After roughly four decades as a band, the Mighty Mighty Bosstones announced their breakup in a brief Facebook post on Thursday afternoon. “After decades of brotherhood, touring the world and making great records together, we have decided to no longer continue on as a band,’’ the post read. On Instagram, the breakup announcement came in the form of an animation: a world split in two, soundtracked by the recent track “Bruised.’’ (“We might be bruised/But we’re not broken/We might be down but we’re not out,’’ proclaims the chorus of that cut, from 2021’s now-final Bosstones full-length “When God Was Great.’’)

It was a surprisingly unceremonious exit for a band that had carved out a crucial piece of Boston’s rock scene during their four-decade existence. Beyond the obvious connection to Boston through their name, their high-energy, forthright blend of bright brass and mosh-pit-ready riffs was as much a sound of Boston as J. Geils Band’s bluesy licks or New Edition’s sweeping harmonies.

The Bosstones initially formed in the early ’80s, when eventual frontman Dicky Barrett came together with bassist Joe Gittleman through connections made in the Boston hardcore punk scene. The group disbanded for a few years, then came back just in time to release records embraced by the then-nascent alt-rock scene — first on the storied Boston indie Taang!, then on a major label. At the tail end of 1993, they ascended to Boston rock’s royal tier by opening for fellow local boys gone good Aerosmith at the then-Boston Garden. “It was like, ‘These guys are proud of where they’re from and are also giving it back to a local band that’s making noise,’ ’’ former Bosstones guitarist Nate Albert told the Globe Magazine in 2017.

Over time, they honed a thrashing, yet playfully soulful sound that landed somewhere “right in between Madness and Minor Threat,’’ as Gittleman quipped in a 1994 Billboard article about what the music-biz bible referred to as the “ska underground.’’ (The piece also noted that Boston’s former alt-rock radio haven WFNX played ska because of the town being “such a college city, with [a] thriving ska scene’’ that would go on to include bands like Bim Skala Bim and Big D and the Kids Table.)

I first heard the Bosstones during the early ’90s; I was in high school in the New York suburbs, and a pal with exquisite taste repped particularly hard for them. Back then, I was intrigued by their loud plaids and the horns animating tracks like the simmering “Where’d You Go’’ and the breakneck “Cowboy Coffee.’’ (That they sported Converse sneakers, the footwear of choice for gym-class outcasts, didn’t hurt.)

As “alternative’’ rock got bigger, their star rose, with the pogo-worthy “Someday I Suppose’’ becoming a minor radio hit in 1993 and later being featured in Amy Heckerling’s Austen-in-the-Valley comedy “Clueless.’’ At the time, alt-rock’s tent was big enough to sustain a ska-revival annex, with acts like No Doubt and Rancid spearheading the charge on the West Coast and the Bosstones leading the way on the Eastern Seaboard.

In 1996 the all-Boston-star benefit compilation “Safe and Sound’’ included the Bosstones’ “The Impression That I Get,’’ a peppy track which masked its existentially questioning lyrics with a roaring chorus and sprightly guitars. The next year, it would go on to become the group’s biggest crossover hit, reaching the top 25 on the Hot 100 and landing the band on “Saturday Night Live.’’ It distilled the band’s appeal perfectly, its pugilistic spirit balanced out by reflective moments that showed the depth lurking beneath the band’s dynamic exterior.

After that song’s success, the band kept at it, with some personnel turnover and a move back to the indies with 2002’s “A Jackknife to a Swan.’’ They then took a break from 2004 until 2007, when they came back for another installment of their Hometown Throwdown; in addition to the band’s frequent touring, those shows continued through 2019, and were supplemented by the ska-showcasing Cranking & Skanking Fest in 2018 and 2019.

Before the first Cranking & Skanking Fest, which had the ferociously fusion-minded Fishbone and the legendary Toots & the Maytals on its bill alongside the Bosstones, I had a chance to chat with Barrett. I asked him about “After the Music Is Over,’’ the mini-epic that closed their then-most-recent album “While We’re at It’’; it opens as a devil-may-care rave-up, then shifts moods from teary to jubilant, eliciting the defiantly alive vibe of an Irish wake’s later hours. “As long as we have today and as long as we have each other, then we have something,’’ said Barrett. “There’s a reason to rejoice, and there’s a reason to feel good.

“Even in the darkest of times, you still want to believe that there will be light. That’s always been the general message of the Mighty Mighty Bosstones.’’ While the band might have ended, that defiant optimism remains in the band’s recorded output, and the way they’ve inspired other artists around the world.