This Dendronotus orientalis nudibranch seen by anudibranchmom in Redwood City, California, is our Observation of the Week!

Robin Agarwal (anudibranchmom) is currently travelling and wasn’t able to write us back by publication time, so we have two awesome iNatters chiming in on this find. We’ll post an updated version once we hear back from Robin.

One of iNaturalist’s most prolific users (12,000+ observations!), Robin Agarwal got into nudibranchs due to her daughter’s interest in marine biology, and has quickly branched out into observing many forms of life. But her experience with nudibranchs of the San Francisco Bay Area caused one to catch her eye, as she was unfamiliar with it. She posted photos of it on iNaturalist and Alison Young (@kestrel) the California Academy of Sciences Citizen Science Engagement Coordinator, was able to identify it as Dendronotus orientalis, a species originating in Asia and, as far as we can tell, never before documented in the U.S.! Rebecca Johnson (@rebeccafay), a marine biologist and Citizen Science Lead at the Cal Academy, asked nudibranch expert Terry Gosliner to confirm the ID, and marine invertebrate expert Gary McDonald (@mcduck) also agreed. “This was a truly community effort,” says Rebecca, “and for me, the coolest thing is that the correspondence that would have been normally limited to ‘expert’ emails and hidden is now done in public!”

One of the most active and encouraging members of the iNaturalist community is Susan Hewitt (@invertzoo), a “serious amateur” malacologist, who tells me that nudibranchs are a diverse group of sea slugs, “although the name ‘slug’ hardly does them justice! Many people who are familiar with them feel that nudibranchs are the most beautiful organisms on Earth, their colors and forms rivaling or exceeding even those of butterflies.” Not much is known about this particular species, but Susan points out its most distinguishing feature, which is that the sheaths of its rhinophores (chemoreceptive structures protruding from the body) extend to well past the body length of the animal. And like many other nudibranchs this species eats hydrozoans, tiny predatory (and often colonial) animals related to jellyfish and corals. Some nudibranchs even sequester the stinging cells of hydroids and use them for self-defense!

Due to San Francisco Bay’s use as a major shipping port, “more and more species of marine invertebrates were accidentally introduced,” says Susan, “and a large number of them found habitat to their liking, and flourished there.” Rebecca Johnson took a team to collect some of the Dendronotus orientalis that Robin found, for further study, and says “early detection of invasive species is critical for the protection of the San Francisco Bay, [and] thanks to dedicated naturalists like Robin, and the iNat platform, we can learn more about changes in the bay and beyond more rapidly than ever before - and that information can be shared with a bigger community more quickly - so we 'know' when something is really important.”

- by Tony Iwane

- You can check out more of Robin’s awesome photography on Flickr. She also took a video of the nudibranch!

- Susan Hewitt has a great guide to photographing mollusks on her profile page, and she also appears in a video on Wikipedia about “love darts.” Check it out!

- The California Academy of Sciences team took a video crew with them when collecting their specimens, and we’ll post the video on our Facebook and Twitter pages when it’s finished, so follow us there!

One of the most economically important families of plants, the Pea Family (Fabaceae) is used by humans mostly for its fruits, but this huge family of over 18,000 described species boasts beautiful flowers and wonderful compound leaves as well. We’re featuring this family on the Critter Calendar this week, so let’s dive in and learn what makes it special!

We’re all familiar with a pea pod or bean pod, and this type of fruiting body is called a legume, which is typical of the Fabaceae. A legume is a dry (as opposed to fleshy) fruit which dehisces (opens) along a seam, usually on two sides. Legumes come in many forms, and are long and skinny, as in the acacias, while others are shorter and stouter, like those of a lupine. Peanuts, which are not nuts at all, are legumes that develop underground - a rare trait called geocarpy.

