107 — Cheeseman's trophon, Paratrophon cheesemani

Paratrophon cheesemani, Maori Bay,
west coast of Auckland, March 2011.

Paratrophon cheesemani, between green-lipped
mussels, Maori Bay, west coast of Auckland,
March 2011.

Cheeseman's trophon, Paratrophon cheesemani (Hutton, 1882), is a small gastropod (~14mm) named after Thomas Frederic Cheeseman (1845–1923), an ex-curator at Auckland Museum. It's endemic to the northwest coast of North Island, where it lives in the lower intertidal zone of exposed coasts. There is a transition zone around Port Waikato where this form is replaced by the predominantly southern P. cheesemani exsculptus Powell, 1933.
Once these two forms are genetically analysed* they may turn out to be separate species.

Very little appears to be known regarding their ecology. However, Cheeseman's trophon is a muricid whelk and these whelks feed by boring through the shells of other animals (typically other gastropods, bivalves, and barnacles). My observations suggest that this species possibly fulfils a similar role to that of the oyster borer (Haustrum scobina (Quoy & Gaimard, 1833)), but lower on the shore, especially since vertical distributions of these two species don't appear to overlap. I suspect that this small gastropod is easily overlooked and the exposed nature of its habitat makes working on it difficult in situ.

*Barco et al. (2015) looked at P. cheesemani exsculptus but not P. cheesemani cheesemani, so no comparison was made between the two forms.



More info:

Barco A, Marshall B, Houart R, Olivero M. 2015. Molecular phylogenetics of Haustrinae and Pagodulinae (Neogastropoda: Muricidae) with a focus on New Zealand species. Journal of Molluscan Studies, 81(4): 476–488.

Paratrophon cheesemani http://www.mollusca.co.nz/speciesdetail.php?speciesid=1000&species=Paratrophon%20cheesemani

Paratrophon cheesemani exsculptus http://www.mollusca.co.nz/speciesdetail.php?speciesid=1001&species=Paratrophon%20cheesemani%20exsculptus

106 — Asian paddle crab, Charybdis japonica

Asian paddle crab, Long Bay marine reserve,
Auckland, 24/3/17.

The Asian paddle crab, Charybdis japonica * is a medium-large green-coloured crab (to ~12cm carapace width), which has become established in northeastern New Zealand. At present they are known from the Waitemata Harbour north to Whangarei Harbour, and Opua/Waitangi in Northland.

Asian paddle crabs were first detected in the Waitemata Harbour near the end of 2000. They prefer sheltered estuarine conditions and are very aggressive, with a strong and painful nip (personal experience). They reach maturity at around ~46 mm carapace width (for females) and can reproduce frequently, possibly several times a year, meaning they could become established in a new area quite quickly. However, they need the water temperature to be at least 20˚C to breed and this will probably limit their southward advance.

The invasive asian paddle crabs are of a similar size to the commercially exploited local species of paddle crab (Ovalipes catharus).  Asian paddle crabs feed on a variety of benthic species including gastropods, bivalves, and other crabs; so there is the potential for competition with local species for resources. Recently I was told that in areas where these two species co-occur, asian paddle crabs now predominate: having out-competed the local species.

* (A. Milne-Edwards, 1861)

Asian paddle crab, from under a rock,
Musick Point, Tamaki Estuary, 14/1/17.

Asian paddle crab, from under a rock,
Musick Point, Tamaki Estuary, 14/1/17.

A smaller Asian paddle crab, from under a
different rock, Musick Point, Tamaki
Estuary, 14/1/17.

And less than half a second later...

More info:

http://www.biosecurity.govt.nz/pests/asian-paddle-crab

http://www.cabi.org/isc/datasheet/89054

https://researchspace.auckland.ac.nz/bitstream/handle/2292/6659/whole.pdf?sequence=8

105 — Spotted whelk, Cominella maculosa

Cominella maculosa, low tide at Devonport,
Auckland 2015.

Cominella maculosa, Sumner, Christchurch, 1993.

The spotted whelk, Cominella maculosa * is another small to middle-sized snail (~45mm) endemic to New Zealand. It's very similar to it's near relative the speckled whelk (C. adspersa). However, spotted whelks have a slightly different distribution, tending to occur in shallower, more sheltered waters and harder substrates. They are found throughout North Island and down to at least Christchurch in the south. South Island forms are smaller and more compact than those from the north.

