Cryptically there was nothing whatsoever here to scare the equids, in fact I’d say this is about as straightforward as it gets; but the vocab is so esoteric that unless you were Linnaeus himself, I wouldn’t blame you at all for checking your wordplay-corroborated hunches in a dictionary before hitting the submit button. To be honest I don’t see how else can be sent off into the ether with any confidence!
Elsewhere there were some really very nice clues, several of which wouldn’t have been remotely out of place in a daily 15×15… about half of the down clues, for start. I liked the surface of 30ac very much, was tickled by 17ac’s definition part and impressed by 21ac’s &litty feel, while the culinary flavour of 24ac and 6dn activated my salivary glands. So I hope the massively technical nature of the zoological lingo in about 1/3 of the puzzle won’t put people off appreciating the rest. There was a lot to enjoy here! Thanks to the setter.
ACROSS
1 Gnostic creed’s letters kept in order (6)
OPHISM – PHIS [letters] kept in OM [order]
4 Shoot drug extracted from hairy backed silkworm (8)
BOMBYCID – BOMB [shoot] + DIC{e}Y reversed [E (drug) extracted from DICEY (hairy) “backed”]
10 Biology classes combined with implanting Arabian dandelion (9)
TARAXACUM – TAXA CUM [biology classes | combined with] implanting AR [Arabian]
11 Knot wheeling around exotic ree (sandpiper) (5)
TEREK – KT reversed [knot “wheeling”] around (REE*) [“exotic”]
12 Old boy is going back and forth in journal of a siege (11)
OBSIDIONARY – OB [old boy] + IS “going back” + ON [forth] in DIARY [journal]
14 Bard’s rollicking outburst, not enough for forest outlaw (3)
HOO – HOO{d} [forest outlaw Robin, falling short]
15 Bestriding digger’s truck is advantageous for young urchin (7)
PLUTEUS – “bestriding” UTE [digger’s = Australian truck] is PLUS [advantageous]
17 Wife in revolutionary efforts opposing motion at Holyrood (6)
SWEIRT – W [wife] in TRIES reversed [“revolutionary” efforts]
Sweirt is a Scottish [“at Holyrood”] word for indolent, i.e. reluctant to move.
19 In Austria, I tucked into mostly fowl and fish (6)
BICHIR – ICH [in Austria, I] “tucked into” BIR{d} [“mostly” fowl]
21 Non-western work has ruined one, leading to fatal burn-out (7)
KAROSHI – ({w}ORK HAS*) [“ruined”] + I [one], semi-&lit
23 Chief constituent of phenobarbitone (3)
OBA – {phen}OBA{rbitone}
24 S American native to cook universal sauce base and thin purée, both reduced (11)
DOUROUCOULI – DO U [cook | universal] + ROU{x} and COULI{s} [sauce base and thin puree, “both reduced”]
26 Jazzy folk music recalled beer week (5)
KWELA – ALE WK [beer | week], the whole “recalled”
27 Retriever near edge of Dornoch cracks my large shellfish there (6-3)
CLABBY-DOO – LAB BY [retreiver | near] + D{ornoch} “cracks” COO [my!]
29 Bread, cut and dry, with a cactus fruit (8)
PITAHAYA – PITA HAY [bread | cut and dry] + A
30 Some laid-back dude, lethargically supplying Asian skunk? (6)
TELEDU – hidden reversed in {d}UDE LET{hargically}
DOWN
1 Standard pronunciation record stops scrap on Orkney island (8)
ORTHOEPY – EP [record] “stops” ORT [scrap] on HOY [Orkney island]
2 Daughter wearing woven rush or hemp fibres (5)
HURDS – D [daughter] “wearing” (RUSH*) [“woven”]
3 Spades over by hose (3)
SOX – S O X [spades | over | by]
4 Holding old train up, gives a green light to open boats (7)
OOMIAKS – holding O [old] + reversed AIM [train “up”], OKS [gives a green light to]
6 Herb filling to be in paella base, almost giving a sense of depth? (11)
BATHYMETRIC – THYME [herb] “filling” BAT [to be in] + RIC{e} [paella base, “almost”]
7 Boy with burden supplies fibre-producing plants (9)
CORCHORUS – COR [boy] with CHORUS [burden]
8 Briefly jab gull going over shore bird (6)
DIKKOP – POK{e} KID [“briefly” jab | gull], all reversed
9 Positions without prospects to host Apple founder (6)
MCJOBS – MC JOBS [host (as in emcee) | Apple founder (as in Steve)]
13 Stamp that impresses prime minister when Henry rises to face an unresponsive House? (3,3,5)
DIE THE DEATH – DIE [stamp that impresses] + T{H}ED {h}EaTH [prime minister, H for Henry “rising”]
16 Able to bond only once evil aunt somehow accepts name (9)
UNIVALENT – (EVIL AUNT*) [“somehow”] accepts N [name]
18 Jargon in Pacific Rim books held by Hawaii University (4,4)
HIRI MOTU – RIM OT [Rim | books] held by HI U [Hawaii | University]
20 Earthy cores from Pharaohs’ mounds focus geophysics (7)
RAUNCHY – {pha}RA{ohs} {mo}UN{ds} {fo}C{us} {geop}HY{sics}
21 Gloria certainly upset old gum-chewing Australian (6)
KOOLAH – HALO OK [gloria | certainly] “upset”
22 Reluctantly hand over rowing crew trophy in podcast? (4,2)
FORK UP – homophone [“in podcast”] of FOUR CUP [rowing crew | trophy]
25 Pointed out odd bits from putrid sewer (5)
URDEE – out (as in remove) the odd bits, to be left with {p}U{t}R{i}D {s}E{w}E{r}
28 Social worker possibly in competition (3)
BEE – double def
This was both educational and entertaining. Many thanks.
Midas
I love the words thrown up by this puzzle, though now I’m a bit worried about what the 90s band Kula Shaker might have gotten up to on any of their Australian tours…