The venom that proceeds Egyptian Centipedes

Welcome back to the multi-legged world of centipedes: Where one step can feel like a hundred!

The topic of today’s post focuses on a primary research article about the study into the venom from a particular taxon in Chilopoda. Titled “Phenotypic description of Egyptian endemic centipedes, genus Scolopendra Linnaeus, 1758 with a histological study of its venom glands”, it reads as quite of a mouthful terms that describe its study about the morphology and venom of Scolependra Morsitans s Linneus, more commonly known as the Red-headed centipede. The article was authored by Many Mohammed Mona and Aalaa I. Atlam, as they hypothesized that the anatomical and biological differences found in this taxon compared to other species is the result of their geographical isolation in Egypt.

To proceed with their study, specimens of Scolopendra Morsitans and Scolopendra Canidens from various regions in Egypt were collected and maintained in captivity for a period from July 2019 to August 2020. after these subjects were sedated, their color, head features and appendages were under examination to check for their morphological differences. In a separate examination, their venom glands were removed, decalcified, stained, subjected to a PAS test, and were then photographed under a microscope. The results showed that the morphological and histological characteristics of both of the species were almost identical, and both showed a presence of PAS-positive venom. the findings also showed more examples of Scolopendra Moristans than its counterpart.

None of the specimens collected showed any significant differences between each other, while the distribution of Scolpendra Morsitans is more prevalent than that of Scolopendra Canidens. Both of these findings could be indicative of a number of things. While both species are known to be in the same subfamily in which they may already owe some of their similarities to, an additional reason that they may resemble each other so closely may be convergent evolution due to the adaptations they have made for a particular lifestyle shaped by their geographical location. Assuming that this is true, that would mean that Scolopendra Moristans may have a more widespread distribution due to subtle differences in their biology and behavior that give them a competitive advantage over Scolopendra Canidens. The PAS positive nature of the Venom observed in the specimens is a trait associated with the most venomous arthropods known to science, which could possibly indicate that this level of potency is needed to incapacitate relatively formidable prey items.

What makes the results of this study so important is that it makes a hallmark as the first comprehensive investigation into both of these species in Egypt since they were first described, while a comparative predation study between these species and other centipedes that are not known to carry PAS-postive venom might offer more insight into the epiphanies about their predatory lifestyle.

 

Key Terms

  1. PAS– Abbreviated form of Periodic-acid Schiff, which is a stain used to test for complex carbohydrates, and in this case is applied to the venom samples 
  2. Morphology– The physical characteristics of a species
  3.  Histology– the microscopic arrangement of tissues in an animal or taxon
  4. Convergent Evolution– the independent evolution of a shared feature between two or more organisms as a response to their similar lifestyle

 

Source

Mona, M.M., Atlam, A.I. Phenotypic description of Egyptian endemic centipedes, genus Scolopendra Linnaeus, 1758 with a histological study of its venom glands. Zoomorphology 141, 273–281 (2022).

Link

Crawling down the Tree: a Phylogenetic history

 

https://www.nhm.ac.uk/discover/news/2019/september/centipedes-evolved-complex-venom-five-times.html

Fig 1


The centipede family tree is large enough to make a Greek Wedding look like a kickback. Among their diverse grouping of more than 3,300 members, they share a similar body plan of having a long segmented body with a pair of legs per segment, and the total sum of legs being an odd number (Dell’Anna et al., 2019). This still doesn’t suffice however, as scientists still wonder about the phylogenetic relationships. There is strong evidence to support the idea that they are a monophylectic group that shares the same ancestor based on RNA sequences (Dell’Anna et al., 2019).

Independent of molecular data, Venomous fangs called forcipules are a feature that unite the members of this genus. To the contrary, members of the species Scolopendra Marsitans, or the Red-Headed Centipede have a disproportionately large pair of ultimate legs that set them apart from their crawly brethren (Kraus, 1958).

The organization of the family tree is where things begin to get complicated. There are at least a couple phylogenies to choose from when it comes to chilopods, and a conflict of interest lies between the placement of the family Scutigeridae and its place under the order of Geophilomorpha.