These two Cominella species are thought to be predator/scavengers and can often be found around carrion. Graham (1941) reported C. maculosa as feeding on the rock oyster **  and cockle *** in Manukau Harbour. However, those observations were published before the advent of the Pacific oyster #, which now dominates much of that habitat. It would be interesting to find out if C. maculosa preys on the Pacific oyster.


* (Martyn, 1784)
** Saccostraea glomerata (Gould, 1850)
*** Austrovenus stutchburyi (Wood, 1828)
# Crassostraea gigas (Thunberg, 1793)



More info:

http://www.mollusca.co.nz/speciesdetail.php?speciesid=1088&species=Cominella%20maculosa

Donald K. M. , Winter, D. J., Ashcroft, A. L., Spencer, H. G. 2015. Phylogeography of the whelk genus Cominella (Gastropoda: Buccinidae) suggests long-distance counter-current dispersal of a direct developer. Biological Journal of the Linnean Society, 115, 315–332.

Graham DH 1942. Breeding habits of twenty-two species of marine Mollusca. Transactions and Proceedings of the Royal Society of New Zealand, 71, 152–159.

104 — Absence of stingray...

Stingray 'pit', Te Matuku marine reserve,
Waiheke Island, 25/11/16.

These pictures show the pits left in the mudflat made by the feeding of stingrays, at Te Matuku marine reserve, Waiheke Island.

There are three species of stingray found in New Zealand waters and the most common is the short-tailed stingray (Dasyatis brevicaudata (Hutton, 1875)), which can grow up to 4.3m, making them the largest stingrays in the world.

Another stingray 'pit', Te Matuku marine reserve,
Waiheke Island, 25/11/16.

In the first picture, the orientation of the stingray was such that the head was pointing down to the right, so that its mouth was over where the dark hole in the mud is now. The ray then liquified the sediment beneath its head so that it could get to the invertebrates buried below the surface. If you look carefully you can see its outline in the mud. In the second picture the ray's orientation is with the mouth pointing towards the upper left of the picture. I've sharpened this shot a little to try and bring out a bit more detail.

It is thought that short-tailed stingray feed on crabs and bivalves (Ayling & Cox 1982), but these data are quite old and probably could be updated in light of the invasive species now found in the Auckland region. Stingrays share their habitat with a number of new arrivals, several of which could now be prey items.

Recent research on a closely related species from Japan has revealed that stingrays are bioengineers, and are important in the turnover and re-oxygenation of sediments (Takeucki & Tamaki 2014). By digging these pits, stingrays may therefore help to maintain a healthy mudflat ecosystem.


More info:

http://www.seafriends.org.nz/issues/res/pk/stingrays.htm#short-tailed_sting_ray

http://phys.org/news/2016-09-stingrays-food-swallowing.html

Ayling, T, Cox GJ 1982. Collins guide to the sea fishes of New Zealand. Collins, Auckland, New Zealand.

Takeuchi S, Tamaki A 2014. Assessment of benthic disturbance associated with stingray foraging for ghost shrimp by aerial survey over an intertidal sandflat. Continental Shelf Research, 84, 139–157.

103 — Micro molluscs, Micrelenchus sanguineus

Micrelenchus sanguineus, Mount Beach,
Mt. Maunganui, 2015. 

Micrelenchus sanguineus * is a small herbivorous gastropod endemic to New Zealand. They are found at and below low tide down to a few metres depth on and around the bases of seaweed in clear water locations. They are quite small (~8mm), but can be brilliantly coloured and quite attractive little shells.

North Island examples from tend to be more colourful and patterned than ones from the south, which also differ in having a heavier shell (known as the cryptus form).

*(Gray in Dieffenbach, 1843)





















More info:

http://www.mollusca.co.nz/speciesdetail.php?speciesid=241&species=Micrelenchus%20sanguineus

102 — Palmer's trumpet, Proxicharonia palmeri

Named after the diver who first found it at the Poor Knights Islands, Palmer's trumpet (Proxicharonia palmeri (Powell, 1967)) is a small (~50–60mm), trumpet shell found off northern New Zealand. They are much sought-after by collectors and are an attractive orange beneath a brownish periostracum.

Very little is known about their ecology, but a few have been found offshore and some at considerable depths (~500m). This species is closely related to the fossil P. neozelanica (Marshall & Murdoch, 1923), and there was speculation that they were identical, although now these two are considered separate species. They appear to live in between depths which are too deep to SCUBA dive and too close to rocky outcrops to turn up in dredges or trawls.

The P. palmeri below are from an offshore site and at the time they were collected, probably represented the largest number seen at one time.

Proxicharonia palmeri

Proxicharonia palmeri, showing the animal.

