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/

99 — Small ostrich foot shell, Pelicaria vermis

Pelicaria vermis, off Pakiri Beach ~20–30m.
Cast up on Kohimarama Beach as part of the
2004 beach replenishment programme.

Pelicaria vermis (flemingi form). A larger and
wider form from Mt. Maunganui's Ocean Beach.

Pelicaria vermis (tricarinata form), Castlecliff
Beach, Jan 1985. Pleistocene fossil form.

All three together. The flemingi form
 is on the far left. The largest is about 50mm.

Pelicaria vermis (Martyn, 1784) is the smaller of the two ostrich foot shells (Family: Struthiolariidae) found in New Zealand waters; it is also the less common of the two. Many more species exist in New Zealand's fossil record, some of which date back at least 40 million years.

Pelicaria vermis is restricted to the North Island and the top of South Island—although this distribution doesn't appear to be temperature related, as they are also found in considerable depths (down to ~300m, where the water is quite cold).

Unlike Struthiolaria papulosa, P. vermis is a direct-developer—meaning that there is no planktonic larval stage, so when the egg hatches out crawls a miniature version of the adult. This direct-development has interesting evolutionary implications, as it is possible for populations to become genetically isolated since there is no planktonic dispersal phase. This is one way new species can arise (a process called speciation).

About 40 years ago it was thought that there were several regional sub-species from various parts of New Zealand. However, it is now considered that there is one, rather variable species, since it turns out that these various forms actually intergrade. Maybe in a few thousand years they might become different species, maybe not...

Ecologically, they feed in a similar way to their larger cousin: buried in the sediment, consuming plankton via currents driven by cilia. However, they appear to differ in that they can tolerate muddier sediments and deeper water.









More info:

https://www.gns.cri.nz/static/Mollusca/taxa/BM514.html

98 — Carinated nudibranch, Atagema carinata

Atagema carinata, Mt. Maunganui, 2014.

Atagema carinata, Mt. Maunganui, 2014.

Atagema carinata, Mt. Maunganui, 2014.

Notes on Atagema carinata from Mt. Maunganui
(Williams 1967 p19).

Atagema carinata (Quoy & Gaimard, 1832) is a medium-sized nudibranch (~60mm) endemic to New Zealand (apparently found throughout, although records are very patchy) and one not often seen. This may be because they aren't very common, but it could also be that there are few people looking who would know what it was if they saw one.

They have a "skin two sizes too big" look to them, or look a bit like a nudibranch wearing an overcoat. Larger ones also possess a dorsal keel. This species is another which appears to be an ecological void—pretty much nothing is known about them.

This one was seen under a small rock ledge, at the low tide mark on the northwestern side of the base of Mt. Maunganui, 24/12/14. There was another one in the same large rock pool; it was on some red algae.













More info:

Sea Slug Forum: http://www.seaslugforum.net/find/atagcari

Williams EG, 1967. Molluscs from the Bay of Plenty. Whitcomb & Tombs Ltd.

97 — Ostrich foot shell, Struthiolaria papulosa

Struthiolaria papulosa, Pilot Bay,
Mt. Maunganui, 2015.

The ostrich foot shell Struthiolaria papulosa (Martyn, 1784) is almost ubiquitous on sandy beaches around New Zealand. Examples from the north reach about 70mm and have sharp knobs on the spire whorls, while southern forms (gigas) are larger (~90mm) and are smooth, without sharp knobs. They are considered to be one variable species, as there is a general gradation between the two forms moving north to south.

Struthiolaria papulosa, position buried in sand
while feeding. From Morton (1951).

Struthiolaria papulosa is a deposit feeder and sits just below the surface sediments, using complex ciliary currents to essentially inhale its food. This food consists of coarsely graded detritus and micro-organisms, such as benthic diatoms and Foraminifera. Since they live close to the surface, they are easily disturbed by wave-action and after storms can be washed ashore in their thousands.

The Struthiolariidae have a rich fossil history in New Zealand, although today there are only two extant species: Struthiolaria papulosa and the much smaller Pelicaria vermis (Martyn, 1784). Pelicaria vermis lives in deeper water than S. papulosa and is less common.

Struthiolaria papulosa (gigas form).
Stewart Island Jan 1996.

Struthiolaria papulosa (gigas form).
Detail of spire sculpture,
Stewart Island Jan 1996.

