Baraminology of Danioninae

Anyone familiar with the home aquarium trade has undoubtedly heard of danios. These small, gracile, often colorful fish are staples in the pet trade. Some, specifically Danio rerio have been made into the popular glowfish. They are members of the sprawling family Cyprinidae, better known as the carp or minnow family, depending on who you ask. Danios fall into subfamily Danioninae, but even that is quite large, containing over three hundred and sixty species according to FishBase[1]. Danioninae is separated from the rest of Cyprinidae due to the extreme size of Cyprinidae and the obvious discontinuity within the family.  Danios stay very small, with few species exceeding half a foot in length.  They appear to share a number of similarities, as well as numerous discontinuities.  This article will examine Danios and determine if they are their own baramin, or if the subfamily needs to be split into multiple baramin.

Applying the enhanced cognitum method of baraminology to the subfamily Danioninae yields initial frustration. Hybridization data is barely known in the scientific literature.  Only a few hybrids are known. Two species of rasboras (  Rasbora borapetensis  and R. dorsiocellata ) can hybridize[2]. Members of the genus Danio hybridize fairly frequently, with at least four members of the genus known to hybridize with one another[3][4]. Two species of Devario ( D. anomalus and D. aequipinnatus ) are also known to hybridize[5].  Beyond these few examples, all of which are within the expected bounds of hybridization; ie within the genera.

Given that hybridization is very limited within the subfamily Danioninae, the cognitive method is now employed to determine how many baramins are in found within this sub-family.  If needed, the cognitive outgroup of subfamily Labeoninae, also within Cyprininae. The Labeoninae are an incredibly diverse group consisting of numerous carps and the so-called freshwater sharks.

Cognitively breaking down the Danioninae reveals three cognitive groups and two genera outliers. These groups are delineated in the below chart. Genus Esomus and Betadevario  are the only genera in the subfamily to have barbels as far as I can tell. These barbels are very pronounced, hanging like whiskers from the chin of the fish.  Since no other member of this subfamily has this pronounced feature, Esomus and Betadevario  are considered cognitively discontinuous from the rest of Danioninae. Perhaps placing these genera in subfamily Barbinae would be more appropriate.

The first group cognitively separated out as part of this study is the Danios themselves, a group entitled Danionae.  This group contains the majority of the genera within Danioninae, a total of nineteen genera and one hundred and fifty-three species. One species however, was removed from genus Laubuka. Cognitively, based on body style, Laubuka caeruleostigmata much more closely resembles members of the Chelanae baramin which will be discussed below. Further classification of this species will be discussed in Chelanae.  Danionae is distinguished by upturned mouths, a slight curvature of the stomach, a mid to slightly posterior single dorsal fin, accentuated pectoral fins attached just behind the operculum, a posterior pelvic fin and a further posterior anal fin which is accentuated.  They can be distinguished from the other two groups by body shape in particular.

Chelanae is the second cognitive baramin within Danionae.  This group contains the fewest genera, a mere four and forty-four species. However, Laubuka caeruleostigmata much more closely resembles a member of genus Chela than they do Laubuka. Therefore, tentatively I propose reclassifying it as Chela caeruleostigmata. That aside, members of Chelanae  is distinguished by a deeply rounded anterior tapering to a much slimmer posterior body.  The single dorsal fin is accentuated to varying degrees within this baramin. The anal fin is located along the curvature of the body and is at least slightly accentuated. The pelvic fins are small and slender, often barely noticeable compared to the other fins.

The third cognitive group is the Rasborainae. This baramin contains twelve genera, with one hundred and forty-nine species. Despite having fewer genera than Danionae, Rasborainae has approximately the same number of species. This is due to the large size of the genus Rasbora which consists of close to ninety species.  Rasborinae is characterized by thin, nearly pencil like bodies with centralized dorsal fins, often accentuated, centralized pectoral fins located shortly anterior to the anal fin. In many species, the caudal fin is less lobed than in other members of Danioninae. However, the key feature is the slim, pencil like bodies with little to no curvature of the abdomen.

Genetic data however does mess with these groupings. Boraras and Danionella share a mere 84.8% similarity in the RAG1 gene[6]. However, when Chela is compared to Boraras and Danionella, the similarity is a mere 84.4 and 84.9% respectively[7].  Engraulicypris is about 88% similar in the same gene to Boraras, 84% similar to Danionella, and 85% similar to Chela[8].  Clearly genetics in this one gene is difficult to reconcile with the cognitive groupings. However, this is one gene.  Whole genomes for these fish, outside of common lab fish Danio rerio are completely unavailable so making a comparison based on whole genomes is impossible for the moment.  Therefore, until such time as this data becomes available, these baramins will remain as I have constructed them.

Based on the results of these brief investigations, the subfamily Danioninae is split into three cognitive groupings. These are not necessarily definitive. Hybrid data is lacking. Further, the taxonomy of Cyprididae is in flux and genera may be moved around within the subfamilies. However, until better data becomes available, these groups may be regarded as preliminary baramins which can help guide further creationist baraminology research.

Baramin/genera	Rasborainae	Chelanae		Danionae	Unclassified
	Boraras	Amblypharyngodon		Aspidoparia	Betadevario
	Danionella	Barillus		Cabdio	Esomus
	Engraulicypris	Chela		Chelaethiops
	Leptocypris	Nematabramis		Danio
	Luciosoma	Laubuka caeruleostigmata		Devario
	Paedocypris			Fangfangia
	Pectenocypris			Horadandia
	Rasbora			Inlecypris
	Rastrineobola			Laubuka
	Salmostoma			Malayochela
	Sundanio			Microdevario
	Trigonopoma			Microrasbora
			Neobola
				Opsaridium
				Opsarius
				Raiamas
				Rasboroides
				Securicula
				Trigonostigma

 

[1] FishBase. Accessed May 22, 2019 https://www.fishbase.se/identification/SpeciesList.php?class=&order=&famcode=122&subfamily=Danioninae&areacode=&c_code=&depth=&spines=&fins=&TL=&BD=&resultPage=1&sortby=species

[2]Jack S. Frankel “Patterns of lactate and sorbitol dehydrogenase gene expression during the development of interspecific Rasbora  hybrids.” Comparative Biochemistry and Physiology Part B: Comparative Biochemistry Volume 108, no 4.  (1994) Pages 437-441. https://www.sciencedirect.com/science/article/pii/0305049194900965

[3] David M. Parichy and Stephen L. Johnson. “Zebrafish hybrids suggest genetic mechanisms for pigment pattern diversification in Danio.” Development Genes and Evolution Volume 211 (2001) Pages 319-328. http://genetics.wustl.edu/sjlab/files/2011/10/29-Parichy-and-Johnson-2001-color.pdf

[4] Larissa B. Patterson, Emily J. Bain, and David M. Parichy. “Pigment cell interactions and differential xanthophore recruitment underlying zebrafish stripe reiteration and Danio pattern evolution.” Nature Communications Volume 5 (2014) https://www.nature.com/articles/ncomms6299

[5] Sven O. Kullander, Md. Mizanur Rahman, Michael Noren, and Abdur Rob Mollah. “Devario in Bangladesh: Species diversity, sibling species, and introgression within danionin cyprinids (Teleostei: Cyprinidae: Danioninae)” PLOS One (2017) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186895

 

[6] Accession numbers HM224114.1 and EF452841.1

[7] Accession number FJ753522.1

[8] Accession number JX197015.1