpal cavity with apex of tubercles at proximal end of oblique ridge (Fig. 20C). Distally oblique ridge across palm undeveloped. Dactyl joint with row of 5–8 tubercles (Fig. 20C). Lines of tubercles on pre-dactyl and articulating ridges not parallel. Predactyl ridge forming crescent arch initially extending toward palm but returns to articulation. On walking legs, merus width 37% length. Dorsal surface of dactyl without pubescence (Fig. 20E). No pubescence on ventral surface of manus, carpus or dactyl. Long setae plentiful on manus but sparse on merus of walking legs. Found from southern Trinidad to and Florianopolis in South America (Fig. 20G). This species is morphologically identical to Minuca burgersi (Holthuis, 1967). Species best distinguished based on collecting location and DNA sequencing (Thurman et al. 2023).

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  Figure 21. Minuca pugnax

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  Alt Text: Composite photograph of the Minuca pugnax fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 21. Minuca pugnax (Smith, 1870). UNI 358. Collected: 15-Jul-2001, USA, Massachusetts, Lloyd Center, near Slocum River (41.5271500, -70.9832668). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate sized (< 20 mm). Carapace length 65% width; frontal region 38% carapace width. Eyestalks very short. Carapace smooth and swollen (Fig. 21 A). Antero-lateral margins curving inward, postero-lateral margin curving strongly toward center line. Dactyl and pollex blade-like and longer than manus (Fig. 21B,C). Distal dactyl overlapping pollex, a set of 3-4 large tubercles proximal near articulation (Fig. 21 C). Pollex almost straight with a central cluster of tubercles. Inner manus with strong oblique ridge converging at apex on carpal cavity (Fig. 21C). Carina of tubercles following cavity up to superior edge of cavity. Strong line of tubercles following gap to articulation. Merus of walking legs thin (Fig. 21 E); width 37% length with some pubescence and long setae. Found within the USA along Atlantic coast from northeast Florida to Cape Cod Bay, Massachusetts (Fig. 21 G).

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  Figure 22. Minuca rapax

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  Alt Text: Composite photograph of the Minuca rapax fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 22. Minuca rapax (Smith, 1870)*. UNI 478. Collected: 5- Sep- 1976, Mexico, Yucatan, San Felipe, Boca del Rio Lagartos, near military base (21.594013, -88.161615). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Large species (width < 32 mm). Carapace length 63% width; frontal region 31% carapace width (Fig. 22A). Eyestalks short. Carapace surface rough appearing with small tubercles but no pits. Anterolateral angles pointed inward slightly. Intersection of anterolateral and posterolateral lines forming smooth curve. Major cheliped with ridge on dorsal surface (Fig. 22A). Dactyl and pollex blade-like (Fig. 22B,C). Gap wide. Pollex with mid length large tubercle and terminus trifurcated. Dactyl with 3–4 larger tubercles proximal to articulation. Inner surface of cheliped with carpal carina terminating abruptly in palm (Fig. 22C). Predactyl ridge parallel to row of tubercles on dactyl articulating joint (clearly not curved toward palm and carpal cavity). Oblique ridge simple line of tubercles running from carpal cavity to ventral edge of manus. Proximal apex not prominent. On ambulatory legs, merus width 37% length, dorsal and lateral surfaces with pubescence and long setae (Fig 22A,E). Ventral surface no pubescence or long setae. Pantropical species, found from south Florida and Tabasco, Mx to Florianópolis, Santa Caterina, Brazil (Fig. 22G). * This is species is morphologically indistinguishable from Minuca virens (Fig 24).

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  Figure 23. Minuca victoriana

