TABLE 3. The maximum distances within each clade or singleton lineage and minimum distances between each pair of them, calculated based on the COI sequence dataset. The upper right diagonal shows the distance in the K2P model, and the lower left diagonal shows the p-distance (%). N, number of specimens of the clade or singleton lineage; max p, maximum p distance within the clade or singleton lineage; max K2P, maximum distance in K2P model within the clade or singleton lineage.

Clade or singleton lineage		COI A	B	C	D	E	F	G	H	I	J	K	L	M	N	O
A	Sycanus thuathienhuensis, sp. nov. (N = 18; max p = 1.4 %; max K2P = 0.01)		0.12	0.12	0.12	0.11	0.07	0.12	0.10	0.09	0.12	0.07	0.13	0.12	0.02	0.11
B	Sycanus taynguyenensis, sp. nov. (N = 4; max p = 2.5 %; max K2P = 0.03)	10.6		0.11	0.11	0.02	0.12	0.12	0.11	0.10	0.08	0.11	0.14	0.02	0.12	0.04
C	Sycanus bifidus (Fabricius, 1787) (N = 8; max p = 2.0 %; max K2P = 0.02)	10.8	10.4		0.13	0.12	0.11	0.11	0.08	0.11	0.11	0.12	0.13	0.11	0.12	0.12
D	Sycanus falleni Stål, 1863 (N = 7; max p = 1.7 %; max K2P = 0.02)	11.3	10.1	12.0		0.12	0.14	0.13	0.12	0.14	0.14	0.14	0.16	0.12	0.12	0.12
E	Sycanus sichuanensis Hsiao, 1979 (N = 4; max p = 2.4 %; max K2P = 0.02)	10.3	2.4	10.6	11.1		0.11	0.14	0.13	0.10	0.08	0.12	0.13	0.03	0.12	0.04
F	Sycanus croceus Hsiao, 1979 (N = 3; max p = 0.1 %; max K2P = 0.00)	6.4	10.4	10.3	12.7	10.3		0.14	0.12	0.09	0.11	0.04	0.12	0.11	0.08	0.12
G	Sycanus aurantiacus Ishikawa & Okajima, 2007 (N = 2; identical sequences)	11.1	10.6	9.7	12.1	12.2	12.2		0.12	0.12	0.14	0.13	0.14	0.14	0.13	0.15
H	Sycanus collaris (Fabricius, 1781) (N = 1)	9.6	10.3	7.9	10.9	11.7	10.9	10.9		0.12	0.14	0.12	0.13	0.12	0.10	0.13
I	S. flavicorius Li & Cai, 2024 (N = 3; max p = 0.4 %; max K2P = 0.00)	8.4	9.3	10.0	12.6	9.2	8.6	10.6	10.9		0.10	0.09	0.13	0.09	0.09	0.11
J	S. hainanensis Wang & Cai, 2024 (N = 2; max p = 0.6 %; max K2P = 0.01)	10.6	7.9	10.3	12.7	7.2	9.9	12.4	12.2	9.6		0.11	0.13	0.07	0.12	0.08
K	S. insularis Hsiao, 1979 (N = 3; max p = 0.7 %; max K2P = 0.01)	6.8	10.3	11.2	12.4	10.6	3.5	12.0	10.8	8.0	10.0		0.12	0.11	0.08	0.12
L	S. marginellus Putshkov, 1987 (N = 2; max p = 0.1 %; max K2P = 0.0)	11.5	12.1	11.4	14.5	12.0	10.5	12.4	11.7	11.5	11.4	10.8		0.12	0.12	0.14
M	S. minor Hsiao, 1979 (N = 3; max p = 0.9 %; max K2P = 0.01)	10.8	1.8	9.7	11.4	2.7	10.2	12.2	10.8	8.7	6.5	10.3	10.9		0.11	0.05
N	S. rufus Hsiao, 1979 (N = 3; max p = 0.6 %; max K2P = 0.01)	2.0	10.8	10.6	10.9	11.2	7.1	11.5	9.7	8.3	10.6	7.1	10.9	10.3		0.11
O	S. taiwanensis Zhao & Cai, 2024 (N = 3; max p = 0.9 %; max K2P = 0.01)	10.3	4.0	11.1	11.3	4.0	10.8	13.1	12.0	9.9	7.5	10.9	12.1	4.3	10.3