Most Fabaceae leaves are alternate (not opposite each other on the stem) and pinnately compound (meaning there are many leaflets on the petiole, or leaf stalk). Fascinatingly, compound leaves of the Sensitive Plant (Mimosa pudica) fold inward when touched. At the base of each petiole is a stipule, or growth, that can come in the form of a thorn or a leaf-like shape as in the Garden Pea.

The three subfamilies of the Fabaceae have quite different flowers. Flowers of the Mimosoideae subfamily have enormous stamens and tiny petals often in a spherical shape - kind of like a pom-pom. Faboideae subfamily flowers are Papilionaceous, meaning butterfly-shaped - a large petal on top folds into two smaller petals, with two other small petals forming the bottom of the flower. Overall they are somewhat concave and are bilaterally symmetrical, like the human face. And finally the flowers of the Caesalpinioideae subfamily are also bilaterally symmetrical but the petals are usually all the same shape and the flower is more “open” than concave.

Plants in the Pea Family are found nearly everywhere on Earth, so there’s probably one near you! If you think you see any of these this week, share your observations with us. We’ll be keeping track here. Happy Fabaceae hunting!

This Merismopedia colony seen by sarka in Florida is our Observation of the Week!

Most observations posted to iNaturalist are of macroscopic life - organisms one can see with the naked eye. Much of life on Earth, however, is microscopic, and we’re lucky enough to have some users who specialize in photographing these exquisite tiny organisms, folks like Sarka Martinez.

When she was a professional with a degree in computer science, Sarka always felt that computer science “was a world that was not really me. I needed to be outside delving into the natural world, a world of discovery and research.” After “retiring,” she now has the opportunity to do things that really interest her - like documenting seaweed, diatoms and other types of plankton in both Washington State and Florida! “I must say that looking at all life in the water is my very best hobby,” she says. “Looking at pollen is pretty awesome too.”

Sarka had her first opportunity to work with “fancy” microscopes while volunteering at the Whitney Marine Laboratory in Florida, documenting seaweeds and looking at their cell structures to get her identifications down to species level. She now documents plankton for SoundToxins.org in Washington for six months of the year, and for NOAA in Florida for the rest of the year.

The Merismopedia colony she found in Florida is a type of cyanobacteria, also known as blue-green algae. Ancient organisms, tiny but mighty cyanobacteria are photosynthetic and are believed to have been the cause of the The Great Oxygenation Event 2.3 billion years ago, creating oxygen that accumulated in the atmosphere. Merismopedia is a genus of cyanobacteria, and they divide in only two directions, forming a characteristic grid pattern. Merismopedia can move using filaments called hormogonia.

So how to photograph such a tiny thing? Sarka uses a simple set-up consisting of a used Leitz Laborlux S microscope (bought on eBay) and a cheap Celestron camera that connects to her computer via USB. “Out of 100 images,” she says, “I keep about 20 that turns out to be around 5 organisms.”

“Part of taking photos is to have people tell me if I am identifying them correctly. iNaturalist is a great vehicle to do that and is a great place to store my photos,” says Sarka. She and her husband also use iNaturalist as a motivator to explore new places. “We treat our trips like scavenger hunts, hoping to get an amazing find or to be the first to ‘find’ in the region.”

- by Tony Iwane

- Sarka has two plankton projects on iNaturalist: one for the southeastern US, and one for the Pacific Northwest.

- There is, of course, a Merismopedia video on Youtube. The colony begins to flip around at about 3:17, which is pretty neat to watch.

Breathe in the pungent aromas of the Carrot family (Apiaceae) for the Critter Calendar this week! With over 3,700 species, this huge family of plants include many commonly used vegetables and seasonings, including carrots, coriander, celery, dill, cumin, anise and more. However, some species such as poison hemlock contain powerful toxins, so please don’t ingest any unless you know exactly which plant it is.

The Apiaceae are also known as the Umbelliferae, and that latter name is taken from their distinctive inflorescence (flower cluster), which is known as an umbel. Umbels are made up of many stalks originating from a stem which resemble the ribs of an umbrella. Some umbels have an almost flat top, as in sweet fennel, while others are arranged in a more spherical shape. Apiaceae flowers have five sepals, five petals, and five stamens, and are often small.

