Meet D. rex, the newly crowned giant fungus ‘king’ that measures almost 2 feet tall

Indunil C. Senanayake

As the reign of the dinosaurs crumbled about 65 million years ago , new royalty rose from the ashes: a king among fungi.

Scientists recently identified Dianjunus rex, a gigantic species of fungus in what’s now China that shares part of its name with Tyrannosaurus rex, the renowned dinosaur “king.” D. rex belongs to a family of fungi that appeared following the extinction event that wiped out all non-avian dinosaurs, along with roughly 75% of all plant and animal life on Earth.

D. rex dwarfs its fellow fungi with its upright, pale yellowish reproductive structures, or fruiting bodies, called stromata that can grow to be 20 inches (50 centimeters) tall — about the height of an airplane carry-on suitcase — and weigh nearly 5 pounds (2.2 kilograms).

“It’s always interesting to hear about a new kind of fungus or mushroom species that is spectacular in size,” said Kabir Peay, a professor of biology and Earth system science at Stanford University in California, who was not involved in the new research. “It helps point to all of the really exotic forms of fungal life on this planet that haven’t had a chance to be described by science.”

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Scientists recorded D. rex in forests in southwestern China’s Yunnan province during fungal diversity surveys conducted in 2024 and 2025. The findings were reported September 28 in the journal Frontiers in Fungal Biology .

Farmers in the region had previously seen the fungus’ fleshy fingerlike stromata clustered around a dead tree. While the giant fungus has not been tested for toxins, some locals had even tasted it and reported no ill effects, said study coauthor Indunil Senanayake, an associate professor at the Kunming Institute of Botany in China.

“However, no one noticed it as an important thing,” Senanayake told CNN in an email. But when a curious local sent photos of the peculiar fungus to the scientists, the researchers quickly realized they were looking at something special.

The new study describing D. rex draws attention to how much there is yet to discover about biodiversity in fungi.

The mass extinction that caused the dinosaurs’ demise may have created an environment for the king-size fungus to evolve and thrive, according to the study. Not only was D. rex a newly discovered species — it belonged to a unique family of fungi. Through genetic analysis and comparisons with other fungi, researchers found that the new family, named Dianjunaceae, likely emerged about 1 million years after the asteroid impact that ended the Cretaceous Period (145 million to 66 million years ago).

“During this event, photosynthesis was suppressed, and huge quantities of dead leaves, wood, roots, and carcasses accumulated,” Senanayake said. At a time when other forms of life struggled to survive, decomposers such as fungi that consumed dead organic matter could exploit that banquet.

Nanjing Institute of Geology and Palaeontology; Chinese Academy of Sciences/NIGPAS

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In size, D. rex doesn’t nearly measure up to T. rex, but it does tower over other fungi. This species is the largest known in the phylum Ascomycota, which is the most diverse group of fungi and contains about 65,000 species, including morels, truffles and yeasts.

Before D. rex’s discovery, the largest known member of Ascomycota was a bulbous brown fungus in Kenya called Engleromyces goetzei, which has a diameter of nearly 12 inches (30 centimeters) and weight of around 7 pounds (3.2 kilograms), Senanayake said. All other ascomycetes, also known as sac fungi, that are close relatives of D. rex range from microscopic to just a few inches tall.

One question the scientists want to answer next is why D. rex is so large compared with other fungi in its phylum, Senanayake said.

“Generally, ascomycetes do not produce large stromata, as it is an energy waste,” she explained.

Sac fungi reproduce by actively expelling their spores; in D. rex, the upper part of the fruiting bodies contains thousands of tiny spore-releasing pores. However, the forest floor of its habitats is densely covered with fibrous plant material that may trap spores, Senanayake said.

D. rex’s fruiting body rises high above the forest floor, which may allow spores to disperse more widely and improve reproductive success, she suggested.

Fungi are essential organisms that contribute to Earth’s carbon cycle and support the health and nutrition of many plant species.

“It’s really important that we understand what they do,” Stanford’s Peay said. “The first step in understanding what they do is describing them, acknowledging their existence, and then later trying to understand more details about their ecology.”

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Scientists have described around 150,000 species of fungi to date, but some estimates indicate there are between 2 million and 13 million species on the planet.

“It’s a vastly underappreciated and underdescribed group of organisms,” Peay added.

Fungi can be surprisingly difficult to spot in their forest habitats, even specimens as large as D. rex. A fungus is largely made up of threadlike filaments called hyphae, known collectively as a mycelium. These tendrils typically are buried in soil, decaying wood or vegetation, with the reproductive bits — the stromata — popping above the ground “when the environmental conditions are right, or the fungus comes to the end of its life cycle,” Peay explained.

These features make discovering a new fungus often a matter of being in the right place at the right time. Otherwise, “even really impressive mushrooms like this can go undescribed or unnoticed,” he said, referring to D. rex.

Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American and How It Works magazine. She is the author of “ Rise of the Zombie Bugs : The Surprising Science of Parasitic Mind-Control” (Hopkins Press).