More info:

Morton JE, 1951. The ecology and digestive system of the Struthiolariidae (Gastropoda). Quarterly Journal Microscopical Science, 92, 1–25.

More pictures: http://mollusca.co.nz/speciesdetail.php?speciesid=768&species=Struthiolaria%20papulosa

96 — Knobbed whelk, Austrofusus glans

Austrofusus glans, Waikanae Beeach, 1982.

Austrofusus ?glans. Main Beach, Mt. Maunganui,
2016.

A gradation of Austrofusus cf. chathamensis,
Ocean Beach, Mt. Maunganui.

Austrofusus cf. chathamensis,
Ocean Beach, Mt. Maunganui.

The knobbed whelk, Austrofusus glans (Röding, 1798) is a smallish (~50mm) whelk, endemic to New Zealand and found from the intertidal down to considerable depths (~200–300m). It is very common and the only whelk to be commercially harvested.

They were introduced into New Zealand's quota management system (QMS) in 2006, but as they are a low-value species, they are mostly taken as bycatch in bottom-trawls for other species. A. glans are reported to be scavengers, although data are scant regarding ecological interactions with other species.

The genus Austrofusus has a rich fossil history in New Zealand dating back about 11 million years. But now there are only two extant species: A. glans from mainland New Zealand and A. chathamensis Finlay, 1928, from the Chatham Islands.

Personally, I'm not convinced that A. chathamensis exists, as I have examples from Mt. Maunganui which intergrade between the two forms. I suspect that this is yet another issue to be resolved using molecular techniques. Who knows, I could be completely wrong.











More info:

More pictures: http://www.mollusca.co.nz/speciesdetail.php?speciesid=1068&species=Austrofusus%20glans#prettyPhoto

Fossil history: https://www.gns.cri.nz/static/Mollusca/taxa/BM539.html

95 — Trumpet shell, Charonia lampas

Charonia lampas,
Pilot Bay Wharf, 9/02/15.

The trumpet shell, Charonia lampas (Linnaeus, 1758) is an iconic sea shell and immediately recognisable from their large size (~20–25cm) and colourful markings. For a long time it was thought that there were several species scattered around the world. However, current thinking is that there's one variable species found in temperate waters from the north Atlantic and Mediterranean Sea, to the south Pacific. They can be found in a variety of habitats from shallow waters down to continental shelf depths.

Charonia lampas feed on echinoderms, particularly sea stars, but will also consume sea-cucumbers and urchins. While they are occasionally seen sub-tidally, your best chance to see one of these large gastropods is during the summer months, when they come into the intertidal zone to breed and lay eggs.

Their numbers have been depleted through collecting and from the affects of toxic antifouling paints. However, it does seem like they are making a comeback, which is great as they appear to perform an important ecological role controlling the sea star populations. It would be nice if these large charismatic gastropods continued to recover.

Charonia lampas, Pilot Bay, 9/02/15.
This is how you find them. My bag for scale.

Charonia lampas,
Pilot Bay, 9/02/15.

Charonia lampas,
Pilot Bay Wharf, 9/02/15.

More info:

http://www.tandfonline.com/doi/full/10.1080/00222933.2012.724721?scroll=top&needAccess=true

More pictures: http://mollusca.co.nz/speciesdetail.php?speciesid=856&species=Charonia%20lampas

94 — Siphon whelk, Penion sulcatus

Penion sulcatus, Enclosure Bay,
Waiheke Island, in ~1m, Feb 2015.

The siphon whelk, Penion sulcatus (Lamarck, 1816) is a moderately large whelk (~170mm), endemic to New Zealand and found from low-tide down to depths of ~100m. They like areas of medium wave exposure where there is a mixture of sand and rock. However, they can also be found in muddy inshore habitats and also off exposed sandy beaches, so they seem indifferent to the sediment type. They are not what you would call common, but you will occasionally see them washed up after a storm with ostrich foot shells (Struthiolariidae).

Siphon whelks are very easily confused with P. cuvierianus, which is a deeper-living species (although the deep end of P. sulcatus' distribution overlaps the shallow end of the distribution for P. cuverianus). Their shell morphology overlaps as well, but generally speaking, P. sulcatus has coarser sculpture and the shell is of a heavier build than P. cuvierianus.

