Leptuca genus

This University of Northern Iowa collection contains composite photographs of the Leptuca genus of fiddler crabs. The collection is a subset of the parent Fiddler Crabs Image Gallery.

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Figure 006. Leptuca cumulanta

5-2025

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.
Figure 007. Leptuca leptodactyla

5-2025

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).
Figure 008. Leptuca Panacea

5-2025
Figure 009. Leptuca pugilator

5-2025

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.
Figure 010. Leptuca speciosa

5-2025

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).
Figure 011. Leptuca spinicarpa

5-2025

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).
Figure 012. Leptuca subcylindrica

5-2025

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).
Figure 013. Leptuca thayeri

5-2025

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 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).
Figure 014. Leptuca uruguayensis

5-2025

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).