Other general characteristics of Apiaceae:

• Mostly herbaceous, meaning they lack woody stems.
• Stems are often hollow.
• Leaves are usually alternately arranged, dissected (divided into many deep segments), and pinnatifid (the lobes are not discrete).
• Crushing the leaves of most Apiaceae plants produces a strong odor.

In addition to its culinary uses by humans, many pollinators use the flowers of the Apiaceae as a source of nectar, and ambush predators like crab spiders can often be found on the umbels if you take a close look.

If you think you see any of these this week, share your observations with us. We’ll be keeping track here. Happy Apiaceae hunting!

This Stegodyphus tibialis spider seen by vipinbaliga outside of Bangalore, India, is our Observation of the Week!

Not only is this gorgeous male Stegodyphus tibialis the first one posted on iNaturalist, Vipin Baliga found and photographed it under pressure and in front of a crowd! He spotted the spider while waiting for a bus outside of Bangalore. “The bus i was waiting for would reach any minute,” he writes. “If i miss it, I would have to wait for at least 3 hours for the next one. With this in mind I quickly got my camera out and started photographing this fast little spider from every angle possible.”

As Vipin followed the spider, which was a “nightmare to photograph,” he began to draw a crowd. Taking the spider in hand so it wouldn’t be stepped on, he had to “answer all the curious questions from the watching audience while holding my breath, trying to get the focus right and frame well.” After he safely released the spider, the bus soon arrived and Vipin says “the bus journey turned into a Q&A session. The interested students and local people taking a closer look at the pictures, asking all kinda questions, narrating their version of spider stories, etc.” A wonderful example of interest in nature sparking a conversation between strangers.

The spider was identified on iNaturalist by Vijay Barve, who coordinates DiversityIndia - which “started as a Yahoo group for Butterflies of India in 2001 and then expanded to other groups of taxa and Social Networks as well as now specialized portals like iNaturalist and Indian Biodiversity Portal.” His SpiderIndia project on iNaturalist has nearly 600 observations!

Siddarth Kulkarni is a spider expert who helps SpiderIndia with identifications, and he was kind enough to give me some information on this particular species. He says that S. tibialis has been recorded in India, Myanmar, Thailand and China, and that “they are mostly known to construct solitary webs on thorny plants...Phanuel (1963) records that these webs are generally kept clean than other Stegodyphus species with all prey bodies dumped in a corner of web.” And fascinatingly, “young ones of S.tibialis are reportedly known to feed upon their mother,” which is a trait found in other Velvet Spiders (Family Eresidae). In fact, mothers in the Stegodyphus genus have been known to liquefy their own insides (!) to aid in this, as spiders can only eat liquid food.

As for Vipin, his spider story session with kids on the bus is similar to his own childhood, when he was an avid bug catcher, pretending each of his captured fireflies was a “magical bulb.” On weekends he currently works for Bangalore-based NGO Wildlife Conservation Group (WCG), which is “actively executing independent conservation programs, assisting the Forest Department in their activities and conducting nature awareness programs for kids in the forest fringes.”

An avid nature photographer, Vipin says his archive of wildlife photos is “meaningless” just sitting on his hard drive. Therefore, “I use iNaturalist to give a purpose to my pictures, to share them with the scientific community and...like minded people.”

- by Tony Iwane

- He also shot a video of the spider running, and a close-up of it cleaning its legs.

- You can check out more of Vipin’s awesome nature photos on Flickr.

- Here’s a detailed description of matriphagy (yes, matriphagy) in Stegodyphus lineatus spiders.

It’s Forget-me-not Week on the 2016 Critter Calendar! Get out in the field and search for the huge Boraginaceae family of plants, also known as borages or forget-me-nots. There are over 2,000 known species of these plants, and they range widely throughout tropical, subtropical, and temperate regions around the world, so there should be some near you!