(Bonato et al., 2010; Ishiwata et al., 2011). Lithobiomorpha and its possibility of being the parent order to Scutigeridae is still up for debate, with an analysis of mitochondrial genes offering as evidence to support a closer relation to Lithobiomorpha (Fig 1). On the contrary, a more recent study comparing morphological characteristsics has argued in favor of it being closer to Scutigeridae. This is a phylogenetic mystery that continues to puzzle researchers.

To put the biodiversity into perspective, my species of choice which is Scolependra Marsitans differs from Scolopendra Gigantea in terms of size. The latter are similar in that they both have venomous fangs and share a similar body structure. But, S. Gigantea dwarfs S. Marsitans almost triple fold in some specimens, as well as a pattern difference and significant differences in their genomic sequences (Kraus, 1958; Zhang et al., 2019).

In conclusion, chilopods have a fascinating evolutionary lineage that we may not be all that familiar with. The differences between these taxa can be as subtle as the curved tips of each feet, or as significant as the stark colouration difference or defense features. When it comes to the family tree, there remains only more for scientists to discover.

 


Works Cited

Dell’Anna, L., Akkari, N., Alqarni, A. S., Ashouri, A., & Murienne, J. (2019). Phylogenomic inference in centipedes unravel the evolutionary history of a morphologically conservative group of arthropods. Cladistics, 35(2), 113-138.

Edgecombe, G. D., Giribet, G., & Murienne, J. (2018). A revised time-scale for the origin of terrestrial vertebrates. Palaeontology, 61(3), 435-448.

Kraus, O. (1958). Centipedes (Chilopoda) of the Philippine Islands. Fieldiana. Zoology, 40(12), 231-261.

Bonato, L., Dohle, W., Maruzzo, D., & Edgecombe, G. D. (2010). A phylogenetic analysis of geophilomorph centipedes (Chilopoda: Geophilomorpha) inferred from morphological and molecular data. Zoologica Scripta, 39(6), 596-606.

Ishiwata, K., Sasaki, G., Ogawa, J., Miyata,T., & Su, Z.-H. (2011). Phylogenetic relationships among insect orders based on three nuclear protein-coding gene sequences. Molecular Phylogenetics and Evolution, 58(2), 169-180.

Zhang, Y., Wen, J., Chen, J., Wang, B., & Chen, J. (2019). A comparative analysis of complete mitochondrial genomes of two Scolopendra species and phylogenetic relationships within Myriapoda. International Journal of Biological Macromolecules, 126, 1001-1009.

Red tails for the Red-Heads: Ultimate Legs

Millipedes of Petroglyph - Petroglyph National Monument (U.S. National Park Service)

    figure 1. Source: Cryton, Inga. “All There Is to Know about the Different Types of Centipedes.” PESTKILL, 14 Jan. 2023, https://pestkill.org/centipedes/types/.

in class Chilopoda, or what are more commonly known as centipedes, their most readily identifiable characteristic is the presence of more than 15 pairs of legs, which peculiarly always come out to an odd number of limbs for every centipede. speaking of legs, the legs of a centipede are broken up into different categories based on where they are located. Ultimate legs, for example are the pair of legs that are located at the caudal segment of the centipede’s body, which are also known as terminal legs (Bonato, 2010).

With the presence of ultimate legs, they do not have the primary function of locomotion which differ from the other pairs of legs on the centipede. As featured on the figure above, the ultimate legs have a pair of hooks that are used for defensive purposes against attacking predators, or as a intimidating deterrent for would-be predators who recognize the danger of these appendages (Kenning, 2017).

In the case of the Red-Headed Centipede (Scolopendra Marsitans), it is the presence of a proportionally large pair of ultimate legs that is used to identify members of that specific species among centipede taxa. In relation to other species within Chilopoda, the ultimate legs have become an very convenient way for field researchers to distinguish between the species of centipede that they come across, and have encouraged inquiry into the nature of these appendages as they relate to the locomotive legs.

while not “true” locomotive legs in form and function, the ultimate legs are equipped with unique sensory organs called chemo sensitive sensilla. they work in an analogous fashion to the olfactory organs present in other animals, by way of obtaining chemical information from their surrounding environment. This may come with the purpose of navigating their environment, or recognizing opposite-sex members of the same species to initiate reproductive behavior (Kenning, 2017).