Penion sulcatus are thought to feed on bivalves (particularly Dosina spp. and Condylocardia crassicosta Bernard, 1897—but probably others, depending on habitat). This is another species I've seen live amongst the low-tidal rocks along Tamaki Drive in central Auckland.

Penion sulcatus, Enclosure Bay,
Waiheke Island, in ~1m, Feb 2015.

Penion sulcatus, ex-harbour dredge, Tauranga
Harbour, 1970's. Ex-Cath Fletcher collection.

Penion sulcatus, ex-harbour dredge, Tauranga
Harbour, 1970's. Ex-Cath Fletcher collection.

More info:

3D model:
http://www.nzfauna.ac.nz/penions

More pictures: http://www.mollusca.co.nz/speciesdetail.php?speciesid=1124&species=Penion%20sulcatus

93 — Small lined whelk, Buccinulum vittatum

Buccinulum vittatum, Lion Rock, Piha, 2015.
The shell in the middle has a polychaete
tube-worm attached to it.

Buccinulum vittatum, Lion Rock, Piha, 2015.

Endmic and found throughout New Zealand, Buccinulum vittatum * is a small whelk, reaching about 33mm. They are extremely variable in shape and colour and many species were originally described based on these variations. These days the number of species has been reduced, so at present there is one variable species and a regional sub-species from the Chatham Islands.

They are common under rocks at low tide and down to a few metres. The examples pictured here are a form called motutaraense (Powell, 1929) and was originally described from the west coast of Auckland. These ones were found living in deep rock pools on the south side of Lion Rock, Piha, an area with very high wave exposure.

* (Quoy & Gaimard, 1833)





More info:

More images: http://mollusca.co.nz/speciesdetail.php?speciesid=1080&species=Buccinulum%20vittatum

92 — Cushion star, Patiriella regularis

Many Patiriella regularis disappearing into the
harbour channel depths, Pilot Bay
Mt. Maunganui, 2015.

An unusual four-sided Patiriella regularis,
Pilot Bay, Mt. Maunganui, 2015.

The cushion star, Patiriella regularis (Verril, 1867) is probably the most common sea star in New Zealand waters, and is found throughout. It is also believed to be an invasive species in southern Australia. In Tasmania it was thought that it was introduced in the 1930's on the shells of imported oysters.

They can get up to about 70mm across and can be many colours: from red to orange to greeny-blue, and combinations in between. Most commonly they have five arms, but occasionally they can be seen with six or four.

They prefer shores with moderate to low wave exposure (although I have seen them on rock pools at Piha, which is very exposed) and will eat pretty much anything slow enough to catch.





More info:

NIWA's echinoderm guide

91 — Crab megalopa

Crab megalopa (live), Piha, 2/05//15.

Crab megalopa (live), Piha, 2/05//15.

Crab megalopa (dead), Piha, 2/05/15.

The lifecycle of a crab is really interesting and larval crabs are quite different from adults. In fact larval crabs were considered to be different species, until it was shown that they were just juvenile forms.

After a crab larvae hatches, it joins the plankton. Then, as they grow they go through several developmental stages, shedding their exoskeleton between each stage. Some of these stages bear very little resemblance to the adult crab. The megalopa stage is the last planktonic stage, during which the crab settles and then later moults and emerges as a small version of the adult form.

The cues controlling where and when a megalopa will settle are very important to the crab's survival, as various crab species are adapted to survive in particular habitats. Ambient sound is believed to be an important settling cue, with some crab species being more sensitive than others. For example, megalopae of the mud crab, Austrohelice crassa (Dana, 1851), are not very sensitive to sound cues and it is thought that this could be related their choice of habitat: soft sediments with little wave action (low ambient noise). Conversely the megalopae of the rocky-reef crab, Leptograpsus variegatus, (Fabricius, 1793) are quite sensitive to sound cues and their preferred habitats are rocky reefs with moderate to high wave exposure (high ambient noise).

These two megalopa were found in the cove at south Piha 2/05/15 and are probably (educated guess here) L. variegatus. They were about 1 cm across.




More info:

Stanley JA, Radford CA, Jeffs AG 2011. Behavioural response thresholds in New Zealand crab megalopae to ambient underwater sound. PLoS ONE 6(12): e28572. doi:10.1371/journal.pone.0028572

90 — Another deep-water volute, Alcithoe jaculoides

Alcithoe jaculoides (johnstoni form).

Alcithoe jaculoides (johnstoni form).

