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Moore BC, Kelly DA, Piva M, Does M, Kim DK, Simoncini M, Leiva PML, Pina CI. Genital anatomy and copulatory interactions in the broad snouted Caiman (Caiman latirostris). Anat Rec (Hoboken) 2021; 305:3075-3087. [PMID: 34236769 DOI: 10.1002/ar.24699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/29/2021] [Indexed: 11/09/2022]
Abstract
The broad snouted caiman is a crocodylian native to South America that is subject to extensive conservation management in both wild and farming environments. Although reproductive behaviors like egg laying and clutch care have been examined in this species, little else is known about their copulatory system. We examined the anatomy of male and female cloacal and genital tissues ex vivo to build hypotheses of their interactions during copulation and the effects of that interaction on insemination. Male phallic glans tissues were artificially inflated to expand into their copulatory state, allowing the examination and quantification of structural changes at the gross and tissue levels. Digital reconstruction of MRI stacks yielded three-dimensional tissue compartment specific glans models of the inflated state. Silicone molds of female cloacae and oviducts in conjunction with dissection and diceCT analysis allowed us to assess internal geometry and infer how male and female features interact in copulo. We observed glans expansion within the female proctodeum would result in a copulatory lock limiting deeper intromission or retraction. Intromission and subsequent creation of the copulatory lock produces extensive clitoral compression, providing a possible mechanism for female assessment of male copulatory performance. Further, glans expansion forms a distal lumen that positions the glans tip in or near the vaginal openings. A coiled, muscular vagina provides a possible mechanism for postcopulatory sexual selection by excluding semen. Together, the complex male-female interaction supports evidence for cryptic selection by female choice, which can act as a driver of genital coevolution.
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Affiliation(s)
- Brandon C Moore
- Department of Biomedical Science, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.,Deartment of Biology, School of Health Sciences, Stephens College, Columbia, Missouri, USA
| | - Diane A Kelly
- Department of Psychological and Brain Sciences, University of Massachusetts, Amherst, Massachusetts, USA
| | - Milan Piva
- Department of Biomedical Science, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Mark Does
- Department of Biomedical Engineering, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Dong Kyu Kim
- Department of Biomedical Engineering, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Melina Simoncini
- CICyTTP (CONICET-Prov. ER-UADER), Proyecto Yacare, FCYT/UADER, Diamante, Entre Ríos, Argentina
| | - Pamela M L Leiva
- CICyTTP (CONICET-Prov. ER-UADER), Proyecto Yacare, FCYT/UADER, Diamante, Entre Ríos, Argentina
| | - Carlos I Pina
- CICyTTP (CONICET-Prov. ER-UADER), Proyecto Yacare, FCYT/UADER, Diamante, Entre Ríos, Argentina
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Francis M, Morel PCH, Wilkinson BHP, Wester TJ. Alginate increases water stability whilst maintaining diet digestibility in farmed saltwater crocodiles (). J Anim Sci 2017; 95:820-826. [PMID: 28380593 DOI: 10.2527/jas.2016.0908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Saltwater crocodile () farming in Papua New Guinea is an emerging industry that supplies high-quality skins to the fashion industry. Crocodiles are semiaquatic and fed high-quality feed made from extrudated animal byproducts (i.e., forced through a die at low pressure but not heat treated); however, it disintegrates on contact with water, and this leads to low utilization. Alginate is used extensively in food and pharmaceutical processes because it quickly forms a gel at room temperature; however, its effects on nutrient availability are equivocal, and its utility in crocodile diets is unknown. Extrudated chicken byproduct-based crocodile diets were formulated (as-fed) with and without 1.7 and 3.3% Na alginate with either CaCl or CaCO to cross-link. After immersion in water at 30°C for 24 h, feed retained on a 0.5-mm screen was measured to determine DM retention (DMR). Regardless of inclusion level, alginate addition resulted in a 13-fold increase in DMR ( < 0.05) when CaCO was used as a Ca source; however, CaCl use resulted in a much lower DMR. In a digestibility trial, 10 juvenile crocodiles (2.2 to 2.4 yr of age; 1.2 to 1.9 kg BW) were chosen from farm-raised stocks and fed extrudated chicken byproduct-based diets with and without 1.5% Na alginate and 1.9% CaCO. Animals fed 2% BW for 12 d and with excreta collected the last 5 d were slaughtered and had digesta sampled from the ileum. There were no differences in apparent ileal digestibilities of any AA, N (65.0 vs. 55.8%, SE = 12.2%), and OM (46.8 vs. 39.6%, SE = 12.8%) between diets with and without alginate, respectively. Total-tract digestibilities of OM (69.8 vs. 39.2%, SE = 9.1%) and energy (72.2 vs. 44.4%, SE = 8.3%), however, were greater in alginate-containing diets ( < 0.05). Our study showed that alginate addition to crocodile feed improved its stability in water and did not impair nutrient digestion. Application of these findings should greatly decrease feed wastage, which ultimately will benefit Papua New Guinea by simultaneously increasing economic returns and decreasing environmental impacts.
