Showing posts with label animals. Show all posts
Showing posts with label animals. Show all posts

27 Jan 2014

Ants of Singapore #10 - Amblyopone (reclinata)

Amblyopone

Species accounts


Amblyopone reclinata Mayr, 1879


Distribution: Luzon


Saw these really cool Amblyopone cf reclinata ants. They belong to the subfamily Amblyoponinae. Check out those mean jaws. 

These ants belong to a group of "Dracula ants".

Ants of the genus Amblyopone has "footprint gland" which is used in recruitment via secretion of a pheromone [1]. This allows for quick recruitment [2].




16 Dec 2013

What's going on at Pasir Ris beach?

I had a short and relaxing break at a family-organised chalet in Aloha Loyang and thoroughly enjoyed the good food and company in my 2D1N stay there. As usual, I went on a very small scale exploration of the Pasir Ris breah coastline just outside the chalet area but was taken aback by the amount of trash and dead organisms on the beach.

Heavily littered coastline. I believe that most of the trash is derived from Pulau Ubin that is directly opposite..

More trash and P. Ubin in the distance

I am not very sure why there is just so many dead organisms here. Within a 50 metre stretch of sand, I have counted about 5 dead horseshoe crabs, 6 dead fishes, 2 dead crabs and likely to be many many more, since I wasn't paying attention to every detail. The Loyang Shipyard was close by and the pollution derived from it could be a possible reason.

Dead horseshoe crab

Dead filefish

Dead unidentified fish

Dead catfish?

Dead flower swimming crab

Dead swimming crab

More trash is seen during the lowest tide of about 80 cm

Durian husk. (hrmm)

Grey heron flew by. :)

Pair of Oriental Pied Hornbills in the distance..

Was mind-blowned by the trashy beach until I heard some squeaks and spotted a pod of Smooth-coated Otters swimming pretty fast along the coast. Most had fishes in their mouth and I wonder if those fishes are even healthy/fresh ones to begin with. :/

In short, this experience serves as a great reminder of the need to manage our waste properly and not throw them into the sea in an irresponsible manner... Gotta keep our beaches clean!! >_<

4 Dec 2013

Things we do for class - Species pages

For most of the last semester, we have been working on these species pages for our taxonomy class. Eunice's page is none other than being focused on what she does best, ANTs. And so her target species is Proatta butteli, a really interesting ant. As for me, I have decided to focus on a bird species, the Common Hill Myna (Gracula religiosa). The reason for doing so is because I have a love for birds too (not just dung beetles) and this species is one of my favourites.


Screenshots of our species pages. TOP: Proatta butteli. BOTTOM: Gracula religiosa

Our pages are found at this website, http://taxo4254.wikispaces.com/, together with other species pages done by other students as well. Enjoy~

13 Oct 2013

Things we do for class - Bivalve dissection


Chama pacifica Chamidae

Just last week we did another dissection practical. This time, for bivalves! We got to dissect a Meretrix sp. ("La La", a heterodont), Nuculana sp. (which was really tiny, a protobranch), Anodonata sp. ("Mussel", family Mytillidae, a pteriomorph), Anadara sp. ("Blood Cockle", a heterodont).

Bivalves are molluscs that are laterally compressed and have a hinge, enclosing two hinged parts. The shell is made up of calcium carbonate secreted by the mantle lobes and mantle. The calcium carbonate can be either aragonitic (nacreous inner layer - sheet or lenticular, prismatic, cross lamellar structure - simple or complex) or calcitic (outer foliose, prismatic). The calcium carbonate of a shell is never entirely calcitic though, mostly it is a mix of aragonite and calcite. Certain bivalves though, like oysters have almost all calcitic. On the contrary, some families are entirely aragonitic.

Lima vulgaris Limidae with wholly aragonitic shells
They have a D-larva split into two stages, Prodissoconch I and Prodissoconch II which have the velum to help it with motility with the exception of the Paleoheterodonts which have glochidium/ lasidium larvae.

They are generally split into different clades based on gill type, presence of palps, type of stomach, fusion of mantle & siphon position (higher taxa); hinge teeth type (higher or lower taxa); foot size, position of adductor muscles (lower taxa):

(photographs were identified by Tan Siong Kiat in 2011 as part of Project Semakau: bivalve page)

- Protobranch (small group, 3 orders, considered 'ancient', small in size, bipectinate lamellae (simple) gills with palp probocoides (for Nuculidae and Nuculanidae), foot frilled with papillae, do not filter feed but scrape detritus or symbiotic with sulphur oxidising bacteria in gills (only Solemyida))
e.g. Nuculana

- Paleoheterodont (mostly in the family Unionidae but there are 6 other families; mostly are freshwater except one of which is salt-water - Trigoniidae)

