Semiodera Chamberlin, 1919

Salazar-Vallejo, Sergio I., 2012, 3562, Zootaxa 3562, pp. 1-62 : 9

Key to species of Semiodera Chamberlin, 1919 , redefined

1 Dorsal shield restricted to dorsal and lateral surfaces, often well-developed, projected posteriorly...................... 2

– Dorsal shield extended towards lateral and ventral surfaces, or dorsal but poorly-developed into a thin crust with sparse sediment particles, or absent............................................................................... 8

2(1) Chaetiger 6 with 2 or 3 rows of long dorsal papillae.......................................................... 3

– Chaetiger 6 with a single row of large dorsal papillae......................................................... 6

3(2) Integument scaly with many irregular areas, grayish or pale, opaque................................................................................................ S. caribea (Grube & Ørsted in Grube, 1859) n. comb., n. spell.

– Integument smooth with the exception of the rows of papillae, pale, often transparent; median chaetigers with four neurohooks per bundle........................................................................................... 4

4(3) First falcate neurohooks from chaetiger 6, weakly falcate; anterior chaetigers with large lanceolate papillae.. S. blakei n. sp.

– First falcate neurohooks from chaetiger 7; anterior chaetigers with small, rounded papillae........................... 5

5(4) Median chaetigers with subdistally swollen neurohooks; dorsal shield not projected laterally................................................................................................... S. dubia ( Treadwell, 1929) n. comb.

– Median chaetigers with tapering neurohooks; dorsal shield projected laterally......................... S. tovarae n. sp.

6(2) Noto- and neurochaetal lobes with three papillae........................................................... 7

– Noto- and neurochaetal lobes with or without a single papillae; median chaetigers with papillae about as long as ¼–¼ segment length.................................................................................... S. cinari n. sp.

7(6) Median chaetigers with papillae about as long as ¼–¼ segment length; noto- and neurochaetal lobes with small papillae............................................................................ S. inflata ( Treadwell, 1914) n. comb.

– Median chaetigers with papillae about as long as ½–⅔ segment length; noto- and neurochaetal lobes with large papillae........................................................................................... S. mezianei n. sp.

8(1) Median chaetigers with two or more neurohooks per ramus.................................................... 9

– Median chaetigers with a single neurohook per ramus, starting in chaetiger 4..................................... 14

9(8) Median chaetigers with 2–4, rarely more neurohooks per bundle.............................................. 10

– Median chaetigers with only two neurohooks per bundle..................................................... 12

10(9) First falcate neurohooks in chaetiger 7(6 in smaller specimens)............................................... 11

– First falcate neurohooks in chaetiger 8...................................... S. curviseta ( Caullery, 1944) n. comb.

11(10) Dorsal shield restricted to dorsal surface; three transverse rows of papillae per segment................... S. glynni n. sp.

– Dorsal shield extended laterally and ventrally; one transverse row of papillae per segment............ S. villalobosi n. sp.

12(9) First falcate neurohooks in chaetiger 8; dorsal shield delicate, continued laterally and ventrally reaching the midventral line........................................................................................... S. nishii n. sp.

– First falcate neurohooks in chaetiger 9.................................................................... 13

13(12) Dorsal shield robust, extending laterally and ventrally, reaching the midventral line................... S. salazarae n. sp.

– Dorsal shield missing, or delicate, continued laterally and ventrally, not reaching the midventral line.... S. treadwelli n. sp.

14(9) Anterior chaetigers (4–6) with a single row of medium-sized papillae behind neurohooks.. S. tenera ( Grube, 1868) n. comb.

– Anterior chaetigers (4–6) with two rows of small papillae behind neurohooks......... S. laevis ( Stimpson, 1856) n. comb.