Minuca genus

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

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Figure 015. Minuca burgersi

5-2025

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).
Figure 016. Minuca longisignalis

5-2025

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.
Figure 017. Minuca marguerita

5-2025

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).
Figure 018. Minuca minax

5-2025

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).
Figure 019. Minuca mordax

5-2025

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).
Figure 20. Minuca panema

5-2025

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).

This is a composite image of the Leptuca cumulanta fiddler crab. It is a part of the parentFiddler Crabs Image Gallery (URL: https://scholarworks.uni.edu/fiddlercrabs/) collection at the University of Northern Iowa, which has images of Fiddler Crabs located in the Atlantic Ocean and the Gulf of Mexico from the following genera:Afruca,Leptuca,Minuca, andUca.
Figure 21. Minuca pugnax

5-2025

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).
Figure 22. Minuca rapax

5-2025

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).
Figure 23. Minuca vicoriana

5-2025

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).
Figure 25. Minuca vocator

5-2025

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).