Baraminology of Butterflyfish

Baraminology of Butterflyfish

Some of the most colorful and conspicuous of the reef fishes are the members of the family Chaetodontidae, better known as the butterflyfishes.  There are around one hundred and thirty species classified within the family, most of which are confined to one genus. Based on the enhanced cognitum concept of baraminology that has been previously proposed, this article will evaluate the baraminological status of the butterflyfishes.

The enhanced cognitum concept of baraminology begins with a careful examination of any available data, then formulating this data in the form of a discontinuity matrix.  In order to use the discontinuity matrix, an outgroup should be selected.  This study will use members of family Pomacanthidae, the well-known marine angelfish, as the cognitive outgroup.  According to evolutionary phylogenies, marine angelfish and the butterflyfishes are closely related[1]. Therefore, selecting the marine angels as a cognitive outgroup makes sense as, if the butterfly fish are a distinct baramin, there should be a cognitive distinction between them and even their “close relative” marine angels.

Question Yes? No?
Is there Scriptural discontinuity? (TCW, KPW) No
Is Hybridization data available? Yes
Does hybridization fail outside the group? (KPW) Unknown Unknown
Are there extinct organisms classified in this group? No (there are a few that are nebulous)
Do most members of the group possess unique structures or metabolic pathways? (TCW) Yes
Is the group more morphologically similar within the group than it is with things outside the group? (TCW) (KPW) Yes
Is there strong genetic discontinuity among many genes? (TCW) (KPW) Unknown Unknown
Does this group occupy a specialized environment? (TCW) (KPW) Yes
Does this group lack fossil evidence linking it to other groups? (KPW) (TCW) Yes  

 

 

Does this group naturally appear discontinuous from other groups? Yes
Are there any members of the group with highly specialized traits? Yes

Based on the above discontinuity matrix, the baraminological status of butterflyfish a bit nebulous. Several questions are unknown. However, the most important question, that of hybridization, can be answered, at least in part.  Likely due to their status as denizens of the reefs, information about hybridization is limited. However, there is some information available.  At least one hybrid between Chaetodon ocellatus and Chaetodon striatus is known from as far back as 1985[2]Chaetodon kleinii and Chaetodon rafflesi are also known to hybridize[3] as are several other species from the Chaetodon genus[4]. There are also two species which hybridize with multiple species.  Chaetodon trifasciatus will breed with Chaetodon lunulatus[5] and Chaetodon melapterus[6] leading to the simple conclusion that C. lunulatus and C. melapterus would be able to breed together given the opportunity.  Chaetodon punctatofasciatus will breed with both C. guttatissimus[7]  and C. pelewensis[8]  which makes it likely that C. guttatissimus and C. pelewensis interbreed as well.

All these hybridizations between species are expected under the enhanced cognitum concept because the enhanced cognitum assumes that species breeding together within the genus happens since members of the same genus are supposed to be closely related.  Because the members of a same genus should be closely related, they should interbreed. Thus, the interbreeding between members of Chaetodon is not surprising.

Hybrid data for genera other than Chaetodon is completely absent. This forces us to look at them cognitively.  This is where the outgroup becomes important.  Comparing Chaetodontidae against Pomacanthidae reveals some differences.  Chaetodontidae tends to have slimmer, sleeker bodies than members of Pomacanthidae.  Chaetodontidae also has a distinctive snout, which tapers to a point where the mouth is, and in the case of Forcipiger and Chelmon an extended mouth. Pomacanthidae has a much less pointed snout, and most exhibit a slight underbite as well. Some Pomacanthidae also exhibit pointed caudal, anal and adipose fins, something that is essentially unknown in Chaetodontidae, though some members of the family do exhibit much extended dorsal fins.  Pomacanthidae also exhibits spines on the gill covers, a feature absent it Chaetodontidae.

However, within Chaetodontidae, there are several potential cognitive groups. Chaetodon, Chelmon, Chelmonops,  Coradion, Forcipiger, Johnrandallia, Parachaetodon, Prognathodes, and Roa all group together fairly readily cognitively. There are a few differences. Chelmon, Chelmonops,  Coradion, and Forcipiger exhibit extended snouts, while Prognathodes, and Roa have noticeably more extended dorsal spines.  However, the general body plan and style is very similar. Only two genera do not necessarily fit in this cognitive grouping.  Heniochus is a small genus, characterized by either one extended dorsal spine, or several extended in a step like pattern. Unlike Prognathodes, which exhibit pronounced dorsal spines which are roughly equally pronounced, Heniochus usually exhibits one spine which is very pronounced, and sometimes several others which are progressively less noticeable. However, tentatively Heniochus is left within Chaetodontidae, as spinal variation is probably not enough to split it out.

Genus Hemitaurichthys is another matter. The genus is species poor, with only four members. While there are some dorsal spines, the body shape is much less square than the remainder of Chaetodontidae. Instead, the body is more elongated, more closely resembling a standard fish body, and lacking the obvious extended snout.  Tentatively, it appears that this genus should be split from the rest of Chaetodontidae. However, examining genetic data reveals a different side of the coin.

