SPY PICS: Next-gen BMW Z4 spotted

BMW made a big play at the iconic Pebble Beach Concours d'Elegance in the USA last year when it unveiled the concept version of its next-generation Z4.

The bronze two-seat show car told us a couple of things about the next Z4, which is being jointly developed with Toyota to form the basis for a reborn Supra: One, it will only (initially at least) be available as a fabric soft-top, not as a metal-lidded hardtop-convertible and, two, it will present a watered-down interpretation of the current model's extended-snout, short-boot look.

Although not as pronounced in this respect as previous Z4s, the new model is still clearly a rear-drive sports car that needs to provide space for longitudinal six-cylinder engines.

The spy photos show a production mule in the final phases of development before the official launch of the new Z4, which is expected to take place some time in the first half of this year.

And it's clear that while many of the styling signatures that appeared on the concept car will find their way through to the final iteration, there will still be visual differences – as is invariably the case in the transition from concept to reality.

It seems we'll have to forget the concept's heavily-sculpted lower side sills, the gaping jet-fighter apertures front and rear, the sliver-size side mirrors and the eyebrow-high, spyder-style windscreen.

While we can see clear similarities in areas such as the tapered upper creasing in the doors, which swoops down to meet the front wheel arches and forms a starting point for the in-guard side vents, the swept-back headlights and the high-set, slitted tall lights flanking a built-in lip spoiler, the visual impact has been considerably watered down

Another styling feature that appeared on the concept Z4 – the twin buttresses extending rearwards from the headrests – can't be confirmed for the production car because the test mule had its roof up.

Despite being a joint development with Toyota, the Z4 will exhibit plenty of BMW DNA. The Bavarians are reportedly responsible for the four and six-cylinder powerplants and have had a major influence on the jointly-developed platform's suspension.

If the Z4 makes its European debut as expected in the first half of this year, a local unveiling could be a possibility for later in the year, or early in 2019.