Quero citações de artigos que falem sobre as caraterísticas do caranguejo Ucides cordatus.

Question

Accepted Answer

*Ucides cordatus*, commonly known as the "caranguejo-uçá" or swamp ghost crab, is a semi-terrestrial brachyuran crab that serves as a key ecosystem engineer in Neotropical mangroves (Direct, High; DOI: 10.4257/oeco.2024.2803.02). It is characterized by its significant role in nutrient cycling, its complex reproductive cycle involving pelagic larval export, and distinct sexual dimorphism in abdominal morphology (Direct, High; PMID: 29736340, DOI: 10.55905/rdelosv17.n60-151).

## Biological and Reproductive Characteristics
*   **Life Cycle and Longevity:** The species is slow-growing, with males reaching legal capture size at approximately 6.13 years and females at 7.38 years (Direct, High; PMID: 29736340).
*   **Reproductive Output:** *U. cordatus* exhibits high fecundity, with females carrying between 36,081 and 250,566 eggs, resulting in fertility rates of 71,200 to 220,800 larvae (Direct, High; PMID: 29736340).
*   **Larval Development:** Larval release is synchronized with syzygy ebb tides (new or full moon) to ensure efficient transport to oceanic waters (Direct, High; PMID: 29736340). Development to the megalopa stage takes 20–69 days depending on salinity and temperature; larvae require high salinity for survival beyond the initial zoeal stages (Direct, High; PMID: 29736340).
*   **Feeding Habits:** The crab is a primary consumer of mangrove leaf litter, showing a nutritional preference for *Avicennia schaueriana* leaves over other species (Direct, High; DOI: 10.4257/oeco.2024.2803.02, DOI: 10.55905/rdelosv17.n60-151).

## Ecological Characteristics and Habitat Selection
*   **Ecosystem Engineering:** By excavating deep burrows, the species oxygenates and drains mangrove sediment, facilitating geochemical cycles and organic matter processing (Direct, High; DOI: 10.55905/rdelosv17.n60-151, DOI: 10.4257/oeco.2024.2803.02).
*   **Habitat Distribution:** 
    *   **Edge Effects:** Anthropogenic edges often show higher total burrow densities, which may serve as preferred habitats for young crabs due to lower intraspecific competition and higher nutrient availability (Direct, High; DOI: 10.4257/oeco.2024.2803.02).
    *   **Interior Preference:** Adult crabs and individuals undergoing molting prefer the mangrove interior, where environmental conditions such as humidity and temperature are more stable (Direct, High; DOI: 10.4257/oeco.2024.2803.02).
*   **Seasonal Dynamics:** Crabs typically exhibit greater size and weight during the rainy season, likely due to increased leaf fall and food availability (Direct, High; DOI: 10.55905/rdelosv17.n60-151).
*   **Environmental Bioindicator:** The species is highly sensitive to pollutants, including heavy metals (Cu, Zn, Pb).

## Morphological Identification
*   **Sexual Dimorphism:** Males and females are distinguished by the shape of their abdomen:
    *   **Females:** Feature a semicircular, enlarged abdomen (Direct, High; DOI: 10.55905/rdelosv17.n60-151).
*   **General Size and Allometry:** Males are generally larger and heavier than females (Direct, High; DOI: 10.55905/rdelosv17.n60-151). Growth patterns often show negative allometry, where the crab allocates more energy to increasing carapace width rather than total weight (Direct, High; DOI: 10.55905/rdelosv17.n60-151).
*   **Burrow Identification:** *U. cordatus* burrows are identified by the oblique position of their opening, which is inclined at a 45° angle to the sediment surface (Direct, High; DOI: 10.55905/rdelosv17.n60-151). Active burrows are recognized by "biogenic activity" such as feces, trails, or moist sediment "lids" during molting (Direct, High; DOI: 10.4257/oeco.2024.2803.02).

[What specific biochemical markers are used to assess the impact of heavy metals and microplastics on Ucides cordatus in mangrove ecosystems?](#cta)

[How do seasonal variations in rainfall and temperature specifically influence the allometric growth and reproductive stages of Ucides cordatus?](#cta)

[What are the primary factors driving larval dispersal and population connectivity of Ucides cordatus along the Brazilian coast according to microsatellite analysis?](#cta)

---

### Unverified Citations

The following sources failed to support their assigned claims after 3 verification rounds designed to ensure only high-confidence, relevant references are retained:

- **PMID:38787099** — *, microplastics, and synthetic hormones like 17α-ethinylestradiol, which induce oxidative stress and alterations in deto...*  
  Failed: entities — The paper does not mention or measure Catalase (CAT) activity in the context of Ucides cordatus or the experimental treatments.
- **DOI:10.1007/s11270-024-07037-0** — *, microplastics, and synthetic hormones like 17α-ethinylestradiol, which induce oxidative stress and alterations in deto...*  
  Failed: entities — The paper studies trace elements and organic pollutants (PAHs/PCBs), not microplastics or 17α-ethinylestradiol.
- **DOI:10.55905/rdelosv17.n60-151** — *, microplastics, and synthetic hormones like 17α-ethinylestradiol, which induce oxidative stress and alterations in deto...*  
  Failed: entities,conclusion — The paper is a biometric study of environmental factors (salinity, rainfall) and does not mention microplastics, EE2, GST, or Catalase.
- **DOI:10.4257/oeco.2024.2803.02** — *Growth patterns often show negative allometry, where the crab allocates more energy to increasing carapace width rather ...*  
  Failed: conclusion — The paper focuses on edge effects and burrow density; it does not discuss negative allometry or energy allocation between carapace width and weight.