Byne’s decay on microscopic calcareous shells: case study of Alcide d’Orbigny’s foraminifera collections stored in Paris and La Rochelle, France Author Hairie, Clara Centre de Recherche sur la Conservation (CRC), UAR 3224, CNRS, MNHN, Sorbonne Université, Muséum national d’Histoire naturelle, case postale 21, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) and Institut Lavoisier de Versailles (ILV), UMR 8180 (UVSQ-CNRS), Université Paris-Saclay, 45, avenue des États-Unis, 78000 Versailles (France) and Institut photonique d’analyse non destructive européen des matériaux anciens (IPANEMA), UAR 3641 (CNRS-MNHN-MC-UVSQ), Université Paris-Saclay - site du synchrotron SOLEIL, BP 48 Saint-Aubin, F- 91192 Gif-sur-Yvette, (France) Centre de recherche en paléontologie - Paris (CR 2 P), UMR 7207, CNRS, MNHN, Sorbonne Université, Département Origines et Évolution, Muséum national d’Histoire naturelle, case postale 38, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) Author Forel, Marie-Béatrice Centre de recherche en paléontologie — Paris (CR 2 P), UMR 7207, CNRS, MNHN, Sorbonne Université, Département Origines et Évolution, Muséum national d’Histoire naturelle, case postale 38, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) Author Bartolini, Annachiara Centre de recherche en paléontologie - Paris (CR 2 P), UMR 7207, CNRS, MNHN, Sorbonne Université, Département Origines et Évolution, Muséum national d’Histoire naturelle, case postale 38, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) Author Müller, Camille Centre de Recherche sur la Conservation (CRC), UAR 3224, CNRS, MNHN, Sorbonne Université, Muséum national d’Histoire naturelle, case postale 21, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) Author Steunou, Nathalie Institut Lavoisier de Versailles (ILV), UMR 8180 (UVSQ-CNRS), Université Paris-Saclay, 45, avenue des États-Unis, 78000 Versailles (France) Author Rouchon, Véronique Centre de Recherche sur la Conservation (CRC), UAR 3224, CNRS, MNHN, Sorbonne Université, Muséum national d’Histoire naturelle, case postale 21, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) veronique.rouchon@mnhn.fr text Geodiversitas 2025 2025-10-09 47 16 659 685 https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/geodiversitas2025v47a16.pdf journal article 10.5252/geodiversitas2025v47a16 1638-9395 17302384 urn:lsid:zoobank.org:pub:CC61025B-E168-4BC7-9017-686F442D323B

TABLE 2. — A, Byne’s decay vs composition and age of the specimens. Percentages are calculated in relation to the number of foraminifera presenting the same feature (hyaline,porcelaneous, fossil,recent).“Fossil” refers to foraminifera sampled on a continental outcrop while “recent” refers to foraminifera sampled at sea or on the coast; B, Repartition of the damage grades and features observed on the specimens suffering by Byne’s Decay vs composition and origin. Percentages are calculated in relation to the number of foraminifera presenting a specific feature (hyaline, porcelaneous, fossil, recent). “Fossil” refers to foraminifera sampled on a continental outcrop while “recent” refers to foraminifera sampled at sea or on the coast. Deviations of the percentages calculated within the hyaline and porcelaneous (respectively fossil and recent) populations are ranked in the middle line (respectively last line) of the table. =, no significant deviation (<4%); ≈, limited deviation (4% <x <10%); ×, obvious deviation (≥ 10%). Abbreviations: Spec., specimen; Diss., Dissolution; Cracks, presence of cracks; White, presence of white crystals; Transp., presence of transparent crystals; Orange colour., orange colouration of the test; Snowball, covered by white efflorescence with a snowball aspect.

A	Feature		Total Byne specimens decay			Proportion		Independancy test (α = 0.05; DL = 1, critical chi 2 = 3.84)
Composition	Hyaline		2451	1397		57%			p = 0.00000125
	Porcelaneous		877	582		66%			chi2 = 23.50: H0 rejected
Origin	Fossil		1938	1113		57%			p = 0.173
	Recent		1241	743		60%			chi2 = 1.85: H0 retained
		Degradation				among				among
B		grades			Altered	which (nb.) Cristal. growth or				which (nb.) Orange		Snow
	A	B	C	D+E	struct.	Diss	Cracks colour.		White Transp. colour.			ball
Hyaline	1%	51%	28%	20%	67%	29%	17%	87%	61%	15%	16%	3%
(1397 spec.)
Porcelaneous	0%	50%	24%	26%	58%	11%	10%	96%	86%	7%	12%	12%
(582 spec.)
	=	=	≈	≈	≈	×	≈	≈	×	≈	≈	≈
Fossil (1113 spec.)	1%	59%	27%	13%	56%	22%	18%	89%	73%	8%	17%	4%
Recent (743 spec.) 0%		40%	26%	34%	72%	25%	9%	89%	61%	19%	9%	8%
	=	×	=	×	×	=	≈	=	×	×	≈	≈