115 — Miller's nudibranch, Phidiana milleri

Phidiana milleri, from under Ngapipi Bridge,
Tamaki Drive, central Auckland 15/6/18.

Phidiana milleri, from under Ngapipi Bridge,
Tamaki Drive, central Auckland 15/6/18.

Phidiana milleri, crawling in between
green-lipped mussels, the Gap, Piha, 2015,
(~30mm).

Phidiana milleri, crawling on red algae,
Lion Rock, Piha, 2017, (~10mm).

Phidiana milleri, from under Ngapipi Bridge,
Tamaki Drive, central Auckland 15/6/18,
(~30–40mm).

Miller's nudibranch, Phidiana milleri * is a small (to 42mm) and attractive sea slug endemic to New Zealand. It's named after Prof. Michael Miller, an expert in this field. It's reported be found in exposed clean water situations north of Banks Peninsula.

They are thought to feed on hydroids, possibly mussel's beard, which is neither a mussel, nor a beard, but a type of thecate hydroid called Amphisbetia bispinosa (Gray, 1843).

Willan & Miller (1984) considered this to be a commonly seen nudibranch, but this has not been my experience (maybe I'm looking in the wrong places). I've seen it a handful of times and mostly at Piha, on Auckland's west coast: crawling between green-lipped mussels (Perna canaliculus) at the Gap (where there were also hydroids), and then in a rock pool on Lion Rock, where a tiny juvenile was crawling on red algae. I've also seen it under Ngapipi Bridge on Auckland's Tamaki Drive, from under a rock adjacent to the bridge supports—another hydroid-rich habitat.

* Rudman, 1980




































More info:

Sea slug forum: Phidiana milleri

Willan, R. C., Morton, J. E. 1984: Marine Molluscs Part 2: Opisthobranchia. University of Auckland, Leigh Marine Laboratory, Leigh, New Zealand. 106 pp.

113 — Bioluminescence and camouflage in the deep-sea

Once you get down to 1000m in the ocean sunlight is gone, absorbed by the water above.

One thing I noticed during my doctoral research was that many of the fishes at this depth were drab shades of brown, some darker than others. If you live in a world of complete darkness why be brown? For that matter why be any colour at all, what evolutionary advantage could being brown give you?

Well the thing is—it’s not completely dark at these depths—far from it. There may no longer be any sunlight, but there is light from other sources. The world at 1000m is full of point-source bioluminescence, created by the animals that live there. Watch this great TED talk by marine scientist Edith Widder for a more detailed look at deep-sea bioluminescence.

If you’ve watched that talk, you may have noticed that most of the bioluminescence was light-bluish. Now the interesting thing here is that if you invert light blue: you show the colour not being reflected by that object, and that is brown.

What does this mean: If you are a brown fish in a world where the only light is bluish, then you are camouflaged against it, since brown absorbs blue.

Big-scaled slickhead (Alepocephalus australis),
northestern Chatham Rise, 1196m.

Big-scaled slickhead - inverted colour.

Baxter's dogfish (Etmopterus baxteri),
Puysegur Seamount, 1050m.

Baxter's dogfish - inverted colour.

Warty oreo, (Allocyttus verrucosus),
northeastern Chatham Rise, 901m.
~30cm total length (TL).

Warty oreo - inverted colour

The photos show a few examples of brown-coloured fishes and what they look like when the colour is inverted; that is, the colour they absorb.

Apologies for my dodgy 2004 photography. Thanks again to NIWA for providing the fishes.

112 — Gruesome creatures live in the deep-sea…

I took a lot of pictures during my doctoral research, most of which I didn’t end up using for anything. Occasionally though, I would stumble upon something interesting, and by interesting I mean horrific.

A parasitic copepod attaching through the
body wall of a notable rattail.

Fish are often beset by parasites, not only internally, but also externally. Some of the external ones can be quite hideous. In this instance a notable rattail (Coelorinchus innotabilis, McCullock, 1907) has been attacked on its underside by a parasitic copepod. Copepods are crustaceans and these belong in the Order Siphonostomatoida and within that, probably the family Sphyriidae.