Works Cited

      Kenning, Matthes, Carsten HG Müller, and Andy Sombke. “The ultimate legs of Chilopoda (Myriapoda): a review on their morphological disparity and functional variability.” PeerJ 5 (2017): e4023.

       Bonato, Lucio, et al. “A common terminology for the external anatomy of centipedes (Chilopoda).” ZooKeys 69 (2010): 17.

 

Creepy, Crawly Chilopoda

Link

centipede

Prior Knowledge
Chilopoda Centipedes are segmented invertebrates that possess many legs, hence the name of centipede translating to 100 legs. Many examples of these creatures are venomous and have toxins in their bite that can paralyze and kill prey, as well as an escape mechanism for predators

Distribution

Chilopoda have a nearly worldwide distributionEdgecombe, Gregory D., and Gonzalo Giribet. “Evolutionary biology of centipedes (Myriapoda: Chilopoda).” Annu. Rev. Entomol. 52 (2007): 151-170.

Fun Facts

Centipedes do not actually have 100 legs, as they often times possess an odd number.

there was an extinct species of centipede that measured to be about 6 feet in length, dwarfing the size of many human adults.

 

 

The March from Selma to Montgomery

Dear John Lewis,

In the reading from the pages 174-246, I came to learn all about the events that surrounded the march from Selma to Montgomery, following the brutal murder of Jimmy lee Jackson, a participant in the protest of the arrest of an SClC member. The devastating psychological blow prompted them to do this March, at which the first attempt they were put to a halt and violently attacked by the police, causing them to have to reschedule several times. The violent attack

African Americans are attacked during a civil rights march

John Lewis is Pictured being attacked in the violent confrontation

against the participants came to be known across the nation as Bloody Sunday, causing the ramifications of revolt across the country, and inspired the president at that time to take some action through signing into law the voting rights act that would ultimately lead to African Americans no longer being denied the right to vote.

 

In reading the pages, I could not help but be inspired by the persistence of those involved in the march, setting off a course of events that would eventually lead to them finally making a difference and attaining the right to vote. Although frustrated, and traumatized by friends, brothers and family they lost throughout the way, they still kept their dignity in insisting that these demonstrations remain nonviolent, and it is because of these brave men and women why a person of color like me have the some say in our government.

It is with the peaceful methods demonstrated in the Novel that we can use to combat racism in 2019, as one cannot use hate and violence to fix more hate and violence, and instead of focusing on what makes us different, people should find some common ground and put their differences aside.

Your Inspired reader, Oral

Oral’s Spatial analysis

               

A picture of me and my brother as kids in Jamaica

My Younger self (right) with my older brother (left) as children In Jamaica

Currently, I am enrolled at Georgia State University as an interdisciplinary studies major with a concentration in Biomedical Science and Engineering. This is my first year in college, and as a college student, the scenery around me is ever changing depending on the time of day. As opposed to the more stark, college-oriented

spaces in my current life, I prefer something more colorful and cultural such as a restaurant. In this case, my space of choice was a carribean restaurant, in which people of my cultural background came together to congregate and have a good time, not more than an 8 minute walk from my dorm. Choosing this space was relatively easy, as I am always eager to go out of my comfort zone and visit new environments I haven’t had the chance to immerse myself in before . My primary reason for going was to focus on the content of this analysis, but ultimately, my experiences were good enough to warrant me visiting again sometime, despite a noticeable iniquity being present.

 

From the moment entering the establishment, It was almost like two worlds collided, with the colorfully painted floors and the polished wooden countertops clashing with the concrete and metal atmosphere of the outside. One could almost describe it like stepping into another dimension, one away from the urban life and high paced activity, transitioning into a setting that would mimic an island, with relaxed people and cultural music. The vibrant wall painting emanated the cultural background of the establishment, completely independent of the urban way of life on the outside, and people who once treated each other like total strangers outside actually interacted with each other and took the time to “slow down” to engage in conversation. Come time for the dance floor to open up, new guests converged their way in like a gust of wind and with a swagger of bliss.