Many many Proxicharonia palmeri. This was but a sub-sample.

More info:

http://www.mollusca.co.nz/speciesdetail.php?speciesid=866&species=Sassia%20palmeri

101 — Crimson (immortal) jelly, Turritopsis rubra

Turritopsis rubra, mussel farm,
Waiheke Island, Auckland, 27/02/14.

Turritopsis rubra, south Piha, 26/04/17.

Turritopsis is a genus of small hydrozoan jellies (<10mm). There are a few species and there appears to be some debate regarding the number. They have a complex lifecycle, which starts off when eggs are released by the medusa (jelly) phase into the plankton. Assuming they survive, they then hatch and settle as a cyst-like blob and form polyps. The polyps then grow and bud off small medusa, which then swim off and grow, produce eggs, and then die. The end.

Turritopsis rubra, mussel farm,
Waiheke Island, Auckland, 27/02/14.

Turritopsis rubra, mussel farm,
Waiheke Island, Auckland, 27/02/14.

Except in Turritopsis dornii it's not necessarily the end. This species can reverse this process, so when times get tough they can revert back into a polyp and wait for conditions to improve. This lifecycle reversal is called transdifferentiation and essentially cheats death, making the jelly biologically immortal.

This transdifferentiation ability enables the jelly to survive long ocean voyages in the ballast tanks of ships and so there is a perception that these little jellies are silently taking over the world's oceans.

As a consequence of their biological immortality, there has been interest regarding the implementation of transdifferentiation in regenerative medicine. However, so far, it appears that the jellies are really hard to keep alive in aquaria making them difficult to study (which seems ironic).

The species pictured here is T. rubra (Farquhar, 1895), which has a south Pacific distribution. It is currently unknown whether this species can transdifferentiate its cells like its close relatives.

These little jellies have quite a painful sting, especially if their tentacles get trapped between a swimmer's (or surfer's) clothing and their skin. The tentacles are long and very fragile, so can break off easily. There was quite a bloom of these little jellies during the summer of 2016–17 on the North Island west coast. Many people thought they were being bitten by sea lice, when in fact they were probably being stung by these jellies. I think "being bitten by sea lice" is a myth.


More info:

Regenerative medicine: http://singularityhub.com/2011/04/25/immortal-jellyfish-provides-clues-for-regenerative-medicine/

100 — Giant squid, Architeuthis dux

A large female giant squid at AUT, 2004.

Three giant squid, defrosting at AUT,
June 2014. Squidcicles...

The least damaged of the three, being made ready
for a live dissection webcast, June 2014.

Giant squid sucker rings from a large female.
These are this colour due to being kept in
alcohol since 2008.

A giant squid sucker ring from a large female.

A giant squid sucker attached to a tentacle.

Another giant squid at AUT, 2008.

The giant squid or legendary Kraken, Architeuthis dux, Steenstrup, 1857, is a very large and iconic squid. It is monophyletic, which means it's the only member of its family, Architeuthidae. In the past there were thought to be many different species, but this was more a reflection of the range of the giant squid and the geographic isolation of the scientists studying them. Giant squid are found worldwide at depths between ~250–1000m. There's quite a lot of information out there regarding giant squid, but some of it isn't very accurate.

Arguably, the biggest piece of misinformation regarding giant squid is their size; they don't get as large as has been reported, but, you can make them quite long if you really stretch the tentacles. The body gets to about 2–3m, while most of their length is made up the feeding tentacles, which can be several metres long. So they can get to around 10–13m in total length depending on which sex they are; females are larger. Also, they can't sink ships.

Ecologically giant squid are thought to be ambush predators, hanging inert in the water column waiting to snatch prey with their two long feeding tentacles. in turn they are preyed on by sperm whales. Stranded sperm whales (Physeter macrocephalus) are often seen with head scars from the suckers of giant squid they have attacked (and probably eaten). It's unlikely that a giant squid would have much of a chance against a sperm whale.

In the past giant squid were really only seen when they washed up (usually quite damaged). However, these days they turn up as bycatch in deep-sea trawl fisheries. In New Zealand waters they are occasionally taken as bycatch in the hoki fisheries off the west coast of the South Island.

One last point: you can't eat them, as they are filled with ammonia. The ammonia ions are lighter than water, so it is thought that is aids in buoyancy.

Here's a video of giant squid expert Dr. Steve O'Shea examining a giant squid at AUT in 2008 (he's a bit sweary, so nsfw).



















More info:

http://squid.tepapa.govt.nz/resources

https://www.tonmo.com/pages/architeuthis-age/