- Heterodont (unequal hinge teeth, eulamellibranch gills, mantle edges are fused at the posterior end as an inhalant tube) and Anomalodesmatans (typically lack hinge teeth, aragonitic shells, long siphons, fourth pallial aperture, vestigial gill filaments; Septibranchia is carnivorous with a type II stomach)
e.g. Heart Cockle (Cartiidae), La La Siput (Veneridae), Meretrix (Veneridae)


Cordissum cardissa Cartiidae
Dosinia amphismoides Veneridae

Teredo sp. Terenidae
Tellina virgata Tellinidae


- Pteriomorphs  (reduced foot, filibranch gills (Oysters (orders Ostreida, Pectinida) are exceptions - they have eumellibranch gills with the exception of Plicatuloidea (superfamily)), mantle edges generally not fused, taxodont or dysodont hinge teeth)
 e.g. Green Mussel Perna sp. (Mytilidae), Hammer Oyster (Isognomonidae), See Hum Anadara sp. (Arcidae), File Shell (Limopsidae), Scallops (Pectinidae), Spiny Oysters (Spondylidae)

Lithophaga teres Mytilidae
Isognomon isognomon Isognomidae

Pinna bicolor Pinnidae

Spondylus niobarensis Spondylidae
A related species to Spondylus, the Comptopallium radula
Notes:
- filibranch is ancestral to eulamellibranch gills
- heterodont/schizodont/isodont/dysodont teeth is more derived than taxodont teeth


Important parts of the bivalves are:

Of the valves
- Hinge teeth: either cardinal or lateral; isodont/schizodont/heterodont/dysodont/taxodont

Taxodont hinge of Anadara antiquata Arcidae
- Umbo: a knobbly protuberance (determines dorsal)
- Lunule (typically anterior but the mouth position determines anterior/posterior)
- Estucheon (typically posterior)
- Periostracum - either secreted by the mantle edge or foot

- Pallial line, where the mantle edge is
- Pallial sinus, a groove where the siphons are retracted into

Anatomy
- Ligament: inner (lamellar), outer (fibrous); can be alivincular, duplivincular, parivincular, multivicular, either amphidetic (either side of the umbo; usually only for alivincular or dulivincular only) or opisthodetic (anterior of umbo; usually for parivincular or multivincular only); e.g. opisthodetic parivincular are typically of the heterodonts, multivincular opisthodetic are typically of the Isognomidae ("Hammer Oysters"), duplivincular amphidetic (Arcidae), alivincular amphidetic (Limopsidae),

- Gills: made up of lamellae with cillia (Protobranchs); when fused, form demibranches connected by tissue between lamella but not always so; might have cillary junctions (filibranch; Pteriomorphs); when filaments are fused with adjacent filaments, form interfilament junctions, exclusively NO cillary junctions (eulamellibranch; Heterodonts); typically one pair of ctenidia on each side of the visceral mass; each ctenidia with a descending and descending lamella for the eulamellibrach condition; Septibranch condition is a poorly-developed septum with vestigial gills but has tentacles on inhalant siphons to suck small prey up

- Adductor muscle - present most of the times in the anterior and posterior position (isomyarian/heteromyarian/monomyarian); typically one pair of adductor muscle(s) on each valve; for example, Green Mussels (Perna viridris) only has posterior adductor mussel, scallops have one large adductor (central) muscle (monomyarian)

Saccostrea cucullata Ostreidae with an adductor muscle scar

- Other retractor muscles 

- Mantle (inner, mid, outer folds; outer - secretory, may be sensory; mid - sensory, have tentacles, sometimes eyes; inner - muscular and attached to shells) with type A/B/C fusion

- Visceral mass which contains heart (2 auricles, 1 ventricle; open circulatory but certain families have haemoglobin and is 'bloody'), digestive organs (esophagus/ stomach - crystalline style, typhosole, sorting area/ intestines/ anus), reno-pericardial complex, gonads

- Periocardial complex
- Two ganglia (cerebro-pleural ganglia innervates palps, anterior adductor muscle, otocysts, part of mantle and visceral ganglia innervates gills, heart, pericardium, posterior adductor muscle, most mantle regions, siphons and pallial sense organs) 

- Byssus - secreted by foot typically
- Eyes - pallial (marginal or siphonal, innervated by mantle) or cephalic (inner demibranchs of ctenidia, innervated by cerebral ganglia)

- Siphon - for respiratory purposes/ suspension feeding

- Labial palps (2 pairs)/ palp probosoides (not always present)/ mouth; sometimes labial palps can be hypertrophied (such as in Scallops) to helps food items not 'fall out' while swimming


That was a spam of essential terms. Anyway, here're some photographs by Xin Rui during the practical.


Meretrix sp. ("La La") which is a heterodont. Photo source: Ong Xin Rui

The internal anatomy of the Meretrix sp. ("La La"), the same as above. For our practical session, we were required to draw the anatomy. Please note that the posterior and anterior ends should be exchanged. Photo source: Ong Xin Rui

Further reading
[1] About Glochidium/Lasidium larvae: http://mussel-project.uwsp.edu/evol/syst/larvae.html
[2] About hinge types: http://paleo.cortland.edu/tutorial/Bivalves/bivalvemorph.htm
[3] Pictures of bivalves: http://www.nmr-pics.nl/index.htm

I shall update this page again, after I have dug up my bivalve photographs. Everything makes more sense now after this class...