     On the scene of the dance floor, there were different huddles of guests mingling within their clique, but the rhythms in the beats were so contagious that they seemed to move in synchrony with each other. Gone was the typical boisterous energy of more “typical parties”, and present was a plethora of social interaction and interconnective conversation in every direction. The music guided the movement of the crowd in a near autonomous fashion, with each beat working the crowd as if it had a mind of its own. The genre of music being played soon took a sharp change of pace as what were once optimistic lyrics about dancing and romancing  delved into a hate filled extravaganza. Homophobic slurs were being casually thrown about throughout the song and the partygoers were swaying from side as if it wasn’t any of their business to stop and listen.

Partygoers enjoying their time at The Sound Table

An look at the interior of the establishment

       The fact that people were so indifferent to the context of the music was quite almost out of place, and some even went on to chant some of the lyrics. In the wider setting of Atlanta, homophobic music would not gel with several niches of people, but despite all of the pride marches and movements in this city, it is clear that there are still places that find no problem with playing hate filled homophobic music. It was very clear that the DJs were aware of the content of this music, but made a rushed attempt at a discretion warning before each “questionable” song as a way to justify that their intentions were not malicious, despite sometimes playing a few of these types of songs in a follow up, back to back fashion.

      On a closing note, the problem of homophobia within popular culture, namely music, is still an ongoing issue despite some groups pretending that playing it aloud is a harmless practice, when in reality it comes at the expense of the already oppressed individuals in the LGBT community. The fact that this is going on not to far away in the city that has been the host of marches and festivals promoting gay pride makes this predicament all the more damning in terms of severity, while the people promoting it beleive that a simple discretion warning or apology is more than sufficient enough to cleanse their involvement in such a hateful expression. Lyrics of homophobic expression are not only confined to dancehall music, but multiple examples of it can be found in modern mainstream  hip-hop songs from various popular artists, but are often overlooked in the way of criticizing other things such as the objectification of women. Homophobia in our music and popular culture is a very real problem that cannot be ignored any longer in the light of a more diverse, accepting society in this day and age, and it is the responsibility of the listening audiences in our society to pay closer attention to ensure that progress to change this is being made.

March Blog post #3

                     In response to reading pages 80-170 of March, I was able to get a much more broad insight as to the specifics and the personal level of events that went on during the civil rights movement. The reading mainly had to do with the disenfranchisement of African Americans, and showcased what exactly was being done in the fight for their voting rights. John Lewis himself makes an appearance in one of the panels of the pages, and is recognized by an opposing white man during the movement for voting rights, highlighting him as a firsthand source of the events that took place around him (ethos). 

         While African a Americans were going missing and bodies were being found in remote areas, it threw the black community and the organizers of the civil rights movement into a sense of panic and despair, as the (Mostly white) policemen did not care about the missing persons, but instead questioned them about their involvement in random suspicious activity. Police calls due to bottle throwing and violence against blacks in their own neighborhoods were going unanswered, in the heat of the tensions that faced the civil rights movement in the fight against disenfranchisement over the summer.

      Later on In the reading, I was enlightened to get to know more about the inner workings of the SNCC, and the efforts by them to not only eliminate tighter racial tensions in the south, but their efforts abroad in South Africa and other countries as well, much to the dismay of the racial southerners. This shows that the interests of the members of the SNCC were not only confined to their problems, but were generally altruistic in opposition to the discrimination that they faced in their time. At another point came desperation, as the SNCC was going bankrupt and losing money after organizing a number of events, in some of which Dr. King himself was involved.

What’s in a space?

           For my space of choice, i visited a Caribbean bar/ restaurant over the weekend on a Sunday. Being from a Carribean background myself, it was a natural choice, as the ,music, food, drinks and overall vibes reflected things that I was already familiar with and gave me a chance to feel like I was at a home away from home. While I was there, I was even able to speak in my Carribean patois with the people that were there, putting me at ease and making me overall feel more comfortable in my own skin, being surrounded by people with the same cultural background. All around me people were chatting, laughing and mingling, setting the comfortable friendly atmosphere throughout the entire establishment. The sweet aroma of jerk seasoning stung the inside of my nostrils, while I sipped on an ice cold coke trying to take in as much of my surroundings as I possibly could. There bright colors painted on the wall reminded me of the sunshine I would expect “back home”, an aesthetic choice that one could argue was done on purpose. 