因杜尼尔·C·塞纳纳亚克

大约 6500 万年前，随着恐龙的统治走向终结，新的王者从灰烬中崛起：真菌之王。

科学家最近在中国境内发现了一种名为“帝王菌”（Dianjunus rex）的巨型真菌，它的名字与著名的恐龙“之王”霸王龙（Tyrannosaurus rex）的名字有部分重合。帝王菌属于一类真菌，这类真菌出现于导致所有非鸟类恐龙以及地球上大约75%的动植物灭绝的那次大灭绝事件之后。

D. rex 的直立淡黄色繁殖结构（或称子实体）被称为子座，比其他真菌要矮小得多。子座可以长到 20 英寸（50 厘米）高——大约相当于飞机随身行李箱的高度——重达近 5 磅（2.2 公斤）。

“听到发现一种体型惊人的新型真菌或蘑菇物种总是令人兴奋，”加州斯坦福大学生物学和地球系统科学教授卡比尔·佩伊（Kabir Peay）说道，他并未参与这项新研究。“这有助于我们了解地球上所有那些尚未被科学描述过的奇特真菌生命形式。”

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科学家在 2024 年和 2025 年进行的真菌多样性调查中，在中国西南云南省的森林中发现了 D. rex。该研究结果于 9 月 28 日发表在《真菌生物学前沿》杂志上。

该地区的农民此前曾在枯树周围发现过这种真菌肉质的指状子座。该研究的合著者、中国昆明植物研究所副教授因杜尼尔·塞纳纳亚克表示，虽然这种巨型真菌尚未进行毒素检测，但一些当地人甚至品尝过它，并表示没有出现任何不良反应。

“然而，没有人意识到这有多么重要，”塞纳纳亚克在给CNN的邮件中写道。但当一位好奇的当地居民将这种奇特真菌的照片发给科学家们后，研究人员很快意识到他们发现了非同寻常的东西。

这项描述 D. rex 的新研究引起了人们对真菌生物多样性的关注，也让我们意识到还有很多东西有待发现。

研究表明，导致恐龙灭绝的大规模物种灭绝事件可能为这种巨型真菌的进化和繁衍创造了适宜的环境。D. rex 不仅是一个新发现的物种，它还属于一个独特的真菌科。通过基因分析和与其他真菌的比较，研究人员发现，这个被命名为 Dianjunaceae 的新科很可能是在小行星撞击白垩纪末期（距今 1.45 亿至 6600 万年前）约 100 万年后出现的。

“在此期间，光合作用受到抑制，大量的枯叶、枯木、根系和动物尸体堆积起来，”塞纳纳亚克说。在其他生物挣扎求生之时，以死亡有机物为食的分解者，例如真菌，却能充分利用这顿盛宴。

中国科学院南京地质古生物研究所/NIGPAS

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就体型而言，巨菌（D. rex）远不及霸王龙（T. rex），但它确实比其他真菌高大得多。这种真菌是子囊菌门中已知最大的物种，子囊菌门是真菌中种类最多的类群，包含约65,000个物种，其中包括羊肚菌、松露和酵母。

塞纳纳亚克说，在发现雷克斯巨孢菌（D. rex）之前，已知最大的子囊菌是肯尼亚一种名为戈氏恩格勒菌（Engleromyces goetzei）的球状棕色真菌，直径近30厘米（12英寸），重约3.2公斤（7磅）。所有其他与雷克斯巨孢菌亲缘关系密切的子囊菌（也称囊状真菌）的体型都介于微观到几英寸高之间。

塞纳纳亚克说，科学家们接下来想要解答的一个问题是，为什么与同门的其他真菌相比，D. rex 的体型如此之大。

她解释说：“一般来说，子囊菌不会产生大的子座，因为这是一种能量浪费。”

子囊菌通过主动释放孢子进行繁殖；在雷克斯菌（D. rex）中，子实体的上部含有数千个微小的孢子释放孔。然而，塞纳纳亚克表示，其栖息地的森林地面密布着纤维状植物材料，这些材料可能会滞留孢子。

她认为，D. rex 的子实体高高耸立在森林地面之上，这可能使孢子传播得更广，从而提高繁殖成功率。

真菌是地球碳循环的重要组成部分，它们对许多植物物种的健康和营养起着至关重要的作用。

斯坦福大学的佩伊说：“了解它们的习性非常重要。了解它们的第一步是描述它们，承认它们的存在，然后再尝试了解更多关于它们生态习性的细节。”

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迄今为止，科学家已经描述了大约 15 万种真菌，但一些估计表明，地球上有 200 万到 1300 万种真菌。

“这是一类被严重低估和描述不足的生物，”佩伊补充道。

令人惊讶的是，即使是像霸王龙（D. rex）这样体型庞大的真菌，在森林栖息地中也很难被发现。真菌主要由称为菌丝的丝状体组成，统称为菌丝体。这些菌丝通常埋藏在土壤、腐木或植被中，而其繁殖部位——子座——则会在“环境条件适宜或真菌生命周期结束时”从地面冒出，皮伊解释道。

这些特点使得发现一种新的真菌往往取决于在正确的时间出现在正确的地点。否则，“即使是像这样令人印象深刻的蘑菇，也可能不被描述或注意到，”他指的是帝王菌（D. rex）。

明迪·韦斯伯格是一位科学作家和媒体制作人，她的作品曾发表在《Live Science》、《Scientific American》和《How It Works》杂志上。她是《僵尸虫的崛起：寄生虫精神控制的惊人科学》（霍普金斯出版社）一书的作者。