關於墨西哥淡水魚的新聞

亞馬孫摩利魚如何挑戰演化的概率
亞馬孫摩利魚如何挑戰演化的概率

作者 Juan Miguel Artigas Azas ()

一項發表在 Nature 上的新研究探討了亞馬孫摩利魚 Poecilia formosa 如何在克隆繁殖的情況下延續了超過 100,000 年。該論文由 Edward S. Ricemeyer、Nathan K. Schaefer、Manfred Schartl 和 Wesley C. Warren 等人主導，研究了演化生物學中的一個長期謎題：為什麼一個不進行有性繁殖的物種沒有出現理論所預測的基因組衰退？

Poecilia formosa 是一種全雌性、具有雜交起源的魚，源自 Poecilia mexicana 和 Poecilia latipinna 之間的一次古老雜交。由於牠產生的女兒本質上是母親的遺傳複製品，牠缺少有性繁殖通常帶來的基因重組。這種重組通常幫助自然選擇清除有害突變，並傳播有用突變。

利用高品質的基因組組裝，研究人員將亞馬孫摩利魚基因組中的兩個祖先來源部分分離出來，並將它們與其有性親緣物種的基因組進行比較。他們發現，克隆基因組確實比有性物種的基因組更快地累積了變化。然而令人驚訝的是，這並沒有導致預期中的遺傳衰退。

關鍵似乎在於基因轉換，這是一種類似 DNA 修復的過程，其中一個遺傳副本可以覆蓋另一個副本。在 Poecilia formosa 中，基因轉換似乎有助於清除有害突變、保存有用變異，並減少由其雜交起源帶來的問題。

這項研究並不是說有性繁殖在演化中不重要。相反，它表明某些克隆動物可能擁有意想不到的基因組工具，使自然選擇能夠繼續發揮作用。對於水族愛好者和自然愛好者來說，亞馬孫摩利魚不只是一個生物學奇觀：它是一個活生生的提醒，說明演化常常會在水族箱過濾器裡藏著一個備用小妙招.

Ricemeyer, Edward S & Nathan K. Schaefer, Kang Du, Irene da Cruz, Susanne Kneitz, Rafael D. Acemel, Darío G. Lupiáñez, Rachel A. Carroll, Rosie Drinkwater, Manfred Schartl, Wesley C. Warren. 2026. "Gene conversion empowers natural selection in a clonal fish species". Nature. (652):398–404 - [摘要] · (ffm01333)

墨西哥南部發現新種年魚：Profundulus hectori
墨西哥南部發現新種年魚：Profundulus hectori

作者 Juan Miguel Artigas Azas ()

一種新的淡水年魚——Profundulus hectori，在墨西哥東南部的梅斯卡拉帕河上游流域及特萬特佩克地峽的河流中被描述。該發現發表於期刊《Neotropical Ichthyology》，增進了人們對中美洲淡水生物多樣性的認識，並凸顯了該地區的生態重要性與脆弱性。



本研究的作者均來自墨西哥，他們結合了形態學特徵與遺傳數據，確認了該物種的獨特性。隨著這一新增，Profundulus 屬現已包含 12 個有效物種，全都為中美洲特有。



Profundulus hectori 的特徵是體側鱗片上具有一組大型黑斑，其中許多至少達到眼徑的一半。這一特徵使其與該屬所有其他已知物種區別開來。它還表現出沿側線和背鰭前方具有更多的鱗片數。



基於粒線體 DNA 的遺傳分析顯示，與其他 Profundulus 物種相比，其差異至少為 3.86%，支持其作為獨立物種的認定。系統發育結果將 P. hectori 定位為 P. chimalapensis 的姊妹種，並與 P. punctatus 和 P. oaxacae 組成一支。



種加詞 hectori 用以紀念已故的墨西哥著名魚類學家、墨西哥國立自治大學生物學研究所的 Héctor Espinosa Pérez 博士。作者們肯定了 Espinosa 博士在墨西哥淡水魚研究上的卓越貢獻，以及他對新一代研究者的指導。