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  Alt Text: Composite photograph of the Minuca victoriana fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 23. Minuca victoriana (von Hagen, 1987). UNI 168. Collected: 9 July 2009, Brazil, Espirito Santo, Vitoria, Bairro Joana D’arc mangroves (-20.283984, -40.305919). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate sized (width < 15 mm). Carapace length 59% of width (Fig. 23A). Frontal region 33% carapace width. Eyestalks short. Surface of carapace smooth, shiny and finely granular. H-depression deep with pubescence in lateral sulcus. Carapace surface irregular near anterolateral margin. Anterolateral angles pointing outward (Fig. 23A). Intersection of lateral and posterolateral margins form sharp obtuse angle. On major cheliped, dorsal surface with ridge (Fig. 23A). Moderate-size tubercles decreasing in size toward ventral manus (Fig. 23B). A triangular depression with pubescence dorsal to origin of pollex (Fig. 23B). Dactyl and pollex blade-like, gap large (Fig. 23B, C). Dactyl articulation without tubercles. Pollex with one large tubercle in gap. Gap wide. Dactyl with several larger tubercles proximal to articulation in gap with a single large distal tubercle. On inner surface, dorsal carina of carpal cavity with elongate tubercles, terminus trifurcated (Fig. 23C). Carina extends around distal cavity margin to prominent tubercles at proximal end of oblique ridge. Structure sharply defined with clearly separate tubercles. Pre-dactyl tubercle ridge parallel to dactyl articulation. Tubercles on dactyl articulation fused. Dorsal surface of carpus in cavity with no large teeth. Merus width of ambulatory legs 1–3 about 29% length (Fig. 23E). Dorsal merus and carpus with pubescence and long setae. No setae or pubescence on ventral merus of ambulatory legs. Endemic to the coast of Brazil from Fortaleza, Ceará to Bertioga, São Paulo (Fig. 23 G).

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  Figure 24. Minuca virens

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  Alt Text: Composite photograph of the Minuca virens fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 24. Minuca virens (Salmon and Astaides, 1968). UNI 457. Collected 22 April 1977, USA, Texas, San Patricio Co., Corpus Christi Bay, Ingleside Cove (27.837838, -97.220076). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: M. virens is a cryptic species closely related to M. rapax. There is no taxonomic character to distinguish M. virens from M. rapax. Some variation exists in morphological and behavioral characters, but they are not discrete nor consistent enough to be dependable diagnostics. However, differential growth of anatomical structures appears to vary between Gulf and other population of M. rapax. However, the morphologically cryptic M. virens can be identified as a molecular operational taxonomic unit (Morard et al. 2016) due to its unique DNA sequences. Clearly, M. virens is an evolutionarily significant unit (Chu et al. 2015) geographically separated from the more widely distributed M. rapax complex. Since M. virens offspring are not apparently dispersed widely by tidal and ocean currents, successive generations appear to have inbred while surviving stressful environmental pressures. Thus, they have become genetically distinct from ancestral M. rapax populations. It is notable that the split between the current M. rapax and M. virens was around 2mya (Thurman et al. 2018). Fig. 24G illustrates the distribution of M. virens is in the north and western Gulf of Mexico. Fig. 24 F is the typical color of live M. virens.

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  Figure 25. Minuca vocator

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  Alt Text: Composite photograph of the Minuca vocator fiddler crab which includes several black & white images of different views of the crab, a color photograph, and a distribution map.

  Composite Image Description: Figure 25. Minuca vocator (Herbst, 1804). UNI 698. Collected: April 2011, Mexico, Veracruz, Laguna Tamiahua-intracoastal Canal (20.96569, -97.31073 to 22.10059, -97.77755). Scale Bar = 10mm. (A) Dorsal view. (B) Front view. (C) Inner cheliped. (D) Ocular view. (E) Ambulatory. (F) Color Photo. (G) Distribution Map (Finke 2024).

  Species Description: Moderate-sized species (< 25 mm). Carapace moderately convex with conspicuous patches and lines of pile (Fig. 25A). Carapace length 70% width; frontal region about 36% carapace width. Antero-lateral margins curving inward; anterolateral angle blunt. Postero-lateral margins strongly inward. Large cheliped appears elongated in comparison to width (Fig. 25B). Dactyl and pollex longer than manus, blade-like. Gap large, terminus of dactyl overhangs pollex. Tubercles on dactyl gap mostly small; a single large tubercle on proximal third. Pollex with two tubercles located distally (Fig. 25B,C). Tip of pollex trifurcated. Oblique ridge on inner manus poorly developed, apex at carpal cavity forming “knob-like” structure (Fig. 25C). On walking legs, merus is broad (Fig. 25E); width 40% length. Pubescence and long setae present on upper surface of propodus and carpus (Fig. 25A). Pantropical species collected between Nueces Co, Texas, USA and Santos in Sao Paulo, Brazil (Fig. 25G).