Sphyriid copepods attach through (yes, that’s through) the body wall of the fish by means of an anchored stalk and feed on the fish’s bodily fluids. The part you see on the outside is the body of the copepod and it’s reproductive parts ( ~1 cm). These particular copepod parasites are thought to only attack fishes that live close to the bottom and this feature can be used to ascertain details regarding the fish’s habits in lieu of other information. This was corroborated by the diet of this species, as notable rattails are bottom feeders (Jones 2008).

Notable rattail, NE Chatham Rise, 901m

Notable rattail, NE Chatham Rise, 901m.
Dorsal view.

Notable rattail, NE Chatham Rise, 901m.
Ventral view.

Don’t worry though, as these parasites don’t attack people (as far as I know). Plus, they tend to live in deep-water and if you happen to find yourself down at 1000m you probably have bigger problems.

As for the fish itself, rattails are ubiquitous in the deep-sea and about sixty species occur in New Zealand waters. Notable rattails live at an average depth of 985m (Anderson, et al. 1998), so most people won't have seen one. These came from a research trawl for orange roughy, which occurred on northeastern Chatham Rise, during July 2004 (Thanks go to NIWA).

Notable rattails feed on small invertebrates, which they pick from the sea bed (Jones, 2008). As such, they play an important role in the structuring of demersal (near the bottom) communities.























More info:

Anderson OF, Bagley NW, Hurst RJ, Francis MP, Clark MR, McMillan PJ 1998. Atlas of New Zealand fish and squid distributions from research bottom trawls. NIWA Technical Report 42.

Doonan IJ, Dunn MR, Dunford A, Hart AC, Tracey D 2006. Acoustic estimates of orange roughy abundance on the northeastern and eastern Chatham Rise, July 2004: wide-area and hill survey. New Zealand Fisheries Assessment Report 58.

Jones MRL 2008. Dietary analysis of Coryphaenoides serrulatus, C. subserrulatus and several other species of macrourid fish (Pisces: Macrouridae) from northeastern Chatham Rise, New Zealand. New Zealand Journal of Marine and Freshwater Research 42: 73–84.

111 — Wheel shell, Zethalia zelandica

Zethalia zelandica, north Piha Beach, 27/4/17.
These aren't that common here on the west coast. 

Zethalia zelandica, showing animal and
position in the sand. After Morton & Miller,
1968, p467.

The wheel shell, Zethalia zelandica, * is a small (~20 mm across), gastropod endemic to New Zealand and found throughout the three main islands. They are found off exposed sandy beaches and can wash up in great numbers after storms, particularly on the north eastern coast of North Island.

There are some morphological differences over their range, with examples from Stewart Island being higher in the spire and correspondingly narrower than those from the northeast of North Island. I can remember walking around the base of Mt. Maunganui as a boy and seeing banks of dead shells.

Wheel shells are thought to feed on diatoms and other organic matter; they do this through the ingestion of large amounts of sand, although their ecology isn't really all that well-known.

* (Hombron & Jacquinot, 1854)



More info:


Beu, A. G. & Maxwell, P. A. (1990). Revised descriptions of New Zealand Cenozoic Mollusca.

Morton, J. E. & Miller, M. (1968). The New Zealand seashore. Collins.

110 — Sea slug, Alloiodoris lanuginata

Alloiodoris lanuginata, Warrior Rocks,
 Mt. Maunganui, 2017.

Alloiodoris lanuginata, with coil of eggs,
Warrior Rocks, Mt. Maunganui, 2017.

The sea slug Alloiodoris lanuginata (Abraham, 1877) is another species for which there is no common name. It's endemic to New Zealand's North Island and not particularly common. They are quite coarse to the touch and feel like they are covered in fine sand paper. This coarseness comes from fine spicules contained within tiny tubercles, which cover the dorsal surface of the sea slug.

Ecologically they prefer clean, but sheltered waters and are thought to feed on sponges. But, it's not known which species of sponge they prefer.

This one was found between boulders, on Warrior Rocks, at the base of Mt. Maunganui. It had just laid a coil of eggs. It's overall size was about 80mm, which is about as large as they get.

