Minuca longisignalis

Salmon & Atsaides, 1968

longwave gulf fiddler, Gulf Marsh Fiddler Crab

Minuca longisignalis, formerly Uca longisignalis, is a fiddler crab to Gulf of Mexico salt marshes. It exhibits striking reproductive seasonality characteristic of warm-temperate lineages, with ovigerous females appearing no earlier than April and peak ovigery in June. The constructs burrows in vegetated marsh areas, with burrow and depth varying by elevation and distance from shoreline. It co-occurs with such as Uca spinicarpa, though shows substrate preferences for different clay compositions.

Pronunciation

How to pronounce Minuca longisignalis: /ˈjuːkə lɒŋɡɪˈsɪɡnəlɪs/

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Identification

Distinguished from sympatric Uca spinicarpa by substrate preference: U. longisignalis prefers lower clay substrates while U. spinicarpa occupies higher clay substrates. In mixed , the two partition microhabitat by elevation and substrate composition. Burrow aperture diameter correlates with width, enabling size-based identification of occupied burrows.

Habitat

Coastal salt marsh of the Gulf of Mexico. Occurs in vegetated areas preferentially over sparsely vegetated or nonvegetated zones. Burrow distribution co-varies with elevation and landward distance from shoreline. Associated with temperate marsh plants that may provide nutritional resources.

Distribution

to the Gulf of Mexico. Documented in Louisiana coastal salt marshes.

Seasonality

Reproductive activity seasonally restricted to warm months. Ovigerous females first appear in April, with peak ovigery in June (67% of females in one study year). Later ovarian development and delayed laying compared to sympatric . Burrow aperture diameters and numbers exhibit seasonal variations.

Behavior

Constructs burrows in marsh substrate. Burrow depth increases with distance from water's edge. Burrow densities range from 26–182 m⁻². Shows seasonal variation in burrow construction and maintenance.

Similar Taxa

Uca spinicarpaSympatric in Gulf of Mexico salt marshes with which it shares but differs in substrate preference—U. spinicarpa occupies higher clay substrates while U. longisignalis prefers lower clay substrates.

More Details

Taxonomic history

Originally described as Uca longisignalis Salmon & Atsaides, 1968. Reclassified to Minuca longisignalis in 2016 when Minuca was elevated from subgenus to . Still listed as synonym Uca longisignalis in some databases.

Population characteristics

Mean estimates range 13.2–17.6 g ash-free dry weight per square meter. Significant correlation exists between ash-free dry weight and width for combined sexes (mean 0.26 g individual⁻¹).