DNA data does little to clear the waters or delineate a potential Chaetodontidae baramin. For example, a partial sequence of the RAG1 gene in Forcipiger flavissimus is very similar to that of Heniochus chrysostomus and Chatedodon striatus[9].  This same gene has a 97% similarity to these species in Hemitaurichthys polylepis[10]. Comparing these sequences to the outgroup from Pomacanthidae, it averages much closer to 90% similarity[11]. A partial sequence of the sidkey gene of Forcipiger flavissimus, Heniochus varius, Chaetodon reticulatus, and Prognathodes aya are also incredibly similar, averaging well above 97% similar[12]. An outgroup from Pomacanthus imperator average a smaller 94% similarity[13]. A partial sequence of the glyt gene of Forcipiger flavissimus, Chelmon rostratus, Hemitaurichthys polylepis, Johnrandallia nigrirostris and Prognathodes aculeatus was also very similar, over 96% on average[14]. Using a Holocanthus passer gene as an outgroup revealed an average similarity between the two groups of just under 92%[15]. The plagl2 gene sequence in Chaetodon striatus, Forcipiger flavissimus and Heniochus chrysostomus shows similar average similarities[16].  An outgroup gene from Pomacanthus rhomboides  reveals a similarity between the groups of around 95-96%, almost identical to the similarity within Chaetodontidae[17].  As one final example, partial sequences of zic1 gene in Chaetodon ornatissimus, Forcipiger flavissimus, Prognathodes aculeatus, Hemitaurichthys polyepis, and Johnrandallia nigrirostris are all very similar, with an average similarity well over 97%[18].  Outgroup genetic data from Pomacanthus zonipectus reveals an average similarity of 96%[19].

Obviously, these are only a very small sample and many of the genes are only partial sequences. Whole genome data is not available and, while mitochondrial sequences for a few species are available, but mitochondrial DNA is considered unreliable for the purposes of baraminology.

Based on the DNA data, folding Hemitaurichthys into the Chaetodontidae baramin makes sense, pending further genetic data. Due to the genetic similarity in this small sample, it is impossible to genetically confirm that Pomacanthidae and Chaetodontidae are separate baramin. Whole genome data will be required before they can be genetically split.

However, based on cognition, Chaetodontidae would seem to be its own baramin, particularly based on the extended rostrum and unique body plan. Further, many of the species are obligate corallivores, requiring coral as food, whereas no member of Pomacanthidae is known to feed in this way.  The marine angels also have a special spine covering their gills, something the butterflyfish lack. Based on these traits, Chaetodontidae is believed to be its own created baramin.  This could change and Pomacanthidae may be merged into the baramin depending on hybrid data and whole genome data.  Pomacanthidae will be examined in the future to determine if it also is a discrete baramin.

 

 

References

[1] D. Timothy J. Littlewood, Sarah M. McDonald, Anthony C. Gill, and Thomas H. Cribb. “Molecular phylogenies of Chaetodon and the Chaetodontidae (Teleostei: Perciformes) with reference to morphology.” Zootaxa Volume 779 (2004) Pages 1-20. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.580.1924&rep=rep1&type=pdf

[2] Ileana E. Clavijo “A Probable Hybrid Butterflyfish from the Western Atlantic.” Copeia Volume 1985, no. 1 (1985) Pages 235-238. https://www.jstor.org/stable/1444819?seq=1#metadata_info_tab_contents

[3] Yusri Yusuf and Ahyaudin B. Ali. “The Use of Butterflyfish (Chaetodontidae) as Bioindicator in Coral Reef Ecosystem.” in Biomonitoring of tropical coastal ecosystems  (eds) Phang, S., -M. and M. T. Brown. University of Malaya Maritime Research Center (UMMReC), Kuala Lumpur, 2004. https://www.researchgate.net/profile/Yusri_Yusuf/publication/237732408_The_Use_of_Butterflyfish_Chaetodontidae_as_Bioindicator_in_Coral_Reef_Ecosystem/links/579ed7d508ae6a2882f5468d/The-Use-of-Butterflyfish-Chaetodontidae-as-Bioindicator-in-Coral-Reef-Ecosystem.pdf

[4]Jean-Paul A. Hobbs, Ashley J. Frisch, Gerald R. Allen, and Lynne Van Herwerden. “Marine hybrid hotspot Indo-Pacific biogeographic border.” The Royal Society Biology Letters Volume 5, no. 2 (2009) Pages 258-261. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2665801/

[5] Ibid

[6] Joseph D. DiBattista, Luiz A. Rocha, Jean-Paul A. Hobbs, Song He, Mark A. Priest, Tane H. Sinclair-Taylor, Brian W. Bowen, and Michael L. Berumen. “When biogeographical provinces collide: hybridization of reef fishes at the crossroads of the marine biogeographical provinces in the Arabian Sea.” Journal of Biogeography Volume 42, no. 9 (2015) Pages 1601-1614.  https://onlinelibrary.wiley.com/doi/abs/10.1111/jbi.12526

[7] Hobbs et al, 2009.

[8] Chris D. Jiggins and James Mallet. “Bimodal hybrid zones and speciation. “ TREE Volume 15, no. 6 (2000) Pages 250-255). https://www.ucl.ac.uk/taxome/jim/pap/Jiggins&MalletTREE00.pdf

[9] Accession #s EF530086.1 EF530087.1 EF530085.1

[10] Accession # EU167838.1

[11] Accession # EF530089.1 EU167832.1

[12] Accession # KC829407.1 KC829408.1 KC829410.1 KC829411.1

[13] Accession # JQ937696.1

[14] Accession # JX188713.1 JX190350.1 KF139764.1 KF139773.1 JX190351.1

[15] Accession # JX188747.1

[16] Accession # EF536246.1 EF536247.1 EF536248.1

[17] Accession # EF536252.1

[18] Accession # JX189046.1 JX189047.1 JX191340.1 KF140549.1 KF140555.1

[19] Accession # JX189073.1

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