If I see another one I hope to get better pictures.





More info:

Sea Slug Forum: Alloiodoris lanuginata

Willan, R. C.,& Morton, J. E. (1984). Marine Molluscs part II - Opisthobranchia, pp. 1–106. University of Auckland, Leigh Marine Laboratory.

109 — The rare sand chiton, Pseudotonicia cuneata

Pseudotonicia cuneata, The base of
Mt. Maunganui, Opposite Stony Point, 2017

Pseudotonicia cuneata, The base of
Mt. Maunganui, Opposite Stony Point, 2017

Pseudotonicia cuneata, The base of
Mt. Maunganui, Opposite Stony Point, 2017

There are a few dozen species of chitons (coat-of-mail shells) found on New Zealand coasts. However, as most of them could be considered to be unremarkable-looking, they aren't really noticed by your average beach-goer.

Many chitons are light-adverse and have light-sensing organs (ocelli) on their upper surface. They use these to orient themselves away from the light. As a consequence these species are often found under rocks or ledges. Most of the shallow water chitons are thought to be vegetarian grazers, feeding on algal films on hard surfaces. 

Pseudotonicia cuneata (Suter, 1907), is quite a rare and unusual chiton. It's found mostly around North Island and the top of South, at and below low tide down to a few metres deep.

What makes this chiton species unusual is that, unlike almost all other chitons, it's found in sand. But not just any sand, P. cuneata lives in areas with clean fast-flowing waters, but not those not open to wave action, and where there are also dead shells for it to attach to. These are conditions which aren't all that common, so as a consequence not many people have seen one.

It has been speculated that this species grazes on the algal films found on dead bivalve shells, as it's often found attached to them. However, this is another one of those species for which virtually nothing is known. These ones were about 40–50mm in length and from sand around the base of Mt. Maunganui during a spring low tide.

I've only ever found this species in length of beach about 10–20m long, so their habitat is quite vulnerable.



More info:


Ashby, E. (1928). The rediscovery of Tonicia cuneata Suter and Acanthochites thileniusi Thiele (Order Polyplacophora) together with the description of a new Genus and short review of the New Zealand Acanthochitonidae. Transactions and Proceedings of the Royal Society of New Zealand 1868–1961, 58, 392–607.

Powell, A.W.B. (1979). New Zealand Mollusca. Collins

108 — Striped anemone, Diadumene neozelanica

Lion Rock, Piha, 2016: this clip is a little
over-exposed. In the top left corner there is a
solitary ascidian and below that another
?dead solitary ascidian covered in
 athecate hydroids.

Piha, Jan 2017.

The striped anemone, Diadumene neozelanica* is a smallish anemone (~20 across the disc) found on the lower shore on exposed coasts throughout New Zealand. They get their common name from the light and dark brown vertical stripes on the anemone’s stalk. There are many tentacles, these are quite long and fine, and can be orange/beige in colour. They possess an inner ring of blunt-tipped catch tentacles and these are diagnostic for this species.

The plumose anemone Mimetridium cryptum, Hand 1961 is very similar, but doesn't have these catch tentacles. Apparently, both species can reproduce asexually and form large patches. The problem here is that I have imagery where there are anemones in a large patch, some with the catch tentacles and some without, so at the moment I'm not sure how reliable this feature is.

Piha, Jan 2017

Very little appears to be known regarding the ecology of striped anemones. They appear to like the shade and don't seem to be found in open sunlight. It's interesting that they are orange/beige in colour, as these are colours which absorb higher wavelengths of light; those which can penetrate deeper into the water or into more shaded areas. It may mean that they have photosynthetic zooxanthellae, but this is currently unknown.

Moturiki Island, Mt. Maunganui, 2016.

Moturiki Island, Mt. Maunganui, 2016.

* (Carlgren, 1924)




























More info: 

de Cook, S. (2010). New Zealand Coastal Marine Invertebrates 1. Canterbury University Press.

Morton, J. A., Miller, M. E. (1968). The New Zealand Sea Shore. Collins.

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.