Alcithoe jaculoides, Powell 1924 is another one of those little-known New Zealand sea shells. It's a large shell (~180m) with a distribution limited to the north of North Island, on the continental shelf down to at least 450m. However, recent work has inferred that a closely related southern species (Alcithoe calva, Powell, 1928), is actually a smooth form of A. jaculoides. Just to complicate matters the specimen shown here is the 'johnstoni' form, which has a large flared aperture and shorter spire than typical jaculoides.

Closely related shallow water species are known to feed on bivalves, so it is likely that A. jaculoides does also. I was given this shell as part of a collection when I was about 16. The collection had been accumulated by a fisherman in the 1960's and that's all I can remember. Sadly, I have no locality data for this shell. However, chances are this came from the Bay of Plenty.

89 — Eleven-armed starfish, Coscinasterias muricata

Coscinasterias muricata, Piha, 9/2/15.

Coscinasterias muricata, Piha, 9/2/15.

Coscinasterias muricata, Piha, 9/2/15,
macro shot showing the pedicellariae.

Coscinasterias muricata Verrill, 1870, is a large sea star (~20cm across). They are found throughout New Zealand and southern Australia where they are inter-tidal to sub-tidal. Although they are known as eleven-armed sea stars, this number can vary. For example, the one pictured her only has ten arms.

They are especially common under mussel farms, where they prey on fallen mussels. Elsewhere, they are reported to feed on gastropods and bivalves, particularly (again mussels and) oysters.

In the third picture below you can see the small upward-facing wrench-like appendages called pedicellariae, in a ring around white-coloured spines. These guard against ant attempts by encrusting organisms to settle. Encrusting organisms could reduce the flexibility and mobility of the starfish and therefore reduce its chances of survival.















More info:

Morton, J. E., Miller, M. C. 1968. The New Zealand Sea Shore. Collins.

NIWA sea star identification guide:
https://www.niwa.co.nz/static/extraordinary_echinoderms.pdf

88 — Depressed olive, Amalda depressa

Amalda (B.) depressa, Devonport,
Auckland, 17/6/18.

Amalda (B.) depressa, Devonport,
Auckland, 17/6/18.

The depressed olive, Amalda (Baryspira) depressa * is a small (~18mm) and attractive olive species. Its name derives from its squat shape, not any perceived snail-mood. They are endemic to New Zealand and are found down to the top of South Island.

Amalda (B.) depressa, Devonport,
Auckland, 2016.

Amalda (B.) depressa, Devonport,
Auckland, 2016.

Amalda (B.) depressa, Mount Beach,
Mt. Maunganui 14/11/16.

Amalda (B.) depressa, Mount Beach,
Mt. Maunganui, 14/11/16.

They prefer fine sandy sediments in areas of moderate shelter; essentially similar habitat to the southern olive (A. (B.) australis). However, A. (B.) depressa is less common.

Behaviourally, they are very fast burrowers and will re-bury themselves in about a minute if disturbed. This is yet another small species for which there is very little ecological knowledge available.


* (G.B.Sowerby II, 1859)

87 — Lemon nudibranch, Dendrodoris citrina

Dendrodoris citrina, Tamaki Drive, 2016.

Dendrodoris citrina, under Ngapipi Bridge,
Tamaki Drive, 2016. The chiton in the
top right is Acanthochitona zelandica
(Quoy & Gaimard, 1835).

Dendrodoris citrina, Takapuna Reef, 2015.

Dendrodoris citrina, under Ngapipi Bridge
Tamaki Drive, 2016.

The lemon nudibranch, Dendrodoris citrina * is found throughout New Zealand waters and are endemic. They are frequently seen around the low tide mark, amongst coraline algae and in pools.

Dendrodoris citrina is one of the most silt-tolerant of New Zealand's nudibranchs and is one of the most common nudibranchs seen off Auckland's Tamaki Drive. However, they are also found on more exposed coasts and are supposedly nocturnal.

They are thought to feed on the orange solitary ascidian (Microcosmus sp.), but they may also feed in sponges. For such a common species I was surprised at how little information I could find regarding their ecology. The individuals pictured below were found in less than half a metre of water and ranged in size between ~50–70mm.

* (Cheeseman, 1881)

Two Dendrodoris citrina,  mating,
Mission Bay, Tamaki Drive, 2016.

More info:

http://www.seaslugforum.net/find/dendcitr

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