目前，該物種僅知分布於恰帕斯東部梅斯卡拉帕河及鄰近流域的少數地點。這些河流通常清澈、涼爽，水流中等至湍急，底質為礫石與岩石。雖然部分棲地仍保持良好狀態，但另一些則面臨污染、棲地改造與人類活動的威脅。

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Domínguez-Cisneros, Sara Elizabeth & Ernesto Velázquez-Velázquez, Omar Domínguez-Domínguez, Rosa Gabriela Beltrán-López. 2025. "A new species of Profundulus (Cyprinodontiformes: Profundulidae) from southeastern Mexico". Neotropical Ichthyology. 23(2): - [摘要] · (ffm01319)

Rediscovery and redescription of Cynodonichthys myersi
Rediscovery and redescription of Cynodonichthys myersi

作者 Juan Miguel Artigas Azas ()

After being lost to science for nearly 90 years, the rare killifish Cynodonichthys myersi has been rediscovered in the mangroves of northern Yucatán. Originally described in 1936, it was later thought to be the same species as C. tenuis, but new research confirms it’s a distinct species. DNA analysis shows that C. myersi is actually more closely related to species found far away in Panama than to its Mexican neighbors, suggesting a surprising and separate evolutionary path. With its unique coloration—males have blue-green hues with dark spots and females have speckled tails—and a possible ability to survive briefly out of water, this rediscovered fish adds a fascinating twist to the story of Central American freshwater biodiversity.

Dominguez-Castanedo, Omar & Stefano Valdesalici, Waldir M. Berbel-Filho, Liliana García-Calva, Sharon Valdez-Carbajal. 2025. "Rediscovery and redescription of Cynodonichthys myersi from the mangroves of northern Yucatan Peninsula, Mexico (Cyprinodontiformes, Rivulidae)". Journal of Fish Biology. 1–11 - [摘要] · (ffm01307)

A new species of Profundulus is described from Oaxaca
A new species of Profundulus is described from Oaxaca

作者 Juan Miguel Artigas Azas ()

A new species of killifish in the genus Profundulus has been described in the journal Ichthyology & Herpetology 109(4):949–957 2021 by Sara E Dominguez-Cisneros, Ernesto Velázquez-Velázquez, Caleb D. McMahan, and Wilfredo A. Matamoros.

The new species significantly extends the known distribution of Profundulus in the Atlantic slope of Mexico to the upper reaches of the Papaloapan drainage in Oaxaca [México], from which Profundulus until now wasn’t known. The new species has been given the name Profundulus adani, to honor the Mexican ichthyologist Adán E. Gómez González, who tragically passed away in January 2018. P. adani is diagnosed from all congeners by the absence of a humeral spot in individuals larger than 45 mm SL.

Dominguez-Cisneros, Sara E & Ernesto Velázquez-Velázquez, Caleb D. McMahan, Wilfredo A. Matamoros. 2021. "A new species of killifish of the genus Profundulus (Atherinomorpha: Profundulidae) from the upper reaches of the Papaloapan River in the Mexican state of Oaxaca". Ichthyology & Herpetology. 109(4):949–957 - [摘要] · (ffm01006)

New species of Poeciliopsis described
New species of Poeciliopsis described

作者 Juan Miguel Artigas Azas ()

A new species of livebearer fish: Poeciliopsis jackschultzi from the state of Sonora in Mexico has been recently described by Kevin Conway, Mariana Mateos and Robert C. Vrijenhoek in the journal Zookeys. The new species is currently only known from four sites in the Río Concepción, where it is sympatric with P. occidentalis. It is mainly diagnosed by the absence of a black spot at base of the frontal part of the dorsal fin on males, unique in the Leptorhaphis species group of Poeciliosis. The specific name is given to honor Jack Schultz, a pioneer of studies on hybridization and all-female reproduction in Poeciliopsis.

Conway, Kevin W & Mariana Mateos, Robert C. Vrijenhoek. 2019. "A new species of the live-bearing fish genus Poeciliopsis from northern Mexico (Cyprinodontiformes, Poeciliidae)". Zookeys. (883):91-118 - [摘要] · (ffm00905)