Please correct if you spot any errors. Information taken and summarized from Bivalve lecture notes.

4 Sept 2013

Things we do in class - Fish dissection

Figure 1 - The Tilapia (Osteichthyes: Actinopterygii: Teleostei: Perciformes: Cichlidae: Tilapiine), before dissection. Instruments of the trade
Today marks the first time dissecting an animal during a practical session in "Topics in Aquatic Biodversity". Have watched people do it, and have heard people do it but have never done it myself before because it was never compulsory during biology classes in Junior College and in university, until now. It was quite an interesting experience, albeit frightening at first because it was fish but it really was not so bad.

*****

Fishes, a general introduction


Fishes are a diverse group of animals, that both live in marine and freshwater environments.

They are generally split into these extant groups:
  • Hagfishes (Myxiniformes)
  • Lampreys (Pteromyzontiformes)
  • Jawed Fishes
    - Cartilagenous fishes
    - Bony fishes [ray finned - split into Sacropterygii and Actinopetrygii and lobe finned] 
Note: the Sacropterygii are further split into lungfishes, Tetrapods and Coelacanth; Actinopterygii further split into Neoptergyii and Chondrostei (bichirs, surgeons: which have some what ossification but are generally cartilagenous). Neopterygii is further split into gars (swim bladders function as lungs; heteroceral tail, ganoid scales), bowfins (similar to gars; which are actually able to breathe air, storing the air in its swim bladder connected to its digestive tract) and Teleostei
They are, however, paraphyletic, because any animal that "has a cranium, gill-bearing and lack limbs with digits" are lumped to this clade whereas the 'Tetrapods' are nested within this clade. Thus, it is not monophyletic.

Though, that is, besides the point. Most would be interested in fish as a commodity because it is important for food, which leads to problems of overfishing and is popular in the pet trade, which can lead to the proliferation of invasive animals, in the context of Singapore.

****

Morphology: the exterior and interior

note: the information presented here is learnt during lessons by Dr Tan Heok Hui

Just looking at the morphology of a fish can yield lots of interesting information. One can never divorce morphology from taxonomy and classification of fishes.

By looking at its exterior morphology (Figure 2), one can infer life history traits, habitat and food preferences about the fish based on certain generalizations -- but of course, there are always exceptions! Further, there are specialised structures, indicating some form of adaptations (e.g. barbels for sensory purposes).

1. Position of mouth: superior, terminal, inferior (and a whole suite of in-betweens)
2. Shape of body: torpedo, streamlined like the Tuna; oval shaped/ compressed laterally like the Mola Mola
3. Dentition: the type of teeth/ teeth plates (hooked, grazer-type, flesh-cutting, grinding; fused that is beak-like), the arrangement of the teeth (cartilagenous fishes have rows of teeth, unlike bony fishes), presence of pharyngeal teeth (to act as grips, not masticatory) which is located in the skull
4. Fins: shape of the five fins (ventral fins: pelvic, anal; dorsal fin(s); caudal fin, pectoral fins), whether it is fused or not; caudal fins can be truncate, emarginate, forked, deeply forked, rounded; pelvic fins can be fused; there can be one or two pectoral fins
5. Lateral line: can be complete or incomplete, from the top of the operculum to the (mid-) end of the peduncle; hyped-up lateral line systems with strong/weak voltage, the former for defense/finding prey and the latter for navigation.
6. Buccal cavity adaptations: in mudskippers it is used to store water, projectile expulsion in archer fishes, egg brooding in Osphronemidae/ Cichlidae/ Apogonidae/ Ariidae
7. Scales: Ctenoid/Cycloid (usually for higher fishes like the Teleostei; Ctenoid have a toothed outer edge, fishes with spiny rays as opposed to soft rays); Ganoid (garfishes, bichirs); Placoid (dermal/epidermal origins for Cartilagenous fishes)

Further, dissection to look at the internal morphology of the fish can further confirm the inferences (based on external morphology) such as the diet (gut content, length of gut), gender (male or female, by the gonads) and age (from otoliths in temperate fishes). Also, one can look at the gill rakers.

Figure 2 - Anatomy of a female fish. In a male fish, the ovary is replaced by the testicles.The bones are dorsal to the organs.
Source: http://en.wikipedia.org/wiki/Fish_anatomy

Figure 3 - Bamboo sharks (Chondrichthyes: Orectolobiformes: Hemiscylliidae), a male and a female. The males have a pair of claspers at the anal fins.

Figure 4 - Xin Rui's neat dissection area. She found two little crabs and one fish in the stomach of the predatory fish (second fish from the left).