With such a diverse family there are many variants among the Boraginaceae. Plus the family has been recently expanded to include the formerly separate waterleaf family, Hydrophyllaceae! But here are several borage traits you can look for. If the plant has all or most of these traits, it’s likely a borage.

• The leaves are mostly alternately arranged (they do not appear on the stem across from each other), and are usually narrow and hairy. Sometimes the hairs can be irritating to the skin.
• Flowers are usually with fused petals. They generally have five petals, five sepals, and five stamens (where pollen is produced). Flower bunches are sometimes arranged in a helicoid or spiral pattern, like the fiddlenecks.
• Fruit a capsules are composed of four individual nutlets.
• Most borages are herbaceous, meaning they lack persistent woody stems. However, some are shrubs or trees.

Some well-known members of the Boraginaceae are the forget-me-nots (Myosotis sp.), flddlenecks (Amsinckia sp.), scorpionweeds (Phacelia sp.), viper’s bugloss (Echium vulgare), Geiger tree (Cordia sebestena), and heliotropes (Heliotropium sp.). Borage (Borago officinalis) has edible leaves and is sometimes cultivated for food.

If you think you see any of these this week, share your observations with us. We’ll be keeping track here. Happy forget-me-not hunting!

This larval Elopiform seen in Texas by saraj is our Observation of the Week!

Sara Jose is the Recreation Coordinator at the Oso Bay Wetlands Preserve & Learning Center in Corpus Christi, Texas, and the Learning Center itself will be opening to the public this week. She and her colleagues, including iNat user @justinquintanilla were using a seine net to catch fish and other organisms for the Learning Center’s freshwater tank, “meant to highlight our local freshwater species.” (They have an Educational Display Permit to do so.) After collecting specimens of interest for the tank, Sara and a park technician were returning stranded fish to the water when this tiny, transparent larval fish caught her eye - she thought it could be a larval eel. “I recently attended the Texas Academy of Science conference and knew that researchers in the central part of the state were beginning to do eel research, specifically larval eels and were hoping people in coastal areas would begin contributing sightings.” After taking some photos, she returned the larva to the water.

Once Sara posted her photo on iNaturalist, Dr. John Friel (@friel on iNaturalist), Director of the Alabama Museum of Natural History, was able to help her ID it as an Elopiform, which he says includes “ tarpons, tenpounders and ladyfishes with a total of 9 species worldwide…[they] are closely related to bonefishes, halosaurs, and true eels, and evidence for this includes the fact that all these fishes have a unique larval form known as a leptocephalus.”

So what the heck is a leptocephalus? Leptocephali are the larvae of Elopomorpha, and are transparent due to their insides consisting of clear, jelly-like substances, and due to their lack of red blood cells. They won’t gain red blood cells until they enter the “glass eel” stage of metamorphosis. Oh, and at this point they lose the sharp fang-like teeth they have has leptocephali.

The aquatic world is where Sara got her start in science and studied marine biology in college, intending to do research. However, she says that “by the end of my four years I realized that I enjoyed sharing science with the public more than spending time in the lab. I began learning more about local, native species as I took environmental education jobs that required me to share this information with the public.”

Sara found out about iNaturalist through her colleague Colleen Simpson (@colleenm on iNaturalist) and together they started a project to document the life of the Oso Bay Wetlands. Colleen has taught iNaturalist to educators in Texas, and Sara plans to incorporate it into public programs at the Learning Center there. “iNaturalist has encouraged me to look for more ‘small stuff’ on the trails,” she says. “Since I know that the members of iNaturalist can help me ID insects, bugs, and flowers I am more inclined to pause and check out those life forms these days.”

- by Tony Iwane

- Here are two awesome videos of leptocephali swimming - one a presumed moray larva off of Bali, and the other an ophichthid with green chromatophores, swimming off of Hawaii.

- Photos of leptocephali were also used as part of a “scary” meme, which purported them to be giant water parasites. 