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Boggs ASP, Hamlin HJ, Nifong JC, Kassim BL, Lowers RH, Galligan TM, Long SE, Guillette LJ. Urinary iodine and stable isotope analysis to examine habitat influences on thyroid hormones among coastal dwelling American alligators. Gen Comp Endocrinol 2016; 226:5-13. [PMID: 26684734 PMCID: PMC4778256 DOI: 10.1016/j.ygcen.2015.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/20/2015] [Accepted: 12/08/2015] [Indexed: 11/29/2022]
Abstract
The American alligator, generally a freshwater species, is known to forage in marine environments despite the lack of a salt secreting gland found in other crocodylids. Estuarine and marine foraging could lead to increased dietary uptake of iodine, a nutrient necessary for the production of thyroid hormones. To explore the influence of dietary iodine on thyroid hormone health of coastal dwelling alligators, we described the seasonal plasma thyroxine and triiodothyronine concentrations measured by radioimmunoassay and urinary iodine (UI) concentrations measured by inductively coupled plasma mass spectrometry. We also analyzed long-term dietary patterns through stable isotope analysis of scute tissue. Snout-to-vent length (SVL) was a significant factor among UI and stable isotope analyses. Large adult males greater than 135cm SVL had the highest UI concentrations but did not display seasonality of thyroid hormones. Alligators under 135 SVL exhibited seasonality in thyroid hormones and a positive relationship between UI and triiodothyronine concentrations. Isotopic signatures provided supporting evidence that large males predominantly feed on marine/estuarine prey whereas females showed reliance on freshwater/terrestrial prey supplemented by marine/estuarine prey. UI measurement provided immediate information that correlated to thyroid hormone concentrations whereas stable isotope analysis described long-term dietary patterns. Both techniques demonstrate that adult alligators in coastal environments are utilizing estuarine/marine habitats, which could alter thyroid hormone physiology.
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Affiliation(s)
- Ashley S P Boggs
- National Institute of Standards and Technology, Environmental Chemical Sciences, 331 Fort Johnson Rd, Charleston, SC 29412, USA; Hollings Marine Laboratory, 331 Fort Johnson Rd, Charleston, SC 29412, USA.
| | - Heather J Hamlin
- University of Maine, School of Marine Sciences, 316 Murray Hall Orono, ME 04469, USA
| | - James C Nifong
- University of Florida, Fisheries and Aquatic Sciences, NW 71st Street, Gainsville, FL 32653, USA
| | - Brittany L Kassim
- National Institute of Standards and Technology, Environmental Chemical Sciences, 331 Fort Johnson Rd, Charleston, SC 29412, USA; Hollings Marine Laboratory, 331 Fort Johnson Rd, Charleston, SC 29412, USA
| | - Russell H Lowers
- National Aeronautics and Space Administration, InoMedic Health Applications Inc., SR 405, Kennedy Space Center, FL 32899, USA
| | - Thomas M Galligan
- Hollings Marine Laboratory, 331 Fort Johnson Rd, Charleston, SC 29412, USA; Medical University of South Carolina, Department of Obstetrics and Gynecology, 331 Fort Johnson Rd, Charleston, SC 29412, USA
| | - Stephen E Long
- National Institute of Standards and Technology, Environmental Chemical Sciences, 331 Fort Johnson Rd, Charleston, SC 29412, USA; Hollings Marine Laboratory, 331 Fort Johnson Rd, Charleston, SC 29412, USA
| | - Louis J Guillette
- Hollings Marine Laboratory, 331 Fort Johnson Rd, Charleston, SC 29412, USA; Medical University of South Carolina, Department of Obstetrics and Gynecology, 331 Fort Johnson Rd, Charleston, SC 29412, USA
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Ganswindt SB, Myburgh JG, Cameron EZ, Ganswindt A. Non-invasive assessment of adrenocortical function in captive Nile crocodiles (Crocodylus niloticus). Comp Biochem Physiol A Mol Integr Physiol 2014; 177:11-7. [DOI: 10.1016/j.cbpa.2014.07.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 07/01/2014] [Accepted: 07/17/2014] [Indexed: 11/30/2022]
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