                   After a while I was comfortable enough to “come out of my shell” and talk to some of the rather more attractive women that I saw there, having a warmer response and a generally more welcome demeanor than one would typically expect from an American girl, to a slight amount of surprise from me. Minutes and hours merged into each other, and soon I found myself not wanting to leave, despite knowing that I would have to eventually go home to write about my experiences in this space. At around 5 PM, the dance floor opened, and the guests were so enthusiastic, that some of them left their drinks behind and I soon followed suit. The Island rhythm of the reggae beats felt like they were vibrating through my very bones, and soon I found myself dancing with one of the women I was crushing on earlier. With every groove I felt my muscles loosen, as I “let loose” and it almost felt like I became one with the rhythm. We moved in synchrony, as I kept my hands steady on her waist as she got down low with a circular motion of her hips and pulled me closer to her body by my wrists.

     With the sudden song transition, my mood changed on the edge of a dime while listening to some of the lyrics and realizing what was being said. The contents of the song were mainly homophobic condescending lyrics, demeaning homosexuals and at certain point calling for violence, a predicament that made me snap out of the euphoric trance I once had on the dance floor. Some of the other partygoers seemed not at all phased, still rocking back and forth ands even chanting some of the lyrics as if they were ignoring the negative implications of it all, making the atmosphere no longer as relaxing to me as it initially was. After a few more drinks, I made my way out of the door and headed back to my dorm. On the way there i could not help but think to myself that there are people that are still homophobic to this extent, especially in a place like Atlanta, and even more puzzling that they would even promote or be allowed to play this type of music in a public setting. Common knowledge would be that the content of this type of music is insensitive toward certain groups of people, and neither the DJs or the partygoers cared to be keen on this fact, instead got carried away by the music and danced on like it wasn’t at all something to be concerned about. I usually thought of homophobia as a minor more “undercover” issue somewhat exclusive to a certain group of people, but this experience showed me that homophobia can exist anywhere you go, sometimes even creeping into the places where you find yourself the most at ease, which is a very uncomforting thought, especially for those of the LGBT community.

 

A Letter to John Lewis #2

Dear John Lewis,

  In my further reading, I have come to understand more of some of the racial tensions and inequality that happened during the events of the book, with the example that stood out the most to me that happened in Roseville Mississippi in June. Colored clergymen looking for their other missing church members were stopped and questioned by police officers on their way to look for them and were arrested without further question and brought into custody. Even while explaining the context as to why they were looking around, the police just made the basic assumption that these ordinary black men were up to no good, with the questions. This resonated deep within me, as I feel like I would feel violated if something like this was to happen to me, with police officers making up their mind that they were going to put me through turmoil, especially in a state of crisis where I am just looking for my missing church brothers. This brings attention to the fact that Law enforcement during that time simply just didn’t care, and you were automatically branded for being a person of color. In this situation, I would only wonder why this is the case. Why I was getting arrested when I should instead be getting help. Why the predetermined hate? Why the lack of empathy? And many more questions still burning inside me. In the midst of this turmoil, media attention was drawn to this seemingly ordinary town in the racist south with the conspiracy of weapons being stolen from the national guard being amidst, which puts priority into perspective. And to think that arresting colored people was really all that more important.

your avid reader, Oral

Cows with typewriters?

My first experience with Literacy

As early as I can recall, I was in first grade in a general class when classes were not divided into sections when we just did everything together in one class. Oddly enough it was a class with a substitute teacher reading a book about cows with typewriters and electric blankets. The story is vague in my mind but we were tasked about what we would ask for in writing if we were the cows in the story, and while I did not know it at the time we were asked to make a connection to self from the story we read. I did what any first grader would do and I let my imagination run wild, asking for aquariums, pet dinosaurs and five star hotels. Writing in this type of context was new to me, and I was excited to present to the class when we were asked to share what we wished for.

 With some of the others they made wishes such as spaceships and some even wished for autographs from WWE superstars (something really popular with kids at the time) with this literacy experience, I learned that other people have a different view on the desired outcome of the story. Although I enjoyed sharing what I would ask for, I honestly thought that the story was stupid (cows with typewriters, electric blankets and all) but my takeaway was that everybody had a different takeaway