- Sara is a Windows Phone owner, and while there is no official iPhone app for Windows Phone, iNat user @coachbenson created the iNaturalist Observer app for Windows Phone. It’s a cool use of our open API.

Go back in time to the days when plants began to invade the land - we’re talking bryophytes on the Critter Calendar this week!! The bryophytes are the most primitive of land plants. They lack true vascular tissue and reproduce via spores, not with flowers or seeds. While there is some uncertainty as to whether they share a common ancestor, for the purposes of the Critter Calendar this week we are considering mosses, liverworts, and hornworts as bryophytes.

Bryophytes spend most of their lives as gametophytes, which is what you’ll most likely see when you find them. The gametophytes contain chlorophyll and are thus green. They in turn produce sperm and eggs - sometimes on the same gametophyte (monoicous), sometimes on separate plants (dioicous). In order for the sperm cells to reach eggs, there must be water on the gametophyte, which is why nearly all bryophytes are found in damp, wet areas. A fertilized bryophyte will grow a sporophyte, which extends outwards and eventually releases spores to be spread by the wind.

While superficially similar and often sharing the same habitat, lichens are not plants but composite organisms comprised of a symbiotic relationship between algae (or cyanobacteria) and fungi. In general, bryophytes will be green and have stalk-like sporophytes. Lichens are often more grey and pale and their fruiting bodies are usually disc- or cup-shaped.

It can be difficult to differentiate and identify mosses, liverworts and hornworts from each other without a microscope and some studying, but here are some guidelines you can use:

True Mosses (Division Bryophyta) more often have stems with leaves, the leaves can be spiraly arranged and often have a middle rib. The sporophytes of mosses can be green, brown or red and the capsule at the tip has a well-formed opening, however the opening may be covered.

Liverworts (Division Marchantiophyta) usually have a “flattened” appearance in comparison to mosses and often lack clearly differentiated stems and leaves. The leaves can be deeply lobed, and sporophytes are usually pale or colorless and the tips often split open, as opposed to the well-formed openings of moss sporophytes.

And finally the Hornworts (Division Anthocerotophyta), who are so named for their distinctive thin, horn-like sporophytes, which emerge from deep within the gametophyte. The leaves of hornworts can have a distinctive blue-green shade, as they are sometimes invaded by cyanobacteria colonies.

If you think you see any of these this week, share your observations with us. We’ll be keeping track here. Happy moss hunting!

This Zombie Ant Fungus seen by jonathan_kolby in Cusuco National Park, Honduras is our Observation of the Week.

“I was walking down the trail, in pursuit of a frog, when this alien-like creature suddenly grabbed my attention out of the corner of my eye,” says National Geographic Explorer Jonathan Kolby. “This was the first time I had ever seen cordyceps fungus and didn’t know what it was at the time.” What he photographed (identified by Prof. David Hughes of Penn State), is likely the incredible fungus known as the Zombie Ant Fungus, which parasitizes its insect host and basically controls its brain. The host is often compelled to climb up the stem of a plant and uses its mandibles to latch onto it (known as the “death grip”). Fruiting bodies of the fungus eventually grow out of the host and release spores back into the forest. “After seeing this in person, I don’t think anyone would argue that nature is more amazing than the best sci-fi movie,” he says. “I now keep my eyes peeled every time I return to the forest to see if I can find another zombie insect! Just a few weeks ago, I found another one, this time of a moth (see below).”

(By the way, the BBC has incredible footage of an ant afflicted by Zombie Ant Fungus, you should definitely check it out.)

It is, however, another fungus which brings Jonathan to the rainforests of Honduras - Batrachochytrium dendrobatidis, commonly known as chytrid. It and the newly discovered B. salamandrivorans cause the disease chytridiomycosis, which is devastating amphibian populations around the world. The fungus does its damage by affecting the keratin-producing layer of skin in amphibians, disrupting electrolyte balance and chemical flow, “and ultimately kills the amphibian by causing a little froggy heart attack,” says Jonathan. For the past 10 years, Jonathan has specifically been working to combat the global amphibian extinction crisis and recently established the Honduras Amphibian Research & Conservation Center (http://www.FrogRescue.com), where they are working to protect three endangered species of frogs from chytrid. He’ll be finishing up his PhD at James Cook University in Australia and “now wants to help develop policies to protect biodiversity from emerging infectious diseases, reduce the spread of invasive species, and combat the illegal wildlife trade.” 

Believing  that photography and social media are important for raising awareness about these issues, Jonathan is active on many social media outlets (see below) one of which is iNaturalist. In addition to adding his own observations, he created an iNaturalist Project called Saving Salamanders with Citizen Science, where he’s asking folks to upload any photos they have of dead salamanders. “A new chytrid fungus disease [B. salamandrivorans] is beginning to spread around the world killing salamanders and we’re having a hard time tracking where it’s going,” he says. “With so many people outside looking at nature, anyone who snaps a picture of a dead salamander can provide valuable scientific data that might help us pinpoint where an outbreak is happening, so we can respond as quickly and efficiently as possible.” He invites anyone who’s interested in the issue to join, as he’ll be providing updates via the project; “iNaturalist has provided me with a way to communicate this message and raise awareness with a large audience of people who want to help protect nature.”

- by Tony Iwane

- You can follow Jonathan on Tumblr, Twitter, and Instagram, and check out his photos on SmugMug. Proceeds from SmugMug sales go to supporting his frog rescue operation at the Honduras Amphibian Rescue and Conservation Center.

- Here are links to two other cordyceps observations Jonathan has uploaded.

- Cordyceps fungus have even inspired video games! The acclaimed survival horror video game The Last of Us posits a world where a mutant strain of cordyceps affects humans, turning them into cannibalistic monsters. 

The most numerous and diverse order of mammals, the Rodentia, are the focus of the Critter Calendar this week. A huge order, Rodentia includes mice, rats, porcupines, beavers, gophers, squirrels and many more! Rabbits, hares and pikas, while similar, are not rodents but lagomorphs and are in a different order.

It’s the front teeth of rodents that set them apart from other mammals. All rodents have a pair of large incisors on both their upper and lower jaws, and these teeth continue to grow throughout their lives. The incisors have thick enamel layers on the front and softer dentine on the back, cause the back to wear away more quickly with every bite, thus continually sharpening the tooth. These impressive choppers allow rodents to bite through the tough husks of seeds or even cut down trees. Most rodents have a diastema, or large gap, between the incisors and molars, allowing them to suck in their cheeks and avoid inedible material as they chew.

Rodents are mostly herbivorous but will eat animal matter, and some, like the Shrewlike rats of the Phillipines are, mainly predatory. And because of their large numbers and prolific breeding habits (House mice, for instance, average over 5 litters a year, with each litter averaging over 5 babies), rodents are an important food source for many other animals, such as raptors, snakes, and other mammals.

With these four front teeth as a shared trait, rodents have evolved to inhabit every continent on Earth (except Antarctica) and many islands as well. Flat grasslands are home to rodents such as Prairie Dogs, and Naked mole-rats, who have a complex social life and networks of burrows. With their sharp claws and bushy tails, squirrels have also adapted well to forests and trees, and some, such as the flying squirrels, can glide from tree to tree using outstretched membranes.

Rodents have also adapted to life in waterways. The world’s largest rodent, the Capybara, is semiaquatic and uses its webbed feet to swim and find aquatic plants. Beavers have enormous incisors with which they gnaw down trees, to be used as food and as building material for their dams and dens.

The most common and widespread rodents are the rats and mice of the family Muroidea, who are mainly nocturnal seed eaters. Many of them, like the Black rat and House mouse, are commensal with humans and have been introduced to numerous areas around the world.

If you think you see any of these this week, share your observations with us. We’ll be keeping track here. Happy rodent hunting!